Water Quality Indicative Organisms
(Southeastern United States)
Federal Water Pollution
Control Administration
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KEYS TO WATER QUALITY INDICATIVE ORGANISMS
(Southeastern United States)
edited by
Fred K. Parrish
Georgia State College
Atlanta, Georgia
Federal Water Pollution Control Administration
U. S. Department of the Interior
November, 1968
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CONTENTS
PREFACE i
ACKNOWLEDGEMENTS ii
CONTRIBUTORS iii - iv
INTRODUCTION A 1 - 6
FUNGI C 1 - 8
ALGAE • E 1 - 27
MOLLUSCA G 1 - 26
OLIGOCHAETA I 1-16
CRUSTACEA K 1 - 36
EPHEMOROPTERA M 1 - 10
PLECOPTERA P 1 - 6
TRICHOPTERA S 1-19
CHIRONOMIDAE V 1-22
FISH Y 1 - 15
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PREFACE
This manual was written to be used as a reference for Southeastern
biologists involved in water quality studies. It was used first at Georgia
State College as a text in a course designed to teach workers to identify
the groups of organisms discussed herein.
The keys are designed to supply useable, accurate aids for the
identification of organisms usually encountered in water quality surveys.
In all except three sections, a sketch is included to illustrate nearly
all couplets. The study of fungi requires specialized equipment and
sophisticated techniques. Furthermore, it is not possible to teach the
recognition of the forms in a short period of time. The emphasis in
this group, therefore, is directed toward an introduction to the fungi,
their occurrence in nature, and a guide to the literature. Accurate, up-
to-date, illustrated keys are readily available for the algae and fish;
thus it was thought unnecessary to duplicate those works here, although
a key and illustrations of the most commonly encountered algae are in-
cluded.
The sections were numbered independently and holes were punched
for insertion into a standard three-ring binder. It is anticipated that the
various sections will be revised from time to time and that workers will
want to insert pages with notes. This format will allow for both these
actions. It is hoped that comparable regional manuals and courses will
be an outgrowth of our effort.
Fred K. Parrish
Atlanta, Georgia
November, 1968
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ACKNOWLEDGEMENTS
I would like to express my deep appreciation to each of the con-
tributors for their cooperation. Mrs. Margo H. Corley (my secretary
and typist) and Miss Pat Phillips, Miss Coy Berry, Miss Susan Grochan,
and Miss Brenda Bailey (the illustrators and page composers) all
deserve thanks. The initial stimulation for the project came from
John, Victor, Christopher, Anthony, and William. Mr. Ralph
Sinclair, Mr. Edward Hall, and Dr. Louis Carrick all gave valuable
assistance. Professor R. J. Reiber, Chairman of the Department,
did everything possible to lighten departmental duties, and Dr. Anita
Bolinger read and corrected portions of the manuscript.
ii
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CONTRIBUTORS
Dr. Donald G. Ahearn
Department of Biology
Georgia State College
Atlanta, Georgia 30303
Mr. William M. Beck, Jr.
Chief Biologist
Florida State Board of Health
Jacksonville, Florida 32201
Dr. Lewis Berner, Chairman
Department of Biological Science
University of Florida
Gainesville, Florida 32601
Dr. R. O. Brinkhurst
Department of Zoology
University of Toronto
Toronto 5, Canada
Dr. John Hanson
Department of Entomology
University of Massachusetts
Amherst, Massachusetts 01002
Dr. William H. Heard
Department of Biological Science
Florida State University
Tallahassee, Florida 32306
Dr. Horton H. Hobbs, Jr.
Senior Zoologist
Department of Invertebrate Zoology
Smithsonian Institution
Washington, D. C, 20560
iii
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Dr. C. Mervin Palmer
Biological Treatment Research Activities
Cincinnati Water Research Laboratory
Advanced Waste Treatment Branch
Cincinnati, Ohio 45226
Dr. John Ramsey
Fisheries Building
Auburn University
Auburn, Alabama 36830
Dr. J. B. Wallace
Department of Entomology
University of Georgia
Athens, Georgia 30601
iv
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Writing and publication of this manual and the train-
ing course -were made possible by grant number 1TT1-
WP-19-01 from the Training Grants Branch, Federal
Water Pollution Control Administration.
Mention of trade names in this manual does not con-
stitute an official endorsement by any state or federal
agency.
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INTRODUCTION
Fred K. Parrish
The illustrated keys in this manual represent an attempt to supply
non-specialists with means of identifying those organisms most im-
portant in water quality surveys in the southeastern United States. An
effort was made to supply a labeled figure with each couplet to clarify
any situation in which the appearance of the character is in doubt. For
most of the groups, this attempt is the first time that such an approach
has been made. Several problems exist both in the construction of
useable keys and in relating the organisms to specific ecological sit-
uations.
The freshwater biota of the southeastern United States is not as well
known as that in some other sections of the country. For example,
Beck and Beck (1959) reported that 50% of the Georgia-Florida
chironomids are unnamed; it is estimated that 50°/o - 60°/o of the may-
flies and 30°/o - 40°/o of the caddisflies are unknown. Lack of associ-
ation of larval stages with adults and a lack of. knowledge of eco-
logical requirements at different periods in the life history of many
species further complicate matters.
Many statements in the literature concerning life histories and eco-
logical requirements are based on mountain, northern, or European
forms. These forms need to be distinguished from southern or coastal
plain organisms. My work with oyster culture several years ago first
alerted me to this situation; recent research on the invertebrates in
southern swamps (Parrish and Rollings worth, 1968; and Parrish, in prep.)
further bears out this difference. Berner (1950, p. 21) shows in detail
that some statements in the literature regarding behavior and life history
of mayflies and craneflies are not applicable to southern forms. The in-
vestigator working in the Southeast, therefore, should be wary of evaluat-
ing his findings on the basis of current literature statements unless the
statements relate directly to local forms.
Basic library
Each laboratory in which biological water quality determinations
are being performed should have references with descriptions of the forms
which have been keyed; only in this way can one be certain that an identi-
fication is correct. Each contributor to this manual was asked to cite
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available sources for such descriptions. Many of these papers can be
obtained free of charge.
Every laboratory also should be equipped with certain basic general
references in addition to "Ward and Whipple" and "Pennak". Many ref-
erences are available from government agencies such as the Geological
Survey or the Federal Water Pollution Control Administration for a small
cost. Some of the "standard" references are almost useless for macro-
organisms. The following comments are based on my own experiences
and are intended only as a guide.
Kleins's River Pollution and Hynes' The Biology of Polluted Waters
should both be accessible. Standard Methods is much better for physical,
chemical, and microbiological studies than for macro-organisms.
Biological Problems in Water Pollution contains ecological information
for numerous organisms and is quite valuable while Biology of Water
Pollution contains a collection of some of the earlier classical papers in
water pollution research.
Other useful guides are the training course manuals occasionally
available from The Robert A. Taft Engineering Center in Cincinnati. The
guides applicable here are Freshwater Biology and Pollution Ecology.
«
For biologists interested in thermal pollution problems, Mackenthun
(ed), Temperature and Aquatic Life, brings together ecological infor-
mation and bibliographies while Rose (ed), Thermobiology, utilizes
the physiological approach. Both of these books provide a good intro-
duction to the literature.
Additional titles of general works and sources for aid in reporting
data are contained in the bibliography.
Seeking aid
When consulting specialists, ask for specific information. Any
letter which contains the phrase "please send me all the information you
have on. ..." is headed for the wastepaper basket. Let them know that
you have attempted to search the literature; state what you have found
briefly, only then ask a question or questions, and make them pointed.
The same principles apply when asking for help in identifications.
Contact the specialist beforehand and indicate that you have tried to
identify the organisms, if you really have; to which taxon they were keyed
and how many individuals are in each group. Inquire about possible fees,
how he wants the material prepared and shipped, and whether he wants a
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series of organisms or a single specimen. Offer to let him keep any or
all of the specimens he wants. If you want to build a reference collection,
keep duplicates; do not gamble on any particular individual being
returned. Do not be too impatient for a response. If necessary, indicate
deadlines which you have to meet, but allow the specialist plenty of time.
Do not expect all identifications to species. As pointed out above, in
many cases larval forms cannot be related to adults and some species
may be new to science. Many closely related larval forms cannot, at
present, be separated.
Some of the contributors to this manual will be willing to identify
material. Again, ask each individual first!
Preserving collections
The collection should be screened in the field for forms that require
special attention (see the introductions to the various sections) and the
correct concentrations of fixative added. Animals that require
anesthetization for proper fixation should be taken alive to the base of
operations and treated properly. If necessary, help the animal die relaxed
"naturally" by sealing off in a jar, increasing the temperature, etc.
A little care in determining when the organism is dead but not deterior-
ating is all that is needed, and it has worked many times.
It is common practice at present to drop everything that is collected
into what is estimated to be 10°/o Formalin or 70% ethyl alcohol. A
label is dropped in and the top screwed on - not to be taken off for months.
Fragmented worms and snails fixed while contracted into their shells are
the result, indicating poor collection techniques. I have seen thousands
of organisms disintegrating" due to too much Formalin or too little
alcohol. In some cases the Formalin was sufficiently strong to disinte-
grate the label. My own preference is to carry 20°/o Formalin into the
field and dilute by half, which is easy and accurate, or to carry 100°/o
isopropyl and preserve in 40°/o alcohol. Fixing and hardening for two
or three days in 10°/o alcohol followed by a change into 40°/o isopropyl
alcohol has proven the most satisfactory.
Each contributor was asked to include information concerning eco-
logical requirements, distribution, etc., when this information was known
and where it would aid in water quality evaluations. The paucity of such
information in this manual is a reflection of the need for much additional
research. The numbers of organisms which have been collected at
places where environmental parameters were measured simultaneously
represents a valuable collection of information. As soon as this material
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can be examined by specialists and the results published, a great deal
of pragmatic data should be generally available. Laboratories are en-
couraged, therefore, either to maintain their collections or to deposit
them in an institution where the material will be both maintained and
made available to others.
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Literature Cited
Beck, Elisabeth, and W. M. Beck, Jr. 1959. A checklist of the
Chironomidae (Insecta) of Florida (Diptera: Chironomidae).
Bull. Fla. St. Mus. 4: 85-96.
Berner, Lewis. 1950. The mayflies of Florida. Biological Science
Series, Vol. 4(4). Univ. Fla. Press, Gainesville. 267 p.
Parrish, F. K. and Felicia H. Rollingsworth. 1968. A limnological
reconaissance of the eastern prairies of the Okefenokee Swamp.
A.S.B. Bull. 15: 49- (abstract).
Selected References
Hynes. H. B. N. I960. The biology of polluted waters. Liverpool
Univ. Press, Liverpool. 202 p.
Ingram, W. M. , K. M. Mackenthun, and A. F. Bartsch. 1966. Bio-
logical field investigative data for water pollution surveys. WP -
13, F.W.P.C.A. , Cincinnati, Ohio. 139 p.
Keup, L. E., W. M. Ingram, and K. M. Mackenthun. 1967. Biology
of water pollution. CWA-3, F.W.P.C.A., Cincinnati, Ohio
290 p.
Klein, L. 1962. River pollution. 2: Causes and effects. Butterworths,
London. 456 p.
Love, S. K. (ed) 1962. Quality of surface waters of the United States
1958. Parts 1-4. North Atlantic slope basins to St. Lawrence
River Basin. Water-supply paper 1571, U. S. Geological Survey.
773 p.
Macan, T. T. 1963. Freshwater ecology. John Wiley and Sons, New
York. 338 p.
Mackenthun, K. M. 1967. Temperature and aquatic life. Lab. Investiga-
tions Series, 6. F.W.'P.C.A. , Cincinnati, Ohio. 151 p.
, and W. M. Ingram. 1967. Biological associated
problems in freshwater environments. Their identification, investiga-
tion, and control. F.W.P.C.A., Cincinnati, Ohio. 287 p.
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Orland, H. P. (ed.) 1965. Standard methods for the examination of
water and wastewater. Amer. Pub. Health Assoc. , New York
769 p.
Pennak, R. W. 1953. Fresh-water invertebrates of the United States.
Ronald Press, New York. 769 p.
Rose, A. H. (ed.). 1967. Thermobiology . Academic Press, New
York. 653 p.
Ruttner, F. 1953. Fundamentals of limnology. Univ. of Toronto
Press, Toronto. 242 p.
Sinclair, R. M. 1967. Select and current bibliographies. Benthic
macroinvertebrates and periphyton. Midwest Benthological Society.
49 p. Order from Mr. R. M. Sinclair, F.W. P. C.A. , Cincinnati,
Ohio.
Stewart, R. K. , W. M. Ingram and K. M. Mackenthun. 1966. Water
pollution control: Waste treatment and water tre'atment: selected
biological references on fresh and marine waters. WP - 23, F.
W.P.C.A. , Cincinnati, Ohio. 126 p.
Tarzwell, C. M. (ed. ). 1965. Biological problems in water pollution:
Third Seminar 1962. U.S.P.H.S. Pub. No. 999 - WP - 25.
Robert A. Taft Sanit. Engineering Center, Cincinnati, Ohio. 424 p.
U. S. Geological Survey. 1966. Water quality records in Florida and
Georgia. Gov. Services Admin. , Atlanta. 100 p.
Ward, H. B., and G. C. Whipple (W.T. Edmondson, ed.). 1959.
Fresh-water biology. Second edition. John Wiley and Sons, New
York. 1248 p.
Welch, P. S. 1952. Limnology. McGraw - Hill, New York. 538 p.
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FUNGI
Donald G. Ahearn
I INTRODUCTION
Fungi are heterotrophic achy lor ophyllous plant-like organisms which
possess true nuclei with nuclear membranes and nucleoli. Dependent
upon the species and, in some instances, the environmental conditions, the
body of the fungus, the thallus, varies from a microscopic single cell to
an extensive plasmodium or mycelium. Numerous forms produce
macroscopic fruiting bodies. The life cycles of fungi vary from simple to
complex and may include sexual and asexual stages with varying spore types
as the reproductive units. Traditionally, the true fungi are classified with-
in the division Eumycotina of the phylum Mycota of the plant kingdom.
Some authorities consider the fungi an essentially monophyletic group
distinct from the classical plant and animal kingdoms.
In general fungi possess broad enzymatic capacities. Various species
are able to actively degrade such compounds as complex polysaccharides
(e.g. cellulose, chitin, and glycogen), proteins (casein, albumin, keratin),
hydrocarbons (kerosene) and pesticides. Most species possess an oxidative
or microaerophilic metabolism, but anerobic catabolism is not uncommon.
A few species show anerobic metabolism and growth.
It is not possible within the short time allocated for this introductory
session to do more than bring an awareness of the presence and role of
fungi in polluted and pristine waters. Fungi are ubiquitous in nature and
members of all classes may occur in large numbers in aquatic habitats.
Sparrow (1968) has briefly reviewed the ecology of fungi in freshwaters with
particular emphasis on the zoosporic phycomycetes. The occurrence and
ecology of fungi in marine and estuarine waters has been examined
recently by a number of investigators (see Johnson and Sparrow, 1961;
Johnson, 1968; Meyers, 1968; van Uden and Fell, 1968). Wm. Bridge Cooke
in a series of investigations (see Cooke, 1965) has established that fungi
other than phycomycetes occur in high numbers in sewage and polluted
waters. His reports on organic pollution of streams (Cooke 1961; 1967)
show that the variety of the Deuteromycete flora is decreased at the
immediate sites of pollution, but dramatically increased downstream from
these regions. Yeasts, in particular, have been found in high numbers in
organically enriched waters (Cooke et al. , I960; Cooke and Matsuura, 1963;
Cooke, 1965b; Ahearn et. al. , 1968). Certain yeasts are of special interest
due to their potential use as "indicator" organisms and their ability to
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degrade or utilize proteins, various hydrocarbons, straight and branch
chained alkyl-benzene sulfonates, fats, metaphosphates, and wood sugars.
A few microorganisms have long been termed "sewage fungi". The
most common microorganisms included in this group are the iron
bacterium Sphaerotilus natans and the phycomycete Leptomitus lacteus.
Sphaerotilus natans is not a fungus, rather it is a sheath bacterium of the
order Chlamydobacteriales. This polymorphic bacterium occurs com-
monly in organically enriched streams where it may produce extensive
slimes. Characteristically, S_. natans forms chains of rod shaped cells
(1.1-2. Op x 2. 5-17|j) within a clear sheath or trichome composed of a protein-
poly saccharidae-lipid complex. The rod cells are frequently motile
upon release from the sheath; the flagella are lophotrichous. Occasionally
two rows of cells may be present in a single sheath. Single trichomes may
be several mm in length and bent at various angles. Empty sheaths,
appearing like thin cellophane straws, may be present. The trichomes
are cemented at one end to solid substrata such as stone or metal and
their cross attachment and bending gives a superficial similarity to true
fungal hyphae. The ability to attach firmly to solid substrates gives S.
natans a selective advantage in the population of flowing streams. For
more thorough reviews of EL natans see Prigsheim (1949) and Stokes (1954).
Leptomitus lacteus also produces extensive slimes and fouling floes
in fresh waters. This species forms thalli typified by regular constric-
tions. Cellulin plugs may be present near the constrictions and there may
be numerous granules in the cytoplasm. The basal cell of the thallus may
possess rhizoids. The segments delimited by the partial constrictions
are converted basipetally to sporangia. The zoospores are diplanetic (i. e.,
dimorphic) and each possesses one whiplash and one tinsel flagellum. No
sexual stage has been demonstrated for this species. For further infor-
mation on the distribution and systematics of L. lacteus see Sparrow (I960),
Yerkes (1966) and Emerson and Weston (1967). Both £L natans and JL.
lacteus appear to thrive in organically enriched cold waters (5°-22° C)
and both seem incapable of extensiv^ growth at temperatures of about 30° C.
Their metabolism is oxidative and growth of both species may appear as
reddish brown floes or stringy slimes of 30 cm or more in length.
Sphaerotilus natans is able to utilize a wide variety of organic compounds,
whereas L. lacteus does not assimilate simple sugars and grows most
luxuriantly in the presence of organic nitrogenous wastes.
Although the "sewage fungi" on occasion attain visually noticable con-
centrations, the less obvious populations of deuteromycetes and many
phycomycetes may be more important in the ecology of the aquatic
habitat. Investigations of the past decade indicate that numerous fungi
are of primary importance in the mineralization of organic wastes; the
overall significance and exact roles of fungi in this process are yet to
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be established.
In recent classification schemes the classes of fungi are distinguished
primarily on the basis of the morphology of the sexual and zoosporic
stages. In practical systematics, however, numerous fungi do not demon-
strate these stages. Classification must therefore be based on the sum
total of the morphological and/or physiological characteristics. The ex-
tensive review by Cooke (1963) on the methods of isolation and classification
of fungi from sewage and polluted waters precludes the need herein of
extensive keys and species illustrations. A brief synopsis of the classifi-
cation of the fungi adapted in part from Alexopholous (1962) is presented
below.
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II KEY TO THE MAJOR TAX A OF FUNGI
1 Definite cell walls lacking, somatic phase a free living Plasmodium
Sub-phylum Myxomycotina . . (true slime molds). .Class Myxomycetes
I1 Cell walls usually well defined, somatic phase not a free-living Plasmodium
(true fungi) Sub-phylum Eumycotina 2
2 Hyphal filaments usually coenoctytic, rarely septate, sex cells when present forming
oospores or zygospores, aquatic species propagating asexually by zoospores, terrestrial
species by zoospores, sporangiospores conidia or conidia-like sporangia .'.'Phycomycetes". . . 3
The phycomycetes are generally considered to include the most primitive of the true
fungi. As a whole, they encompass a wide diversity of forms with some showing relation-
ships to the flagellates, while others closely resemble colorless algae, and still others
are true molds. The vegetative body (thallus) may be non-specialized and entirely con-
verted into a reproductive organ (holocarpic), or it may bear tapering rhizoids, or be
mycelial and very extensive. The outstanding characteristics of the thallus is a tendency
to be nonseptate and, in most groups, multinucliate; cross walls are laid down in vigorously
growing material only to delimit the reporductive organs. The spore unit of nonsexual re-
production is borne in a sporangium, and, in aquatic and semiaquatic orders, is provided
with a single posterior or anterior flagellum or two laterally attached ones. Sexual activity
in the phycomycetes characteristically results in the formation of resting spores.
2' (I1) Hyphal filaments when present septate, without zoospores, with or without sporangia,
usually with conida; sexual reproduction absent or culminating in the formation of asci
or basidia 8
3 (2) Flagellated cells characteristically produced 4
3' Flagellated cells lacking or rarely produced 7
4 (3) Motile cells uniflagellate 5
4' Motile cells biflagellate 6
5 (4) Zoospores posteriorly uniflagellate, formed inside the sporangium. . . class. . .Chytridiomycetes
The Chytridiomycetes produce asexual zoospores with a single posterior whiplash
flagellum. The thallus is highly variable; the most primitive forms are unicellular and
holocarpic and in their early stages of development are plasmodial (lack cell walls), more
advanced forms develop rhizoids and with further evolutionary progress develop mycelium.
The principle chemical component of the cell wall is chitin, but cellulose is also present.
Chytrids are typically aquatic organisms but may be found in other habitats. Some species
are chitinolytic and/or keratinolytic. Chytrids may be isolated from nature by baiting (e. g.
hemp seeds or pine pollen) Chytrids occur both in marine and fresh water habitats and are
of some economic importance due to their parasitism of algae and animals. The genus
Dermocvstidium may be provisionally grouped with the chytrids. Species of this genus
cause serious epidemics of oysters and marine and fresh water fish.
5' Zoospores anteriorly uniflagellate, formed inside or outside the sporangium , , class
Hyphochytridiomycetes
These fungi are aquatic (fresh water or marine) chyt rid-like fungi whose motile cells
possess a single anterior flagellum of the tinsel type (feather-like). They are parasitic on
algae and fungi or may be saprobic. Cell walls contain chitin, with some species also demon-
strating cellulose content. Little information is available on the biology of this class and
at present it is limited to less than 20 species.
6 (41) Flagella nearly equal, one whiplash the other tinsel class Oomycetes
A number of representatives of the Oomycetes have been shown to have cellulosic cell
walls. The mycelium is coenocytic, branched and well developed in most cases. The sexual
process results in the formation of a resting spore of the oogamous type, i. e. , a type of
fertilization in which two heterogametangia come in contact and fuse their contents through
a pore or tube. The thalli in this class range from unicellular to profusely branched
filamentous types. Most forms are eucarpic; zoospores are produced throughout the class
except in the more highly advanced species. Certain species are of economic importance due
to their destruction of food crops (potatoes and grapes) while others cause serious diseases of
fish (e.g. Saprolegina parasitica). Members of the family Saprolegniaceae are the common
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"water molds" and are among the most ubiquitous fungi in nature. The order Lagenidiales
includes only a few species which are parasitic on algae, small animals, and other aquatic
life. The somatic structures of this taxon are holocarpic and endobiotic. The sewage fungi
are classified in the order Leptomitales. Fungi of this order are characterized by the
• formation of refractile constrictions; "cellulin plugs" occur throughout the thalli or, at least,
at the bases of hyphae or to cut off reproductive structures. Leptomitus lacteus may
produce rather extensive fouling floes or slimes in organically enriched waters.
6' Flagella of unequal size, both whiplash class. . . .Plasmodiophoromycetes
Members of this class are obligate endoparasites of vascular plants, algae, and fungi.
The thallus consists of a plasmodium which develops within the host cells. Nuclear division
at some stages of the life cycle is of a type found in no other fungi but known to occur in
protozoa. Zoosporangia which arise directly from the plasmodium bear zoospores with two
unequal anterior falgella. The cell walls of these fungi apparently lack cellulose,
7 (3') Mainly saprobic, sex cell when present a zy go spore. class Zygomycetes
This class has well developed mycelium with septa developed in portions of the
older hyphae; actively growing hyphae are normally non-septate. The asexual spores are
non-motile sporangiospores (aplanospores). Such spores lack flagella and are usually
aerialy disseminated. Sexual reproduction is initiated by the fusion of two garnetangia
with resultant formation of a thick-walled, resting spore, the zygospore. In the more
advanced species, the sporangia or the sporangiospores are conidia-like. Many of the
Zygomycetes are of economic importance due to their ability to synthesize commercially
valuable organic acids and alcohols, to transform steroids such as cortisone, and to
parasitize and destroy food crops. A few species are capable of causing disease in man
and animals (zygomycosis).
7' Obligate commensals of arthropods, zygospores usually lacking class. . . . Trichomycetes
/
The Trichomycetes are an ill-studied group of fungi which appear to be obligate
commensals of arthropods. The trichomycetes are associated with a wide variety of insecta,
diplopods, and crustacea of terrestrial and aquatic (fresh and marine) habitats. None of
the members of this class have been cultured in vitro for continued periods of times with any
success. Asexual reproduction is by means of sporangiospores. Zygospores have been
observed in species of several orders.
8 (Z') Sexual spores borne in asci class Ascomycetes
In the Ascomycetes the products of meiosis, the ascospores, are borne in sac
like structures termed asci. The ascus usually contains eight ascospores, but the number
produced may vary with the species or strain. Most species produce extensive septate
mycelium. This large class is divided into two subclasses on the presence or absence
of an ascocarp. The Hemiascomycetidae lack an ascocarp and do not produce ascogenous
hyphae; this subclass includes the true yeasts. The Euascomycetidae usually are divided
into three series (Plectomycetes, Pyrenomycetes, and Discomycetes) on the basis of
ascocarp structure.
8' Sexual spores borne on basidia class Basidiomycetes
The Basidiomycetes generally are considered the most highly evolved of the fungi.
Karyogamy and meiosis occur in the basidium which bears sexual exogenous spores,
basidiospores. The mushrooms, toadstools, rusts, and smuts are included in this class.
8" Sexual stage lacking .Form class.(Fungi Imperfecti)..Deuteromycetes
The Deuteromycetes is a form class for those fungi (with morphological affinities
to the Ascomycetes or Basidiomycetes) which have not demonstrated a sexual stage.
The generally employed classification scheme for these fungi is based on the morphology
and color of the asexual reproductive stages. This scheme is briefly outlined below.
Newer concepts of the classification based on conidium development after the classical
work of S. J. Hughes (1953) may eventually replace the gross morphology system (see
Barren 1968).
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KEY TO THE FORM-ORDERS OF THE FUNGI IMPERFECT.!
1 Reproduction by means of conidia, oidia, or by budding 2
1' No reproductive structures present Mycelia Sterilia
2 (1) Reproduction by means of conidia borne in pycnidia Sphaeropsidales
2' Conidia, when formed, not in cycnidia 3
3 (21) Conidia borne in acervuli Melanconiales
3' Conidia borne otherwise, or reproduction by oidia or by budding Monillales
KEY TO THE FORM-FAMILIES OF THE MONILIALES
1 Reproduction mainly by unicellular budding, yeast-like; mycelial phase, if present,
secondary, arthrospores occasionally produced, manifest melanin pigmentation lacking 2
1' Thallus mainly filamentous; dark melanin pigments sometimes produced 3
2 (1) Ballistospores produced Sporobolomycetaceae
2' No ballistospores Cryptococcaceae
3 Conidiophores, if present, not united into sporodochia or synnemata 4
3' Sporodochia present Tuberculariaceae
3" Synnemata present Stilbellaceae
4 (3) Conidia and Conidiophores or oidia hyaline or brightly colored Moniliaceae
4' Conidia and/or Conidiophores, containing dark melanin pigment Dematiaceae
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Ill SELECTED REFERENCES
Ahearn, D. G., F. J. Roth, Jr., and S. P. Meyers. 1968. Ecology and
characterization of yeasts from aquatic regions of South Florida.
Marine Biology 1: 291-308.
Alexopoulos, J. C. 1962. Introductory mycology. 2nd ed. John Wiley
and Sons, N. Y. 613 p.
Barron, G. L. 1968. The genera of Hyphomycetes from soil. Williams
and Wilkins Co. , Baltimore. 364 p.
Cooke, W. B. 1961. Population effects on the fungus population of a
stream. Ecology 42: 1-18.
1963. A laboratory guide to fungi in polluted waters,
sewage, and sewage treatment systems. U. S. Dept. of Health,
Education and Welfare, Cincinnati. 132 p.
1965a. Fungi in sludge digesters. Purdue Univ. Proc.
20th Industrial Waste Conf. pp. 6-17.
1965b. The enumeration of yeast populations in a sewage
treatment plant. Mycologia 57: 696-703.
1967. Fungal populations in relation to pollution of the
Bear River, Idaho-Utah. Utah Acad. Proceedings 44(1): 298-315.
and Matsurra, Geroge S. 1963. A study of yeast pop-
ulations in a waste stabilization pond system. Protoplasma 57;
163-187.
, Phaff, H. J. , Miller, M. W, Shifrine, M. , and Knapp, E.
I960. Yeasts in polluted water and sewage. Mycologia 52: 210-230.
Emerson, Ralph and W. H. Weston. 1967. Aaualinderella fermentans
Gen. et Sp. Nbv. , A phycomycete adapted to stagnant waters. I.
Morphology and Occurrence in nature. Amer. J. Botany 54: 702-
719.
Hughes, S. J. 1953. Conidiophores, conidia and classification. Can.
J. Bot. 31: 577-659.
Johnson, T. W. , Jr. 1968. Saprobic marine fungi, pp. 95-104. In
Ainsworth, G. C. and Sussman, A. S. The Fungi, III, Academic
Press, N. Y.
-------
and Sparrow, F. K. , Jr. 1961. Fungi in oceans
and estuaries, Weinheim, Germany. 668 p.
Meyers, S. P. 1968. Observations on the physiological ecology of
marine fungi. Bull. Misaki Mr. Biol. Inst. 12; 207-225.
Prigsheim, E. G. 1949. Iron bacteria. Biol. Revs, Cambridge
Phil. Soc. 24: 200-245.
Sparrow, F. K. , Jr, I960. Aquatic phycornycetes. 2nd ed. , Univ.
Mich. Press, Ann Arbor. 1187 p.
1968. Ecology of freshwater fungi, pp. 41-93.
In Ainsworth, G. C. and Sussman, A. S. The Fungi III. Academic
Press, N. Y.
Stokes, J. L. 1954. Studies on the filamentous sheathed iron bacterium
Sphaerotilus natans. J. Bacteriol. 67: 278-291.
van Uden, N. and Fell, J. W. 1968. Marine yeasts, pp. 167-201. In
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the sea, I. Academic Press, N. Y.
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lacteus in Wisconsin. Mycologia 58: 976-978.
8
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ALGAE
C. M. Palmer
I INTRODUCTION
Algae are common and normal inhabitants of surface waters and are en-
countered in water that is exposed to sunlight. While a few of the algae are
found in soil and on surfaces exposed to air, the great majority of them are
truly aquatic and grow submerged in the waters of ponds, lakes, reservoirs,
streams, and oceans.
One of the principal reasons for the importance of algae is their ability
to give rise to very large quantities of organic matter in the water. It has
been estimated, for example, that more than 130 tons of algae per day flow
into Fox River, Wisconsin, from Lake Winnebago. The volume of plankton
algae in the Scioto River, Ohio, has reached a maximum of more than 8, 000
p. p.m. Algal counts for Lake Michigan at Chicago have at times been over
4, 000 organisms per ml. , and the White River in Indiana has records of
counts exceeding 100, 000 algae per ml. Comparatively low concentrations
of most of the algae are often an asset rather than a liability in raw waters.
Unattached, visible, and sometimes extensive accumulations of algae
at or near the surface of the water are designated as "blooms" or "mats"
or "blankets, " the last two terms generally being applied when the algae
are in the form of threads or filaments. Many of the algae attached to sub-
merged rock, wood, soil, or the surface of trickling filters may form con-
tinuous carpets of growth. When the water becomes turbulent, fragments
of the algal carpet may become detached and be carried away. These mas-
sive growths of algae can be troublesome in clogging screens, in the pro-
duction of slime, and as a source of tastes and odors particularly if
anaerobic decomposition occurs. The blooms and surface mats can be the
cause for complaints by persons using the body of water for recreational
purposes. They also may be one cause of fish kills by acting as a barrier
to the penetration of oxygen into water under the algae. Algae that are
dispersed and not in blooms or mats normally would have just the opposite
effect.
All surface waters contain dissolved and suspended materials which
serve as nutrients and support the growth not only of algae but of many
other kinds of aquatic life, the numbers of which are governed to a great
extent by the amounts and kinds of nutrients available. Some of the aquatic
plants and animals are large, such as the fish, turtles, cattails, and
-------
water lilies, but there are immense populations of small forms, many of
them microscopic in size. The microscopic organisms in addition to algae
include bacteria, actinomycetes, molds or fungi, yeasts, protozoa, rotifers,
micro-crustacea, minute worms, and mites. Many of these may play a
major part in affecting the quality of the water. The present account deals
primarily with the algae but it is obvious that the activities of one group
of organisms are closely associated with activities of the other organisms
present in the same environment.
The unattached organisms that are dispersed individually or in
colonies in the water are designated collectively as the "plankton." Included
are the plankton algae, which constitute most of the "phytoplankton" (mean-
ing plant plankton), and the planktonic animals or "zooplankton. "
Several of the larger groups of algae are recognized by their common
names, such as the diatoms, desmids, armored flagellates, euglenoids,
greens, blue-greens, yellow-greens, browns, golden-browns, and reds.
Included in these groups are numerous individual kinds which total probably
more than twenty thousand. A few of the less specific kinds of algae have
common names as well as scientific names, as for example, the names
'water net' for Hydrodictyon, "green felt" for Vaucheria, "sea lettuce" for
Ulva. "water silk" for Spirogyra, and "stone wort" for Chara. Each one
of these is known as a genus (plural, "genera") and is composed of specific
kinds known as species (plural also is "species"). For example, two
species of the genus Spirogyra would be Spirogyra ellipsospora and Spirogyra
varians. For the great majority of algae there are only scientific names
available, no common names having as yet been applied to them.
Some aquatic, pigmented forms containing chlorophyll are able to
swim or crawl, although most of the typical algae are not capable of self
locomotion. Many of these pigmented swimming forms have whip-like
structures called flagella and have been classified by some workers as
protozoan animals rather than as algae. However, it seems best, in sani-
tary science, to list them as algae.
For convenience, most of the algae of importance in sanitary science
may be characterized in four general groups, the blue-green algae, the
green algae, the diatoms, and the pigmented flagellates. This is a
simplification of the grouping which is used in more extensive treatises on
the classification of algae. As might be expected, there are a few miscella-
neous forms which do not fit into these four groups. The blue-green algae
include such forms as Oscillatoria, Anacystis (Microcystis) and Desmonema.
As the name implies, many of the specimens have a blue-green color.
They are surrounded by a slimy coating. Their form and internal structure
is comparatively simple. The green algae are exemplified by Chlorella,
Pediastrum, and Spirogyra. Their most common color is grass green to
-------
yellow-green and is localized in plastids. Reserve food is generally starch.
The desmids are a subgroup of the green algae. The diatoms are represen-
ted by the genera Cyclotella and Navicula. They have a rigid wall contain-
ing silica which is sculptured with regularly arranged markings. Their
plastids are brown to greenish in color.
In the pigmented flagellates are placed all of the swimming algae which
have flagella. Euglena and Synura are representatives of this group. A
comparison of the more significant characteristics of the four groups of
algae is summarized in the following table.
COMPARISON OF FOUR MAJOR GROUPS OF ALGAE
Color
Location
of pigment
Starch
Slimy
coating
Nucleus
Flag e Hum
Cell Wall
"Eye" spot
Blue-Green
Blue-Green
(Brown)
Throughout
cell
Absent
Present
Absent
Absent
Inseparable
from slimy
coating
Absent
Pigmented
flagellates
Green
Brown
In
plastids
Present or
Absent
Absent
in most
Present
Present
Thin or
Absent
Present
in most
Greens
Green
In
plastids
Present
Absent
in most
Present
Absent
Semi-rigid
smooth or
with spines
Absent
Diatoms
Brown
(Light- Green)
In
plastids
Absent
Invisible
in most
Present
Absent
Very rigid,
with regular
markings
Absent
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Effect of Pollution on Algae
Many algae are affected adversely by the gross pollution of streams
with organic wastes such as domestic sewage. After partial self-purifica-
tion of the stream has occurred, however, the populations and kinds of
algae become much more numerous than are present in the clean portion
of the stream above the area of pollution. This increase is due to the
nutrients that are made available from the decomposing organic wastes.
The undecomposed organic wastes affect the algae by causing chemical
and physical changes in the stream. Increased turbidity reduces the light
available for photosynthesis. Increased organic content in the water
stimulates saprophytic and saprozoic organisms which then compete for
space with the algae. Certain constituents of the waste are toxic to many
algae. Thus, many factors of the environment that are changed by the
organic wastes have an effect on the algae.
Information on the physiological and morphological effects of organic
pollution on algae is very limited at present. There have been, however,
many studies of the change in the algal flora as a result of pollution.
Gross pollution causes a great reduction in the number of kinds of
algae in the stream. Those able to remain have frequently been called
"indicators" of pollution, but no specific kinds individually are reliable
indicators of grossly polluted water. Polluted water varies too much to
ensure an environment satisfactory for the growth or persistence of any
one particular algal species. Any individual species tolerant of pollution
may also be found in unpolluted areas of a stream or may be absent in some
areas of pollution.
When a jiumber of the tolerant genera and species are considered, it
becomes likely that many of these will be present in all areas of streams
grossly polluted with organic wastes. The presence of such a community
of algae in a stream, therefore, is a reliable indicator of the condition of
the water.
Many workers have listed the genera and species of algae found in
polluted waters, particularly in the United States and in Europe. The
number of kinds which they have considered to be pollution tolerant is gen-
erally quite limited for any one area or survey, but becomes very large
when all of the results of many investigators are combined.
The lists of pollution-tolerant algae reported by 110 workers have
been examined by the writer. The genera and species of algae tolerant
to sewage or to related conditions have been recorded, and a total or more
than 600 species and varieties has been compiled.
-------
In order to tabulate the information, the writer has allotted
arbitrary numerical values to each author's record of an alga. A
value of two was given to each alga reported as very highly tolerant, and
a value of one to each alga highly tolerant to the presence of organic
matter. Lightly tolerant and non-tolerant algae were not recorded in the
compilation. The total points from all of the 110 authors were then determin-
ed for each genus and species. The algae were arranged in the order of
decreasing emphasis by the authors as a whole as indicated by the compara-
tive total scores for each alga. Theoretically an alga considered as very
highly tolerant by all 110 authors would have had a perfect score of 110
multiplied by 2, or 220 total points.
For studies in sanitary science the algae are frequently placed into
four groups. All flagellates containing photo synthetic pigments constitute
one of the four groups. The other three groups are the blue-green algae,
the diatoms, and the green algae, the last group including all of the non-
flagellated green,yellow-green, and other related forms.
All four groups are well represented among the genera and species
having high scores as pollution-tolerant algae. For example, of the ten
genera having the highest scores, two are blue-green algae, two are
flagellates, three are diatoms, and three are green algae (Table 1). Of the
four species having the four highest scores, each belongs to a different
group. Among the fifty most tolerant species, the range in number per
group is from ten to fifteen.
The 22 most tolerant genera are listed in Table 1. Leading the list,
in order of decreasing total scores, are Euglena, Oscillatoria, Chlamy-
domonas, Scenedesmus, Chlorella, and Nitzschia. The first two were
considered as tolerant genera by 62 and 61 authors and rated 110 and 105
total points, respectively.
The 20 most tolerant species are given in Table 2. Euglena viridis,
followed by Nitzschia palea. are at the top of the list with total scores of
63 and 46, respectively.
I The lists of algae in the tables are meant to be aids for individuals
engaged in stream pollution surveys or related projects. They give a
general consensus of opinion as to the relative significance of the many
algae tolerant of organic wastes which have been reported. Particular
care can thus be taken in biological surveys to check for the presence of
these genera and species of algae during the microscopic examination of
samples.
E
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TABLE 1.
Pollution Tolerant Genera of Algae
List of 22 Most Tolerant Genera
In Order of Decreasing Emphasis by 110 Authorities
No. of Total*
Genera Group Authors Points
1. Euglena F 62 110
2. Oscillatoria B 61 105
3. Chlamydomonas F 42 70
4. Scenedesmus G 40 65
5. Chlorella G 36 63
6. Nitzschia D 38 63
7. Navicula D 35 55
8. Stigeoclonium G 34 50
9. Phormidium B 30 45
10. Synedra D 25 33
11. Phacus F 23 32
12. Ankistrodesmus G 19 31
13. Gomphonema D 20 30
14. Spirogyra G 19 29
15. Cyclotella D 22 29
16. Pandorina F 18 25
17. Closterium G 19 25
18. Lepocinclis F 14 24
19. Melosira D 18 24
20. Chlorogonium F 14 23
21. Anabaena B 17 23
22. Ulothrix G 17 23
* Tolerance by author: "Very High", 2 points; "High", 1 point.
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TABLE 2.
Pollution Tolerant Species of Algae
List of the 20 Most Tolerant Species
In Order of Decreasing Emphasis by 110 Authorities
No. of Total
Species Group Authors Points
1. Euglena viridis F 34 63
2. Nitzschia palea D 30 46
3. Stigeoclonium tenue G 17 26
4. Oscillatoria tenuis B 17 25
5. Oscillatoria limosa B 14 21
6. Scenedesmus quadricauda G 12 18
7. Chlorella vulgaris G 11 17
8. Pandorina morum F 12 17
9- Arthrospira jenneri B 9 16
10. Ankistrodesmus falcatus G 11 16
11. Cyclotella meneghiniana D 12 16
12. Chlorella pyrenoidosa G 8 15
13. Gomphonema parvulum D 8 15
14. Euglena gracilis F 9 15
15. Oscillatoria chalybea B 10 15
16. Synedra ulna D 12 15
17. Oscillatoria chlorina B 9 14
18. Nitzschia acicularis D 10 14
19- Oscillatoria formosa B 10 14
20. Oscillatoria princeps B 10 14
* Tolerance by author: "Very High", 2 points; "High", 1 point.
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II KEY TO ALGAE OF IMPORTANCE IN WATER POLLUTION
1 Plant a tube, thread, strand, ribbon, or membrane; frequently visible to the unaided eye 2
I1 Plants of microscopic cells which are isolated or in irregular, spherical, or microscopic
clusters; cells not grouped into threads 123
2 (1) Plant a tube, strand, ribbon, thread, or membrane composed of cells 3
2" Plant a branching tube with continuous protoplasm, not divided into cells 120
3 (2) Plant a tube, strand, ribbon, thread, or a mat of threads 4
3' Plant a membrane of cells one cell thick (and 2 or more cells wide) 116
4 (3) Cells in isolated or clustered threads or ribbons which are only one cell thick or wide 5
4J Cells in a tube, strand, or thread all (or a part) of which is more than one cell thick or
wide 108
5 (4) Heterocysts present 6
5' Heterocysts absent 23
6 (5) Threads gradually narrowed to a point at one end 7
6" Threads same width throughout 12
7 (6) Threads as radii, in a gelatinous bead or mass 8
7' Threads not in a gelatinous bead or mass 11
8 (7) Spore (akinete) present, adjacent to the terminal heterocyst (Gloeotrichia) 9
8' No spore (akinete) present (Rivularia) 10
9 (8) Gelatinous colony a smooth bead .Gloeotrichia echinulata
9' Gelatinous colony irregular Gloeotrichia natans
10 (8') Cells near the narrow end as long as wide Rivularia dura
10' Cells near the narrow end twice as long as wide . . Rivularia haematites
11 (7') Cells adjacent to heterocyst wider than heterocyst Calothrix braunii
11' Cells adjacent to heterocyst narrower than heterocyst Calothrix parjetina
12 (61) Branching present .• 13
12' Branching absent 14
13 (12) Branches in pairs Scytonema tolypothricoides
13' Branches arising singly. Tolypothrix tenuis
14 (12") Heterocyst terminal only (Cyclindrospermum). 15
14' Hetrocysts intercalary (within the filament) 16
15 (14) Heterocyst round Cylindrospermum muscicola
15' Heterocyst elongate Cylindrospermum stagnate
16 (141) Threads encased in a gelatinous bead or mass 17
16' . Threads not encased in a definite gelatinous mass 18
17 (16) Heterocysts "and vegetative cells rounded Nostoc pruniforme
17' Heterocysts and vegetative cells oblong Nostoc carneum
18 (16') Heterocysts and vegetative cells shorter than the thread width Nodularia spumigena
18' Heterocysts and vegetative cells not shorter than the thread width J9
19 '(18') Heterocysts rounded (Anabaena) 20
19' Heterocysts clindric. AphanizornLenon flos-aquae
20 (19) Cells elongate, depressed in the middle; heterocysts rare. Anabaena constricta
20' Cells rounded; heterocysts common - - 21
21 (201) Heterocysts with lateral extensions. Anabaena planctonica
21' Heterocysts without lateral extensions 22
-------
22 (211) Threads 4-8|» wide Anabaena flos-aquae
22' Threads 8-14^ wide Anabaena circinalis
23 (5') B ranching absent 24
23' Branching (including "false" branching) present 84
24 (23) Cell pigments distributed throughout the protoplasm 25
24' Cell pigments limited to plastids 49
25 (23) Threads short and formed as an even spiral 285
25' Threads very long and not forming an even spiral 26
26 (25') Several parallel threads of cells in one common sheath Microcoleus subtorulosus
26' One thread per sheath if present 27
27 (261) Sheath or gelatinous matrix present 28
27' No sheath nor gelatinous matrix apparent (Oscillatoria) 35
28 (27) Sheath distinct; no gelatinous matrix between threads (Lyngbya) 29
28' Sheath indistinct or absent; threads interwoven with gelatinous matrix between (Phormidium). . .
32
29 (28) Cells rounded Lyngbya ocracea
29' Cells short cylindric 30
30 (29') Threads in part forming spirals Lyngbya lagerheimii
30' Threads straight or bent but not in spirals 31
31 (301) Maximum cell length 3. 5n ; sheath thin Lyngbya digueti
31' Maximum cell length 6. 5M ; sheath thick Lyngbya versicolor
32 (28') Ends of some threads with a rounded swollen "cap" cell 33
32' Ends of all threads without a "cap" cell 34
33 (32) End of thread (with "cap") abruptly bent Phormidium uncinatum
33' End of thread (with "cap") straight Phormidium autumnale
34 (32') Threads 3-5H in width Phormidium inundatum
34' Threads 5-12M in width.. Phormidium retzii
35 (271) Cells very short; generally less than 1/3 the thread diameter 36
35' Cells generally 1/2 as long to longer than the thread diameter 39
36 (35) Cross walls constricted Oscillatoria ornata
36' Cross walls not constricted 37
37 (36') Ends of thread, if mature, curved 38
37' Ends of thread straight Oscillatoria limosa
38 (37) Threads 10-14H thick Oscillatoria curviceps
38' Threads 16-60|» thick Oscillatoria princeps
39 (351) Threads appearing red to purplish Oscillatoria rubescera
39' Threads yellow-green to blue-green .40
40 (391) Threads yellow-green 41
40' Threads blue-green 43
41 (40) Cells 4-7 times as long as tiie thread diameter .Oscillatoria putrida
41' Cells less than 4 times as long as the thread diameter 42
42 (41') Prominent granules ("pseudovacuoles") in center of each cell Oscillatoria lauterbornii
42' No prominent granules in center of cells Oscillatoria chlorina
43 (40') Cells l/Z-2 times as long as the thread diameter 44
43' Cells 2-3 times as long as the thread diameter 48
44 (43) Cell walls between cells thick and transparent Oscillatoria pseudogeminata
44" Cell walls thin, appearing as a dark line 45
-------
45 (441) Ends of thread straight Oscillatoria agardhii
45' Ends of mature threads curved 46
46 (45') Prominent granules present especially at both ends of each cell Oscillatoria tenuis
46' Cells without prominent granules 47
47 (46') Cross walls constricted Oscillatoria chalybea
47' Cross walls not constricted Oscillatoria formosa
48 (43') End of thread long tapering Oscillatoria splendida
48' End of thread not tapering Oscillatoria amphibia
49 (24') Cells separate from one another and enclosed in a tube (Cymbella) 251'
49' Cells attached to one another as a thread or ribbon 50
50 (49') Cells separating readily into discs or short cylinders, their circular face showing radial
markings 233
50' Cells either not separating readily, or if so, no circular end wall with radial markings 51
51 (50') Cells in a ribbon, attached side by side or by their corners 52
51' Cells in a thread, attached end to end 56
52 (51) Numerous regularly spaced markings in the cell wall 53
52' Numerous markings in the cell •wall absent (Scenedesmus) 128
53 (52) Wall markings of two types, one coarse, one fine. 185
53' Wall markings all fine (Fragilaria) 54
54 (53') Cells attached at middle portion only Fragilaria crotonensis
54' Cells attached along entire length 55
55 (54') Cell length 25-100|i • Fragilaria capucina
55' Cell length 7-25|» I Fragilaria construens
56 (51') Plastid in the form of a spiral band (Spirogyra) 57
56' Plastid not a spiral band 6l
57 (56) One plastid per cell 58
57' Two or more plastids per cell 60
58 (57) Threads 18-26|»wide , Spirogyra communis
58' Threads 28-50>i wide 59
59 (58') Threads 28-40,1 wide Spirogyra varians
59' Threads 40-50|i wide • Spirogyra porticalis
60 (57') Threads 30-45H wide; 3-4 plastids per cell Spirogyra fluviatilis
60' Threads 50-80|i wide; 5-8 plastids per cell Spirogyra majuscula
61 (56') Plastids two per cell • 62
61' Plastids either one or more than two per cell °°
62 (61) Cells with knobs or granules on the wall
62' Cells with a smooth outer wall
63 (62) Each cell with two central knobs on the wall ........................... Desmidium grevillii
63' Each cell with a ring of granules near one end ........................... Hyalotheca mucosa
64(62') Cells dense green, each plastid reaching to the wall ........................ Zygnema sterile
64' Cells light green, plastids not completely filling the cell ........................ • ....... &5
65 (641) Width of thread 26-32u; maximum cell length 60p .......................... Zygnema insigne
65' Width of thread 30-36p; maximum cell length 120|t ..................... . Zygnema pectinatum
66 (61') Plastid a wide ribbon, passing through the cell axis (Mougeotia) .......................... 67
66" Plastid or plastids close to the cell wall (parietal) .......................... . ............ 69
E 10
-------
67 (66) Threads with occasional "knee-joint" bends Mougeotia genuflexa
67 ' Threads straight 68
68 (671) Threads 19-24|» wide; pyrenoids 4-16 per cell Mougeotia sphaerocarpa
68' Threads 20-34ji wide; pyrenoids 4-10 per cell Mougeotia scalaris
69 (661) Occasional cells with one to several transverse wall lines near one end (Oedogonium) 70
69' Occasional terminal transverse wall lines not present 73
70 (69) Thread diameter less than 24p 71
70' Thread diameter 25n or more 72
71 (70) Thread diameter 9-14(1 Oedogonium suecicum
71' Thread diameter 14-23|i Oedogonium boscii
72 (70) Dwarf male plants attached to normal thread, when reproducing. .Oedogonium idioandrosporum
72' No dwarf male plants produced Oedogonium grande
73 (69') Cells with one plastid which has a smooth surface 74
73" Cells with several plastids or with one nodular plastid 78
74 (73) Cells with rounded ends Stichococcus bacillaris
74' Cells with flat ends (Ulothrix) .75
75 (741) Threads 10p or less in diameter 76
75' Threads more than I0f in diameter -77
76 (75) Threads 5-6ji in diameter Ulothrix variabilis
76' Threads 6-lOy in diameter Ulothrix tenerrima
77 (751) Threads 11-17^1 in diameter '. Ulothrix aequalis
77' Threads 20-60)1 in diameter Ulothrix Zonata
78 (731) Iodine test for starch positive; one nodular plastid per cell .79
78' Iodine test for starch negative; several plastids per cell 80
79 (78) Thread when broken, forming "H" shape segments Microspora amoena
79' Thread when fragrrfentei, separating irregularly or between cells (Rhizoclonium) 100
80 (78') Side walls of cells straight, not bulging. A pattern of fine lines or dots present in the wall
but often indistinct (Melosira) I 81
80' Side walls of cells slightly bulging. Pattern of wall markings not present (Tribonema). ..... .83
81 (80) Spine-like teeth at margin of end walls 82
81' No spine-like teeth present Melosira varians
82 (81) Wall with fine granules, arranged obliquely Melosira crenulata
82' Wall with coarse granules, arranged parallel to sides Melosira eranulata
83 (80') Plastids 2-4 per cell Tribonema minus
83' Plastids more than 4 per cell Tribonema bombycinum
84 (23') Plastids present; branching "true" 85
84' Plastids absent; branching "false" Plectonema tomasiniana
85 (84) Branches reconnected, forming a net Hydrodictyon reticulatum
85' Branches not forming a distinct net 86
86 (85') Each cell in a conical sheath open at the broad end (Dinobryon) 87
86' No conical sheath around each cell 90
87 (86) Branches diverging, often almost at a right angle Dinobryon divergens
87' Branches compace often almost parallel 88
88 (87') Narrow end of sheath sharp pointed 89
88' Narrow end of sheath blunt pointed Dinobryon sertularia
11
-------
89 (88) Narrow end drawn out into a stalk Dinobryon stipitatum
89' Narrow end diverging at the base Dinobryon sociale
90 (861) Short branches on the main thread in whorls of 4 or more (Nitella) 91
90' Branching commonly single or in pairs 92
91 (90) Short branches on the main thread rebranched once Nitella flexilis
91' Short branches on the main thread rebranched two to four times Nitella gracilis
92 (90') Terminal cell eacli with a colorless spine having an abruptly swollen base (Bulbochaete). . .93
92' No terminal spines with abruptly swollen bases .94
93 Vegetative cells 20-48y long Bulbochaete mirabilis
93' Vegetative cells 48-88)4 long Bulbochaete insignis
94 (92') Cells red, brown, or violet Audouinella violacea
94' Cells green . . 95
95 (94') Threads enclosed in a gelatinous bead or mass 96
95' Threads not surrounded by a gelatinous mass 99
96 (95) Abrupt change in width from main thread to branches (Draparnaldia) 97
96' Gradual change in width from main thread to branches (Chaetophora) .98
97 (96) Branches (from the main thread) with a central, main axis Draparnaldia plumosa
97' Branches diverging and with no central main axis Draparnaldia glomerata
98 (961) End cells long-pointed, with colorless tips Chaetophora attenuata
98' End cells abruptly pointed, mostly •without long colorless tips Chaetophora elegans
99 (95') Light and dense dark cells intermingled in the thread Pithophora oedogogonia
99' Most of the cells essentially alike in density 100
100 (99') Branches few in number, and short, colorless Rhizoclonium hieroglyphicum
100' Branches numerous and green 101
101 (100') Terminal attenuation gradual, involving two or more cells (Stigeoclonium) 102
101' Terminal attenuation absent or abrupt, involving only one cell (Cladophora) 104
102 (101) Branches frequently in pairs 103
102' Branches mostly single Stigeoclonium stagnatile
103 (102) Cells in main thread 1-2 times as long as wide Stigeoclonium lubricum
103' Cells in main thread 2-3 times as long as wide Stigeoclonium tenue
104 (1Q11) Branching often appearing forked, or in threes Cladophora aegagropila
104' Branches distinctly lateral i 105
105 (1041) Branches forming acute angle with main thread, thus forming clusters..Cladophora glomerata
105' Branches forming wide angles with the main thread 106
106 (105') Threads crooked and bent Cladophora fracta
106' Threads straight 107
107 (106') Branches few, seldom rebranching Cladophora insignis
107' Branches numerous, often rebranching Cladophora crispata
108 (4') Plant or tube with a tight surface layer of cells and with regularly spaced swellings (nodes).
Lemanea annulata
108' Plant not a tube that has both a tight layer of surface cells and nodes 109
109 (108') Cells spherical and loosely arranged in a gelatinous matrix Tetraspora gelatines a
109' Cells not as loosely arranged spheres 110
110 (109') Plants branch Ill
110' Plants not branched Schizomeris leibleinii
111 (110) Clustered branching 112
111' Branches single 115
E 12
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112 (111) Threads embedded in gelatinous matrix (Batrachospermum) 113
112' No gelantinous matrix (Chara) 114
113 (112) Nodal masses of branches touching one another Batrachospermum vagum
113' Nodal masses of branches separated by a narrow space Batrachospermum monillforme
114 (1121) Short branches with 2 naked cells at the tip Chara globularis
114' Short branches with 3-4 naked cells at the tip Chara vulgaris
115 (1111) Heterocysts present; plastids absent Stigonema minutum
115' Heterocysts absent; plastids present Compsopogon coeruleus
116 (31) Red eye spot and two flagella present for each cell 125
116' No eye spots nor flagella present 117
117 (116') Round to oval cells, held together by a flat gelatinous matrix (Agmenellum) 131
117' Cells not round and not enclosed in a gelatinous matrix 118
118(117') Cells regularly arranged to an unattached disc. Number of cells 2, 4, 8, 16, 32, 64, or
128 133'
118' Cells numerous; membrane attached on one surface 119
119 (H81) Long hairs extending from upper surface of cells Chaetopeltis megalocystis
119' No hairs extending from cell surfaces Hildenbrandia rivularis
120 (21) Constriction at the base of every branch Dichotomosiphon tuberosus
120' No constrictions present in the tube (Vaucheria) 121
121 (120') Egg sac attached directly, without a stalk, to the main vegetative tube. . .Vaucheria sessilis
121' Egg sac attached to an abrupt, short, side branch 122
122 (121') One egg sac per branch Vaucheria terrestris
122' Two or more egg sacs per branch Vaucheria geminata
123 (I1) Cells in colonies generally of a definite form or arrangement 124
123' Cells isolated, in pairs or in loose, irregular aggregates 173
124 (123) Cells with many transverse rows of markings on the wall 185
124' Cells without transverse rows of markings 125
125 (1241) Cells arranged as a layer one cell thick 126
125' Cell cluster more than one cell thick and not a flat plate 137
126 (125) Red eye spot and two flagella present for each cell Gonium pectorale
126' No red eye spots nor flagella present 127
127 (1261) Cells elongate, united side by side in 1 or 2 rows (Scenedesmus) 128
127' Cells about as long as wide 131
128 (127) Middle cells without spines but with pointed ends Scenedesmus dimorphus
128' Middle cells with rounded ends '. 129
129 (128") Terminal cells with spines -. 130
129' Terminal cells without spines Scenedesmus bijuga
130 (129) Terminal cells with two spines each Scenedesmus quadricauda
130' Terminal cells with three or more spines each Scenedesmus abundans
131(117) Cells in regular rows, immersed in colorless matrix (Agmenellum quadriduplicatum). . .132
131' Cells not immersed in colorless matrix 133
132 (131) Cell diameter 1. 3 to 2. Zjt Agmenellum quadriduplicatum , tenuissima type
132' Cell diameter 3-5(1 Apmenellum quadriduplicatum, glauca type
133 (1311) Cells without spines, projections, or incisions Crucigenia quadrata
133' Cells with spines, projections, or incisions • 134
13
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134
-------
156 (155') Colonies round to oval 160
156' Colonies not round, often irregular in form 157
157 (156') Straight (flat) walls between adjacent cells (Phytoconis) 278
157' Walls between neighboring cells rounded 158
158 (157') Cells arranged as a surface layer in a large gelatinous tube (Tetraspora) 109
158' Colony not a tube; cells in irregular pattern 159
159 (158') Large cells more than twice the diameter of the small cells (Chlorococcum) 280*
159' Large cells not more than twice the diameter of the small cells (Palmella) 281
160 (156) Cells touching one another; tightly grouped Coelastrum microporum
160' Cells loosely grouped 161
161 (160') Colorless threads extend from center of colony to cells 162
161' No colorless threads attached to cells in colony 164
162 (161) Cells rounded or straight, oval (Dictyosphaerium) 163
162' Cells elongate, some cells curved Dimorphococcus lunatus
163 (162) Cells rounded Dictyosphaerium pulchellum
163' Cells straight, oval Pictyosphaerium ehrenbergianum
164 (1611) Cells rounded ". 165
164' Cells oval Oocystis borgei
165 (164) One plastid per cell . . 166
165' Two to four plastids per cell Gloeococeus schroeteri
166 (165) Outer matrix divided into layers (Gloeocystls) 167
166' Outer matrix homogeneous Sphaerocystis schroeteri
167 (166) Colonies angular Gloeocystis planctonica
167' Colonies rounded Gloeocystis gigas
168 (154') Cells equidistant from center of colony (Gomphosphaeria) ' 169
168' Cells irregularly distributed in the colony 172
169 (168) Cells with pseudovacuoles Gomphospaeria wichurae
169' Cells without pseudovacuoles <• • • I7"
170 (169') Cells 2-4pin diameter (Gomphosphaeria lacustrisj 171
170' Cells ovate Gomphosphaeria appnina^
171 (170) Cells spherical Gomphosphaeria lacustris, kuetzingianum type
171' Cells 4-15 in diameter Gomphosphaeria lacustris, collinsii type
172 (168') Cells ovid; division plane perpendicular to long axis (Coccochloris) 286
172" Cells rounded; or division plane perpendicular to short axis (Anacystis) 286'
173 (123') Cells with an abrupt median transverse groove or incision .~.~. .174
173" Cells without an abrupt transverse median groove or incision . 184
174 (173) Cells brown; flag el la present (armored flagellates) 175
174' Cells green; no flagella'(desmids) 178
175 (174) Cell with 3 or more long horns ^ Ceratium hirundinella
175' Cell without more than 2 horns 17&
176 (175') Cell wall"of very thin smooth plates Glenodinium palustre
176' Cell wall of very thick rough plates (Peridinium) 177
177 (176') Ends of cell pointed Peridinium wisconsinense
177' Ends of cell rounded Peridinium cjnctum
178 (174') Margin of cell with sharp pointed , deeply cut lobes or long spikes 179
178' Lobes, if present, with rounded ends 182
E IS
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179 (178) Median incision, narrow, linear Micrasterias truncata
179' Median incision wide, "V" or "U" shaped (Staurastrum) 180
180 (179) Margin of cell with long spikes '. Staurastrum paradoxum
180' Margin of cell without long spikes 181
181 (180") Ends of lobes with short spines Staurastrum polymorphum
181' Ends of lobes without spines Staurastrum punctulatum
182 (1781) Length of cell about double 'the width Euastrum oblongum
182" Length of cell one to one and one-half times the width (Cosmarium) 183
183 (182') Median incision narrow linear Cosmarium botrytis
183' Median incision wide, "U" shaped Cosmarium portianum
184 (173') Cells triangular Tetraedron muticum
184' Cells not triangular 185
185 (124) Cells with one end distinctly different from the other 186
185' Cells with both ends essentially alike 225
186 (185) Numerous transverse (not spiral) regularly spaced wall markings present (diatoms) 187
186' No transverse regularly spaced wall markings 193
187 (186) Cells curved (bent) in girdle view Rhoicosphenia curvata
187' Cells not curved in girdle view 188
188 (1871) Cells with both fine and coarse transverse lines Meridion circulare
188' Cells with transverse lines all alike in thickness 189
189 (1881) Cells essentially linear to rectangular; one terminal swelling larger than the other
(Asterionella) 190
189' Cells wedge-shaped; margins sometimes wavy (Gomphonema) 191
190 (189) Larger terminal swelling 1-1/2 to 2 times wider than the other. Asterionella formosa
190' Larger terminal swelling less than 1-1/2 times wider than the other. .Asterionella gracillima
191 (189") Narrow end enlarged in valve view Gomphonema geminatum
191" Narrow end not enlarged in valve view 192
192 (1911) Tip of broad end about as wide as tip of narrow end in valve view. . . .Gomphonema parvulum
192' Tip of broad end much wider than tip of .narrow end in valve view. . jGomphonema olivaceum
193 (1861) Spine present at each end of cell . . Schroederia setigera
193' No spine on both ends of cell 194
194 (1931) Pigments in one or more plastids 195
194' No plastid; pigments throughout the protoplast, Entophysalis lemaniae
195 (194) Cells in a conical sheath (Dinobryon) 86
195' Cells not in a conical sheath .', 196
196 (195') Cell covered with scales and long spines..-• Mallomonas caudata
196' Cells not covered with scales and long spines ... 197
197 (196') Protoplasts separated by a space from a rigid sheath (lorica) 198
197' No loose sheath around the cells 202
198 (197) Cells compressed (flattened) .Phacotus lenticularis
198' . Cells not compressed I 199
199 (198') . Lorica opaque; yellow to reddish or brown Trachelbmonas crebea
199' Lorica transparent; colorless to brownish (ChrysocQecus) . . 200
200 (199') Outer membrane (lorica) oval Chrysococcus ovalis
200' Outer membrane (lorica) rounded 201
E 16
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201 (200') Lorica thickened around opening Chrysococcus rufescens
201' Lorica not thickened around opening jChrysococcus major
202 (197') Front end flattened diagonally 203
202" Front end not flattened diagonally ; 206
203 (202) Plastids bright blue-green (Chroomonas) 204
203' Plastids brown, red, olive-green, or yellowish 205
204 (203) Cell pointed at one end Chj^oomonas nordstetii
204' Cell not pointed at one end Chroomonas setoniensis
205 (2031) Gullet present; furrow absent Cryptomonas erosa
205' Furrow present; gullet absent Rhodomonas lacustris
206 (2021) Plastids yellow-brown Chromulina rosanoffi
206" Plastids not yellow-brown; generally green 207
207 (2061) One plastid per cell 208
207' Two to several plastids per cell 211
208 (207) Cells tapering at each end Chlorogonium euchlor'um
208' Cells rounded to oval 209
209 (2081) Two flagella per cell (Chlamydomonas) 210
209' Four flagella per cell Cateria multifilis
210 (209) Pyrenoid angular; eye spot in front third of cell Chlamydomonas reinhardi
2101 Pyrenoid circular; eye spot in middle third of cell Chlamydomonas globosa
211 (207') Two plastids per cell Crvptoglena pigra
211' Several plastids per cell 212
212 (211')
212'
213 (212) Posterior spine short, bent Phacus pleuronectes
213' Posterior spine long, .straight Phacus longicauda
214 (212)
214'
215 (214) Cell margin with spiral ridges .Phacus pyrum
215' Cell margin without ridges, but may have spiral lines (Lepocinclis) 216
216 (2151) Posterior end with an abrupt, spine-like tip Lepocinclis ovum
216' Posterior end rounded Lepocinclis texta
217 (2141) Green plastids hidden by a red pigment in the cell Euglena sanguinea
217' No red pigment except for the eye spot 218
218 (217') Plastids at least 1/4 the length of the cell 219
218' Plastids discoid or at least shorter than 1/4 the length of the cell 220
219 (218) Plastids two per cell Euglena agilis
219' Plasttds several per cell, often extending radiately from the center Euglena viridis
220 (2181) Posterior end extending as an abrupt colorless spine 221
220' Posterior end rounded or at least with no colorless spine 222
221 (220) Spiral markings very prominent and granular Euglena spirogyra
221' Spiral markings fairly prominent, not granular Euglena oKyuris
222 (2201) Small; length 35-55^ Euglena gracilis
222' Medium to large; length 65|i or more 223
223 (2221) Medium in size; length 65-200ji 224
223' Large in size; length 250-290(1 Euglena ehrenbergii
17
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224 (223) Plastids with irregular edge; flagellum 2 times as long as cell Euglena polymorpha
224' Plastids with smooth edge; flagellum about 1/2 the length of the cell Euglena deses
225 (1851) Cells distinctly bent (arcuate); with a spine or narrowing to a point at both ends 226
225' Cells not arcuate ^ 230
226 (225) Vacuole with particles showing Brownian movement at each end of cell. Cells not in
clusters. (Closterium) 227
226' No terminal vacuoles. Cells may be in clusters or colonies 228
227 (226) Cell wide; width 30-70(i Closterium mpnilifertirn
227' Cell long and narrow; width up to 5p Closterium aciculare
228 (226') Cell with a narrow abrupt spine at each blunt end OtfiiOcytium capitatum
228' No blunt ended cells with abrupt terminal spines 229
229 (228') Sharp pointed ends as separate colorless spines 193
229' Sharp pointed ends as part of the green protoplast 137
230 (225) One long spine at each end of cell 231
230' No long terminal spines 232
231 (230) Cell gradually narrowed to the spine J37
231' Cell abruptly narrowed to the spine Rhizosolenia gracilis
232 A regular pattern of fine lines or dots in the wall (diatoms) 233
232' No regular pattern of fine lines or dots in the wall 276
233 (50, Cells circular in one (valve) view; short rectangular or square in other (girdle) view. . ,. 234
232)
233' Cells not circular in one view. 240
234 (233) Valve surface with an inner and outer (marginal) pattern of striae (Cyclotella) 235
234' Valve surface with one continuous pattern of striae (Stephanodiscus) 238
235 (234) Cells small; 4-10j» in diameter Cyclotella glomerata
235' Cells medium to large; 10-80 in diameter 236
236 (2351) Outer half of valve with two types of lines, one long, one short 237
236' Outer half of valve with radial lines all alike Cyclotella meneghiniana
237 (236) Outer valve zone constituting more than 1/2 the diameter Cyclotella bodanica
237" Outer valve zone constituting more than 1/2 the diameter Cyclotella compta
238 (234') Cell 4-25|i in diameter 239
238' Cell 25-65(i in diameter '. Stephanodiscus niagarae
239 (238) Cell with two transverse bands, in girdle view Stephanodiscus binderanus
239' Cell •without two transverse bands, in girdle view Stephanodiscus hantzschii
240 (233') Cells flat, oval (Cocconeis) 241
240' Cells neither flat nor oval 242
241 (240) Wall markings (striae) 18-20 in K>n Cocconcis pediculus
241" Wall markings (striae) 23-25 in 10t» Cocconeis placentula
242 (240') Cell sigmoid in one view 243
242' Cell not sigmoid in either round or point ended (valve) or square ended (girdle) surface
view 244
243 (242) Cell sigmoid in valve surface view Gyrosigma attenuatum
243" Cell sigmoid in square ended (girdle) surface view. Nitzschia acicularis
244 (2421) Cell longitudinally unsymmetrical in at least one view 245
244' Cell longitudinally symmetrical 254
245 (244) Cell wall with both fine and coarse transverse lines (striae and costae) 246
245' . Cell wall with fine transverse lines (striae) only 247
18
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246 (245) Valve face about as wide at middle as girdle face Epithemia turgida
246' Valve face 1/2 or less as wide at middle as girdle face Rhopalodia gibba
247 (245) Line of pores and raphe located at edge of valve face 248
247' Raphe not at extreme edge of valve face 250
248 (247) Raphe of each valve adjacent to the same girdle surface Hantzschia amphioxys
248' Raphe of each valve adjacent to different girdle surfaces (Nitzschia) 249
249 (2481) Cell 20-65^ long Nitzschia palea
249' Cell 70-180(i long Nitzschia linearis
250(247') Cell longitudinally unsymmetrical in valve view 251
250' Cell longitudinally unsymmetrical in girdle view Achnanthes microcephala
251 (250) Raphe bent toward one side at the middle Amphora ovalis
251' Raphe a smooth curve throughout (Cymbella) 252
252 (2511) Cell only slightly unsymmetrical Cymbella cesati
(246)
252' Cell distinctly unsymmetrical 253
253 (2521) Striations distinctly cross lined; width lO-SOp Cymbella prostrata
253' Striations indistinctly cross lined; width 5-12[i Cymbella ventricosa
254 (2441) Longitudinal line (raphe) and prominent marginal markings near both edges of valve 255
254' No marginal longitudinal line (raphe) nor keel; raphe or pseudoraphe median 257
255 (254) Margin of girdle face wavy Cymatopleura sole a
255' Margin of girdle face straight (Surirella) 256
256 (255') Cell width 8-23y Surirella ovata
256' Cell width 40-60(i Surirella splendida
257 (254) Gridle face generally in view and with two or more prominent longitudinal lines. In valve
view, swollen central oval portion bounded by a line. (Tabellaria) 258
257' Girdle face with less than two prominent longitudinal lines. In valve view, whole central
portion not bounded by a line 259
258 (257) Girdle face less than 1/4 as wide as long Tabellaria fenestrata
258' Girdle face more than 1/2 as wide as long Tabellaria floccutosa
259 (257') Valve face with both coarse and fine transverse lines Diatoma vulgare
259' Valve face with transverse lines, if visible, alike in thickness 260
260 (259') Valve face naviculoid; true raphe present 261
260' Valve face linear to linear-lanceolate; true raphe absent 270
261 (260) Valve face with wide transverse lines (costae) (Pinnularia) 262
261' Valve face with thin transverse lines (striae) 263
262 (261) Cell 5-6j» broad Pinnularia subcapitata
262' Cell 34-50(1 broad Pinnularia nobilis
263 (261') Transverse lines (striae) absent across transverse axis of valve face
Stauroneis phoenicenteron
263' Transverse lines (striae) present across transverse axis of valve face. 264
264 (263') Raphe strictly median (Navicula) 265
264' Raphe located slightly to one side 252
265 (264) Ends of valve face abruptly narrowed to a beak Navicula exigua var. capitata
265' Ends of valve face gradually narrowed 266
266 (2651) Most of Striations strictly transverse Navicula gracilis
266' Most of Striations radial (oblique) 267
19
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267 (266') Striae distinctly composed of dots (punctae) Navicula lanceolata
267' Striae essentially as continuous lines 268
268 (2671) Central clear area on valve face rectangular Navicula graciloides
268' Central clear area on valve face oval 269
269 (268') Cell length 29-40(i; ends slightly capitate. Navicula cryptocephala
269' Cell length 30-120|i; ends not capitate Navicula radiosa
270 (2601) Knob at one end larger than at the other (Asterionella) 189
270' Terminal knobs if present equal in size (Synedra) 271
271 (270') Clear space (pseudonodule) in central area Synedra pulchella
271' No pseudonodule in central area 272
272 (271'} Sides parallel in valve view; each end with an enlarged nodule Synedra capitata
272' Sides converging to the ends in valve view 273
273 (272') Valve linear to lanceolate-linear; 8-12 striae per lOp Synedra ulna
273' Valve narrowly linear-lanceolate; 12-18 striae per 10^ 274
274 Valve 5-6|j wide. Synedra acus
274' Valve 2-4^ wide 275
275 (2741) Cells up to 65 times as long as wide; central area absent to small oval. . .
Synedra acus var. radians
275' Cells 90-120 times as long as wide; central area rectangular
Synedra acus var. augustissima
276 (232') Green to brown pigment in one or more plastids 277
276' No plastids; blue and green pigments throughout protoplast 284
277 (276) Cells long and narrow or flat 233
277- Cells rounded 278
278 (2771) Straight, flat wall between adjacent cells in colonies .Phytoconis botryoides
278' Rounded wall between adjacent cells in colonies 279
279 (2781) Cell either with 2 opposite wall knobs or colony of 2-4 cells surrounded by distinct mem-
brane or both 164
279' Cell without 2 wall knobs; colony not of 2-4 cells surrounded by distince membrane 280
280 (279') Cells essentially similar in size within the colony 281
280' Cells of very different sizes within the colony Chlorococcum humicola
281 (1591) Cells embedded in an extensive gelatinous matrix . Palmella mucosa
281' Cells with little or no gelatinous matrix around them (Chlorella) 282
282 (2811) Cells rounded 283
282' Cells ellipsoidal to ovoid Chlorella ellipsoidea
283 (282) Cell 5-10(1 in diameter; pyrenoid indistinct Chlorella vulgaris
283' Cell 3 -5n in diameter; pyrenoid distinct Chlorella pyrenoidosa
284 (2761) Cell a spiral rod 285
284' Cell not a spiral rod 286
285 (25) Thread septate (with crosswalls) Arthrospira jenneri
285' Thread non-septate (without crosswalls). gpirulina nordstedtii
286 '(172) Cells dividing in a plane at right angles to the long axis Coccochloris stagnina
(284')
286' (1721) Cells sperical or dividing in a plane parallel to the long axis (Anacystis) 287
287 (2861>^Cell containing pseudovacuoles Anacystis cyanea
287' {Jell not containing pseudovacuoles 288
20
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288 (287') Cell 2-&n in diameter; sheath often colored Anacystis montana
288' Cell 6-50|« in diameter; sheath colorless 289
289 (288') Cell 6-12j* in diameter; cells in colonies are mostly spherical Anacystis thermalis
289' Cell 12-50(i in diameter; cells in colonies are often angular. Anacystis dimidiata
E 21
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GREEN ALGAE, NON-FILAMENTOUS
Golenkinia
Pediastrum
Planktosphaeria
Dictyosphaerium
Polyedriopsis
E 22
-------
GREEN ALGAE, FILAMENTOUS
Spirogyra
E 23
-------
BLUE-GREEN ALGAE
Coccochloris
(Gloeothece)
Anacystis
(Chroococcus)
Lyngbya
Aphanizomenon
Schizothrix
Anabaena
Gomphosphaeria
Calothrix
Agmenellum
(Merismophedia)
24
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FLAGELLATE ALGAE
Chlorogonium
Pandorina
E 25
-------
DIATOMS
Cyclotella
(Valve View)
Cyclotella
(Girdle View)
Gomphonema
(Valve and Girdle View
Navicul
(Girdle Vie
Nitzsehia
E 26
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Ill SELECTED REFERENCES
Cocke, E. C. 1967. The Myxophyceae of North Carolina, Edwards Bros.,
Ann Arbor, Mich. 206 p.
Fogg, G. E. 1965. Algal cultures and phytoplankton ecology. Univ.
Wisconsin Press, Madison, Wis. 126 p.
Jackson, D. F. (ed. ). 1964. Algae and man. Plenum Press, N. Y. 434 p.
Leedale, G. F. 1967. Euglenoid flagellates. Prentice-Hall, Englewood
Cliffs, N. J. 242 p.
Palmer, C. M. 1959- Algae in water supplies. U. S. Public Health
Service Publication No. 657. U. S. Gevernment Printing Office,
Washington, D. C. 88 p.
Palmer, C. M. 1963. The effect of pollution on river algae. Ann. N. Y.
Acad. Sci. 108(2): 389-395.
Palmer, C. M. 1967. Algae and associated organisms in West Virginia
waters: problems and control measures. Castanea 32: 123-133.
Palmer, C, M. 1967, Biological aspects of water supply and treatment
in Virginia with particular reference to algae. Virginia Jour. Sci. ,
18(N.S. 1): 6-12.
Patrick, R. andC. W. Reimer. 1966. The diatoms of the United States.
Vol.1 Acad. Natural Sciences of Philadelphia, Monograph 13.
Philadelphia, Pa. 688 p.
Prescott, G. W. 1968. The algae: a review. Houghton Mifflin, Boston,
Mass. 436 p.
Round, F. E. 1965. Biology of the algae. St. Martin's Press, N,Y, 269 p.
Smith, G. M. 1950. The fresh-water algae of the United States. 2nd Ed.
McGraw-Hill, N. Y. 719 p.
Taft, C. E. 1965. Water and algae - world problems. Educational
Publishers, Chicago, 111. 236 p.
E 27
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MO LLUSCA
William H. Heard
I INTRODUCTION
The fresh waters of the southeastern United States contain a diverse
assemblage of gastropods ( = snails) and pelecypods ( = clams). Some
species, and even some genera, are known to be confined only to certain
regions or specific drainage systems, while others are quite widespread
in distribution. On the other hand, the distribution of some groups is
poorly and inadequately known (e.g. , bythiniid snails which, because of
their minute size, are frequently overlooked or ignored).
The taxonomic characters employed in the identification of mollusks
often appear somewhat inconsistent. Sometimes features of the shell are
used, while in other instances soft-part anatomical characters define the
taxa. Consequently, keys to the identification of mollusks are difficult to
compose and also, at least initially, difficult to use. In the present treat-
ment, separate keys to the snails (univalved) and clams (bivalved) are
provided. Only the most striking or unique shell characters are employed,
except when soft-part characters alone are applicable.
T e chnique s
All collections of freshwater mollusks should be treated in such a
manner as to preserve and present the available soft-part characters,
while at the same time keeping the shell characters intact. This is not
always done, and frequently one set of characters is destroyed or rendered
unusable.
The first step is narcotization (the relaxation of the living animals in
as life-like a position as possible, and to such an extent that they do not
contract when fixed). This may be accomplished by a variety of reagents
(see Runham, Isarankura, and Smith, 1965), although menthol crystals or
Nembutal ( = Diabutal = sodium pentabarbitone) are most commonly used.
Menthol crystals are simply sprinkled on top of the water in the container
holding the animals. Nembutal can be applied either in the ^concentrated
form or as a 1 °/o or 10 °/o solution added in varying amounts (initially
determined by trial and error) to the water surrounding the animals.
-------
When the animals, partially extended from the shells, no longer re-
spond (by contraction) to poking or stroking with a probe, they are ready
for the next step, fixation. A number of different histological fixatives
can be used to kill the animals. Bouins fluid, Lavdowsky's mixture ( =
AFA = acetic acid/formalin/ethyl alcohol), or 10 °/o formalin are the
standard fixatives ordinarily used. However, each will serve to decalcify
the shell, destroying the accompanying characters. This harmful effect
can be neutralized by adding MgCOj or CaCCX, to the fixative.
After fixation, the animals are subjected to preservation, ordinarily
with 70°/o ethyl alcohol (although 70 °/o isopropyl alcohol or l°/o propylene
phenoxetol may be used instead).
The final product is an animal showing minimal contraction and with-
drawl into the shell. The shell is unharmed, and the soft-parts are also
available for the dissection of the reproductive system and/or the prepara-
tion of radular mounts for additional aid in identification (especially to the
specific level).
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II KEYS TO THE FRESH WATER MOLLUSCA OF THE SOUTHEASTERN UNITED STATES
CLASS GASTROPODA (SNAILS)
The following keys for identification of the genera of freshwater snails of the southeastern
United States are modified from those in Walker (1918), Baker (1928), and Pennak (1953) and
from the descriptions by Clench (in Edmondson, 1959).
KEY TO THE FAMILIES OF FRESHWATER SNAILS
Animal without an operculum (Subclass Pulmonata) 2
1' Animal with an operculum (Subclass Prosobranchia) 5
2 (1) Shell spirally coiled 3
2' Shell a flattened cone Ancylidae
3 (2) Shell extended, coiled in either of two planes (Fig. 1) 4
3' Shell falttened, coiled in a single plane or nearly so (Fig. 19) Planorbidae
4 (3) Shell coiled dextrally (aperture on right when spire is upright) (Figs, la-b) Lymnaeidae
4' Shell coiled sinistrally (aperture on left when spire is upright) (Fig. Ic) Physidae (Physa)
Fig. 1. Gastropoda, a. Dextral view of Fossaria cubensis (Lymnaeidae); b. Dextral view
of Pseudosuccinea columella (Lymnaeidae); c. Sinistral view of Physa (Physidae). (a, aperture;
sp, spire).
5 (!') Operculum with concentric growth lines (Figs. 2a-b).
5' Operculum with spiral growth lines (Figs. 2c-e)
Fig. 2. Gastropoda, a. concentric operculum; b. concentric operculum; c. spiral
operculum (multispiral form); d. spiral operculum (paucispiral form); e. spiral operculum
(subspiral-nucleus form) ,nu, nucleus).
-------
6 (5) Animal with one lung and one gill
7 <5')
7'
8 (7)
8'
Pilidae
Animal with one gill only Viviparidae
Operculum multispiral (Fig. 2c).
Operculum paucispiral (Fig. 2d).
Shell carinated or angulated (Fig. 3) Valvatidae (Valvata)
Shell smooth-sided g<=™s LY°RYrus of familY Bythiniidae
Fig. 3. Gastropoda, a. Dorsal view of Valvata tricarinata (Valvatidae); b. Dextral view of
Valvata tricarinata. (c, carina).
9 (71) Shell depressed, with a very broad parietal wall; restricted to the Alabama River system (Fig.
4) Neritidae
9' Shell rounded or extended, with a narrow parietal wall 10
Fig. 4. Gastropoda, a. Dorsal view of Lepyrium showalteri (Neritidae); b. Dextral view
of Lepyrium showalteri. (a, aperture; ap, apex; pw, parietal wall).
10 (9') Shell less than 5 mm high; male animal with an external verge (= penis) Bythiniidae*
10' Shell more than 10 mm high; males lacking a verge altogether Pleuroceridae
* The subfamily Pomatiosinae, containing Pomatiopsis and other related genera, is not
infrequently considered to warrant full family status, viz. , the Pomatiopsidae.
KEY TO THE GENERA OF THE PLEUROCERIDAE
1 Aperture canaliculate below (Figs. 5a-d) 2
I1 Aperture not canaliculate below {Figs. 6a-c) 5
2 (1) Shell fusiform, canal long; shell spinose to smooth-sided; confined to eastern Tennessee and
western Virginia (Fig. 5a) I°_
2' Shell conical, canal short 3
3 (21) Spire elongated (Fig. 5b).
3 ' Spire short
Pleurocera
4 (31) Parietal wall thickened, with a callous above and below (Fig. 5c) Lithasia
4' Parietal wall with a callous above only; limited to the Tennessee River system (Fig. 5d)
Eurycaelon
-------
-col
Fig. 5. Gastropoda. Dextral views of pleurocerid snails; a. lo; b. Pleurocera; c. Lithasia;
d. Eurycaelon. (spire eroded), (can, canal; cal, callous; sp, spire).
Fig. 6. Gastropoda. Dextral views of pleurocerid snails; a. Goniobasis; b. Anculosa
(spire eroded); c. Gyrotoma. (a, aperture; sp, spire; ss, sutural slit).
5 (1M
5'
6 (5'
-
i .~. Goniobasis
re elongated (Fig. 6a)
Spi
Spire short, shell somewhat globose.
. Anculosa
Aperture entire (Fig. 6b)
Aperture .with a sutural slit at the top; known only from the Coosa River, Alabama (Fig. 6c). . .
Gyrotoma
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KEY TO THE GENERA OF THE PILIDAE
Shell large, globose- turbinate; only occasionally banded (Fig. 7a) Pomacea
1> Shell discoid, planorbiform; usually banded; introduced into the Miami, Florida, area (Figs.
7b-c).
Marisa
Fig. 7. Gastropoda. Shells of pi lid snails; a. Dextral view of Pomacea paludosa; b. Dorsal
view of Marisa. cornuarietis_; c. Dextral view of Marisa cornuarietis. (ba, color band).
KEY TO THE GENERA OF THE VIVIPARIDAE
Operculum entirely concentric (Figs. 8a-b)
1' Operculum with subspiral nucleus (Figs. 8c; shell Fig. 9a).
Fig. 8. Gastropoda. Opercula of viviparid snails; a. concentric form of Viviparus and
Campeloma; b. concentric form of Tulotoma; c. subspiral-nucleus form of Lioplax. (im,
inner margin; nu, nucleus).
2 (1) Aperture round (shell Fig. 9b)
2' Aperture subangulated, sinuous, or incurved at base
.Viviparus
. .3
3 (2') Inner margin of operculum reflected, forming an elevated marginal fold (Fig. 8b); confined to
the Alabama River system (shell Fig. 9c) Tulotoma
3' Inner margin of operculum simple (shell Fig. 9d)
. Campeloma
-------
Fig. 9. Gastropoda. Shells of viviparid snails; a. Lioplax; b, Viviparus; c. Tulotoma;
d. Campeloroa.
KEY TO THE GENERA OF THE BYTHINIIDAE
Operculum paucispiral (Fig. lOa) 2
1' Operculum multispiral (Fig. 10b; shell Fig. lla) Lyogyrus
Fig. 10. Gastropoda. Opercula of southeastern bythiniid snails; a, paucispiral form; b.
multispiral form (Lyogyrus only).
2 (1) Foot divided at anterior third by a transverse sulcus (shell Fig. lib) Pomatiopsis
Foot simple, undivided 3
Fig. 11. Gastropoda. Shells of bythiniid snails; a. Lyogyrus; b. Pomatiopsis.
G 7
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3 (21) Columella thickened (Fig. 12a) 4
3' Columella not thickened (Fig. 12b) £
Fig. 12. Gastropoda. Dextral views of bythiniid snails; a. Somatogyrus; b. Amnicola.
(col, columellar thickening).
4 (3) Shell widely umbilicate (Figs. 13a-b) Clappia
4' Shell imperforate (Fig. 13c) or narrowly perforate . . 5
Fig. 13. Gastropoda. Shells of bythiniid snails; a. Dextral view of Clappia clappi; b. Ventral
view of Clappia clappi; c. Dextral view of Notogillia. (u, umbilicus).
5 <4') Aperture subcircular; outer lip thickened (Fig. 14a) Notogillia
5' Aperture oblique; outer lip thin (Fig. 14b) Somatogyrus
Fig. 14. Gastropoda. Dextral views of bythiniid snails; a. Notogillia; b. Somatoeyrus
(ol, outer lip of aperture).
G 8
-------
6 (3')
6'
'
7'
Shell smooth, periphery of whorls rounded or relatively straight-sided (Figs. 15a-c) 7
Periphery of whorls angulated, carinated, or with spines (Figs. 16a-b) 9
Shell slender; body whorl about as long as spire (Fig. 15a) Paludestrina*
Shell rather ventricose; body whorl longer than spire (Figs. 15b-cl 8
-
-bw
Fig. 15. Gastropoda. Dextral views of bythiniid snails; a. Paludestrina; b. Amnicola; c.
Littoridina. (bw, body whorl; sp, spire).
8 (7M Periphery of whorls convex (Fig. 15b) Amnicola
Periphery of whorls flattened, giving the spire a flat-sided appearance (Fig. 15c). . . Littoridina
9 (61) Shell spinose (Fig. 16a) Pomatopyrgus
9' Shell angulated or carinated (Fig. 16b) Pyrgulopsis
Fig. 16. Gastropoda. Dextral views of bythiniid snails; a. Pomatopyrgus; b. Pyrgulopsis.
(c, carina; sn, spine).
* These groups have been considered by some authors to represent subgenera of the genus
Hydrobia.
-------
KEY TO THE GENERA OF THE ANCYLIDAE
Shell planorbiform (Fig. 17a) or neritiform (Fig. 17b-c); restricted to the Alabama River
system
I1 Shell patelliform (Fig. 18a-c) 3
2 (1) Shell planorbiform (Fig. 17a) Neoplanorbis
21 Shell neritiform (Figs. 17b-c) Amphigyra
Fig. 17. Gastropoda. Shells of ancylid snails; a. Dextral view of Amphigyra alabamensis
(planorbiform); b. Dorsal view of Neoplanorbis (neritiform); c. Ventral view of Neoplanorbis.
(a, aperture; ant, anterior direction; ap, apex; cav, cavity).
3 (I1) Shell and apex unicolored 4
3' Shell with pink apex Rhodacmea
4(3) Apex near posterior margin of she 11; with a horizontal septum in maturity (Fig. 18al.Gundlach.ia
4' Apex only slightly posterior; lacking a horizontal septum 5
5 (4T) Radial striations present around apex (Fig. 18b) Ferrissia
5' Apex without radial striations (Fig. 18c) Laevipex
Fig. 18. Gastropoda. Shells of patelliform ancylid snails; a. Ventral view of Gundlachia;
b. Dorsal view of Ferrissia; c. Dorsal view of Laevipex. (ant, anterior direction; ap, apex;
cav. cavity; hs, horizontal septum; rs, radial striation).
-------
KEY TO THE GENERA OF THE LYMNAEIDAE
Spire elongated, as long or longer than the height of the aperture (shell Fig. la) Fossaria
Spire acute, much shorter than the elongated aperture (shell Fig. Ib) Pseudosuccinea
KEY TO THE GENERA OF THE PLANORBIDAE
1 Interior of aperture armed with several teeth or lamellae (Figs. 19a-b) .Planorbula
I1 Interior of aperture without lamellae or'teeth 2
2 (I1) Shell, large, greatest diameter more than 10 mm (Figs. i9c-d) Helisoma
2' Shell small, greatest diameter less than 10 mm 3
3 (2') Periphery of shell rounded (Figs. 19e-f) Gyraulus
3' Periphery of shell carinate (Figs. 19g-h) Promenetus
Fig 19 Gastropoda. Shells of planorbid snails (a. c. e. and g. : dextral views; b. d. f. and
i. : dorsal views); a. and b., Planorbula; c. and d., Helisoma; e. and f. , Gyraulus; g, and h. .
Promenetus. (c, carina; t, tooth).
i I
-------
ALPHABETICAL LIST OF GENERA
Subclass Prosobranchia
FAMILY BYTHINIIDAE
Amnicola (Figs. 12b, 15b)
Clappia clappi * (Figs. 13a-b)
Littoridina (Fig. 15c)
Lyogyrua (Figs. lOb, lla)
Notogillia (Figs. 13c, 14a)
Paludestrina (Fig. 15a)
Pomatiopsjg (Fig. lib)
Pomatopyrgua (Fig. 16a)
Pyrgulopsis (Fig. 16b)
Somatogyrua (Figs. 12a, 14b)
FAMILY NERITIDAE
Lepyrium showalteri* (Fig. 4)
FAMILY PILIDAE
Marisa (Figs. 7b-c)
Pomacea (Fig. 7a)
FAMILY PLEUROCERIDAE
Anculosa (Fig. 6b)
Eurycaelon (Fig. 5b)
Goniobasis (Fig. 6a)
Gyrotoma (Fig. 6c)
lo fluvialis* (Fig. 5a)
Lithaaia (Fig. 5c)
Pleurocera (Fig. 5b)
FAMILY VALVATIDAE
Valyata** (Fig. 3)
FAMILY VIVIPARIDAE
Campeloma (Fig. 8a, 9b)
Lioplax (Figs. 8c, 9a)
Tulotoma (Figs. 8b, 9c)
Viviparus (Figs. 8a, 9b)
Subclass Pulmonata
FAMILY ANCYLIDAE
Amphigyra alabamensis* (Fig.
17a)
Ferrissia (Fig. 18b)
Gundlachia (Fig. 18a)
Rhodacmea (not illustrated)
Laevipex (Fig. 18c)
Neoplanorbis (Figs. 17b-c)
FAMILY LYMNAEIDAE
Fossarja (Fig. la)
Pseudosuccinea (Fig. Ib)
FAMILY PHYSIDAE
Physa (Fig. Ic)
FAMILY PLANORBIDAE
Gyraulus (Fig. 19e-f)
Helisoma (Fig. 19c-d)
Pianorbula (Figs. 19a-b)
Promenetus (Figs. 19g-h)
*
**
mono specific, i.e. , the only species in the genus.
Valvata tricarinata is the only species likely to be encountered. It is rare in the
Tennessee River system, and while there are some museum records of this species
from Georgia and Alabama they may be erroneous.
CLASS PELECYPODA (CLAMS)
The freshwater clams inhabiting North America comprise four families, viz. , Corbiculidae,
Margaritiferidae, Sphaeriidae, and Unionidae. Corbicula manilcnsis (Corbieulidae), an introduced
asiatic species, is found in the western states, the Ohio and Tennessee River systems, and all
major Gulf Coastal streams from the Mississippi River east to the Hillsborough River in the Florida
peninsula. Margaritifera hembeli (Margaritiferidae) is an extremely rare species confined to specific
tributaries (viz. , Patsaliga Creek, Burnt Corn Creek, and Murder Creek) of the Conecuh (-Escambia)
River drainage in south-central Alabama and to Bayou Teche, Louisiana. Cumberlandia monodonta
(Margaritiferidae), also very rare, is known principally from the Cumberland and Tennessee drainages
in Tennessee. The family Sphaeriidae contains 35-40 species in North America, and 18 of these occur
in the southern states where four genera are represented (Heard, 1963, 1965). The most conspicuous,
widespread, and abundant group of freshwater clams in the southeast is the family Unionidae, contain-
ing 40 genera in the area.
G
12
-------
The following keys have been adapted largely from Pennak (1953). Keys to the identification of
freshwater clams are all but impossible (particularly for the Unionidae), but Pennak's key is by far
the best, and in addition to the biological information provided there are also some fine photographs
of representative species of the different genera. Clench (in Edmondson, 1959) does not provide keys
but illustrates representatives of the genera and gives rather complete characterizations of each.
KEY TO THE FAMILIES OF FRESHWATER CLAMS
1 Shell non-nacreous; hinge with cardinal and lateral teeth (Fig. la) 2
1' Shell nacreous; hinge with lateral and pseudocardinal teeth (Fig. Ib) or lacking teeth
altogether (= edentulous) , 3
Fig. 1. Pelecypoda. Interior views of left valves (anterior to the right); a. Corbicula manilensii:
(Corbiculidae); b. Proptera purpurata (Unionidae). (al, anterior lateral tooth; ct, cardinal
teeth; It, lateral teeth; pi, posterior lateral tooth; pt, pseudocardinal teeth).
2 (1) Hinge with cardinal and smooth lateral teeth (Fig. 2a)
2' Hinge with cardinal and serrated lateral teeth (Fig. 2b) Corbiculidae
. Sphaeriidae
(Corbicula)
Fig 2 Pelecypoda. Interior view of valves; a. left valve of Sphaerium (Sphaeriidae); b.
iEht valve'of Corbicula (Corbiculidae). (sm, smooth lateral tooth; se, serrated lateral tooth).
right v
3 (I') Gills with distinct interlamellar septa either parallel with (Fig. 3) or perpendicular to
(Strophitus) to the gill filaments
Gills without interlamellar septa or, when present, oblique to the gill
Unionidae
Margaritiferidae
13
-------
Fig. 3. Pelecypoda. Frontal section of a unionid gill, (f, filament; s, interlamellar
septum; wt, water-tube).
KEY TO THE GENERA OF THE SPHAERIIDAE
Shell nearly equipartite, beaks subcentral (just anterior of center) (Fig. 4a) 2
Shell inequipartite, anterior end longer (beaks posterior of center) (Fig. 4b) Pisidium
Fig. 4. Pelecypoda. Exterior views of sphaeriid clams (anterior to the right); a. Sphaerium;
b. Pisidium. (b, beak = umbo = umbone; ce, center of shell).
2 (1) Nepionic valves not distinctly separated from the rest of the shell (Fig. 5a) 3
2' Nepionic valves usually inflated, usually separated from subsequent shell growth by a
distinct sulcus (Fig. 5b) Musculium
Fig. 5. Pelecypoda. Enterior views of sphaeriid clams (anterior to the right); a. Eupera;
b. Musculium. (nv, nepionic valve; su, sulcus).
14
-------
3 (2) Shell oval, relatively thick; right valve with one, and left valve with two cardinal teeth (shell
Fig. 4a) Sphaerium
3' Shell subrhomboidal, thin, and usually mottled; just one cardinal tooth in each valve (shell
Fig. 5a) Eupera
KEY TO THE GENERA OF THE MARGARITIFERIDAE
1 Gills lacking interlamellar septa Margarltifera
I1 Interlamellar septa oblique to the gill filaments Cumberlandia
KEY TO THE UNIOIDAE
In this group, commonly called mussels or freshwater oysters, some genera are defined by shell
characters while others are dependent upon features of the soft-parts (e. g. , the morphological nature
of the marsupial gills). The fanally has been divided into several subfamilies; the somewhat conserva-
tive use of three such groupings will be followed here.
It is impossible to construct a single key to all genera of unionid clams. Consequently, a separate
key to the genera of each of the three subfamilies is provided. In addition to the characters employed
in the following key to the subfamilies, other distinguishishing features of these three groups will be
listed with the keys to the genera.
KEY TO THE SUBFAMILIES
1 Water-tubes of marsupial gills simple, undivided (see (Fig. 3) 2
1' Water-tubes of marsupial gills divided into three chambers Anodontinae
2 (1) Entire outer gills only, or both inner and outer pairs of gills marsupial (contain the glochidial
larvae) .Unioninae
2' Only specific portions of the outer pair of gills marsupial Lampsilinae
The Subfamily Unioninae
Short-term breeders (i. e. , gravid only during the summer); glochidia spineless, parasitic on the
gills of fishes; sexual dimorphism in the shell only in Tritigonia; marsupium either (1) filling the entire
outer pair of gills and forming smooth pads (homogenae), or (2) filling all four gills entirely, forming
smooth pads (tetragenae).
1 All entire four gills serving as marsupia (Fig. 6a). . . .
I1 Entire outer gills only serving as marsupia (Fig. 6b).
Fig. 6. Pelecypoda. Transverse views of unionid clams showing locations of marsupial gills
in the subfamily Unioninae; a. all four gills marsupial; b. only outer gills marsupial, (ft, foot;
m, mantle; mg, marsupial gill; nmg, non-marsupial gill).
G
15
-------
2 (1) Male and female shells alike
2' Male and female shells different (Fig. 7) Tritigonia
Fig. 7. Pelecypoda. Exterior veiws of the right valves of Tritigonia verrucosa (Unionidaei
Unioninae) showing sexual dimorphism; a. female shell; b. male shell.
3 (2)
3'
4 (3')
4'
5 (4)
5'
Surface of shell smooth Fusconaia
Surface of shell sculptured, not smooth '
Surface of shell pustulose (Fig. 8)
Surface of shell plicate (Figs. 9, 10) °
Shell with prominent, projecting beaks (Fig. 8a) Quadrula
Beaks projecting only slightly (Fig. 8b); 2 species in the Gulf drainages from the Suwannee t
the Choctawhatchee River, Florida Quincuncma
Fig. 8. Pelecypoda. Exterior views of the right valves of unionid clams (both Unioninae); a.
Quadrula; b. Quincuncina. (b, beak = umbo = umbone; p, pustule).
6 (4') Posterior ridge of shell prominent (Fig. 9) 7
6' Posterior ridge of shell absent or poorly-defined 8
7 (6) Entire surface of nacre purple (shell Fig. 9a) Plectomerus
7' Nacre purple only outside the pallial line; interior is white (shell Fig. 9b); confined to the
Ochlockonee and Apalachicola River systems in Georgia and Florida Elliptoideus
16
-------
Fig. 9. Pelecypoda. Exterior views of the right valves of unionid clams (both Unioninae)- a
Plectornerus dombeyanus; b. Elliptoideus sloatianus_. (pc, plication; pr, posterior ridge).
Sculpturing on shell surface not extending anterior of beaks (Fig. 10a); short-ter
m breeders. . .
Amblema
Sculpturing extending anterior of beaks (Fig. lOb); long-term breeders' '.'.'.'.'.'.'.'.'.'. ^Megalonai
b \* ^
Fig. 10. Pelecypoda. Exterior views of the right valves of unionid clams (both Unioninae);
a. Amblema; b. Megalonaias. (pc, plication).
Fig. 11. Pelecypoda. Exterior views of the right valves of unionid clams (both Unioninae); a.
Cyclonaias tuberculata; b. Plethobasus. (p, pustule; tu, tubercle).
G 17
-------
9 (I1) Surface of shell pustulose (Fig. lla) or tuberculose (Fig. lib).
9' Surface of shell smooth or prominently spined
.10
]
10 (9) Shell rounded (Fig. lla); nacre purple
10' Shell irregularly oval (Fig. lib); nacre white or tinged with pink Plethobasus
11 (9') Hinge with well-developed pseudocardinal and lateral teeth
11' Hinge teeth imperfect, vestigial; a single, rare species in the Ohio, Cumberland, and
Tennessee River drainages (shell Fig. 12) Hemilastena
Fig. 12. Pelecypoda. Exterior view of right valve of Hemilastena lata (Unionidae: Unioninae).
12 (11) Shell short; rounded, quadrate, oblique, trapazoidal, triangular or rhomboidal in shape of
outline 13
12' Shell usually elongated and straight 14
13 (12') Shell subquadrate or subtrapezoidal; beaks only slightly elevated (shell Fig. 13a); distribution
confined largely to Virginia and North Carolina Lexingtonia
13' Shell triangular to rhomboid; usually with prominent beaks (shell Fig. 13b); one species, P.
collina of the James River, Virginia, possesses spines Pleurobema
Fig. 13. Pelecypoda. Exterior views of the right valves of unionid clams (both Unioninae);
Lexingtonia; b. Pleurobema. (b, beak = umbo = umbone).
14 (12') Shell elongated rhomboidal or slightly oval (shell Fig. 14a); one species, E_. (Cantnyria) spinosa
of the Altamaha River, Georgia, possesses very prominent spines .Elliptio
14' Shell trapezoidal (Fig. 14b) Uniomerus
Fig. 14. Pelecypoda. Exterior views of the right valves of unionid clams (both Unioninae);
a. Elliptio; b. Uniomerus.
18
-------
The Subfamily Anodontinae
Long-term breeders (i.e. , gravid except during the summer); glochidia with spines, usually
parasitic on fins of fishes; no sexual dimorphism in shell; entire outer pair of fills marsupial
(homogenae, digenae); water-tubes (see Fig. 3) divided into 3 chambers.
1 Beak sculpture concentric (Fig. 15a). . . .
I1 Beak sculpture double-looped (Fig. ISbt.
Fig. 15. Pelecypoda. Frontal (top) views of the left valve of unionid clams (Anodontinae); a.
concentric beak sculpture; b. doubl«-looped beak sculpture, (b, beak = umbo = umbone).
2 (1) Beak sculpture fine; hinge edentulous (lacking teeth) Anodontoides
2' Beak sculpture coarse; hinge teeth present 3
3 (Z1) Shell rhomboidal, with prominent posterior ridge; pseudocardinal teeth prominent, laterals
reduced or absent (shell Fig. 16a) Alasmidonta
3' Shell elliptical to rhomboid, with low posterior ridge; pseudocardinal teeth vestigial, laterals
absent (shell Fig. 16b) Strophitus
Fig. 16. Pelecypoda. Exterior views of right valves of unionid clams (both Anodontinae); a.
Alasmidonta; b. Strophitus. (pr, posterior ridge).
4 (I1) Hinge entirely edentulous .Anodonta
4' Hinge teeth more or less developed; pseudocardinal teeth present, laterals present,
rudimentary or absent 5
5 (41) Beak sculpture tubercular, continuous on the disc. Arcidens
Beak sculpture not tubercular; surface of shell smooth, or costate on the posterior slope 6
6 (5') Pseudocardinal teeth (2 in the left valve, 1 in the right) fully developed; length of shell greater
than 60 mm Lasmigona
6' Only a single pseudocardinal tooth in each valve; shell length less than 60 mm . Simpsoniconcha
The Subfamily Lampsilinae
Long-term breeders (i.e. , gravid except during the summer); glochidia spineless or axe-head
shaped (Proptera), parasitic on gills of fishes; sexual dimorphism in shells frequent, often very
marked; only restricted portions (location variable) of outer pair of gills marsupial (heterogenae,
eschatigenae, mesogenae, ptychogenae).
1 Male and female shells alike 2
1' Male and female shells different
-------
Fig. 17. Pelecypoda. Exterior views of right valves of a. lampsiline unionid showing sexual
dimorphism; a. male; b. female.
2 (1) Shell elongate-triangular (Fig. 18a); lateral teeth thickened Ftychobranchus
2' Shell rounded-triangular or oval; lateral teeth not thickened 3
3 (2M Shell oval, with a single vertical row of large tubercles on the center of each valve (Figs. 18b-
c) Obliquaria
Shell rounded-triangular, with nodulously-wrinkled or lachrymose sculpture 4
Fig. 18. Pelecypoda. Exterior views of unionid clams (all Lampsilinae); a. right valve of
Ptychobranchus; b. right valve of Obliquaria reflexa; c. transverse view of Obliquaria reflexa.
(t, tubercle).
4 (31) Sculpture of shell nodular, radiately-wrinkled. or lachrymose; beak cavities shallow, con-
fined to the Ohio, Cumberland and Tennessee River systems (shell Fig. 19a) Cyprogenia
4' With a series of humps running from the beaks to the central part of the base of the shell,
which is otherwise sculptured by irregular ridges; beak cavities deep; limited to the Cumberland
and Tennessee drainages (shell Fig. 19b) Conchodromus
Fig. 19. Pelecypoda. Exterior views of the right valves of unionid clams (both Lampsilinae);
a. Cyprogenia irrorata; b. Conchodromus dromas. (h, hump; n, nodule).
20
-------
5 (!') Female shell expanded behind the middle of the base
5' Female shell only slightly swollen just behind the middle of the base Medionidus
6 (5) Nacre purple; dorsal margin of shell winged, or not winged; pseudocardinal teeth
heavy, thick and broadly triangular (Fig. 20a) Proptera
6' Nacre white; dorsal margin of shell winged (Fig. 20b), or not winged; pseudocardinal teeth
either lamellar (Fig. 20b), laminar (Fig. 20c), or complete and well-developed 7
7 (6') Pseudocardinal teeth thin and lamellar (Fig. 20b) Leptodea
7 ' Pseudocardinal teeth prominent and well-developed *
iz 20 Pelecypoda. Interior views of the left valves of unionid clams (all Lampsilinae);
: b Llptodea; c. ^lebula rotundata. ,pt, pseudocardinal teeth; w, wing).
8 (7') Pseudocardinal teeth divided into irregular radiating laminae (Fig. 20c); restricted to Gulf
drainages from Florida to Texas
8' Pseudocardinals complete, not divided
9(8') Shell with a well-marked posterior ridge; dorsal slope smooth . .
Shell usually without a distinct posterior ridge, or, if distinct, then the dorsal slope wit ^ ^
radiating sculpture
10 (9) Hinge and teeth heavy and strong; epidermis with scattered, broken rays (Fig. 2la); up toJOO^
10' "andTetth "small,' comparatively weak;' epidermis of some species with a pattern of con-
tinuous, broken, or arrow-marked rays; up to 60 mm in length (shell Fig. 21b) Truncilla
Fig. 21. Pelecypoda. Exterior views of the right valves of unionid clams (both Lampsilinae);
a. Plagiola lineolata; b. Trucilla; (r, ray).
11 (9') Marsupial expansion of female shell of same texture as rest of shell (Fig 22a) ... . . , .. . 12
n Marsupial expansion of female shell of different texture than rest of shell, usually "^^
sculptured (Fig. 22b).
i: i
-------
Fig. 22. Pelecypoda. Exterior views of the right valve of unionid clams (both Lampsilinae);
a. Conradilla caelata; b. Dysnomia. (me, marsupial expansion of female shell).
12 (11) Inner edge of mantle in front of branchial opening (- incurrent siphon) differentiated into
papillae or flaps in the female (see Fig. 23) 13
12' Inner edge of female mantle not so produced, lacking papillae and flaps 17
13 (12) Shell smooth 14
13' Shell strongly sculptured on posterior half of shell (Fig. 22a); confined to the Tennessee River
system Conradilla
14 (13) Female with 2 well-developed caruncles (one on each'side) on the inner edge of the mantle in
front of the branchial opening (Fig. 23a); shell length usually less than 30 mm Carunculina
14' Females lacking caruncles; shell length greater than 50 mm . . 15
15 (14') Mantle of female distinctly papillate in front of branchial opening (Figs. 23b-c) 16
15' Female of mantle not distinctly papillate in front of branchial opening, but always with a pair
of ribbon-like flaps (Fig. 23d) Lampsilis
Fig. 23. Pelecypoda. Modifications of the mantle in front of the branchial opening in certain
lampsiline unionid clams; a. Carunculina; b. Villosa^ c. Ligumia; d. Lampsilis. (ant, anterior;
bo, branchial opening = incurrent siphon; car, caruncle; fl, flap; Ipa, large papillae; spa, small
papillae).
22
-------
16 (15)
16'
17 <12')
17'
Papillae of female mantle irregular, consisting of large and small elements (Fig. 23bV...ViUosa
Papillae of female mantle small and regular (Fig. 23c) Ligumia
Shell inflated, about as high as long
Shell subcompressed. clearly longer than high
.Obovaria
Ha)
9b)
ALPHABETICAL LIST OF GENERA
FAMILY CORBICULIDAE
Cqrbicula. (Figs, la, 2b)
FAMILY MARGARITIFERIDAE
Cumberlandia monodonta*
Margaritifera
FAMILY UNIONIDAE
Subfamily Unioninae
Amblema (Fig. 10a)
Cvclonalas tuberculata* (Fig.
Elliptio (Fig. 14a)
ElUptoideua sloatianus* (Fig.
Fusconaia (not illustrated)
Hemilastena lata* (Fig. 12)
Lexingtonia (Fig. 13a)
Mejjalonaias (Fig. 10b»
Plectomerus dombeyanus* (Fig. 9a)
Plethobasug (Fig. lib)
Pleurobema (Fig. I3b)
Quadrula (Fig. 8a)
Quin<:uncin» (Fig. 8b)
T_ritieacia vfiimcosa* (Fig. 7)
Uniomerua (Fig. 14b)
Subfamily Anodontinae
Alaamidonta (Fig. 16a)
Anodonta
Anodontoideg
Arcidena
Laamigona
Simpaonieoncha ambigua»
Strophitug (Fig. 16b)
Subfamily Lampsilinae
Actinonaias
Carunculina (Fig. Z3«l
Conchodromua dromas* (Fig. 19b)
Conradilla caelata (Fig. 22a)
Cyprogenia irrorata* (Fig. 19a)
Dysnornia (Fig. 22b)
Glebula rotundata* (Fig. 20c)
LampalliB (Fig. 23d)
Leptodea (Fig. 20b)
Ligumia (Fig. 23c)
Medionidus
Obliquaria reflexa*
-------
MARSUPIAL CONDITIONS IN THE UNIONIDAE
1. tetragenae: marsupium filling all 4 gills entirely, forming smooth pads; some Unioninae;
2. homogenae: Marsupium filling the entire outer pair of gills and forming smooth pads; some
Unioninae and most Anodontinae;
3. digenae: marsupium filling the entire outer gills, ovisacs running crosswise; only Strophitus
of Anodontinae;
4. heterogenae: marsupium confined to posterior parts of outer gills; most Lampsilinae;
5. eschatigenae: marsupium occupying the outer border of the outer pair of gills; only Conchodrpmus
of Lampsilinae;
6. mesogenae: marsupium consisting of a few ovisacs in the central parts of the outer pair of
gills; only Cyprogenia and Obliquaria of Lampsilinae;
7. ptycho^enae: marsupium occupying the entire outer pair of gills in a series of folds; only
Ptyehobranchus of Lampsilinae;
24
-------
Ill SELECTED REFERENCES
Baker, F. C. 1928. The Fresh Water Mollusca of Wisconsin. Parti.
Gastropoda. Bull. 70, Wise. Geol. Nat. Hist. Surv; , 507p. ; Part
II. Pelecypoda. ibid, 495p.
Clench, W. J. 1959. Mollusca, p. 1117-1160. In Edmonson, W. T. (Ed.)
Fresh-water biology. John Wiley and Sons, New York.
and K. J. Boss. 1967. Freshwater Mollusca from James
River, Virginia, and a new name for Mudalia of authors. Nautilus.
80: 99-102.
and R. D. Turner. 1956. Freshwater mollusks of Alabama,
Georgia, and Florida from the Escambia to the Suwannee River. Bull.
Fla. State Mus. 1: 97-239.
Goodrich, C. 1930. Goniobases of the vicinity of Muscle Shoals. Occ.
Pap. No. 209, Univ. Mich. Mus. Zool. 25p.
. 1936. Goniobasis of the Coosa River, Alabama. Misc.
Publ, No. 31, Univ. Mich. Mus. Zool. 6lp.
. 1941. Pleuroceridae of the small streams of the Alabama
River system. Occ. Pap. No. 427, Univ. Mich. Mus. Zool. lOp.
1941. Distribution of the gastropods of the Cahaba River,
Alabama. Occ. Pap. No. 428, Univ. Mich. Mus. Zool. 30p.
. 1942. The Pleuroceridae of the Atlantic Coastal Plain.
Occ. Pap. No. 456, Univ. Mich. Mux. Zool. 6p.
Heard, W. H. 1963. Survey of the Sphaeriidae (Mollusca: Pelecypoda)
of the southern United States. Proc. La. Acad. Sci. 36: 102-120.
. 1965. Recent Eupera (Pelecypoda: Sphaeriidae) in the
United States. Amer. Midi. Nat. 74:309-317.
Herrington, H. B. 1962. A revision of the Sphaeriidae of North America
(Mollusca: Pelecypoda). Misc. Publ. No. 118, Univ. Mich. Mus.
Zool. 74p.
Neel, J. K. , and W. R. Allen. 1964. The mussel fauna of the upper
Cumberland Basin before its impoundment. Malacologia 1: 427-459-
25
-------
Ortmann, A. E. 1918. The naiades of the upper Tennessee drainage with
notes on synonomy and distribution. Proc. Amer. Phil. Soc. 57:
521-626.
. 1924. The naiad-fauna of Duck River in Tennessee.
Amer. Midi. Nat. 9: 18-62.
. 1925. The naiad-fauna of the Tennessee River system
below Walden Gorge. Amer. Midi. Nat. 9: 321-373.
Pennak, R. W. 1953. Fresh water invertebrates of the United States.
Ronald Press Company, New York 769 p.
Runham, N. W. , K. Isarankura, andB. J. Smith. 1965. Methods for
narcotizing and anaesthetizing gastropods. Malacologia 2; 231-238.
van der Schalie^H. 1938. The naiades (fresh-water mussels) of the
C ah aba River in northern Alabama. Occ. Pap. No. 392, Univ. Mich.
Mus. Zool. 29p.
. 1939. Medionjdus mcglameriae, a new naiad from the
Tombigbee River, with notes on other naiades of that drainage. Occ.
Pap. No. 407, Univ. Mich. Mus. Zool. 6p.
. 1939. Additional notes on the naiades (fresh-water
mussels) of the lower Tennessee River. Amer. Midi. Nat. 22: 452-
457.
. 1940. The naiad fauna of the Chipola River, in north-
western Florida. Lloydia 3: 191-208.
Walker, B. 1918. A synopsis of the classification of fresh-water Mollusca
of North America, North of Mexico, and a catalogue of the more
recently described species, with notes. Misc. Publ. No. 6, Univ.
Mich. Mus. Zool. 213p.
26
-------
OLIGOCHAET A
R. O. Brinkhurst
I INTRODUCTION
This group of animals h&s the reputation of being amongst the most •
difficult to identify. This is partly because people believe it to be
necessary to section every specimen before a complete identification can
be made. By making the keys to the most important family (the
Tubificidae) proce.ed directly to species without keying out the genera, it
has become possible to identify specimens from simple whole-mounts.
About half of the Tubificidae may now be identified from immature specimens,
but mature specimens are required for the rest. This may sound as
though it raises difficulties, but fortunately mature specimens are almost
always present in any community. It should also be remembered that these
worms are hermaphrodite, and there are no larval stages. Add to this
the fact that there are fewer than forty important species known from the
North American continent in fresh waters east of the Rockies, and the
traditional attitude towards determing oligochaetes seems to be redundant.
It is still necessary for the systematist to be able to dissect these small
worms and to study serial sections in attempting to describe new species
and place them in the appropriate genera, but once having done this the
species can often be fitted into its place in the key using only the superficial
characters that can be seen in a whole-mount.
With representatives of the Lumbriculidae the problems in part remain
true. Many of the characters cannot be determined without dissection, but
the family is of limited importance both in terms of the number of species
known and the number of specimens usually found at any one site. The
single exception is a species that resembles a tubificid in appearance and
can be readily identified under a stereoscopic microscope, and even this
is apparently limited to the Great Lakes drainage in North America.
As in all keys, obtaining good results depends on knowing the proper
mode of preparation and examination of material and an understanding of
the salient anatomical features used in the key. No amount of time spent
chasing about the key in growing frustration will ever compensate for failure
to read the preamble to a key.
When all else fails read the instructions!
-------
Preparation of Material
The worms may be killed and preserved in 70°/o alcohol with the ex-
ception of Branchiura sowerbyi which tends to fragment. Luckily this is
the one oligochaete which is immediately recognisable in the field. This
must be narcotised in 5 °/o magnesium chloride before preservation.
Preserved worms may be stored in 70°/o alcohol. When required for
identification, they should be transferred to 30°/o alcohol and then to water.
They are next placed on a slide in a few drops of Amman's lactophenol,
prepared as follows:
Carbolic acid 400 g
Lactic acid 400 ml
Glycerol 800 ml
Water 400 ml
The worms should be covered with a cover slip and left in this fluid
for several hours before examination. The time will depend on the size
and maturity of the specimen. Just before examining, slight pressure on
the cover slip will flatten the specimen and render the important features
more readily visible.
If a permanent preparation be required, the Amman's lactophenol can
be replaced by polyvinyl lactophenol. When this has dried sufficiently the
preparation should be ringed, preferably in 'Glyceel'.*
The preparations should be left to clear properly--often a re-examina-
tion of a difficult specimen after a week or two makes an identification
possible.
Identification becomes progressively easier with increasing quality of
the microscope used.
Examination of Whole Mounts
The first point to remember about the anatomy of the oligochaetes is
that the first segment is devoid of setae (Text Fig. 1 ) which are otherwise
arranged in four bundles on each segment, two dorsolateral (termed dorsal)
bundles and two ventro-lateral (termed ventral) bundles (Stephenson, 1930).
In many Naididae the dorsal bundles begin on a more posterior segment in
fully developed specimens. It should, however, be stressed that when
* Products prepared by GURR - available at most laboratory suppliers.
-------
asexual reproduction occurs daughter individuals are budded off, and these
frequently develop the most anterior segments last of all, so that some
specimens may appear to have the dorsal setae starting in segment II when
they are quoted in the key as being more posterior. With practice, these
worms can be recognised as detached asexually-produced forms, from the
absence of the prostomium, and in any case the parent specimen is usually
present in the collection.
The principle features to study are the setae. These may be of several
types. In determining the various sorts of setae in a specimen, dorsal and
ventral setal bundles from several regions of the body should be examined.
Hair setae are more or less elongate slender filaments, present in all
bundles in the Aeolosomatidae and only in the dorsal bundles of many
Naididae and Tubificidae. They sometimes bear fine lateral hairs which
are employed in the key to the Naididae but ignored in the Tubificidae where
they are difficult to see. They are usually broad in the tubificid genus
Peloscolex.
Bifid crotchets are found in both dorsal and ventral bundles in the
Naididae, Tubificidae and Lumbriculidae. They are S-shaped structures
with the distal end bifurcate, and it is the form of these teeth and their
Secondary annulation
Dorsal setal bundles
I
2 Ventral setal bundles
Text Fig. 1. The anterior end of an oligochaete worm (Limnodrilus
hoffmeisteri) to show the relationship between the segments and the
setal bundles. Note that setae are absent from segment I.
-------
relative length which is commonly referred to in the key. The distal ends
of some bifid crotchets are seen in Text Fig. 2.
Sometimes the teeth become reduced so that the seta appears to be
simple-pointed, occasionally with a trace of the reduced tooth visible.
Others again are clearly simple-pointed with no trace of any teeth.
In the Enchytraeidae the setae are broad, and practically always
simple-ended, and usually numerous, radiating fanwise, and are similar
in the dorsal and ventral bundles, whereas in the Naididae and Tubificidae
such uniformity is less common.
Pectinate setae are typical of the dorsal anterior bundles of many
Tubificidae. These are essentially bifid crotchets with a series of fine
intermediate teeth between the two usual teeth. The intermediate spines
may be as large as the outer teeth, e.g. in Psammoryctes barbatus and
Tubifex costatus so that the seta has a broad palmate distal end.
Genital setae are associated with the spermathecal or penial pores in
many Naididae and Tubificidae. They are frequently used in identifying
Tubificidae, where the spermathecal pores are found on segment X and
the male pores on segment XI (the setae therefore being those of the ninth
and tenth ventral bundles respectively) in all but a few species to which
specific reference is given in the key. The setae are missing in immature
worms.
Setae other than hair setae usually have a more or less median
swelling called the nodulus.
The following are the commonest combinations of setae found in the
various families:
Aeolosomatidae Hair setae in both dorsal and ventral bundles
of all species, a single bifid crotchet in mid
and posterior bundles of Aec^lpsoma tenebjra-
rum and in A. beddardi.
Naididae Either ventral setae only (Chaetogaster);
or dorsal and ventral bundles with bifid
crotchets only;
or dorsal bundles with crotchets and
hair setae, ventrals with crotchets;
or dorsal bundles with one simple seta
-------
Tubificidae
per bundle, ventrals bifid crotchets
(Opbidonais serpentina).
Either dorsal and ventral bundles with bifid
crotchets only;
or dorsal bundles (at least anteriorly)
with hair setae and pectinate setae,
ventrals bifid;
or dorsal bundles with hair setae, dorsal
and ventral bundles with bifid crotchets.
Enchytraeidae
Lumbriculidae
All bundles with broad, simple-ended setae.
Two setae in each bundle, usually indistinctly
bifid with the upper tooth reduced, or simple-
pointed.
'Earthworm" families Two setae per bundle, simple-pointed.
Haplotaxidae
B ranchiobdellidae
One seta per bundle, sickle-shaped; the
ventral setae are much larger than the
dorsals which may be absent in most
posterior segments.
Setae absent; a few toothed plates.
The cuticular penis-sheaths referred to in the key are found in seg-
ment X of tubificids. They are absent in immature specimens.
Biology
Several of the families mentioned above need not really concern us
too much here. Perhaps the best way to indicate the relative importance
of the various families is to list the approximate number of species known
from freshwater habitats east of the Rocky Mountains, and the sort of
habitats in which they are normally found.
Aeolosomatidae
Eight species recorded (Brinkhurst and Cook, 1966).
These small worms, with their ciliated prostomium (the projection
in front of the mouth that is presegmental) and often with spots of colour
-------
in the otherwise transparent colorless body, are usually only noticed in
aquaria. Their length is usually measured in millimeters, and their
delicate bodies are not usually noticed in preserved samples. The ecology
of the group is largely unknown.
Naididae
About thirty-five species (Brinkhurst, 1964)
Representatives of this family are also small, usually less than two
centimeters long, but they form chains of individuals that may appear
longer. Whilst some are found in muddy sediments in ponds and lakes,
some are associated with algae or higher plants. These species are
obviously common in ponds, canals and quiet stretches of rivers, and
protected bays in lakes. Naidids are often an important part of the fauna
of small stony streams where tubificids are less abundant.
Some of the species have a pair of simple eyes, an unusual feature
for an oligochaete, and several have a long projection of the prostomium
called a proboscis, a feature found in some lumbriculids (which are much
larger worms) but not found in tubificids.
Tubificidae
Thirty-one species have been reported in fresh water in the eastern
U.S.A. (Brinkhurst, 1965).
These are the red "sludge worms" sold as fish-food in aquarium stores
and found in such abundance in organically polluted situations where they
often coat the entire surface of the sediment. These worms, usually but
not always more than two centimeters long, often coil around the meshes
of nets and screens, and may coil into a grub-screw shape in a dish. When
exposed to the light in a dish they usually form a ball with the heads hidden
in the center and the tails projecting.
The family is of considerable ecological importance in sandy or muddy
sediments in lakes and rivers. Many species may be regarded as pollution
indicators once their identity has been established. The abundance of
species such as L. hoffmeisteri in relation to other tubificid species and the
abundance of tubificids in relation to the other benthic organisms are use-
ful indices of pollution. Such indices may be used to detect the nature and
source of pollution as well as the degree of damage caused (Brinkhurst,
1966, 1968).
-------
Enchytraeidae
These worms are mostly the same size as the tubificids, but the
body wall seems stiffer, less transparent in many specie's, and others
may occupy saturated soils. The identification of species in this family
depends on the examination of the soft parts as well as the setae, and at
present those who work with them prefer to have living material to study.
They are not of great importance to biologists using organisms as in-
dicators of water quality, however, and so no attempt will be made to
provide keys here. There is no recent review of the American represen-
tatives of the family in any case, and so it is only necessary to learn to
separate them from tubificids, which is a very simple matter.
Lumbriculidae
Eight species, several more from western localities only.
Most of these worms are longer, thicker and more robust than the
tubificids or enchytraeids. They are intermediate in size between these
smaller aquatic worms (such as the familiar Tub if ex) and an average
earthworm. Like the earthworms, there are only two setae in each
bundle, either simple-pointed or bifid with only a very weak upper tooth.
Only two species are at all common. Lumbriculus variegatus is of
variable length, but is often several centimeters long. It fragments
readily. The front end often has a greenish hue in life, but the rest of
the worm is red. The setae are indistinctly bifid. The body of the
worm is somewhat unusual in shape in that it does not seem to taper
towards the tail, but remains much the same thickness throughout.
Mature worms are scarce.
This worm is frequent in shallow water amongst leaves, sticks,
stones and rooted plants but it may also be found in other sorts of
habitats.
The second important lumbriculid is Stylodrilus heringianus, a
tubificid-sized worm which is separable from members of that family
by the pair of setae in each bundle and the finger-like soft penes pro-
jecting from the tenth segment (ninth setigerous segment) on the ventral
side. This worm may have been introduced from Europe, where it is
common in stony substrata in unproductive rivers and lakes for the most
part.
-------
e
Text Fig. 2. a. setae of Lumbriculus varlegatus; b. seta and
c. penes of Stylodrilus herjngianus; d. dorsal and e. ventral
setae of Haplotaxis gordioides.
The single species Haplotaxis gordioides is the only representative of
the family likely to be encountered. It has never been identified for
certain from North America, but immature worms resembling it have
been found in a number of places. The species is very long (up to 30 cm),
very thin, and has a large prostomium with a transverse groove. The
setae are very unusual, with large single setae (or paired when new setae
are developing) in the ventral bundles which are sickle-shaped. The
dorsal setae are small, straight, and are often missing from a number of
anterior bundles. The species is very rare, mature specimens even
rarer.
Opi s t o cy s tidae
Worms belonging to this family are small, again very rare. They
are immediately recognisable as the rear end bears two lateral processes
of variable length and a median prolongation of the body. There is one,
(possible two) American species according to Dr. W. J. Harman, Louisiana
State University.
B r anchiobd e llidae
This family consists of parasites of crayfish. -They have no setae and
are ho longer classified as oligochaetes.
8
-------
REPRODUCTIVE ORGANS
The figure shows the basic plan of the genitalia in the majority of the
Tubificidae. The paired spermathecae lie in segment 10 together with the
paired testes. Spermathecae are absent in Bothrioneurum, Sperm may
be free in the spermathecae, or gathered into bundles called spermato-
phores.
spermataphore
Spermatheca
Anterior
spermsac
Posterior
spermsac
Eggsac
u
Ovary
'Vas deferens
Female
Testis
Male P°re
pore
Clitellum
Text Fig. 3. A generalized plan of the genitalia of a tubificid.
The sperm sacs are developed from the intersegmental septae 9/10
and 10/11, the posterior sperm sacs entering the egg-sacs on the interseg-
mental septum 11/12. The posterior sperm sacs and the egg sacs may
project through several segments, i.e. from segment 10 to segment 12 or
13. The sperm funnels lie in segment 10 but most of the vas deferens
lies in segment 11 (except in some species of Bothrioneurum where it is
partly recoiled in the tenth segment). The vas deferens may be elongate,
and it then partly fills the posterior egg sac on each side. A solid pro-
state gland may be attached to the atrium by a short stalk. In some genera
there is a series of separate prostate cells ensheathing the vas deferens
or the atrium. Sometimes there is an ejaculatory duct between the atrium
and the male pore. There may or may not be a true penis, which may or
may not be ensheathed in cuticle. The ovaries lie close to the vas defer-
ens, on the intersegmental septum 10/11, in segment 11. The oviducts are
-------
very short, passing through the septum 11/12 to open at the anterior
end of segment 12.
10
-------
II KEY TO FAMILIES OF FRESHWATER OLIGOCHAETES
^
may be of more immediate use than this formal key
«~^
the preceeding section ma be f de8CriPtlO
1
Setae absent. Ectoparasitic on crayfish ............ Rr^nX- K,I HM
1- Setae present, or if absent (Achaeta, Enchytraeidae) then worm free living.'.'. 2
2 ai> Ion" than.2 se.tae per bundle: hair setae present or absent- Worms usually less
2' One or two setae per bundle (rarely 4 when replacement' setae Vre developing');' no hair ....... 3
setae. Worms mostly more than 3 cm long .......................... ' 5
3 (2) Hair setae in both dorsal and ventral bundles. Worms less than 10 mm long. Prostomium
ciliated. Prominent oil droplets in most species ............. Aeolosomatidae
3 ' Hair setae in dorsal bundles only or absent. Usually more than'l'o' mm long.' ' Prostomium
not ciliated. No prominent oil droplets.
4
4 (31) Asexual reproduction forming chains of individuals. More or less transparent.
Spermathecae in segment 4, 5, or 7; male pores on segment 5, 6, or 8. Usually less than
Z cm long. Some species with eyes. Pectinate setae never nresent Naididae
4 Asexual reproduction uncommon, never forming chains of individuals. Spermathecae in
segment X; male pores on.egment XI. Usually longer than 2 cm. Most species red and
coiling tightly when disturbed. No eyes. All types of setae present. . .. Tubificidae 1
..,, " ' ,' -see key to species
4 No asexual reproduction. Spermathecal pores on segment V; male pores on segment XII Of
similar size to Tubificidae but whitish-pink, and mostly terrestrial in habit. No eyes.
Chaetae usually straight and broad with a simple tip (but absent in Achaeta and bifid in
Propappus). Enchytraeidae
5 (21) Setae 1 per bundle; the dorsal setae frequently absent in posterior segments, and when
present much smaller than the ventrals. Very long, thread-like worms Haplotaxidae
5' Setae 2 per bundle, all alike ^
6 (5') Small worms, mostly 10-40 mm long and less than 3 mm broad. Body more or less transpar-
ent when alive, so that the internal organs and blood vessels are readily visible. The blood
vessels make the worms bright red in colour. Male genital pores usually on segment X, but
may be more anterior where regeneration has occurred Lumbriculidae
6' Much larger and thicker worms, i. e. the familiar earthworms and their relatives. Body wall
thick and muscular so that the internal organs are invisible and the worms are pink in colour.
Male pores more posterior in position Various families of "earthworms'! . .
Some aquatic species
Key to the Tubificidae of Eastern North America including the St. Lawrence Great Lakes
1 Posterior segments with dorsal and ventral gill filaments (Fig. la) Branchiura sowerbyi
1' No gill filaments. 2
2 (I1) Hair setae present, at least anteriorly 3
2' Hair setae absent 19
3 (2) Body wall covered in a crust of cuticular material together with foreign material, often in the
form of papillae Peloscolex (in part). 4
3' Body wall naked 7
4 (31) Papillae in two rows per segment, one row of very large papillae in the line of the setae, the
other row of smaller papillae between the setal lines. Up to fourteen hair setae in anterior
bundles (Fig. Ib) Peloscolex multisetosus
4' Papillae, when fully developed, thickly covering the body with the exception of a few anterior
segments which are introvertible. . . 5
5 (41) All ventral setae bifid (Fig. Ic) Peloscolex ferox
5' At least some ventral setae simple pointed in anteriormost bundles 6
6 (51) Simple pointed setae in ventral bundles of II-IV only, posterior ventral setae normally sigmoid,
spermathecal setae absent (Fig. Id) Peloscolex variegatus
6' Simple pointed setae in ventral bundles of II-VII or DC, each bundle with one simple pointed
seta and one bifid seta, posterior ventral bundles with single setae with rudimentary upper
11
-------
tooth, distal end strongly curved over the shaft , spermathecal setae present (species not
found in Great Lakes) (Fig. 2a). Peloscolex carolinensis
Fig. 1. Tubificidae. a. Branchiura sowerbyi: posterior end, showing gills, b. Peloscolex
multisetoBus (typical form): pectinate setae, anterior and posterior ventral setae. In variant form
the posterior ventral setae resemble the anterior ones. c. P. ferox: pectinate setae, anterior and
posterior ventral setae, d. P. variegatus anterior, ventral simpje pointed and bifid setae, and a
posterior seta.
7 (3')
7'
8(7)
8'
Pectinate setae absent
Pectinate setae present
Mid and posterior setal bundles beyond VII with hair setae and oar shaped setae. Ventral
setae with short upper teeth (Fig. 2b) Aulodrilus piqueti
No oar setae. Ventral setae with upper teeth only slightly shorter than the upper (Fig. 2c)..
Potamothrix vejdovskyi
9 (71) Pectinate setae with reduced upper tooth and only one or two intermediate teeth of the same
size as the upper tooth (Fig. 2d) Aulodrilus pluriseta
9' Pectinate setae with two large lateral teeth, a series of smaller intermediate teeth which
may be more or less fused together 10
Fig. 2. Tubificidae. a. P. carolinensis: setae of ventral bundles on anterior to median seg-
ments, b. Aulodrilus pigueti: dorsal setae of median segment, c. Potamothrix veidovskvi:
dorsal setae of median segment, d. Aulodrilus pluriseta: dorsal setae.
10 (9) Genital setae present in mature specimens, cuticular penis sheaths absent : 11
10' Genital setae absent, cuticular penis sheaths present 15
11 (10) Several blunt tipped penial setae in ventral bundles of XI with tips closely applied. Coelom
full of coelomocytes .12
11' Hollow ended spermathecal setae in ventral bundles of X 14
12 (11) Lateral teeth of pectinate setae very long, almost parallel, intermediate teeth indistinct,
very thin (Fig. 3a) Rhyacodrilus sodalis
12' Pectinate setae with diverging teeth, the upper tooth often thinner than the lower,
pectinations distinct 13
12
-------
m«rT !i' TflflCldae- a" Rhyacodrilus sodalis: anterior and median pectinate setae, anterior.
median and P°"t.rior ventral setae, penial setae, b. R. coccineus: pectinate, penial setae (de ail
and general) and faintly pectinate ventral seta (a common vlrTaHolTin many species), c A
coeiomocyte.
13 (12'
13'
14 (II1)
14'
Hair setae absent beyond median segments. Pectinate setae with upper tooth longer than or
as long as the lower (Fig. 4b) Rhyacodrilus coccineus
Hair setae present posteriorly as well as anteriorly, very long hair setae in II. Pectinate
setae often with the upper tooth much longer than the lower (Fig. 4a). . . Rhyacodrilus montana
Spermathecal setae long with hollow tips (Fig. 4b) Potamothrbc hammoniensis
Spermathecai setae relatively short, broad beyond the nodulus, narrowing distally (Fig. 5a). . .
Potamothrix bavaricus
Fig. 4. Tubificidae. a. II. montana: anterior and median pectinate setae, anterior and
posterior ventral setae, b. Potamothrix hammoniensis: Spermathecal seta, anterior ventral seta,
dorsal pectinate, ventral pectinate (variant).
15 (10') Hair setae very long and thin, much longer than the very narrow body of the worm in median
segments (Fig. 5b) Tubifex ignotus
15' Longest hair setae in anterior segments, not exceptionally long 16
Fig, 5. Tubificidae. a. ^. bavaricus: dorsal pectinate seta, anterior ventral seta, Spermathecal
seta. b. Tubifex ignotus: ventral seta, pectinate seta. c. Peloscolex superiorensis: pectinate
setae, ventral setae, penis sheath.
13
-------
16 (151) Penis sheaths thin walled, tub shaped (Fig. 6a) Tubifex tubifex
16' Penis sheaths elongate, conical or cylindrical 17
17 (16') Penis sheaths cylindrical, with basal part reflected, broad terminal opening (Fig. 5c)
Peloscolex superiqrensis
17' Penis sheaths regular or irregular cone shaped, opening oblique or lateral 18
18 (17') Penis sheaths broad at the base, narrowing abruptly, with pointed distal end, lateral opening. .
(Fig. 6c) Tubifex kessleri americanus
18' Penis sheaths truncated cones, opening subterminal, oblique (Fig. 6b)
Ilyodrilus templetoni
Fig. 6. Tubificidae. a. Tubifex tubifex: pectinate setae, anterior ventral seta, penis sheath.
b. Ilyodrilus templetoni: penis sheath, anterior ventral seta. c. Tubifex kessleri americanus:
pectinate dorsal, pectinate anterior and posterior ventral setae, penis sheath.
19 (21) Inhabiting mud tubes. Anterior setae simple pointed, posterior setae broadly palmate (Fig. 7a)
Aulodrilus americanus
19' Not inhabiting mud tubes. Setae bifid 20
20(19') Prostomium with a pit. Spermathecae absent, sperm bearers attached externally (Fig. 7b).
Bothrioneurum veidovskyanum
20' No prostomial pit. Spermathecae present 21
21 (201) Genital setae present in mature specimens. 22
21' Genital setae absent 25
22 (21) Spermathecal setae on IX, penial setae on XI (not found in the Great Lakes) (Fig. 7c)
Monopylephorus lacteus
22' Spermathecal setae on X, no penial setae 23
Fig. 7. Tubificidae. a. Aulodrilus americanus: anterior dorsal seta, median dorsal
seta. b. Bothrioneum yejdovskyanum: prostomium, dorsal and ventral view showing pit,
seta and penial seta. c. Monopylephorus lacteus: Spermathecal seta (on IX), penial setae.
14
-------
23 (22') Spermathecal setae relatively large and broad. No cuticular penis sheaths (Fig. 8b)
. Potamothrix moldaviensis
23' Spermathecal setae thin. Cuticular penis sheaths present, but thin 24
24 (231) Posterior ventral setae with upper tooth reduced, distal end curved over the shaft. Penis
sheaths thin, indistinct (Fig. 8a) Psammoryctides curvisetoaus
24' Posterior ventral setae with upper tooth thinner than but more or less as long as lower.
Penis sheaths bluntly conical with reflected base (Fig. 9a) Peloscolex freyi
Fig. 8. Tubificidae. a. Psammoryctides curvisetosus: anterior, median and posterior
setae Spermathecal seta. b. Potamothrix moldaviensis: Spermathecal seta, penis.
25 (21') Cuticular penis sheaths absent. Up to 10 setae per bundle with upper teeth thinner and shorter
than the lower, median and posterior setae with lateral keels (Fig. 9b). . .Aulodrjlus limnobius
25' Cuticular penis sheaths present. Setae normally fewer, with upper teeth not usually much
shorter and thinner than the lower, often as long as or longer than the lower, no lateral keels .
26
Fig. 9. Tubificidae. a. Peloscolex freyi: setae, Spermathecal seta, penis sheath, b.
Aulodrilus limnobius: lateral and facial view of seta, median segment.
26 (25') Penis sheaths short, tub shaped (Fig. 6a) Tubifex newaensis
26' Penis sheaths more or less elongate, cylindrical 27
27 (261) Anterior setae at least with upper teeth much longer than the lower (Fig. lla)
Limnodrilus udekemianus
27' Anterior setae with upper teeth as long as the lower or shorter, if longer then not so
markedly longer or as thick .
28
28 (27') Penis sheaths when fully developed at least forty times longer than broad . . . .............. 29
28' Penis sheaths normally less than fourteen times longer than broad ........................ 31
29 (28) Penis sheaths with two layered walls, head with forward and backward projections in
typical specimens (Fig. lOa) .Limnodrilus
.
29' Penis sheaths thin or thick walled but with a single layer, head without backward Projection.-30
30 (29') Walls of penis sheaths very thick, lumen relatively wide, heads large with shaft set ex-
centrically in head (Fig. lOc)
Limnodrilus maumeensis
30' Walls of penis sheaths thin, head small, triangular (Fig. lOb) Limnodrilus claparedeanus
15
-------
31 (28') Penis sheaths broad at the base, narrowing toward the head, head reflected over shaft (Fig.
lOe) Limnodrilus angustipenis
31" Penis sheaths cylindrical, narrowing only slightly towards the head 32
Fig. 10. Tubificidae. a. Lamnodrilus cervix, penis sheaths, b. _L. claparedeanus: penis
sheaths (clap, /cervix intermediate on left), c. L. maumeensis: penis sheath, d. L.
hoffmeisteri: penis sheath, e. L.. angustipenis: penis sheath, f. L. hoffmeisteri: penis
sheath (variant).
32 (31') Penis sheaths up to fourteen times longer than broad, head variable, frequently set at right
angles to the shaft(Figs. lOd, f) Limnodrilus hoffmeisteri
3Z1 Penis sheaths up to seven times longer than broad, head reflected over shaft (unless forced
forward) (Fig. lib) T * "~" «—-"--
. Limnodrilus profundicola
Fig. 11. Tubificidae.
penis sheath.
a. L. udekemianus: penis sheath, anterior seta. b. L. profundicola:
16
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Ill SELECTED REFERENCES
Brinkhurst, R. O. 1964. Studies on the North American aquatic
Oligochaeta I: Naididae and Opistocystidae. Proc. Acad. Nat.
Sci. Philadelphia 116: 195-230.
1965. Studies on the North American aquatic
Oligochaeta II: Tubificidae. Proc. Acad. Nat. Sci. Philadelphia
117: 117-172.
1966. Detection and assessment of water pollution
using oligochaete worms. Water and Sewage Works 113: 398-401,
438-441.
and D. G. Cook. 1966. Studies on the North American
aquatic Oligochaeta III: Lumbriculidae and additional notes and records
of other families. Proc. Acad. Nat. Sci. Philadelphia 118: 1-33.
, A. L. Hamilton, and H. B. Herrington. 1968. Com-
ponents of the bottom fauna of the St. Lawrence, Great Lakes. PR33,
Great Lakes Institute, Univ. of Toronto, Toronto. 49 p.
Stephenson, J. 1930. The Oligochaeta. Oxford University Press, London.
(The standard work in English on the morphology of the Oligochaeta).
I 17
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CRUSTACEA: MALACOSTRACA
Horton H. Hobbs, Jr.
I INTRODUCTION
This illustrated key reflects both the impoverished stage of our
knowledge of the freshwater Malacostraca occurring in the southeastern
United States and my own interest and better knowledge of the Decapoda.
Even in the treatment of the latter, however, there is considerable
imbalance (see below).
Four orders, isopoda, Amphipoda, Mysidacea, and Decapoda, are
represented in the fauna. The Isopoda inhabiting the region are assigned
to two families, the Spheromatidae and Asellidae; the former consists largely
of marine members, and only three species are known to have invaded the
fresh waters of the United States. The family Asellidae is confined to
freshwater habitats, but there is reason,to believe, on the basis of a re-
cently prepared monograph of-the North American members of the genus
Asellus by W. D. Williams, that the currently reported fauna includes no
more than one-half of the existing species. Inasmuch as Dr. Williams'
manuscript is ready to be submitted for publication, a key omitting the new
species described therein would be of little value. The genus Lirceus is
perhaps better known, but the most recent treatment of the genus is that
of Hubricht and Mackin, 1949.
The order Amphipoda is represented by two families, the Talitridae
(one species, Hyalella azteca) and the Gammaridae. Three genera, Gam-
marus, Crangonyx, and Synurella, of the latter family occur with some
degree of regularity in epigean waters of the southeast. Because specific
determinations of the freshwater amphipods is so difficult, the non-
specialist perhaps should not attempt identification beyond the generic level.
Only two species of the order Mysidacea occur within the fresh waters
of the United States, and, because their ranges do not approximate one
another, they may, with reasonable certainty, be distinguished on the basis
of their known distribution.
The order Decapoda has contributed many more species to the epigean
waters of the southeastern states than have the other orders, and the
Astacidae (crayfishes) far outnumber the Palaemonidae (shrimps) of which
only six species belonging to two genera (Palaemonetes and Macrobrachium)
frequent the surface waters. All of the palaemonids are included in the key.
K
-------
The Astacidae, because of their abundance and broad exploitations of
freshwater environments, dominate the key. All of the known epigean
species and subspecies of Procambarus, Cambarellus, Faxonella, and
Hobbseus found in the United States are included, as are all of the species
and subspecies of Orconectes which occur east of the Mississippi River.
(For aid in identifying those frequenting the area west of the River, re-
ference should be made to Greaser and Ortenburger, 1933; Penn, 1959;
Penn and Hobbs, 1958; Williams, 1954; and Williams and Leonard, 1952).
The genus Cambarus is treated less thoroughly than the others because
I have recently completed a manuscript, "On the Distribution and
Phylogeny of the Crayfish Genus Cambarus" in which keys are provided
for all its members. The publication should be available from the Virginia
Polytechnic Institute Press about January 1, 1969-
Because the Malacostraca of the southeastern part of the United
States are so incompletely known, a note of caution in the use of this key
seems appropriate. A number of undescribed species occur within the
area, and at least some of them may seem to fit couplets in the key, re-
sulting in misidentification. Consequently, most determinations based
solely on this key should be considered tentative until comparisons with
full descriptions or, perhaps better, with authoritatively determined
specimens have been made.
Not included in the key are such forms as the blue crab (Callinectes
sapidus Rathbun) and others which are more typically marine, but which
occasionally or, in some localities, even frequently invade fresh water.
The introduced "Saber crab", Platychirograpsus typicus Rathbun, which,
insofar as is known, is confined in the United States to the lower portions
of Hillsborough River, Florida, is likewise omitted. Also excluded from
this treatment are the albinistic (troglobitic) forms which occasionally
are found in epigean waters in or near the mouths of springs or in streams
issuing from underground water courses.
COLLECTING
Isopoda, Amphipoda, and Mysidacea. -- Although a variety of implements
may be utilized in collecting these animals, a fine-meshed (scrim) dipnet
or large seine usually provide satisfactory results if thrust into submergent
aquatic vegetation or masses of organic debris. Taphromy_s_is_ has been
observed repeatedly to congregate in numbers on sandy shoals of a spring
run (Wakulla River, Florida), and there can be secured in numbers with the
aid of a dipnet. Asellid isopods often cling to the lower surfaces of stones
or other objects littering the stream bottoms and can be removed easily with
the aid of forceps. The Sphaeromatidae are almost always found on or
boring into wood-- submerged tree litter, boards, or pilings.
-------
Palaemonidae. -- Members of the genus Palaemonetes may be
secured with the aid of a fine-meshed dipnet or a 1/4-inch-mesh seine.
Few, to my knowledge have employed traps for catching these shrimps,
and usually they are so easily caught with a dipnet that trapping them
hardly seems worth the effort. In contrast, Macrobrachium is perhaps
best obtained in inverted-cone traps baited with meat or vegetable meal.
In relatively clear water, where they are apparently rare in the United
States, they may be caught at night with the aid of a headlight --to reflect
their ruby-colored eyes -- and dipnet.
Astacidae. -- In streams and other bodies of water that are shallow
and not choked with vegetation, no implement provides better results than
a 1/4-inch-mesh seine. In streams, if the seine is anchored downstream
a few feet from the area to be sampled, and stones or debris are
vigorously turned or agitated, the animals will "swim" and be carried by
the current into the seine. Dragging the seine across pools or shallow
ponds is also often most effective. In vegetation-choked, or deep, bodies
of water, the use of wire traps with inverted cones and baited with meat
often net fair samples of the crayfish population, particularly if left in
the water overnight. D-ring dipnets are also useful in some environments.
Some of the most successful "crawfishing" done in the United States is
conducted in Louisiana where several modifications of a "lift net" is
employed. This net consists essentially of two V-shaped metal rods
(about six feet in length) tied together at the apices of the "V". The ends
of the rods are affixed to the corners of a square net, and a lift cord with
a float is attached at the juncture of the rods. The bait ( fish heads, scrap
pieces of chicken, etc.) is centered on the net below the juncture of the rods.
Several nets are then "set out" in a shallow slough or bayou, and the fisher-
man makes his way from one to another, quickly lifting the contraption and
removing the crayfish that have been attracted to the bait.
Collecting at night in shallow water is usually most rewarding in that
members of a number of species, most of the adults of which remain in
their burrows in the stream banks during the day, venture into open water
at night. A headlight for spotting their eyes and a small dipnet are indis-
pensable aids for collecting at night.
To collect the burrowing crayfishes that seldom, or never, invade
open water, four techniques have been found to yield some measure of
success. (1) The chimney should be removed, the burrow opened to the
water table, and the opening sufficiently enlarged so that one's hand may
be thrust below the water. If the water is thoroughly roiled and then left
undisturbed for 2 to 5 minutes, the occupant often comes to the opening
where its antennae may be seen at the surface of the water. The open hand
should be thrust into the opening to "pin" the crayfish against the wall of
the burrow. With careful manipulation, the crayfish can be seized with
-------
the fingers and withdrawn from the burrow. To avoid excessive digging,
frequently water can be poured into the burrow to elevate the water level.
(2) For those species which construct a single vertical passage with
only one or two openings to the surface, the use of a "yabby pump", which
was recently introduced to me at the Gulf Coast Research laboratory where
it was being employed in securing Callianassa, is often most helpful.
This device consists of a cast iron cylinder some three feet long and
about six inches in diameter, open at one end and closed, except for two
small holes (1/8 inch in diameter), at the other. Across the closed end
is a welded foot-long bar (the handle) situated perpendicular to the axis of
the cylinder. In places where the soil is sufficiently wet, the cylinder
may be forced (open end down) into the soil around the vertical passage to
a depth of one to three feet, then closing the two small holes with the
thumbs, it is lifted quickly. Frequently the crayfish, along with much of
its burrow, is removed from the substrate.
(3) To obtain some species, no substitute has been found for a
laborious dissection of the complex (branching) burrows with the naked
hand and the aid of a trowel or shovel. Gloves are almost useless, and,
if used, the crayfish is often crushed before one realizes that it has been
"cornered".
(4) Collecting at night involves the least labor. Particularly follow-
ing rains or when the humidity is high, the burrowing crayfishes come to
the mouths of the burrows and often leave them to wander over the surface
of the ground. With the aid of a headlight or some similar light source,
frequently they can be obtained in numbers.
PRESERVATION
Isopoda, Amphipoda, and Mysidacea. -- Specimens dropped directly
into 70 - 80 percent ethyl alcohol, unless crowded, become well-preserved.
Transferring them to fresh 70 percent alcohol after a few days will assure
long-time safe keeping.
Decapods. -- Crayfishes and shrimps are perhaps best killed in 6
percent formalin, and should remain in the solution, depending on size,
for 12 hours to a week. After being washed in running water for a few
hours, they should be transferred to 70 percent alcohol. Unfortunately,
no method has been devised to preserve coloration. If kept in darkness,
the colors fade more slowly, but most are lost after six months to a year.
Several groups of animals (e.g. , branchiodbellid worms, entocytherid
ostracods, and some harpacticoid copepods) have found the exoskeleton of
-------
the crayfish to provide a suitable substrate on which to live; also some
species occur nowhere else. These symbionts may usually be found in
numbers in the "sludge" on the bottom of the container in which the cray-
fishes are killed.
PREPARATION AND EQUIPMENT NEEDED FOR IDENTIFICATION
Isopoda, Amphipoda, and Mysidacea. -- For most generic determina-
tions, a stereoscopic microscope, forceps, and fine needles are necessities.
All examinations should be made with the specimens immersed in alcohol.
In order to make specific and some generic identifications, it is necessary
to remove certain appendages and to mount them on a microscope slide for
examination with the aid of a compound microscope. Glycerin is recom-
mended for temporary preparations.
Decapoda. -- For many of the decapods, a hand lens is adequate for
identifying the larger specimens; however, many of the smaller ones can-
not be adequately observed without the aid of a stereoscopic microscope.
Forceps, and fine needles are also indispensable tools.
/
Reliable identifications of.members of the genus Macrobrachium can
be made only if adult males with the second pair of pereiopods intact are
available. Such males may be recognized by the well-developed appendix
masculina on the second pleopod (Fig. la). Likewise, the novice should
not attempt to identify crayfishes other than the "first form" (breeding)
males except specimens from areas for which adequate illustrated keys
are available.
The present key to the crayfishes is applicable only to first form
males which may be distinguished from juvenile and second form males by
the presence of one or more corneous ("horny") terminal elements (pro-
jections) on the distal ends of the first pleopods (first abdominal ap-
pendages). These appendages, .in their usual position, extend from the
base of the abdomen forward between the bases of the walking legs and lie
against the sternum of the cephalothoracic region. The first pleopods of
juveniles and second form males have no corneous terminal elements and
these projections are usually much less well-defined, and all are of
similar texture.
The major characters utilized in identification are illustrated in
Figure 8, and details relating to most of them are shown in other figures
interspersed throughout the key. Of especial importance, however, is the
first pleopod for which a simple terminology is in general use. This
terminology is better illustrated than explained, and Figure 1 is substi-
tuted for a long discourse. Reference was made in the preceding paragraph
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Fig. 1. Pleopods of shrimp and crayfishes, a. Mesial view of
second right pleopod of Macrobrachium carcinus (modified from Chace
and Hobbs); b-i. first left pleopods of crayfishes; b. Mesial view of
generalized Procambarus; c. Lateral view of generalized
Procambarus; d. Mesial view of generalized Cambarellus; e. Lateral
view of generalized Cambarellus; f. Mesial view of generalized
Orconectes and Faxonella; g. Lateral view of generalized Orconectes
and Faxonella; h. Mesial view of generalized Cambarus and_Hobbseus:
i. Lateral view of generalized Cambarus and Hobbseus; (ai, appendix
interna; am, appendix masculina; c, cephalic process; d, caudal
process; e, endopodite; k, caudal knob m, mesial process; p,
central projection; s, shoulder; t, subterminal setae).
K
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to the fact that at least one "projection" at the end of the first pleopod
is always corneous in the first form male. If only one is corneous, it
is always the central projection. It may be seen that in the genus Pro-
cambarus (Fig. 1), frequently all four terminal elements are evident; in
most Cambarus and Orconectes and in all Faxonella, and Hobbseus,
only two (mesial process and central projection) are present, while in
Cambarellus there are three -- only the cephalic process is lacking.
For descriptive purposes, the first pleopod is considered to hang
pendant from the abdomen. Toward the attached end is considered
proximal; toward the free end, distal; the side toward the head, cephalic;
that toward the telson, caudal; that facing the corresponding pleopod of
the pair, mesial; and that facing the side of the body, lateral.
For some species groups, a hand lens provides adequate magnifica-
tion for examining the pleopods, but some of the members of the genus
Procambarus possess "subterminal setae" which arise from near the
distal end of the pleopod and partically or completely obscure the termina
elements. To make these elements clearly visible, the setae must be
removed. This can be done successfully only under magnification. It is
recommended that the left (CAUTION! the animal's left) pleopod be re-
moved and placed in a dish of alcohol under a stereoscopic microscope.
By holding the pleopod at its base with a pair of forceps, the setae may
be removed with a fine needle. This should be done carefully so as not
to injure or break one of the terminal elements. Then, if the pleopod
is oriented with the flattened mesial surface against the bottom of the
dish, it is in a position to be compared with the illustrations of the pleopod
included in the key.
Within the body of the key to the crayfishes, only a few references
are made to the ranges of the species; included, however, are lists of
species belonging to each genus together with the known ranges. Inas-
much as the key to the members of the genus Cambarus (beginning with
couplet 69) with two exceptions leads to species groups, the members of
this genus are arranged alphabetically in the several species groups.
For the remaining genera, species groups are disregarded, and all of the
members of each genus are arranged in a single alphabetical series.
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SPECIES LISTS AND RANGES
Genus Procambarus
Procambarus ablusus Penn, 1963. Streams in the Hatchie River system,
Mississippi and Tennessee.
Procambarus acutissimus {Girard, 1852). Most aquatic habitats in the
Tombigbee, Alabama, and Choctowhatcb.ee drainages in Alabama and
Mississippi.
Procambarus acutus acutus (Girard, 1852). Most aquatic habitats in
Coastal Plain and Piedmont from Massachusetts to Georgia and from
Florida panhandle to Texas and Minnesota to Ohio.
Procambarus advena (LeConte, 1856). Burrows in lower Coastal Plain be-
tween the Savannah River and northeastern Florida.
Procambarus alleni (Faxon, 1884). Most aquatic habitats east of St. Johns
River and all of peninsular Florida south of Levy and Marion counties.
Procambarus ancylus Hobbs, 1958. Most aquatic habitats in the Coastal
Plain between the Cape Fear and Combahee rivers in North Carolina
and South Carolina.
Procambarus angustatus (LeConte, 1856). Streams in "Georgia inferiore",
known only from a single type-specimen.
Procambarus apalachicolae Hobbs, 1942. Temporary bodies of water and
burrows in Bay and Gulf counties, Florida.
Procambarus barbatus (Faxon, 1890). Temporary bodies of water and
burrows in Coastal Plain between the Altamaha and Edisto rivers in
Georgia and South Carolina.
Procambarus bivittatus Hobbs, 1942. Streams and sloughs in Escambia and
Pearl river drainages in Florida and Louisiana.
Procambarus blandingii (Harlan, 1830). Most aquatic habitats between the
lower Santee and Pee Dee drainage systems in North Carolina and South
Carolina.
Procambarus chacei Hobbs, 1958. Streams from the Wateree River system
in South Carolina to the Canoochee River system in Georgia.
Procambarus clarkii (Girard, 1852). Most aquatic habitats from Texas to
Escambia County, Florida and north to southern Illinois. (Introduced
into peninsula Florida, California, Virginia, Hawaii, and Japan).
Procambarus dupratzi Penn, 1953. Streams in Red, Neches, Sabine, and
Calcasieu drainage systems in Arkansas, Louisiana, and Texas.
Procambarus echinatus Hobbs, 1956. Streams in Salkehatchie and Edisto
river systems in South Carolina.
Procambarus econfinae Hobbs, 1942. Temporary bodies of water and
burrows in the vicinity of Panama City, Bay County, Florida.
Procambarus enoplosternum Hobbs, 1947. Streams in Ohoopee drainage
system in Emanuel and Toombs counties, Georgia.
Procambarus epicyrtus Hobbs, 1958. Streams in lower Ogeechee drainage
8
-------
system, Georgia.
Procambarus escambiensis Hobbs, 1942. Temporary bodies of water and
burrows in Perdido and Escambia drainage systems in Alabama and
Florida.
Procambarus evermanni (Faxon, 1890). Most types of aquatic habitats in
Escambia and Santa Rosa counties, Florida, and Jackson County,
Mississippi.
Procambarus fallax (Hagen, 1870). Most aquatic habitats from the St.
Marys and Suwannee drainage systems, Georgia south to Manatee,
DeSoto, Glades, and Palm Beach counties, Florida.
Procambarus geodytes Hobbs, 1942. Burrows along the St. Johns River
and its tributaries from Putnam County south to Orange County, Florida.
Procambarus gracilis (Bundy, 1876). Burrows and temporary bodies of
water in Texas, Oklahama, Kansas, Missouri, Iowa, Illinois, and
Wisconsin.
Procambarus hagenianus (Faxon, 1884). Burrows in central and eastern
Mississippi and western Alabama.
Procambarus hayi (Faxon, 1884). Most aquatic habitats in the Tombigbee
and Tallahatchie drainages in northern and eastern Mississippi.
Procambarus hinei (Ortmann, 1905). Pools and roadside ditches west of
athe Mississippi in southern Louisiana and southeastern Texas.
Procambarus hirsutus Hobbs,. 1958. Streams in the Edisto, Salkehatchie,
and Savannah drainage systems in South Carolina.
Procambarus howellae Hobbs, 1952. Streams in the Flint and Altamaha
drainage systems in Georgia.
Procambarus hubbelli (Hobbs, 1938). Temporary ponds, pools, and
burrows in the Choctawhatchee drainage system in Alabama and Florida.
Procambarus hybus Hobbs and Walton, 1957. Temporary bodies of water
and burrows in the Tombigbee drainage system in Alabama and Mis-
sissippi. . .
Procambarus incilis Penn, 1962. Roadside ditches in southeastern Texas.
Procambarus jaculus Hobbs and Walton, 1957. Temporary bodies of
water and burrows in Hines and Rankin counties, Mississippi and
Avoyelles Parish, Louisiana.
Procambarus kilbyi (Hobbs, 1940). Sluggish streams, lentic habitats, and
burrows in coastal flatwoods from Calhoun and Gulf counties to Levy
County, Florida.
Procambarus latipleurum Hobbs, 1942. Temporary ponds, pools, and
burrows in Gulf County, Florida, north of the Wetappo Canal.
Procambarus lecontei (Hagen, 1870). Streams in Mobile County, Alabama,
and Stone County, Mississippi.
Procambarus leonensis Hobbs, 1942. Most aquatic habitats between the
Apalachicola and Suwannee rivers, Florida.
Procambarus lep&odactvlus Hobbs, 1947. Streams in Santee and Pee Dee
Drainage systems in eastern South Carolina and Columbus County,
North Caroliana.
-------
Procambarus lewisi Hobbs and Walton, 1959. Sluggish streams and road-
side ditches in Lowndes, Macon, and Montgomery counties, Alabama.
Procambarus litosternum Hobbs, 1947. Streams in the Canoochee,
Ogeechee, and Newport drainage systems in Georgia.
Procambarus lophotus Hobbs and Walton, I960. Most aquatic habitats in
Elmore, Lowndes, Montgonery, and Wilcox counties, Alabama.
Procambarus lunzi (Hobbs, 1940). Lentic habitats and burrows in Hampton
and Beaufort counties, South Carolina.
Procambarus mancus Hobbs and Walton, 1957. Temporary bodies of
water and burrows in Lauderdale County, Mississippi.
Procambarus natchitochae Penn, 1953. Streams in the Bayou Teche, Red,
and Calcasieu drainage systems in Arkansas, Louisiana, and Texas.
Procambarus okaloosae Hobbs, 1942. Most aquatic habitats and burrows
from the Yellow River system through the Perdido system in Alabama
and Florida.
Procambarus ouachitae Penn, 1956. Streams in the Ouachita and Arkansas
drainage systems in southwestern Arkansas.
Procambarus paeninsulanus (Faxon, 1914). Most aquatic habitats and
burrows in the Gulf watershed from the Choctawhatchee drainage
system to Hillsborough County, Florida.
Procambarus pearsei pearsei (Greaser, 1934). Lentic habitats and
burrows from Johnson and Pitt counties, North Carolina south to Horry
County, South Carolina.
Procambarus pearsei plumimanus Hobbs and Walton, 1958. Lentic habitats
and burrows in the Neuse and Cape Fear drainage systems in North
Carolina.
Procambarus penni Hobbs, 1951. Streams in the Pearl and Pascagoula
drainage systems in Louisiana and Mississippi.
Procambarus pictus (Hobbs, 1940). Streams in Black Creek drainage
system in Clay County, Florida.
Procambarus planirostris Penn, 1953. Temporary lentic habitats and
burrows from the Mississippi River eastward to the Pascagoula River,
Louisiana and Mississippi.
Procambarus pubescens Faxon, 1884. Streams in the Ogeechee and
Savannah drainage systems in Georiga.
Procambarus pubischelae Hobbs, 1942. Temporary bodies of water and
bur rows.from the Altamaha River in Georgia south to Alachua County,
Florida.
Procambarus pycnogonopodus Hobbs, 1942. Most aquatic habitats and
burrows from the Apalachiocola River westward to the Choctawhatchee
drainage system in Florida.
Procambarus pygmaeus Hobbs, 1942. Most types of aquatic habitats south
of the Altamaha River, Georgia and Gulf and Liberty counties, Florida.
Procambarus raneyi Hobbs, 1953. Streams in the Savannah River drainage
in Georgia and South Carolina and headwaters of the Ocmulgee River in
DeKalb County, Georgia.
10
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Procambarus rathbunae (Hobbs, 1940). Temporary bodies of water and
burrows in Okaloosa and Holmes counties, Florida.
Procambarus rogersi campestris Hobbs, 1942. Burrows in Leon and
Wakulla counties, Florida.
Procambarus rogersi expletus Hobbs and Hart, 1959. Burrows in the
we stern part of Calhoun County, Florida.
Procambarus rogersi ochlocknensis Hobbs, 1942. Burrows in Liberty
and Gads den counties, Florida.
Procambarus rogersi rogersi (Hobbs, 1938). Burrows in eastern part of
Calhoun County, Florida.
Procambarus seminolae Hobbs, 1942. Most aquatic habitats south of the
Altamaha River, Georgia to Alachua County, Florida.
Procambarus shermani Hobbs, 1942. Streams and sloughs in the Escambia
drainage system in Florida and the lower Pearl River system in
Mississippi.
Procambarus simulans simulans (Faxon, 1884). Sluggish lotic and lentic
habitats and burrows from New Mexico and Texas to Arkansas.
Procambarus spiculifer (LeConte, 1856). Streams from the Alabama to the
Savannah drainage systems in Mississippi, Alabama, Florida, Georgia.
Procambarus suttkuzi Hobbs, 1953. Streams in the Choctawhatchee
drainage system in Alabama and Florida.
Procambarus tenuis Hobbs, 1950. Springs andfcold streams in eastern
Oklahoma and western Arkansas.
Procambarus troglodytes (LeConte, 1856). Sluggish lotic and lentic habitats
and burrows between the Altamaha and Pee Dee drainage systems in
Georgia and South Carolina.
Procambarus truculentus Hobbs, 1954. Burrows in Emanuel, Treutlen,
Bulloch, and Jenkins counties, Georgia.
Procambarus tulanei Penn, 1953. Sluggish lotic and lentic habitats and
burrows in the Ouachita and Red drainage systems in Arkansas and
Louisiana.
Procambarus verrucosus Hobbs, 1952. Streams in the lower Tallapoosa
drainage in Alabama.
Procambarus versutus (Hagen, 1870). Streams from the Alabama drainage
system in Alabama eastward to the Chattahoochee-Apalachicola system
in Georgia and Florida.
Procambarus viaeviridis (Faxon, 1914). Sluggish streams and lentic
habitats from Green and Clay counties, Arkansas southeastward to
Tuscaloosa County, Alabama.
Procambarus vioscai Penn, 1946. Streams from southern Arkansas,
Louisiana, eastward to Covington, Rankin, and Simpson counties, Mis-
sisippi.
Procambarus youngi Hobbs, 1942. Streams in Leon, \Wakulla, and Gulf
counties, Florida.
11
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Genus Cambarellus
Cambarellus shufeldtii (Faxon, 1884). Lentic and lotic habitats from the
Red River drainage in Texas to southern Illinois and-the Tombigbee
and Pearl rivers in Mississippi.
Cambarellus puer Hobbs, 1945. Lentic and lotic habitats from eastern
Texas to western Mississippi (not east of Mississippi River in south-
ern Louisiana).
Cambarellus ^chmitti Hobbs, 1942. Streams from Mobile County,
Alabama, to.Santa Fe drainage, Florida.
Cambarellus diminutus Hobbs, 1945. Lentic and lotic habitats in Mobile
County, Alabama and Jackson County, Mississippi.
Cambarellus ninae Hobbs, 1950. Lentic habitats in Aransas County, Texas.
Genus Hobbseus
Hobbseus cristatus (Hobbs, 1955). Lotic and lentic habitats and burrows
in Kemper, Lauderdale, Lowndes, and Noxubee counties, Mississippi
(Tombigbee drainage).
Hobbseus orconectoides Fitzpatrick and Payne, 1968. Lentic habitats in
Oktibbeha County, Mississippi (Tombigbee drainage).
Hobbseus prominens (Hobbs, 1966). Lentic habitats and burrows in Sumter
County, Alabama (Tombigbee drainage).
Hobbseus valleculus (Fitzpatrick, 1967). Lotic habitats in'Choctaw County,
Mississippi (Pearl drainage).
Genus Orconectes
Orconectes alabamensis (Faxon, 1884). Stream tributaries of the Ten-
nessee River along the Alabama, Mississippi, Tennessee borders.
Orconectes bisectus Rhoades, 1944. Streams in Crooked Creek drainage
system in Crittenden County, Kentucky.
Orconectes compressus (Faxon, 1884). Stream tributaries of the Cumber-
land, Barren and Tennessee rivers, Alabama, Kentucky, and Tennessee.
Orconectes erichsonianus (Faxon, 1898). Stream tributaries of the Tennes-
see, Elk, and Coosa rivers, Georgia and Tennessee.
Orconecteji hathawayi Penn, 1952. Streams from Jackson and Rapides
parishes south to Vermilion Parish, Louisiana, and Clarke and Choctaw
counties, Alabama.
Orconectes hobbsi Penn, 1950. Streams in Lake Pontchartrain watershed
in Louisiana.
Orconectes illinoiensis Brown, 1956. Streams in Alexander, Gallatin,
Hardin, Pope, and Union counties, Illinois.
Orconectes immunis (Hagen, 1870). Sluggish lotic and lentic habitats and
12
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burrows from Massachusetts to Wyoming, and Alabama to Ontario.
Orconectes indianensis (Hay, 1895). Streams in southern Illinois and
Indiana.
Or cone ct e s iowae n sis Fitzpatrick, 1968. Stream tributaries of the Mis-
sissippi River in eastern Iowa.
Orconectes jeffersoni Rhoades, 1944. Streams in Ohio drainage in
Jefferson and Bullit counties, Kentucky.
Orconectes juvenilis (Hagen, 1870). Streams in the Ohio, Tennessee,
James, and Coosa drainage systems in Kentucky, Tennessee,
Virginia, West Virginia, North Carolina, Georgia, and Alabama.
Orconectes kentuckiensis Rhoades, 1944. Streams in Ohio drainage in
Crittenden and Union counties, Kentucky.
Orconectes lancifer (Hagen, 1870). Sluggish streams and lentic habitats
in eastern Texas, Louisiana, Arkansas, Mississippi, Tennessee, and
southern Illinois.
Orconectes limosus (Rafinesque, 1817). Streams in Atlantic watershed
from Maine to the lower James River, Virginia.
Orconectes mississippiensis (Faxon, 1884). Lentic and lotic habitats in
eastern Mississippi and western Alabama.
Orconectes obscurus (Hagen, 1870). Streams in "Ohio River drainage east
of the eighty-first meridian; Susquehanna, Potomac, and upper
Rappahannock River drainages; miscellaneous Lake Erie and Lake
Ontario drainages in extreme western New York, northern Pennsylvania,
and extreme northeastern Ohio." (Fitzpatrick, 1967: 162).
Orconectes palmeri creolanus (Greaser, 1933). Streams in the Lake
Pontchartrain, Pearl, and Pascagoula drainage systems in Louisiana
and Mississippi.
Orconectes palmeri palmeri (Faxon, 1884). Stream tributaries of Missis-
sippi River between Obion River, Tennessee and southward to, but not
including, the Pontchartrain drainage in Louisiana.
Orconectes placidus (Hagen, 1870). Streams in the Cumberland and Ten-
nessee drainage systems, Kentucky, Tennessee, and Alabama.
Orconectes propinquus (Girard, 1852). Streams and lake margins from
Ontario and New York west to Illinois and Wisconsin.
Orconectes rafinesquei Rhoades, 1944. Streams in Ohio drainage in
Breckenridge, Grayson, and Ohio counties, Kentucky.
Orconectes rhoadesi Hobbs, 1949. Streams in the Nashville Basin, Ten-
nessee.
Orconectes rusticus barrenensis Rhoades, 1944. Streams in the Barren
River drainage, Kentucky.
Orconectes rusticus forceps (Faxon, 1884). Streams in Tennessee River
basin east of Alabama-Mississippi line.
Orconectes rusticus mirus (Ortmann, 1931). Streams in Elk and Duck
drainage systems, Tennessee.
Orconectes rusticus rusticus (Girard, 1852). Streams and cold lakes in
Michigan, Ohio, Indiana, Kentucky, Tennessee and southern Ontario;
K 13
-------
'introduced in Massachusetts.
Orconectes sanborni erismophorous Hobbs and Fitzpatrick, 1962. Streams
in Little Kanawha drainage system in West Virginia.
Orconectes sanborni sanborni (Faxon, 1884). Stream tributaries of the
Ohio River east of the eighty-first meridian, and several streams in
Lake Erie drainage.
Orconectes shoupi Hobbs, 1948. Stream tributary of Cumberland River,
Davidson County, Tennessee.
Orconectes sloanii (Bundy, 1876). Streams in southern Indiana and south-
western Ohio.
Orconectes tricuspis Rhoades, 1944. Streams in Cumberland drainage
system in Lyon, Trigg, and Christian counties, Kentucky.
Orconectes validus (Faxon, 1914). Stream tributaries of the Tennessee
River in Alabama and southern Tennessee.
Orconectes virginiensis Hobbs, 1951. Stream tributaries of the Chowan
drainage system in southeastern Virginia.
Orconectes virilis (Hagen, 1870). Streams and lakes from Saskatchewan
to Ontario and south to Montana, Wyoming, Indiana, Ohio, and New
York is introduced in Maryland.
Orconectes wrighti Hobbs, 1948. Streams in Tennessee drainage system
in Hardin County, Tennessee.
Genus Faxonella
Faxonella clypeata (Hay, 1899). Lotic and lentic habitats and burrows
from eastern Oklahoma and Texas to South Carolina.
Faxonella beyeri (Perm, 1950). Lotic and lentic habitats and burrows in
DeSoto and Natchitoches parishes, Louisiana.
Genus Cambarus
Species not assigned to G r^p u p s .
Cambarus cornutus Faxon, 1884. Streams, Green and Barren drainage
systems in Kentucky.
Cambarus pristinus Hobbs, 1965. Streams, Caney Fork drainage, Ten-
nessee.
Asperimanus group
Cambarus asperimanus Faxon, 1914. Mountain streams in Georgia, North
Carolina, South Carolina, and Tennessee.
Cambarus brachydactylus Hobbs, 1953. Streams on Eastern Highland Rim
in Tennessee.
14
-------
Cambarus carolinus (Erichson, 1846). Burrows in mountains and Ten-
nessee Valley of Georgia, Kentucky, South Carolina, North Carolina,
Tennessee, Virginia, West Virginia, and Pennsylvania.
Cambarus causeyi Reimer, 1966. Burrows in northwestern Arkansas.
Cambarus conasaugaensis Hobbs and Hobbs, 1962. Mountain streams in
Coosa drainage system in Georgia.
Cambarus distans Rhoades, 1944. Streams in upper Cumberland drainage
in Kentucky and Tennessee.
Cambarus friaufi Hobbs, 1953. Streams on Western Highland Rim, Ten-
nessee.
Cambarus monongalensis Ortmann, 1905. Burrows in Pennsylvania and
West Virginia.
Cambarus obeyensis Hobbs and Shoup, 1947. Streams in upper Cumber-
land drainage in Tennessee.
Cambarus parvoculus Hobbs and Shoup, 1947. Streams in upper Cumber-
land and Tennessee drainages in Tennessee and Virginia.
Bartonii Group
Cambarus bartonii bartonii (Fabricius, 1798). Streams, burrows, ponds
from New Brunswick, Canada, to Georgia westward to Kentucky.
Cambarus bartonii carinirostris Hay; 1914. Streams, tributaries of
Monongahela River in West Virginia.
Cambarus bartonii cavatus Hay, 1902. Streams, Tennessee drainage
system above Walden Ridge.
Cambarus ortmanni Williamson, 1907. Streams and burrows in southern
Illinois, Indiana, and adjacent Kentucky.
Cambarus sciotensis Rhoades, 1944. Streams, Kanawha and Scioto drainage
systems in Virginia, West Virginia, and Ohio.
Diogenes Group
Cambarus diogenes diogenes Girard, 1852. Burrows and occasionally
standing water east of the Rockies and south of the Great Lakes (except
peninsular Florida), the Alleghenies, and lower Mississippi drainage
in Louisiana.
Cambarus diogenes ludovicianus Faxon, 1884. Burrows and occasionally
standing water in the lower Mississippi drainage in Louisiana.
Extraneus Group
Cambarus acuminatus Faxon, 1884. Streams in Piedmont and rarely in
Coastal Plain from southern Maryland to Saluda drainage system,
South Carolina.
Cambarus extraneus Hagen, 1870. Streams, Tennessee drainage above
Walden Ridge in Georgia and (? ) Tenness.ee.
15
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Carnbarus robustus Girard, 1852. Streams from Ontario and New York
to Ohio, eastern Kentucky, and West Virginia.
Carnbarus spicatus Hobbs, 1956. Streams in Little River drainage in
Fairfield and Richland counties, South Carolina.
Carnbarus veteranus Faxon, 1914. Streams in Guyandot and Big Sandy
drainages in Kentucky, Virginia, and West Virginia.
Fodiens Group
Carnbarus byersi Hobbs, 1941. Burrows in lowermost Coastal Plain from
Okaloosa County, Florida to Mississippi.
Carnbarus fodiens (Cottle, 1863). Lentic and sluggish lotic habitats and
burrows from Ontario and Great Lakes area southward along the Mis-
sissippi drainage system to southwestern Georgia.
Cambarus hedgpethi Hobbs, 1949. Lentic and sluggish lotic habitats and
burrows from Aransas County, Texas to Tennessee and eastern Mis-
sissippi.
Cambarus macneesei Black, 1967. Lentic habitats and probably burrows
in the Calcasieu drainage, Louisiana.
Cambarus oryktes Penn and Marlow, 1959- Burrows and lentic habitats
in Alton, Covington, and St. Tammany parishes, Louisiana.
Cambarus strawni Reimer, 1966. Burrows in Howard County, Arkansas.
Cambarus uhleri Faxon, 1884. Lentic and lotic habitats, salt marshes
and burrows from Maryland to South Carolina.
Latimanus Group
Cambarus catagius Hobbs and Perkins, 1967. Burrows in Guilford County,
North Carolina.
Cambarus floridanus Hobbs, 1941. Burrows in Apalachicola and Ochlocknee
drainages in Georgia and Florida.
Cambarus halli Hobbs, 1968. Tributaries of the Tallapoosa River in
Alabama and Georgia.
Cambarus latimanus (LeConte, 1856). Streams in Piedmont and Coastal
Plain from North Carolina to Alabama.
Cambarus obstipus Hall, 1959. Streams in Black Warrior drainage,
Alabama.
Cambarus reduncus Hobbs, 1956. Burrows and streams in Piedmont from
Orange County, North Carolina to Richland County, South Carolina.
Cambarus sphenoides Hobbs, 1958. Streams in Cumberland and Sequatchie
drainage systems in Kentucky and Tennessee.
Cambarus striatus Hay, 1902. Streams and burrows from southern
Kentucky to Alabama, Mississippi, and Georgia.
16
-------
Longulus Group
Cambarus chasrnodactylus James, 1966. Streams in New River-Kanawha
drainage system in North Carolina, Virginia, and West Virginia.
Cambarus girardianus Faxon, 1884. Tributaries of westward flowing
segment of Tennessee River in Alabama and Tennessee.
Cambarus longirostris Faxon, 1885. Streams in Tennessee drainage system
above Mussel Shoals in Alabama, Georgia, Tennessee, North
Carolina, and Virginia, and Coosa drainage in Georgia and Alabama.
Cambarus longulus Girard, 1852. Streams in the Yadkin, Roanoke, and
James drainages in North Carolina and Virginia.
Tenebrosus Group
Cambarus hubbsi Greaser, 1931. Streams in southeastern Missouri and
northeastern Arkansas.
Cambarus laevis Faxon, 1914. Streams and caves in southern Illinois,
Indiana, southwestern Ohio, and northern Kentucky.
Cambarus ornatus Rhoades, 1944. Intermittent streams in northern
Kentucky.
Cambarus rusticiformis Rhoades, 1944. Streams in Cumberland drainage
in Kentucky and Tennessee.
Cambarus tenebrosus Hay, 1902. Streams and caves from middle
Kentucky to northern Alabama.
17
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II KEY TO THE GENERA OF SPECIES OF THE SOUTHEASTERN MALACOSTRACANS
(Exclusive of troglobitic groups and species)
1 Carapace absent; eyes sessile (Figs. 2a-e, 3a-c) 2
I1 -Carapace present; eyes stalked (Figs. 4. 6-8) 8
2 (1) Body depressed (Figs. 2a-c); abdominal segments often fused; gill plates, if present, on
pleopods Isopoda 3
2' Body compressed laterally (Fig. 3a); abdominal segments never fused; gill plates at bases
of pereiopods Amphipoda 6
3 (2) Uropods attached to abdomen ante relate rally (Figs. 2b, c). . . . Sphaeromatidae 4
3' Uropods attached to abdomen posteriorly or posterolaterally (Fig. 2a). . Asellidae 5
Fig. 2. Isopoda. a. Dorsal view of Asellus; b. Dorsal view of Sphaeroma; c. Dorsal view of
Exosphaeroma; d. Dorsal view of head of Asellus; e. Dorsal view of head of Lirceus; f. Ventral
view of right third pleopod of Lirceust g. Ventral view of right third pleopod of Asellus;
(m, mandible; p, prominence; s, suture; u, uropod). Modifie from Richardson.
4(3) Lateral margin of outer ramus of uropod serrate (fig. 2b) Sphaeroma Latreille
(S. terebrans Bate, 1866 - Fla.-to Texas).
4' Lateral margin of outer ramus of uropod smooth (Fig. 2c) Exosphaeroma Ste-bbing
(Occasionally invading fresh water on west coast and N. Y. ; one freshwater species, E.
thermophilus (Richardson, 1897) known from warm springs in New Mexico).
5 (3') Head with lateral margins produced to overhang bases of mandibles, and its anterior margin
with prominence between basal portions of antennules (Fig. 2e); mesial end of suture travers-
ing opercuhim (3rd pleopod) almost reaching mesiodistal angle (Fig. 2g). . . Lirceus Ratinesque
(From Florida to Canada, east of the Great Plains).
5' Head with lateral margins never overhanging bases of mandibles and never with prominence
between bases of antennules (Fig. 2d); mesial end of suture traversing operculum far
proximal to mesiodistal angle (Fig. 2f).^ .Asellus St. Hillaire
Fig. 3. Amphipoda. a. Lateral view of Gammarus; b. Lateral view of head of Gammarus;
c. Lateral view of head of Hyalella; d. Lateral view of first antenna of Gammarus; e. Lateral view
of first antenna of Crangonyx; f. Mandible of Gammarus (a, first antenna; f, accessory flagellum;
p, mandibular palp; u, urosome). Modified from several sources.
18
-------
6 (2') First antenna with accessory flagellum (Fig. 3b); mandibular palp present (Fig. 3f)
Gammaridae. 7
6' First antenna without accessory flagellum (Fig. 3c); mandibular palp absent Talitridae
Hyalella azteca (Saussure, 1858)
(Widespread in permanent bodies of water with vegetation).
7 (6) Accessory flagellum of first antenna 3-7 segmented (Fig. 3d); terga of urosomal segments
with median spines Gammarus Fabricius
7' Accessory flagellum of first antenna 2-segmented (Fig. 3e); terga of urosomal segments
without median spines. C rang onyx Bate and Synurella Wrzesniewski
(Synurella has but one ramus on the third uropod, whereas Crangonyx has two, the inner
one, however, is very small. Both genera are commonly encountered in much of the eastern
portion of the United States).
8 (I1) Carapace not fused with at least last two thoracic somites; no chelate legs. (Fig. 4)
Fig. 4. Mysidacea. Lateral view of Taphromysis louisianae (c, carapace; t, free thoracic
somites). Modified from Banner.
Order Mysidacea
8' Carapace fused with all thoracic somites; at least two pairs of legs chelate. (Figs. 7a, 8)
Order Decapoda 9
9 (8') Rostrum and abdomen laterally compressed; third pair of legs never bearing chelae. (Fig. 7a)
Palaemonidae 10
9' Rostrum and abdomen depressed; third pair of pereiopods bearing chelae. (Fig. 8)
Astacidae 15
10 (9) Ventrolateral spine on carapace situated near or on anterior margin (Figs. 6a, b); mandibular
palp absent (Fig. 5b) 11
10' Ventrolateral spine on carapace situated some distance from anterior margin (Figs. 7a-d);
mandibular palp present (Fig. 5a) 12
Fig. 5. Mandibles of a. Macrobra-chium; b. Palaemonetes (p, palp).
K 19
-------
11 (10)
11'
Ventrolateral spine on carapace situated on anterior margin (Fig. 6a); posterior pair of spines
on telson midway between anterior pair and posterior extremity of telson (Fig. 6c)
Palaemonetes paludosus (Gibbes . 1850)
Ventrolateral spine on carapace posterior to anterior margin (Fig. 6b); posterior pair of spines
on telson nearer to posterior extremity of telson than to anterior pair (Fig. 6d)
Palaemonetes kadiakensis Rathbun, 1902
Fig. 6. Palaemonetes. a. Lateral view of anterior portion of P. paludosus; b. Lateral view
of anterior portion of P. kadiakensis; c. Dorsal view of telson of P. paludosus; d. Dorsal view of
telson of P. kadiakensis. (a, anterior spine; p, posterior spine; v, Ventrolateral spine). Modi-
fied from Holthuis.
12 (10') Rostrum with two or three teeth behind orbit; if with four, carpus of second pereiopod longer
than merus and chelae of those appendages similar in size and shape. (Figs. 7a, b) J3
12' Rostrum with more than three teeth behind orbit (Figs. 7c, d) 14
Fig. 7. Macrobrachium, lateral views, a. M. ohione; b. M. acanthurus; c. M. carcinus;
d. M. olfersii. (c, carpus; d, dorsal tooth; m, merus; o, orbit; t, ventral tooth; v, Ventrolateral
spine; I, first pereiopod; II, second pereiopod). Modified from Holthuis.
K 20
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13
13 (IE) Rostrum comparatively shallow dorsoventrally with dorsal teeth almost to apex; fingers
of chelae of second pereiopods with velvet-like pile. (Fig. 7b)
Macrobrachium acanthurus (Wiegmann , 1836)
(Coastal areas from North Carolina to Texas).
Rostrum comparatively deep with neither dorsal nor ventral teeth apically; fingers of
chelae of second pereiopods never with velvet-like pile. (Fig. 7a)
Macrobrachium ohione (Smith , 1874)
(Coastal area from Chesapeake Bay to Georgia and in Texas, and Mississippi drainage system
as far north as Missouri and Ohio).
14 (12') Rostrum strongly arched above eyes; carpus of second pereiopod distinctly shorter than merus
and both chelae of pair similar in size and shape. (Fig. 7c)
Macrobrachium carcinus (Linnaeus, 1758)
(Florida and Texas).
14' Rostrum almost straight above eyes; carpus of second pereiopod at least as long as merus and
chelae of pair dissimilar in size and shape. (Fig. 7d)....Macrobrachium olfersii (Wiegmann,1836)
(St. Johns River drainage and St. Augustine, Florida).
- chela
Fig. 8. Astacidae (Stylized crayfish), a. Dorsal view; b. Ventral view.
15 (91) Ischia of pereiopods of males without hooks (Fig. 9a); females without annulus ventralis
Pacifastacus Bott
(Seven species and subspecies in Pacific drainage).
15' Ischia of second, third, or fourth (combinations) pereiopods of males with hooks (Figs. 9b-d);
females with annulus ventralis * 16
boss
Fig. 9. Basal portions of first through fifth left pereiopods (1, 2, 3, 4, 5) of male crayfishes
(b, basis; c, coxa; i, ischium; h, hooks).
21
-------
REMAINDER OF KEY APPLICABLE ONLY TO FIRST FORM MALES
16 (151) Ischia of second and third pereiopods of males with hooks (Fig. 9b). . . ..(Fig. 10) . . Cambarellus
16' Ischia of third, or third and fourth, pereiopods of males with hooks (Figs. 9c, d) 17
Cambarellus. (a-e. lateral views of first left pleopods) a. C. shufeldtii; b. C.
puer; d. C. schmitti; e. C. diminutus; (f-i, C. diminutus) f. Dorsal view of carapace;
Dorsal view of chela; h. Ischiopodite of second pereiopod; i. Ischiopodite of third pereiopod.
17 (16') First pleopod of male ending in one slender, long (reaching coxa of first pereiopod) terminal and
one short (no more than half length of long one) terminal; long terminal of one pleopod over-
lapping that of other (Figs. lla). JTaxonella
17' First pleopod of male ending in two or more terminals but never with long terminal over-
lapping corresponding terminal of other pleopod distally (Figs. 13b, 15, 27) 18
Fig. 11. Faxonella. a. Caudal view of first pair of pleopods of F. clypeata; b. Caudal view of
first left pleopod of F. clypeata; c. Caudal view of first left pleopod of F. beyeri; d. Dorsal view of
carapace of F, clypeata; e. Dorsal view of ri^t chela of F. clypeata.
18 (17') Coxae of fourth pereiopods always with caudomesial boss (Fig. 9b); first pleopod with only
two rami, both bent caudally or caudolaterally at no less than 90 degrees, (Figs. 12a-d) if
bent less than 90 degrees then central projection blade-like with subterminal notch (Fig.
12e) Cambarus. 69
18' Coxae of fourth periopods with or without caudomesial boss (Fig. 9a - without boss); first
pleopod with two or more rami variously disposed (Figs. 16, 17, 19-25, 28, 29, 31) but if only
two, then central projection never with subterminal notch (Figs. 14a-d, 16a. c, h) 19
Fig. 12. Cambarus (lateral view of first left pleopods). a. C. bartonii bartonii ; b. C.
conasaugaensis; c. jC_. reduncus; d. C. cornutus; e. C_. pristinus (m, mesial process; n, sub-
terminal notch; p. central projection).
22
-------
19 (181) First pleopods bearing two or more processes, (Figs. 16, 17, 19-25) if only two then coxae of
fourth pereiopods with caudomesial boss (Fig. 9b). . Procambarus. 21
19' First pleopods bearing only two processes (Figs. 14, 28, 29, 31) and coxae of fourth pereiopods
without caudomesial boss (Fig. 9a) 20
Fig. 13. Ventral views of thoracic regions of a. Hobbseus, b. Orconectes (m, setiferous mat;
p, first pleopod).
20 (19') First pleopods, in resting position, deeply withdrawn between bases of pereiopods and
covered by dense setiferous mat extending from ventrolateral margins of sternum (Figs. 13a,
14) Hobbseus
20' First pleopods, in resting position, never deeply withdrawn between bases of pereiopods and
never covered by dense setiferous mat extending from ventrolateral margins of sternum
(Figs. 13b, 28, 29, 31) Orconectes 33
Fig. 14. Hobbseus (a-d. lateral views of first left pleopods). a. H. cristatus; b. H. prominens
c. H_. valleculus; d. H. orconectoides; e. Dorsal view of carapace of H_. prominens; f. Dorsal
view of chela of H. cristatus.
Genus Procambarus Ortmann
21 (19) Bases of first pleopods symmetrically arranged (Fig. 15a) 25
21' Bases of first pleopods asymmetrically arranged (Fig. 15b) 22
22 (21) First pleopods extending forward between bases of second pereiopods (Fig. 15c) 23
22' First pleopods extending forward between bases of third pereiopods (Fig. 15d) 24
23
-------
Fig. 15. a. Caudal view of symmetrically arranged first pleopods; b. Caudal view of asymmetri-
cally arranged first pleopods; c. First pleopods reaching anteriorly to coxae of second pereiopods;
d. First pleopods reaching anteriorly to coxae of third pereiopods (c2, coxa of second pleopod; c3,
coxa of third pereiopod; p, pleopod).
23 (22) Hooks present on ischia of third and fourth pereiopods (Fig. 9c). . . . (Fig. 17h)
P. shermani Hobbs, 1942
23' Hooks present on ischia of third pereiopods only (Fig. 9d). . . . (Fig. 16) Advena Section
Fig. 16. Procambarus. Advena Section, (a-c and h, lateral views, and d-g, caudal views, of
first left pleopods). a. P. advena; b. P. geodytes; c. P. pygmaeus; d. P. rogersi rogersi;
e. P. rogersi ochlocknensis; f. P_. rogersi campestris; g. P_. rogersi expletus; h. P. truculentus;
i. Dorsal view of carapace of P. j:. rogersi; j. Dorsal view of chela of P. r_. rogersi.
24 (22') Cephalic process of first pleopod arising distinctly from mesial side of appendage (Figs. 17a-g, 1-
k); palm of chela often barbate (Fig. 17n); one cervical spine may or may not be present on
each side of carapace (Fig. 18a) (Fig. 17) Barbatus Section
24
-------
Fig- 17-
pleopods). a.
latipleurum; f. P.
hubbelli; k. P. alleni;
Procambarus. Barbatus Section (a-k, lateral views of distal portion of first left
P. barbatus; b. P. pubischelae; c. P. escambiensis; d. P. econfinae; e. P.
apalachicolae; g. P. rathbunae; h. P. shermani; i. P. kilbyi; j. P.
1. Dorsal view of carapace of JP. hubbelli; m. Dorsal view of chela of
Dorsal view of chela of P. hubbelli.
24' Cephalic process of first pleopod seldom arising distinctly from mesial side of appendage,
if so, always with two cervical spines on each side of carapace (Fig, 18b); palm of chela
never barbate (Fig. 17m); one or two cervical spines present on each side of carapace (Fig.
18) ............................................. Blandingii Section .................... 27
Fig. 18. Lateral views of carapace illustrating a, one cervical spine; b, two cervical spines.
25 (211) Hooks present on ischia of third pereiopods only (Fig. 9d). . . .(Fig. 19). . . .
25' Hooks present on ischia of third and fourth pereiopods (Fig. 9c)
. . . .Gracilis Section
26
Fig. 19. Procambarus. Gracilis Section (a-d, lateral views of first left pleopods). a. P.
simulans simulans; b. P. gracilis; c. P. hagenianus; d. JP. tulanei; e. Dorsal view of carapace
of P. s. simulans; f. Dorsal view of chela of JP. s^. simulans; g. Dorsal view of chela of P. gracilis.
26 (251) Dactyl of chela longer than inner margin of palm (Fig. 20c) (Figs. 20a-c)
.P. tenuis Hobbs , 1950)
26' Dactyl of chela much shorter than inner margin of palm (Fig, 20g). . . (Figs. 20d-g)
Hinei Section
K
25
-------
Fig. 20. Procambarus. a-c, P. tenuis; d. f. g. P. hinei; g. P. incilis; a. d. e. Lateral views
of first left pleopods; b. f. Dorsal views of carapaces; c. g. Dorsal views of chelae.
27 (241) Two cervical spines present on each side of carapace (Fig. 18b). . . (Figs. 21a-m)
Spiculifer Group
27' Single cervical spine present or absent on each side of carapace (Fig. 18a) 28
Fig. 21. Procambarus. a-m, Spiculifer Group; n. P. simulans simulans; o. P. acutus acutus
(a-k, n, o, lateral views of first left pelopods) a. P. ablusus; b. P. penni; c. P. natchitochae;
d. P. dupratzi; e. P. echinatus; f. P. viosci; g. P. versutus; h. P. raneyi; i. P. Spiculifer;
j. P. ouichitae; k. P. suttkusi; 1. Dorsal view of carapace of _P. Spiculifer; m. Dorsal view of
chela of P. Spiculifer; n. P. simulans simulans; o. P. acutus acutus (s, subterminal setae).
28 (27') Cephalic surface of first pleopod always bearing prominent angular shoulder some distance
proximal to tip (Figs. 22a-e) .Clarkii Group
28' Cephalic surface of first pleopod entire or bearing hump but latter never angular (Figs. 23-
25) 29
Fig. 22. Procambarus. Clarkii Group, (a-e, lateral views of first left pleopods) a. P. clarkii;
b. P. okaloosae; c. P. trogjodytes; d. P. paeninsulanus; e. P. howellae; f. Dorsal view of
carapace of P. paeninsulanus; g. Dorsal view of chela of P. paeninsulanus.
26
-------
29 (28') First pleopod with subterminal setae (Fig. 21o) 30
29' First pleopod without subterminal setae (Fig. 21n) 32
30 (29) Subterminal setae of first pleopod borne on knob on cephalodistal or laterodistal surface (Figs.
23a-h) Blandingii Group
30' Subterminal setae of first pleopod never borne on distinct knob (Figs. 23i, j, 24, 25) 31
Fig. 23. Procambarus. a-h, k, 1, Blandigii Group; i. P. bivittatus; j. P. lewisi (a-j, latera
views of first left pleopods) a. P. hayi; b. P. lophotus; c. P. blandingii; d. P. acutus acutus;
e. P. acutissimus; f. P. lecontei; g. P. verrucosus; h. P. viaviridis; i. P. bivittatus; j. P.
lewisi; k. Dorsal view of carapace of P. acutus acutus; 1. Dorsal view of chela of _P. acutus acutus
(k, setae bearing knob).
31 (30') Cephalic process (if present) arising from cephalic side of central projection; caudal process
prominent, compressed laterally, and arising from caudolateral surface of pleopod; caudal
knob never well-defined (Fig. 24) Planirostris Group
Fig. 24. Procambarus. Planirostris Group, (a-g, lateral views of first left pleopods) a. P.
pearsei pearsei; b. P. pearsei plumimanus; c. P, planirostris; d. P. mancus; e. P. jaculus;
f. P. evermanni; g. P. hybus; h. Dorsal view of carapace of P. hybus; i. Dorsal view of chela
of P. hybus.
K
27
-------
31' Ce .halic process arising from cephalic or lateral side of central projection; caudal process
seldom prominent (sometimes absent) and arising distinctly mesial to caudal knob except in
P. lepidodactylus in which cephalic process situated lateral to central projection (Fig. 25i). . . .
(Figs. 25a-r) Pictus and Seminolae Groups
Fig. 25. Procambarus. Pictus and Seminolae Groups, (a-p, lateral views of first left pleopods)
a. P. youngi; b. P. hirsutus; c. P. chacei; d. P. pubescens; e. P. litosternum; f. P. pictus;
g. P. enoplosternum; h. P. epicyrtus; i, JP. lepidodactylus; j. P. angustatus; k. P. ancylus;
1. P. eeminolae; m. P. lunzi; n. P. leonensis; o. P. fallax; p. JP. pycnogonopodus; q. Dorsal
view of carapace of P. pictus; r. Dorsal view of chela of P. pictus.
32 (29') Cephalic process of first pleopod cephalic to base of central projection (Fig. 23i)
P. bivittatus Hobbs, 1942
32' Cephalic process of first pleopod lateral to base of central projection (Fig. 23j)
P. lewisi Hobbs'and Watson, 1959
Genus Orconectes Cope
33 (2tf) Areola obliterated or linear (reduced almost to a line) near midlength (Figs. 26a-c) 34'
33' Areola broad or narrow but never obliterated or linear (Fig. 26d) 39
Fig. 26. Orconectes. Carapaces of crayfishes illustrating characteristics mentioned in key (a
areola; c, carina; m, marginal spine; s, spines; x, acumen).
34 (33) Rostrum without marginal spines (Fig. 26a) mississippiensis
34' Rostrum with marginal spines (Figs. 26b-d) ' 35
35 (34') Acumen comprising more than 1/2 length of rostrum (Fig. 26c). lancifer
35' Acumen comprising less than 1/2 length of rostrum (Figs.. 26a, b, d) 36
K
2H
-------
36 (351) Terminal processes of first pleopod short and only slightly bent (Fig. 29j) hathawayi
36' Terminal processes of first pleopod long and strongly bent (Fig. 31) 37
37 (361) Areola linear near midlength (Fig. 26b) hobbsi
37' Areola obliterated at midlength (Figs. 26a, c) 38
38 (371) Lake Pontchartrain, Pearl, and Pascagoula drainages (La. and Miss,) (Fig. 31b)
palmeri creolanus
38' Eastern tributaries of Mississippi River from Obion River, Tenn. to Pontchartrain drainage. . .
(Fig. 31a) palmeri palmeri
39 (33') Central projection of first pleopod very slender, almost needle-like and subparallel to mesial
process (Fig. 28) 40
39' Central projection of first pleopod variable but needle-like only in O_. virilis (Fig. 31j) in
which mesial processes directed somewhat caudally (Figs. 29, 31a-i) 45
40 (39') First pleopod with shoulder on cephalic surface (Figs. 28a-c) 41
40' First pleopod without shoulder on cephalic surface (Figs. 28d-f) 43
41 (40) Tip of first pleopod reaching coxa of first pereiopod (Figs. 27a, 28c) juvenilis
41' Tip of first pleopod not reaching beyond coxa of second pereiop od (Fig. 27b) 42
Fig. 27, Orconectes. (ventral view of thorax with first pleopods reaching as far forward as
possible) a. Tip of pleopod reaching coxa of first pereiopod (cheliped); b. Tip of pleopod reaching
coxa of second pereiopod (cl, coxa of first pereiopod; c2, coxa of second pereiopod; p, first pleopod).
42 (411) Length of areola less than 1/3 of total length of carapace; tubercles on chela weak (Fig. 28b). . .
rusticus mirus
42' Length of areola at least 1/3 of total length of carapace; tubercles on chela strong (Fig. 28a). . .
rusticus rusticus
Fig. 28. Orconectes. (lateral views of first left pleopods) a. O. rusticus rusticus; b. O.
rusticus mirus; c. O. juvenilis; d. CX rusticus forceps; e. O_. rusticus barrenensis; f. O.
placidus (m, mesial process; p, central projection; s, shoulder).
K
29
-------
43 (40') Dactyl of chela at least 2 times longer than inner margin of palm (Fig. 28f) placidus
43' Dactyl of chela less than 2 times longer than inner margin of palm 44
44 (431) Rostrum very narrow and deeply excavate above (Barren and lower Green Rivers in Ky. and
perhaps Tenn.) (Fig. 28e) rusticus barrenensis
44' Rostrum broader and shallowly excavate above (Tennessee drainage above Pickwick Dam (Fig.
28d) . rusticus forceps
45 (39") Central projection short and never strongly recurved (Fig. 29) ,46
45' Central projection long and'strongly recurved (Fig. 31) 64
46 (45) Mesial process of first pleopod bearing accessory lobe on caudal surface (Fig. 29o)
sanborni e r igrnopho r ous
46' Mesial process of first pleopod never bearing accessory lobe on caudal surface (Figs. 29 1-n,
p-t) 47
a b V c ' d
Fig. 29. Orconectea. (a-t, lateral views of first left pleopods; u, v, caudal views of first left
pleopods) a. O. limosus; b. O. indianensis; c. O. wrighti; d. O. shoupi; e. O. bisectus; f. O.
tricuspis; g. O. ratinesquei; h. O_. sloanii; i. O_. kentuckiensis; j. O. hathawayi; k. O. lancifer;
1. O. propinqtms; m. O. sanborni sanborni; n. O. iowaensis; o. O. sanborni erismophorous;
p. Q. virginiensis; q. O. obscurus; r. O_. illinoiensis; s. O. jeffersoni; t. O. erichsonianus;
u. O. illinoiensis; v. O_. propinquus (m. mesial process; p, central projection; s, shoulder; z,
accessory lobe).
47 (461) Terminal elements of first pleopod divergent (Figs. 29a-d) 48
47' Terminal elements of first pleopod subparallel or slightly recurved (Figs. 29e-j) 51
48 (47) Lateral surface of carapace with several spines (Figs. 26d, 29a) limpsus
48' Lateral surface of carapace with single spine (Fig. 26b) 49
49 (48') Margins of rostrum convex (Fig. 30a) wrighti
49' Margins of rostrum subparallel, convergent, or concave (Figs. 30b-d) 50
50 (49') Inner margin of palm of chela approximately 1/3 as long as dactyl. . . (Fig. 29d). .shoupi
50' Inner margin of palm of chela distinctly greater than 1/3 as long as dactyl. . (Fig. 29b)
• indianensis
51 (47') Central projection of first pleopod broad distally, often somewhat blade-like. . . . (Figs. 29e, h,
i) 52
51' Central projection of first pleopod tapering from base (Figs. 29 1-t) 54
K
30
-------
52 (51) Mesial process of first pleopod almost straight (Fig. 29e) bisectus
52' Mesial process of first pleopod recurved (Figs. 29h, i) 53
53 (52') Cephalic margin of distal half of first pleopod evenly curved (Fig. 29i) kentuckiensis
53' Cephalic margin of distal half of first pleopod not evenly curved (Fig. E9h) sloanii
54 (51') First pleopod with distinct shoulder on cephalic surface (Fig. 29q) obscurus
54' First pleopod without distinct shoulder on cephalic surface (Figs. 29f, 1, n, p) 55
55 (541) Rostrum with median carina (ridge) (Fig. 26d) 56
55' Rostrum without median carina (Figs. 26a-c) 59
56 (55) Mesial process truncate or spatulate apically (Fig. 29n) iowaensis
56' Mesial process tapering to tip (Figs. 29f, 1, p) 57
57 (56') Caudodistal margin of mesial process curved (Fig. 29f) tricuspis
57' Caudodistal margin of mesial process straight (Figs. 291, p) 58
58 (57') Carapace and chelae strongly pubescent (Chowan drainage in S.E. Va. ) (Fig. 29p)
virginiensis
58' Carapace not pubescent and chelae only weakly so (northern U.S. ) (Fig. 29 1) propinquus
59 (551) Tip of mesial process, in caudal view, situated much lateral to central projection (Fig. 29u). . .
illinoiensis
59' Tip of mesial process, in caudal view, never extending so far laterally (Fig. 29v) 60
60 (591) Carapace strongly pubescent (S. E. Va. ) (Fig. 29p) virginiensis
60' Carapace not strongly pubescent (Elsewhere) 61
61 (60') Margins of rostrum parallel (Fig. 30b) erichsonianus
61' Margins of rostrum concave or slightly converging (Figs. 30c, d) 62
A A A A
Fig. 30. Orconectes. (cephalic regions and chelae) a. Margins of rostrum convex; b. Margins
of rostrum subparallel; c. Margins of rostrum concave; d. Margins of rostrum converging; e. Righl
chela of O. immunis; f. Right chela, generalized, of other species (d, dactyl; x, excision).
62 (611) Margins of rostrum thickened and concave (Fig. 30c), upper surface deeply excavate. . (Fig. 29s)
jeffersoni
62' Margins of rostrum not thickened, slightly convergent, (Fig. 30d) and upper surface shallowly
excavate 63
63 (62') Mesial process of first pleopod broad distally and subspatulate (Fig. 29m). . .sanborni sanborni
63' Mesial process tapering to point distally (Fig. 29g) rafinesquei
64 (45'j Dactyl of chela with distinct angular emargination on opposable surface. . . (Figs. 30e, 31d). . . .
,.,,... immunis
64' Dactyl of chela without distinct angular emargination on opposable surface (Fig. 30f) 65
65 (64') Length of areola less than 30 percent of entire length of carapace and less than 3 time longer
than broad (Fig. 31h) alabamensis
65' Length of areola more than 30 percent of entire length of carapace and at least 4 times longer
than broad 66
66 (65') Carapace strongly compressed laterally; rostrum with median carina (Fig. 26d); areola approx-
imately 4 times longer than broad (Fig. 31i) compressus
66' Carapace not strongly compressed laterally; rostrum without median carina (Fig. 26b); areola
at least 5 times longer than broad 67
K 31
-------
67 (661) Central projection of first pleopod constituting more than 1/3 total length of appendage (Fig.
31j) virilis
67' Central projection constituting less than 1/3 total length of appendage (Figs. 31f, g) 68
Fig. 31. Orconectes. (lateral views of first left pleopods) a. C). palmeri palmeri; b, O.
palmeri creolanus; c. O. hobbsi; d. O_. immunis; e. O. mississippiensis; f. O. validus;
g. O. rhoadesi; h. O. alabamensis; i. C^. compressus; j. O. virilis (m, mesial process; p,
central projection).
68 (671) Central projection curved throughout length (Fig. 31f) validus
68' Central projection almost straight basally (Fig. 31g) rhoadesi
Genus Cambarus Erichson
69 (18) Antennae conspicuously fringed on mesial border (Fig. 32k); lateral margin of fixed finger of
chela with row of spines (Fig. 32a) cornutus Faxon , 1884
69' Antennae not conspicuously fringed on mesial border (Fig. 32 1); lateral margin of fixed finger
of chela never with row of spines (Figs. 32b-j) 70
Fig. 32, Cambarus. (a-j, dorsal view of chelae; k, 1, portions of antennae) a. C. cornutus; b.
Fodiens Group (C. strawni); c, Longulus Group (jC. longulus longulus); d. C. pristinus; e. Asper-
imanus Group (C. asperimanus); f. Tenebrosus Group (C. rusticiformis); g. Extraneus Group (C.
extraneus); h. Bartonii Group (C. bartonii bartonii); i. Diogenes Group (C. diogenes diogenes);
j. Latimanus Group (C. latimanus); k. C. cornutus; 1. Generalized, other than C_. cornutus.
70 (691) Dactyl of chela deeply excised on opposable margin (Fig. 32b) Fodiens Group ( p. K 16 )
70' Dactyl of chela never deeply excised on opposable margin (Figs. 32c-j) 71
32
-------
71 (70') Tubercles on mesial surface of palm of chela forming cristiform row; palm and fingers
often studded with long setae (Fig. 32e) Asperimanus Group (p. K 14 )
71' Tubercles on mesial surface of palm of chela never forming cristiform row; palm and
fingers never studded with long setae (Figs. 32c, d, f-j) 72
72(71') Rostal margins distinctly thickened; areola with crowded, deep punctations; fingers of chela
with poorly defined longitudinal ridges, usually strongly gaping, and almost always with con-
spicuous tuft of setae at base of opposable margin of fixed finger (Fig. 32c)
Longulus Group ( p.K 17)
72' Rostral margins usually not markedly thickened, if so, areola never with crowded deep
punctations; fingers of chela usually with well defined longitudinal ridges, seldom strongly
gaping, and, if so, never with conspicuous tuft of setae at base of opposable margin of
fixed finger (Figs. 32d, f-j) 73
73 (72') Width and length of palm of chela subequal (Fig. 32d); first pleopod with well developed caudal
knob, and central projection and mesial process recurved caudally at much less than 90 degrees
to imaginary distal extension of shaft of appendage (Fig. 12e) pristinus
73' Width of palm of chela distinctly greater than length of inner margin (Figs. 32f-j); first
pleopod usually without caudal knob, if present, central projection and mesial process re-
curved caudally at least at 90 degrees to axis of shaft of appendage (Figs. 12a-d) 74
74 (73') Mesial surface of palm with inner row of 8 or more tubercles (Figs. 32f, g) 75
74' Mesial surface of palm with inner row of fewer than 8 tubercles (Figs. 32h-j) 76
75 (74) Mesial surface of palm with single row of tubercles, if second row present, fingers stocky
(Fig. 32f) Tenebrosus Group (p.K 17)
75' Mesial surface of palm with at least 2 rows of tubercles except in C^ veteranus which has
long acuminate rostrum; fingers always elongate (Fig. 32g) Extraneus Group (p. K 15)
76 (74') Dorsomesial surface of palm with tubercles limited to 1 or 2 rows, usually only one, in mesial
half (Fig. 32h) .Bartonii Group (p.K 15)
76' Dorsomesial surface of palm with tubercles not limited to 2 rows in mesial half (Figs. 32i, j),
or if limited to 2 rows, central projection of'first pleopod of first form male tapering and
lacking subapical notch; otherwise notch may or may not be present 77
77 (76') Dactyl of chela with broad concavity on basal half of opposable margin (Fig. 32i)
Diogenes Group (p.K 15)
77' Dactyl without broad concavity on basal half of opposable margin, tapering from base (Fig. 32j)
Latimanus Group (p.K 16)
33
-------
in SELECTED REFERENCES
Banner, Albert H. 1953. On a new genus and species of mysid from
southern Louisiana (Crustacea, Malacostraca). Tulane Studies
in Zool. 1(1): 1-8.
Bousfield, E. L. 1958. Fresh-water amphipod crustaceans of glaciated
North America. Canad. Field Nat. 72(2): 55-113.
Chace, Fenner A. , Jr., J. G. Mackin, Leslie Hubright, Albert H.
Banner, and Horton H. Hobbs, Jr. 1959. Malacostraca, p. 869-
901. _In_ Edmonds on, W. T. 1959. Fresh-water biology. John
Wiley and Sons, New York.
and Horton H. Hobbs, Jr. (in press). The fresh-
water and terrestrial decapod crustaceans of the West Indies, with
special reference to Dominica. Bull. U. S. Nat. Mus.
Creaser, Edwin P. 1931. The Michigan decapod crustaceans. Pap. Mich.
Acad. Sci. , Arts and Letters 13: 257-276.
1932. The decapod Crustacea of Wisconsin. Trans.
Wis. Acad. Sci., Arts and Letters 27: 321-338.
, and A. I. Ortenburger. 1933. The decapod crustaceans
of Oklahama. Publ. Univ. Okla. , Biological Survey 5(1-4): 12-47.
Crocker, Denton W. 1957. The crayfishes of New York State. Bull. New
York State Mus. (355): 1-97.
Crocker, Denton W. .and David W. Barr 1968. Handbook of the crayfishes
of Ontario. Royal Ontario Mus. by Univ. Toronto Press. 158p.
Faxon, Walter 1914. Notes on the crayfishes in the United States National
Museum and the Museum of Comparative Zoology, with descriptions
of new species and subspecies, to which is appended a catalogue of the
known species and subspecies. Mem. Mus. Comp. Zool. , Harvard
Coll. 40: 347-427.
1885. A revision of the Astacidae. Part I. The genera
Cambarus and Astacus. Mem. Mus. Comp. Zool., Harvard Coll.
10(4): 1-186.
Fitzpatrick, J. F. , Jr. 1967. The Propinquus group of the crawfish genus
Orconectes (Decapoda: Astacidae). Ohio, Jour. Sci. 67(3): 129-172.
34
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Francois, Donald D. 1959. The crayfishes of New Jersey. Ohio Jour.
Sci. 59(2): 108-127.
Hay, W. P. 1892. The Crustacea of Indiana. Proc. Indiana Acad. Sci.
1891: 147-151.
Hobbs, Horton H. , Jr. 1942. The crayfishes of Florida. Univ. Fla.
Publ. , Biol. Sci. Ser. 3(2): 1-179.
1962. Notes on the affinities of the members of the
Blandingii Section of the crayfish genus Procambarus. Tulane Stud.
Zool. 9(5): 273-293.
.(in press). On the distribution and phylogeny of
the crayfish genus Cambarus. Special publication on the Biota of the
Southern Appalachians. Virginia Polytechnic Institute Press.
Holthuis, Lipke B. 1949. Notes on the species of Palaemonetes (Crustacea
Decapoda) found in the United States of America. Koninklijke Neder-
landsche Akademie van Wetenschappen 52(1): 3-11.
1952. A general revision of the Palaemonidae (Crustacea
Decapoda Natantia) of the Americas. II. The subfamily Palaemoninae.
Alan Hancock Fnd. Publ. , Occ. Pap. (12): 1-396.
Hubricht, Leslie and J. G. Mackin. 1949. The freshwater isopods of the
genus Lirceus (Asellota, Asellidae). Amer. Midi. Nat. 42: 334-349-
Ortmann, A. E. 1931. Crawfishes of the Southern Appalachians and the
Cumberland Plateau. Ann. Carnegie Mus. 20(2): 61-160.
Perm, George Henry 1959. An illustrated key to the crawfishes of
Louisiana with a summary of their distribution within the state
(Decapoda, Astacidae). Tulane Studies in Zool. 7(1): 3-20.
and Horton H. Hobbs, Jr. • 1958. A contribution to-
ward a knowledge of the crawfishes of Texas (Decapoda, Astacidae).
Texas Jour. Sci. 10(4): 452-483.
Rhoades, Rendell. 1944. The crayfishes of Kentucky, with notes on vari-
ation, distribution, and descriptions of new species and subspecies
Amer. Midi. Nat. 31(1): 111-149-
Richardson, Harriet. 1905. A monograph of the isopods of North America.
Bull. U. S. Nat. Mus. (54): 1-727.
35
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Schmitt, Waldo L. 1965. Crustaceans. Univ. Mich. Press, Ann Arbor.
204 p.
Turner, C. L. 1926. The crayfishes of Ohio. Ohio State Univ. Bull.
30(11): 145-195.
Van Name, Willard G. 1936. The American land and fresh-water isopod
Crustacea. Bull. Amer. Mus. Nat. Hist. 71: 1-535.
Williams, Austin B. 1954. Speciation and distribution of the crayfishes
of the Ozark Plateaus and Ouachita Provinces. Univ. Kan. Sci. Bull.
36, Part 2 (12): 805-916.
Williams, Austin B. and A. Byron Leonard 1952. The crayfishes of
Kansas. Univ. Kan. Sci. Bull. 34, Part 2 (15): 961-1012.
36
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EPHEMEROPTERA
Lewis Berner
I INTRODUCTION
Mayfly nymphs are characterized by having chewing mouthparts; notice-
able wing pads developing on the mesothorax; tarsal claws single; gills on
abdominal segments 1-7 (some may be modified to form gill covers, others
are vestigial, and, in a few instances, some may be missing from certain
segments); and by having the abdomen terminate in three long tails (a few
genera have only two). All species require fresh water for development,
although one Florida form is tolerant of a certain amount of salinity.
The following key is restrictive, including only those genera known to
occur in the Southeast. Furthermore, nymphs in their early instars are
difficult to identify as distinctive traits may not yet have developed, and
this key should be used only for older insects. Pertinent characteristics
have been sketched using several sources, chiefly the works of Edmunds,
Burks, Day, and Berner. The key is designed to allow rapid identification
based on a minimal number of characters so that, although one may be
reasonably certain of the correctness of the generic name, it would be well
to verify it by referring to a full description of the nymph.
In identifying the number of a particular abdominal segment, it is some-
times difficult to distinguish the first. By starting with the most posterior,
or 10th segment, and counting anteriorly, the correct number can be assigned
to each segment. The segment number is of importance in counting gills.
Another characteristic that may offer some difficulty involves the de-
termination of the presence or absence of hindwing pads. In some of the
Baetidae, in particular, the great reduction of the hind wing in the adult is
reflected in the nymphal anatomy. The forewing pad must be lifted to observe
the hindwing pad; if the latter is very small, the insect must be moved to
allow for best examination. In some species of Baetis, the hind wing is
scarcely more than a thread and in the nymph the wing pad is barely visible.
As each genus is named in the key, a brief statement is made of the
most frequently encountered habitat in which the insect lives. Obviously
the statement is a very general one, and if further information regarding
the specific habitat is needed, more comprehensive works should be con-
sulted. The frequency of occurrence is also given in very general terms
and is meant to serve merely as a guide.
M
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II A KEY TO THE FAMILIES AND GENERA OF SOUTHEASTERN MAYFLIES
1 Thoracic notum greatly enlarged forming a shield extending to sixth abdominal segment and
covering gills (Fig. la) (Baetiscidae) Baetisca
(Sandy streams, usually with rocks or gravel; not common)
1' Thoracic notum not enlarged; abdominal gills exposed • , 2
2 (I1) Anterolateral angles of head and pronotum covered with dense cluster of spines (Fig. Ib); gills
ventral (Behningiidae) Dolania
(Sandy streams; rare)
2' Anterolateral angles of head and pronotum without such a crown of spines 3
3 (21) Mandibular tusks present and projecting forward (Fig. Ic); gills on abdominal segments 2-7
forked and margins fringed (Fig. Id) (Ephemeridae) 4
3' Mandibles not modified to form tusks; abdominal gills variable, not as above 9
Fig. 1. a. Baetisca, mature nymph b. Dolania, head and pronotum c. Hexagenia, mandible
d- Pentagenia. 4th gill, (a, abdomen; h, head; hs, head spines; ma, molar area; mt, mandibular
tusk; ps, pronotal spines; tn.thoroacic notum).
4 (3) Forelegs adapted for digging (Fig. 2a); tibiae flattened; gills dorsal; burrowing nymphs 5
41 Forelegs not adapted for digging; tibiae cylindrical; gills lateral; sprawling nymphs
(Potamanthidae) Potamanthus
(Sandy, rocky streams; not common)
5 (4) Head with a conspicuous frontal process between antennal bases (Figs. 2c, 3a, b, c) 6
5" Head lacking conspicuous frontal process (Fig. 2b) (Polymitarcidae) .Tortopus
(Burrows in clay banks of large rivers; not common)
6 (5) Mandibular tusks curve downward in lateral view; upper surface of tusks tuberculate (Fig. 2c)
(Polymitarcidae). . Ephoron
(Under rocks in swift streams; not common)
6" Mandibular tusks curve upward in lateral view (Fig. Ic); upper surface of tusks may have hairs
or spines but is not tuberculate (Ephemeridae) 7
-------
FiS- 2- a. Ephemera, foreleg b. Tortopus, right side of head c. Ephoron, head, (fp, frontal
process; mt, mandibular tusk).
7 (61) Frontal process bifid (Fig. 3c) 8
7' Frontal process entire (Fig. 3a) Hexagenia
(Streams and lakes, burrowing in soft bottom; common)
8 (7) Mandibular tusks with smooth margins (Fig. 3c) Ephemera
(Streams and lakes, burrowing in sandy bottom; not common in Southeast)
8" Mandibular tusks with outer margins crenate (scalloped with small, blunt rounded teeth)
(Fig. 3b) Pentagenia
(Burrowing in silt of larger streams; not common)
Fig. 3. a. Hexagenia, head b. Pentagenia, head c. Ephemera, head, (fp, frontal process;
mt, mandibular tusk (after Burks, 1953)).
9 (3') Gills on abdominal segment 2 operculate, quadrate; meeting at mid-line (Figs. 4a, b); gills on
1st segment vestigial 10
9' Gills otherwise; if gills on segment 2 are operculate, they are not quadrate and do not meet
at midline 12
10 (9) Hindwing pads present; median carina (ridge) may be present on abdominal segments 6-8
(Fig. 4a); mature nymphs large (8-14 mm) (Neoephemeridae) Neoephemera
(Slow to moderately swift streams; not common)
10'
Hindwing pads absent; no abdominal carina; mature nymphs small (2-7mm). . (Caenidae).
.11
-------
11 (10') Three prominent tubercles on head (Fig. 4c); maxillary and labial palpi 2-segmented (Fig. 4d)
Brachycercus
(Sandy streams; not common)
11' No tubercles on head; maxillary and labial palpi 3-segmented (Fig. 4e) Ca.ea.is
-(Quiet or stagnant water, temporary or permanent; some species in streams; believed to be
pollution tolerant; very common)
Fig. 4. a. Neoenhemera, dorsal view b. Brachycercus, abdomen c. Brachycerus, head
d. Brachycercus, maxilla e, Caenis, maxilla, (g. 1st gill; mp, maxillary palp; og, operculate gill;
t, tubercle).
12 (91) Operculate gills on abdominal segment 2 triangular or ovate (Fig. 5a). . . (Tricorythidae) 13
12' Gills otherwise. 14
13 (12) Operculate gills on segment 2 triangular (Fig. 5a); no scalelike structures on dorsal margin
of femora Tricorythodes
(In alkaline streams; not common)
13' Operculate gills on segment 2 ovate; sealelike structures present on dorsal margin of femora
and across middle of upper side of forefemur (Fig. 5b) Leptohyphes
(In larger rivers; rare) :
14 (12') Gills present on segments 3-7 or 4-7 (Figs. 5c, d); if present on 4-7, fourth gill may be
operculate (Fig. 5d); 1st gill absent or vestigial (Ephemerellidae) Ephemerella
(Occurs in streams and lakes; common)
14' Gills present on segments 1-7 15
M
-------
Fig. 5. a. Trlcorythodes, abdomen b. Leptohyphes, foreleg c. Ephemerella, abdomen
d. Ephemerella, abdomen, (f, femur; og, operculate gill; ss, scalelike structure).
15 <14') Nymph depressed, at least in head and thoracic regions; eyes and antennae dorsal (Fig. 6a). . 16
15' Body not depressed; eyes lateral or anterolateral (Fig. 6b) 27
16 (15) Gills forked, in filamentous clusters or bilamellate (Figs. 6c, d, e); labial palpi 3-segmented
(Leptophlebiidae) 17
16' Gill lamellae single, usually with tuft of filaments at or near base; labial palpi 2-segmented. . .
(Heptageniidae) 21
17 (16) Gills on segments 2-6 consist of 2 clusters of slender filaments (Fig. 6d) Habrophlebia
(In small streams among debris in slow water; occasional)
17' Gills forked or bilamellate (Figs. 6c, e> 18
18 (171) Gills on segment 1 different from those of other segments.. 19
18' Gills on segment 1 like those of other segments; gills on middle segments with lamellae forked
for about half their length (Fig. 6c) 20
19 (18) Gills on segment 1 single, forked; terminal extensions of expanded middle gills slender, thread-
like (Fig. 6e) .Lcptophlebla
(In slowly flowing streams; not common)
19' Gills on segment 1 single, not forked; terminal extension of upper lamellae of middle gills
board and spatulate (Fig. 6f) Choroterpes
20 (18') Labrum rather deeply emarginate on fore margin (Fig. 7a); posterior margins of segments
6 or 7-10 with spinules Habrophlebiodes
(In slowly flowing streams; occasional)
20' Labrum only slightly emarginate (Fig. 7b); spinules on posterior margins of segments 1-10. . . .
Paraleptophlebia
(Moderately or swiftly flowing streams; common)
M
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Fig. 6. a. Stenonema, head. b. Baetis, dorsal view of nymph c. Paraleptophlebia, 4th gill
d. Habrophlebia, 4th gill e. Leptophlebia, 3rd gill f. Choroterpes. 3rd gill, (gl, gill lamella;
h, head; p, pronotum).
21 (16') Fingerlike projection extending from near middle of gill lamellae (Fig. 7c); claws much
elongated; maxillary palpi 3-segmented Pseudiron
(Larger streams, burrowing in sand; rare)
21' No fingerlike projection on gill; claws not greatly elongated; maxillary palpi 2-segmented
(Fig. 7d). 22
22 (21') Two tails present .Epeorus
(Swiftly flowing, rocky streams; common)
22' Three tails present 23
23 (22') Gills inserted ventrally; filamentous protion of gills large, longer than lamellae. . . . Anepeorus
(Habitat unknown)
23' Gills dorsal or lateral; filamentous portion of gills smaller or absent, usually shorter than
lamellae 24
24 (23') Gills of 1st and 7th. segments enlarged and meeting beneath body to form a ventral adhesive
disk Rhithrogena
(In swiftly flowing, rocky streams; not common)
24' Gills of 1st and 7th segments not as above, usually smaller than others 25
25 (241) Gills of 7th segment reduced to slender filament (Fig. 7e) Stencnema
(In streams of all sizes and at edges of lakes; very common)
25' Gills of 7th segment reduced but similar in shape to anterior gills. , 26
-------
Fig. 7. a. Habrophlebiodes, labrum b. Paraleptophlebia, labrum c. Fseudiron, 3rd gill
d. Stenonema, maxilla e. Stenonema, 7th gill, (fe, fingerlike extension; gf, gill filaments; gl,
gill lamella; le, labrum emargination).
26 (E51) Filamentous part of gills absent or* reduced to few small threads (Fig. 8a); front of head
distinctly emarginate Cinygmula
(In swift, rocky streams; very rare in southeast).
26' Filamentous part of gills present on segments 1-6, may be absent from 7; front of head entire
or only slightly emarginate Heptagenia
(In shallow, swiftly flowing streams; common in highland streams, rare in coastal plain)
27 (15') Gills forked, in filamentous clusters of bilamellate (Figs, 6c, d, e); head pro- or hypognathous
(Leptophlebiidae) 17
27' Gills not forked; single or with double lamellae; head hypognathous 28
28 (27'j Forelegs with dense row of long hairs on inner margin (Fig. 8b); tuft of gills at base of maxilla;
gills may be present at base of each forecoxa 29
28' Forelegs not as above; no gill tufts on maxillae and forecoxae 30
29 (28) Gills dorsal on 1st segment; gill tufts present at base of forecoxae; gills platelike, each with
a basal filamentous portion (Siphlonuridae) -Isonychia
(In swiftly flowing streams of all sizes; common)
29' Gills enlarged and ventral on 1st abdominal segment; no gill tufts at base of forecoxae;
lamellate portion of gills on segments 2-7 lanceolate, filamentous portion absent (Fig. 8c). . . .
(Oligoneuriidae) Homoeoneuria
(In sandy-bottomed streams, burrowing in sand; rare)
30 (281) Claws of forelegs bifid (Fig. 8d) (Ametropodidae) Siphloplecton
(In vegetation of slowly flowing streams and at lake margins; rare)
30' Claws of forelegs not bifid; similar to those of other legs 31
31 (30') Posterolateral angles of segments 8 and 9 produced into distinct flattened spines (Fig. 8e)
(Siphlonuridae) 32
31' Posterolateral angles of segments 8 and 9 without such spines. . •. . (Baetidae) 33
32 (31) Maxillae with a crown of pectinate spines (Fig. 9a); gills obovate, with a scleroterized band
along the outer margin and sometimes on the inner; posterolateral spines may be weakly
developed Ameletus
tin small, swift streams; not common).
32' No crown of spines on maxillae; gills platelike and double on 1st and 2nd segments at least
Siphlonuru s
(Quiet areas of streams and in small lakes; rare in Southeast)
33 (311) Gills simple, single lamellae (Fig. 9c) 35
33' Gills double or lamellae with recurved dorsal or ventral flap (Figs. 9b, 9d) 34
M
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Fig. 8. a. Cinygmula, 3rd gill b. Isonychla, foreleg c. Homoeoneuria, 4th gill d. Siphloplecton,
claw of foreleg e. Siphlonurus, dorsal aspect of abdomen, (f, femur; fh, foreleg hairs; gf, gill
filaments; gl, gill lamella; i, inner margin of femur; pi, posterolateral spine; tc, tarsal claw;
viii, ix, 8th and 9th abdominal segments).
34 (331) Hindwing pads present Callabaetis
(In quiet water; may be able to withstand some pollution as well as brackish water,
very common)
34' Hindwing pads absent Cloeon
(In vegetation in flowing water; not common)
35 (33) Two tails present; median tail rudimentary or absent (Fig. 9e) 36
35' Three fully developed tails; median tail may be shorter and thinner than laterals (Fig. 6b). . . 37
36 (35) Hindwing pads present but they may be minute Baetis
(In streams of all sizes; very common)
36' Hindwing pads absent Pseudocloeon
(In streams of all sizes; common)
37 (35") Median tail shorter and thinner than laterals (Fig. 6b); claws denticulate; distal segment of
labial palpi rounded apically (Fig. 9f) (see couplet 36) Baetis
37' Median tail subequal to laterals; claws denticulate or not; distal segment of labial palpi
variable (Figs. 9f, g) 38
38 (371) Tracheae of gills with fully developed branches on inner side (Figs. 9b, c) 39
38' Tracheae of gills with lateral branches poorly developed (Fig. 9h) Paracloeodes
(Larger streams, on surface of sand; rare)
39 (38) Hindwing pads present Centroptilum
(Slowly flowing streams and edges of lakes; occasional)
39' Hindwing pads absent. ...» Neocloeon
(In small to medium size streams; rare)
M
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Fig. 9. a. Ameletus. maxilla b. Centroptilum, 4th gill c. Cloeon, 1st gill d. Callibaetis, 4th
gill e. Pseudocloeon, dorsal aspect of abdomen i. Baetis, labial palp g. Centroptilum labial palp
h. Paracloeodes, 4th gill, (ds, distal segmertt; gl, gill lamella; s, pectinate spines; tr, tracheae;
vmt, vestigial middle tail).
M
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Ill SELECTED REFERENCES
Berner, Lewis. 1950. The mayflies of Florida. Univ. Florida Studies,
Biol. Sci. Series 4(4): 1-267
Burks, B. D. 1953. The mayflies, or Ephemeroptera, of Illinois.
Bull. Illinois Nat. Hist. Surv. 26(1): 1-216.
Day, W. C. 1956. Ephemeroptera, p. 79-105. In R. L. Usinger (ed. ).
Aquatic insects of California. Univ. California Press, Berkeley.
Edmunds, G. F. , Jr. 1959. Ephemeroptera, p. 908-916. Jn W. T.
Edmondson (ed.). Fresh-water biology. John Wiley and Sons,
New York.
Needham, J. G. , J. R. Traver, and Yin-Chi Hsu. 1935. The biology of
mayflies. Comstock Publishing Co. , Ithaca. 759 p.
Pennak, R. W. 1953. Fresh-water invertebrates of the United States.
Ronald Press Co. , New York. 769 p.
Traver, Jay R. 1932-33. Mayflies of North Carolina. Jour. Elisha
Mitchell Sci. Soc. 47(1): 85-161; (2): 163-236; 48(2): 141-206.
M 10
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PLECOPTERA
J. F. Hanson
I INTRODUCTION
The following key is not a natural key. It is designed to identify
the genera and subgenera of stoneflies by the most conspicuous
characters and by characters that are present in all or most of the
stages of naiad growth. Wing pads, though very helpful when present,
exist only in the last few of frequently more than 20 instars.
The characters used in the key are entered in decreasing order
of importance or ease of usage. The first character listed will gen-
erally suffice for a decision but the others will, of course, add to
your general familiarity with the group.
Since stonefly naiads, because of their high oxygen requirements,
live only in moving water, their presence in a stream or river is often
taken to indicate lack of organic pollution. This is reasonable logic for
species with long life cycles having naiads that spend two to four years
in the water. However, most species have a one-year life cycle and
often spend most of the year in the egg stage which is probably quite
resistant to pollutants and quite tolerant of relatively low oxygen content
of the water. Because many species have long egg stages, sampling
difficulties also occur. During the summer it is often difficult to find
any stonefly naiads in a stream that may actually carry a varied and
abundant fauna. Another disconcerting factor is that stoneflies are quite
mobile, especially when the naiads are nearly full grown and ready for
emergence as adults. Thus they may often by carried far downstream
to their development in and emerge from quite polluted waters. There-
fore, considerable caution must be exercised in interpreting sample col-
lections. Much more ecological information on stoneflies is needed
before they can be fully exploited as pollution indicators.
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II KEY TO THE GENERA AND SUBGENERA OF PLECOPTERA NAIADS OF THE SOUTHEASTERN
UNITED STATES
1 " Each thoracic sternal plate overlapping the segment behind; body roachlike both in form
and in its uniform brown color (never over 3/4" long) (Fig. 8). . . Peltoperlidae Peltoperla
1' Not as above 2
2 (1T) Gills, when present, branched (visible best ventrally) 3
2' Gills unbranched or absent 12
3 (2) Gills on first two abdominal segments; pronotum wider than head and with corners usually
produced (Fig. 9); dark brown to black (the largest North American stoneflies, over 1 1/2"
long when mature often present in a variety of sizes since the life cycle is 3 to 4 years long). .
Pteronarcidae. Pteronarcys 4
3' Gills absent on first two abdominal segments 5
4 (3) Abdomen with lateral processes extending from most segments (Fig. 9). . . subgenus Allonarcys
4' Without lateral abdominal processes subgenus Pteronarcys
5 (31) Gills present on neck only .... Nemouridae Nemoura (Amphinemoura)
5' Branched gills on each thoracic segment Perlidae 6
6 (51) Only two ocelli present 7
61 Three ocelli present 8
7 (6) Compound eyes less than one eye diameter from the hind margin of the head; a row of spinules
across back of head; ocelli large and relatively close together Neoperla clymene
71 Compound eyes more than one eye diameter from the hind margin of the head; no row of
spinules across back of head Atoperla ephyre
8 (6') Compound eyes more than one eye diameter from the hind margin of the head.Perlinella drymo
8' Compound eyes less than one eye diameter from the hind margin of the head 9
9 (81) Body light colored and freckled with small brown dots (Fig. 10); second tooth of lacinia
almost as large as the first and followed by a single hair Perlesta
9' Body not freckled; lacinia with second tooth much smaller than the first and usually
followed by a fringe of hairs: mostly strikingly patterned naiads 10
10 (91) No occipital ridge across back of head ; Acroneuria
10' Occipital ridge present (Fig. 11). '.11
11 (10') Gills present between bases of cerci; head crossed by two parallel dark bands one of which
is connected to dark markings over the lateral ocelli (Fig. 11) Neophasganophora capitata
11' Subanal gills absent; head not colored as above Paragnetina
12 (21) Glossae much shorter than the paraglossae (Fig. la) .13
12' Tips of glossae produced about as far forward as the tips of the paraglossae (Fig. Ib). 16
Fig. 1.
-------
Fig. 2.
13 (12) Cerci when parallel to each other never separated by as much as the thickness of the basal
segment partly because of the relatively small subanal lobes (Fig. 2a); cerci never more than
3/4 the length of the abdomen; axis of wing pads parallel to body axis (Figs. 3a, b); Y-shaped
mesoternal suture pale and usually incomplete (Fig. 4a) Chloroperlidae 14
13' Cerci when held parallel to each other always separated by at least the thickness of the
basal segment (Fig. 2b); wing pads (present in late instars only) divergent (Fig. 3c); Y-
Y-shaped suture of mesosternurn reaching furcal pits and usually easily visible. (Fig. 4b)
Perlodidae 15
Fig. 3. a. Hastaperia b. Alloperla c. Isoperla.
Y
Fig. 4.
14 (13) In mature naiads the inner margin of the hind wing pad notched slightly (Fig. 3b) Alloperla
14' In mature naiads the inner margin of the hind wing pad not notched (Fig. 3a) Hastaperia
15 (13') Gills present on corners of submentum (Fig. la) Isogenus
15' Submental gills absent Diploperla, Isoperla
16 (12) First and second tarsal segments subequal in length (Fig. 5a); wing pads (last few instars only)
notably divergent, wide Taeniopterygidae 17
16' Second segment of tarsus much shorter than the first (Fig. 5b) 18
-------
. 5.
Fig. 6.
17 (16)
17'
18 (16')
18'
Each coxa with a single 3-segmented filamentous gill on the inner side (Fig. 6); ninth abdominal
sternite not produced to the rear Taeniopteryx
No gills; ninth abdominal sternite about twice as long as the tergite Brachyptera
Elongate naiads; hind legs when extended backwardly not reaching the last segment of the
abdomen; with non-divergent wing pads (last few ins tars only) (Fig. 12) 19
Stout naiads whose hind legs can be extended to the last abdominal segment or beyond (Fig.
13) Nemouridae Nemoura
19 (18)
19'
20 (19)
20'
21(19')
21'
22 (21')
22'
Abdominal segments beyond 4 not divided into tergal and sternal sclerites and thus
appearing cylindrical; subanal lobes usually longer than wide Leuctridae 20
Abdominal segments 1 to 9 divided laterally by membrane and usually not appearing parallel
sided from above; subanal lobes wider than long. Found in streams only in winter
Capniidae 21
Labial palpi extending beyond paraglossae Leuctra
Labial palpi not extending beyond paraglossae Paraleuctra
Most of the body and appendages densely covered with stout, dark, conspicuous bristles;
thoracic sternum as shown in Fig. 7a Paracapnia
Bristles on the body slender and inconspicuous and often sparse 22
Mesothoracic furcasternum nearly an isosceles triangle and separate from postfurcasternal
plates (Fig. 7b) Allocapnia
Mesothoracic furcasternum transversely elongate and fused to the postfurcasternal plates
(Fig. 7c) Nemocapnia
Fig. 7. a. Paracapnia b. Allocapnia c. Nemocapnia (is, lurcasternal plate; pfs, post-
furcasternal plate).-
-------
Fig. 11. Phasganophora
Fig. 12. Leuctra
Fig. 13. Nemoura
P 5
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Ill SELECTED REFERENCES
Claassen, P. W. 1931. Plecoptera nymphs of America (north of Mexico),
199 pp. Thomas Say Foundation (available from Cornell).
Needham, J. G. and P. W. Claassen. 1925. A monograph of the
Plecoptera or stoneflies of America north of Mexico. Ent. Soc.
America, Thomas Say Foundation 2: 1-397.
Ricker, W. E. 1959. Plecoptera. In Fresh-water Biology by
Edmonson, pp. 941-957.
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TRICHOPTERA
J. B. Wallace
I INTRODUCTION
There are approximately 19 families of caddisflies in North America.
Almost every family has some representatives in the southeast. The
southern Appalachians and their foothills are very lucrative collecting areas.
Caddisfly larvae occupy a variety of habitats ranging from spring seeps
and ponds to swift mountain streams. Techniques used in collecting larvae
range from hand picking from rocks, etc. to the use of dip nets in streams
and ponds.
Larvae and pupae should be preserved in about 80 percent ethyl alcohol
initially. After about one week the original collecting fluid should be re-
placed with fresh alcohol. This procedure keeps the alcohol from becoming
diluted with body fluids and water that was on the specimens and in larval
cases when originally preserved. Killing larvae in boiling H2O before
dropping them into alcohol results in well extended specimens and often facil-
itates identification.
Caddisfly larvae fall into various types; for a complete account see Ross
(1944) or Denning (1956). A brief description of these types is as follows:
Free living forms - larvae living without cases or nets.
Net spinning forms - spin nets which are attached to plants, rocks, etc;
these nets collapse when taken from the water.
Tube making forms - some psychomyiid larvae burrow into the sandy
bottom of stream beds and cement the wall of the tube together.
Saddle case makers - as in the Glossosomatidae live in tortoise-like
cases made of small gravel.
Purse case makers - have a slit at each end of the case for the head and
anal legs respectively; this type of arrangement is found in many of the micro-
caddisflies or Hydroptilidae.
Case makers - a wide variety of cases made from various plant materials
to sand grains.
Some of the more important morphological characters used in larval
identification are indicated in Text Fig. 1. The sclerite and setae pattern of
the mesonotum follows the labeling of Ross (1959). The sclerites and/or setae
may or may not be present, depending upon the group. The anterior pair of
sclerites and/or setae are sa 1 (Text Fig. 1. c), posterior pair sa 2, and
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lateral pair sa 3.
Most of the following keys are modified from the classical works of
Dr. H. H. Ross. We are greatly indebted to Dr. Ross and Dr. O. S.
Flint, Jr. for permission to redraw some of their figures.
vpronotum
Text Fig. 1. Trichoptera. a. Dorsal view, larva of Limnephilidae.
b. Lateral view, head and first thoracic segment, c. Dorsal view,
hypothetical metathorax showing location of Sa 1, Sa Z, and Sa 3; (a and b
resketched from Ross, 1944).
-------
II KEY TO FAMILIES OF TRICHOPTERAN LARVAE *
Dorsum of each thoracic segment with a large, sclerotized shield (Fig. Iss). . 2
Either meso- or metathoracic segment, or both, without such shields or subdivided into sep-
arate plates (Fig. 2a) 3
Fig. 1. Trichoptera. Lateral view of Hydropsyche. (ap, anal prolegs; bg, branched gills;
ss, sclerotized shields).
2 (1) Abdomen with a number of branched gills (Fig. Ibg), larvae net spinners, living in nests
' Hydropsychidae
2' Abdomen without such gills, minute forms, 6 mm or less; late instars living in definite cases. .
Hydroptilidae
3 (1) Larvae free living; or, living in tortoise shaped cases (Fig. 3a); anal prolegs generally pro-
jecting free and beyond membranous lobes of tenth segment 4
3' Larvae living in cases other than tortoise shaped ones above; anal prolegs appearing as lateral
sclerites of membranous lobes of tenth segment (Fig. 3b), or distinct hump on dorsum of first
abdominal segment 6
Fig. 2. Trichoptera. a. Dorsal view, thorax of Neophylax. b. Lateral view, posterior
end of abdomen of Rhyacophila. (I. prothorax; II, mesothorax; in, metathorax; ss, sclerotized
shield).
4 (3) Dorsum of ninth abdominal segment entirely membranous, without a sclerotized shield.
.(Fig. 4a).
4' DorVum'of ninth abdominal segment with a sclerotized shield (Fig. Zb) Rhyacophilidae
*Modified from Ross (1959).
-------
5 (4) Lab rum expanded into a wide, membranous, T-shaped structure anteriorly (Fig. 4bl)
Philopotamidae
5' Labrurn short, sclerotized Psychomyiidae
6 (3') Claws of metathoracic legs very small (Fig. 4c), those of meso- and prothoracic legs large. . .
Molannidae
6' Claws of metathoracic legs as long as those of mesothoracic legs 7
Fig. 3. Trichoptera. a. Case of Glossosoma b. Lateral view, posterior end of abdomen of
Limnephilidae. (c, claw of anal proleg).
7 (61) Antennae long, at least 7-8 times as long as wide and arising near base of mandibles (Fig. 5a).
Leptoceridae
7' Antennae much shorter, not over 3 or 4 times as long as wide, often inconspicuous, arising at
various locations (Fig. 5b) 8
8 (71) Mesonotum largely membranous except for a pair of parenthesis-like sclerotized bars (Fig. 5c)
Leptoceridae
8' Mesonotum without such bars 9
Fig. 4, Trichoptera. a. Lateral view, posterior end of abdomen of Wormaldia. b. Dorsal vie
head of Wormaldia. c. Claws of Molanna. (1, labrum; 1, claws of first leg; 2, claws of second leg; 3
claws of third leg).
9 (8') Larvae living in cylindrical cases of plant material, mesonotum and metanotum almost entirely
membranous or with only minute sclerites (Fig. 21) Phryganeidae
9' Mesonotum and usually metanotum with a few conspicuous sclerotized plates (Figs. 2a, 23b, c)
10
10 (91) Hind tarsal claws long and without a basal tooth (Fig. 6a); pronotum with a deep, transverse
furrow across the middle (Fig. 7b, slf) Beraeidae
10' Without furrow on pronotum or hind tarsal claw, with a large basal tooth (Fig. 6b, tt) 11
11 (10') Pronotum in lateral view with a deep furrow running from the pleural suture just in front of
posterior margin of the pronotum, completely transversing the pronotum (Fig. 6c) 12
11' Pronotum in lateral view without such suture (Fig. 7a) 16
-------
Fig. 5. Trichoptera. a. Lateral view, head of Leptocerus. b. Lateral view, head of Neophylax.
c. Dorsal view, head, pro- and mesothorax of Athripsodes. (a, antenna; e, eye; Plb, parenthesis-like
bars).
12 (11) Mesonotum with 2 pairs of dorsal plates (Fig. 7b, c) 13
12' Mesonotum with only a single, rectangular sclerite with a median fracture (Fig. 23b, c) 15
Fig. 6. Trichoptera. a. Hind lee of Berae b. Hind leg of Brachycentrus c. Lateral view,
pronotum of Limnephilus. (f, furrow; tt, tooth of tar sal claw; vs, ventroapical spur of tibia), (a,
redrawn from Ross).
13 (12) Antennae located at margin of head near base of mandibles, or difficult to distinguish 14
13' Antennae located between margin of head and the eye, or close to eye (Fig. 8a) 15
14 (13) Mesonotum with rectangular plates; pronotum with a sharp furrow transversing the middle;
metanotum with sa 1 absent (Fig. 7b) Brachycentridae
14' Mesonotum with trianguloid plates; pronotum without above furrow; metanotum with sa 1 present,
in form of small plates (Fig. 7c) Goeridae
15 (12') Antennae located close to eye (Fig. 8a); no hump on first abdominal tergite, metanotum gen-
US') erally with single hairs at sa 1 and sa 2 Lepidostomatidae
15' Antennae located midway between eye and margin of head (Fig. 5b) or closer to margin of head
than eye; hump present on first abdominal tergite; metanotum with sa 1 and sa 2 with small
plates (Fig. 23b) or with a cluster of setae Limnephilidae
-------
Fig. 7. Trichoptera. a. Lateral view, pronotum of Leptoceridae. b. Dorsal view, thorax
of Brachycentrus. c. Dorsal view, thorax of Goera. (slf, suture like furrow; I, prothorax; II,
mesothorax; III, metathorax).
16 (II1) Metanotum with sa 1 in the form of a wide plate, often weakly sclerotized, with a row of hairs
(Fig. 8b); antennae situated on or under a ridge at anterior margin of head (Fig. 8c> 17
16' Metanotum with only a single hair at sa 1; antennae not on a ridge; antennae midway between
the margin of the head and eye (Fig. 9a) 18
I
Fig. 8. Trichoptera. a. Lateral view, head of Lepidostoma b. Dorsal view, thorax of
Psilotreta c. Lateral view, head of Psilotreta. (a, antenna; e, eye; r, ridge; I, pronotum; II,
mesonotum; III, metanotum).
17 (16) Gills consisting of tufts of fine threads, metanotum with sa 2 consisting of a row of hairs, on
a narrow elongate plate (Fig. 8b) Odontoceridae
17' Each gill single; metanotum with sa 2 represented by a single setae on a small plate
Sericostomatidae
18 (161) Larvae in cases resembling snail shells (Fig. 9b), anal hooks with a comb of teeth (Fig. 9c). . .
Helicopsychidae
18' Case not as above; anal hooks with at most 2 accessory teeth Calamoceratidae
Fig. 9. Trichoptera. a. Lateral view, head of Helicopsyche b. Case of Helicopsyche c.
Lateral view, claw of anal proleg of Helicopsyche. (a, antenna; e, eye; t, teeth of claw of anal proleg)
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FAMILY PHILOPOTAMIDAE
Three widespread genera Chimarra. Wormaldia and Sortosa are found over most of the U. S.
They construct long, narrow, finger-like nets which always collapse when removed from the water
All 3 genera are found in rapid streams. The genera Wormaldia and Sortosa are generally re.tricted
to colder streams. The following key is modified from Ross (1944).
Apex of frons deeply emarginate (Fig. lOa) and very irregular in outline Chimarra
Apex of frons only slightly asymmetrical (Fig. lOb) or perfectly symmetrical (Fig. 4b) 2
Apex of frons slightly asymmetrical; posterior portion of frons uniform in width (Fig. lOb)
.Sortosa
Apex of frons symmetrical, posterior portion of frons wider than constricted mid portion
' 4b> . .Wormaldia
Fig. 10. Trichoptera. a. Dorsal view, head of Chimarra b. Dorsal view, head of Sortosa
c. Lateral view, base of front leg of Polycentropus d. Lateral view, base of front leg of Lype. (af,
apex of frons; e, episternum; t, trochantin).
FAMILY PSYCHOMYIIDAE
A large family with 9 North American genera. The larvae are all net spinners; however, they
differ somewhat from others of the net spinning group in that some of them are found in lakes as well
as rivers. The following key is adapted from that of Flint (1964).
1 Fore trochantin at base of front leg represented by a long, sharp point (Fig. lOc), fused com-
pletely with the episternum and no suture at its base (Polycentropinal) 2
I1 Fore trochantin squarish distally (Fig. lOd), set off from episternum by a distinct sclerotized
ridge (Psychomyiinae) .7
2 (1) Mandibles short, triangular, each with a thich bush of hair me sally (Fig. lla). . .Phylocentropus
2' Right mandibles without a brush of hair mesally, mandibles longer than broad (Fig. 11, b). . . . 3
3 (21) Muscle scars of head and pronotum as light or lighter than surroundings 4
3' Muscle scars darker than surroundings .' 6
4 (3) Claws of anal prolegs with ventral teeth (Fig. lie) 5
4' Claws of anal prolegs without such teeth Cyrnellus
Fig. 11. Trichoptera. a. Dorsal view, mandibles of Phylocentropus b.
of Polycentropus c. Lateral view, claw of anal proleg of Nyctiophylax. (mb,
t, teeth), (c, redrawn from Flint).
Dorsal view, mandibles
mandibular brush;
-------
5 (4) Claws of anal prolegs with ventral teeth much shorter than apical hook (Fig. lie) and with an
external hook Nyctiophylax
51 Claws of anal prolegs with ventral teeth nearly as long as apical hook, no external hook
(Fig 12a) (Cernotina? ) Genus C (Flint)
6 (31) Tenth abdominal segment with numerous long hairs Polycentropus
6' Tenth abdominal segment without hairs • • • Neureclipis
7'
7 (I1) Tibia and tarsi fused, southwestern species Xiphocentron
Tibia and tarsi not fused.
8 (7') Claws of anal proleg with several long teeth ventrally (Fig. 12b) Fsychomyia
8' Claw of anal proleg without ventral teeth 9
9 (81) Mandibles in dorsal view longer than broad, western species .Tinodes
9' Mandibles forming almost an equilateral triangle in dorsal view LYPe
bf,
Fig. 12. Trichoptera. a. Lateral view, claw of anal proleg of Psychomiid Genus C Flint
b. Lateral view, claw of anal proleg of Psychomyia c. Lateral view, head of Macronemum d.
Dorsal view, head of Macronemum. (bfa, broad flat area; c, carina; t, teeth of anal claw), (a and
b, redrawn from Flint).
FAMILY HYDROPSYCHIDAE
Probably the most abundant family of caddisflies (in numbers) encountered in southeastern streams.
The family and most of the genera are found over a wide range of ecological conditions in streams.
This is especially true for the genera Hydropsyche and Cheumatopsyche. The immature stages of two
eastern genera, Oropsyche and Aphropsyche, each comprised of a single species, are unknown. The
larvae spin nets over the entrance of various retreats housing them. Hydropsyche Genus A Ross is
found in springs in the central and eastern portions of the U. S.
As Ross (1959) states, it is very important to have cleaned larvae prior to attempting identi-
fication of this group. A camel's hair brush is recommended.
1 Head with a broad, flat, dorsal area set off by an extensive accurate carina (Figs. 12c, d) found
in large streams and rivers Macronemum
1' Head without such an area _. 2
2 (I1) Left mandible with a thumb-like dorsolateral projection on the basal portion (Figs. 13a, b).
Found in small spring-fed streams in central, eastern, and southern U. S
Hydropsy chid Genus A_ Ross
21 Left mandible not as above 3
3 (2') Fore trochantin forked (Fig. 13c) 4
3' Fore trochantin not forked (Fig. 14a). 5
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Fig. 13. Trichoptera. a. Dorsal view, left mandible of Hydropsychid Genus A Ross b. Lateral
view, head of Hyropsychid Genus A Ross c. Lateral view, trochantin at base of front leg of
Hydropsyche. (dp, dorsal projection of mandible; t, trochantin).
4 (3') With a pair of detached prominent sclerites posterior to prosternal plate (Fig. 14b). Widespread
and common Hydropsyche
4' Prosternal plate with only 1 pair of minute sclerotized dots posteriorly (Fig. 14c). Widespread
and common Cheumatopsyche
Av,
V
Fig. 14. Trichoptera. a. Lateral view, trochantin at base of front leg of Diplectrona b.
Ventral view, prosternum of Hydropsyche c. Ventral view, prosternum of Cheumatopsyche d. Ventral
view, head of Parapsyche . (bfl, base of front legs; ge, genae; gu, gula; psp, prosternal plate; sd,
sclerotized dots; sp, sclerotized plate).
5 (31)
Gula rectangular and elongate, separating genae completely (Fig. 14d); each branched gill with
all branches arising at distal end of the basal stalk (Fig. 15a). ............................. 6
Gula triangular and short genae meeting for most of their width (Fig. 15b); each gill with its
branches arising from sides and apex of basal stalks (Fig. 15c) ............................ 7
Fig. 15. Trichoptera. a. Abdominal gill of Parapsyche. b. Ventral view, head of Diplectrona.
c. Abdominal gill of Diplectrona. d. Ventral view, head of Arctopsyche. (ge, genae; gu, gula).
-------
6 (5)
6'
8 (7'
Gula rectangular and of even width (Fig. 14d) Parapsyche
Gula narrowed posteriorly (Fig. 15d) Arctopsyche
7 (51) Basal portion of mandibles with wing-like dorsolateral flanges (Fig. 16a). Larvae found in
warm streams. Potamyia
7' Mandibles without such flanges 8
Anterior margin of head with frons expanded laterally (Fig. 16b). Widespread species
Diplectrona
Southwestern species, frons without such expansions.
Smicridea
Fig. 16. Trichoptera. a. Dorsal view, mandibles of Potamvia b. Dorsal view, head of
Dipleetrona. (dlf, dorsolateral flange; ea, epicranial arms; lef, lateral extension of frons).
FAMILY RHYACOPHILIDAE (including GLOSSOSOMATIDAE)
This family is almost entirely limited to swift flowing streams. The mountain streams are especially
lucrative sources for specimens of this family. The Rhyacophilidae (sensu stricto) are free living and
predaceous. The Glossosomatidae are saddle case makers living in cases resembling tortoise shells.
Flint (1962) has keys to species for the eastern Rhvacophila.
1 Larvae free living without cases (Rhyacophilidae) 2
1' Larvae living in saddle - shaped cases resembling a tortoise shell (Fig. 3a) (Glossosamatidae). .
3
2(1) Front legs similar, differing little from middle and hind legs; prosternum membranous. Wide-
spread Rhyacophila
21 Front legs rather chelate (Fig. 17a) other leg sample; with a large sclerotized plate on the
prosternum. Southwestern U. S Atopsyche
3 (I1) Tarsal claws trifid (Fig. 17b). Southern Appalachian region Matrioptila
3' Tarsal claws not as above. Widespread species. . 4
4 (31) Anal claw divided into many teeth (Fig. 17c). Widespread Protoptila
4' Anal claw with one large tooth and 1 or 2 small ones 5
Fig. 17. Trichoptera. a. Front leg of Atopsyche. b. Trifid tarsal claw of Matrioptila. c. Ho
on anal claw of Protoptila posterior and lateral, (a and c, redrawn from Ross, b, redrawn from Flin
10
-------
5 (41) Pronotum notched at extreme anterolateral margin at which point the legs are attached (Fig. 18a).
Widespread Glossosoma
5' Legs attached near center of pronotum; pronotum tapering inward from middle to anterior
margin (Fig. 18b) 6
Fig. 18. Trichoptera. a. Dorsal view, pronotum of Glossosoma. b. Dorsal view, pronotum of
Agapetus. (fl, front legs; p, pronotum). (b, redrawn from Ross).
6 (51) Rocky mountain region only, sa 1 generally present on abdominal tergites 3 and 6
Anagapetus
6' Sa 1 generally absent on abdominal tergites 3 and 6. Widespread including Western U. S
Agapetus
FAMILY HYDROPTILJDAE
This family is known as the microcaddisflies. The larvae are generally less than 6 mm long.
They occupy a wide range of habitats, ranging from ponds and lakes to streams. The last instar
larvae build purselike or barrel shaped cases. The first four instar s are free living. The follow-
ing key is adapted from those of Ross (1944) and (1,959).
1 Abdomen slender, not much larger than thorax, free living forms without cases, early in-
star larvae [[[ Not
1' Abdomen large, at least some portions of the abdomen are much thicker than the thorax
(Fig. 19c), larvae living in cases of definite construction .................................. 2
2 All legs similiar, submentum divided, case flattened dorsoventially and made of liverwort.
Small springs in mountainous regions ........................................ Paleagapetus
2" Not with above combination of characters ................................................
3 (2') Each abdominal tergite with a dark, sclerotized dorsal area (Figs. 19a, b, c) ............... 4
3' Abdominal segments 2 to 7 without dark, sclerotized dorsal areas, though a small delicate
sclerotized ring (Fig. 19c) may be present ............................................... 5
4 (3) Middle of dorsal sclerites of abdomen membranous (Figs. 19b, c) ............... Ochrotrichia
4' Dorsal sclerites of abdomen solid with no membranous area in the middle ........ Leucotrichia
5 (3') Abdomen with distinct dorsal and ventral projections (Fig. 19d) ................... .Ithytrichia
5' Abdominal segments without such projections ............................................
6 (5') Middle and hind legs approximately 3 times longer than front legs (Fig. ZOa) ........ Oxyethira
6' Middle and hind legs no more than 1-1/2 times as long as front legs (Fig. 20c) ............... 7
7 (6') Tarsal claws and tarsus subequal in lengthjcase purselike (Figs. 20b, d)
7' Tarsal claws much shorter than tarsus; case barrel shaped, not purseUke
8 (7) Each tarsal claw with a long, stout tooth. Case purselike (Fig. 20d, to)
v ' Stactobiella (=Tascobia)
8' TaVsaVclawB without such stout teeth, though smaller teeth may be present; case purselike or
cylindrical
9 (8') Hind tibia twice as long as deep (Fig. 20c, III) ABraYle*
-------
Fig. 19. Trichoptera. a. Dorsal view of Ochrotricha b. Dorsal view, abdominal segment with
enlarged sclerite of Ochrotricha c. Same of another Ochrotricha d. Lateral view, abdomen of
Ithytricha. (ds, dorsal sclerite; I, prothorax; II, mesothorax; III, metathorax). (b, c, and d, re-
drawn from Ross).
10 (91) Metanotum with a widened area ventrolaterally (Fig. 20e) Ochrotrichia
10' Metanotum without a widened area ventrolaterally (Fig. 20f) Hydroptila
Fig. 20. Trichoptera. a. Legs of Oxyethira b. Legs of Ochrotricha c. Legs of Agraylea
d. Tarsus and claw of first leg of Stactobiella e. Mesonotum of Ochrotricha f. Mesonotum of
Hydroptila. (c, claw; ti, tibia; to, tooth; I, first leg; II, second leg; III, third leg), (redrawn
from Ross).
12
-------
11 (7') Anal prolegs with only the claws projecting from the last abdominal segment; doraum of eighth
abdominal segment with only 1 or 2 pairs of small setae Qrthotrichia
11' Most of anal proleg projecting from the last abdominal segment (as Fig. 2b); dorsum of eighth
abdominal segment with numerous setae 12
12 (11') Thoracic tergites with long, slender, inconspicuous setae; evenly tapered case of sand grains
without posterior slit Neotrichia
12' Thoracic tergites with shorter, stout setae appressed to surface of thorax; semitransluscent
case evenly tapered with dorsal side ringed or fluted with raised ridges Mayatrichia
FAMILY PHARYGANEIDAE
Caddisfly larvae belonging to this family are generally easily recognized by the elongate,
cylindrical, cigarette-like case. This case is generally composed of pieces of grass or leaves
arranged in a spiral pattern. The larvae are found in ponds, lakes, and pool areas of streams.
Larvae of Ptilostomis are frequently picked up in spring fed pools and pool areas of springs at
higher elevations in the southeast. The following key follows that of Ross (1959).
1 Frons with a median black line (Figs. 21a, b).
1' Frons without such a line (Figs. 21c, d, e) . . .
Fig. 21. Trichoptera. a. Dorsal view, head, pronotum and mesonotum of Phryganea b. Same
of Banksiola c. Same of Agrypnia d. Same of Phryganeid Genus A Rosa e. Same of Ptilostomis.
(I, pronotum; II, mesonotum). (b, c, d, redrawn from Ross).
2 (1)
2'
3 (!')
3'
4 (3)
41
5 (3')
5'
6 (5')
6'
Pronotum with anterior margin black, without a diagonal black line (Fig. 21a) Phryganea
Anterior margin of pronotum without black margin, a diagonal black line present (Fig. 21b). . . .
Banksiola and some Agrypnia
A pair of small sclerites near anterior margin of mesonotum. Northeastern 4
Mesonotum without such sclerites (Figs. 21c, d, e) 5
Mature larvae 30 mm in length; one northeastern species Eubasilissa
Mature larvae only about 20 mm in length, one northeastern species Oligostomis
Anterior margin of pronotum black and without a diagonal black line (Fig. 21c). .some Agrypnia
Anterior margin of pronotum mostly yellow, pronotum with a diagonal black line 6
Diagonal lines on pronotum meeting at posterior margin to form the letter V (Fig. 21d)
Phryganeid Genus A_
Diagonal lines on pronotum not reaching posterior margin but joining each other on the meson
(Fig. 21e) Ptilostomis
S 13
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FAMILY GOERIDAE
This family is now considered by some (set- Flint, 1960) to be a distinct subfamily, Goerinae.
of the family Limnephilidae. Larvae g< nerally build stone cases in swift, cold streams. Key
to Known Goeridae Larva.
1 Gills present, head with a circular ridge between the eyes Goera
1' Gills absent, head without such ridpes Goerita
FAMILY BRACHYCENTRIDAE
Larvae are generally found in cold, rapid streams. The cases are either cylindrical or square
or a combination of the two types consisting of spun silk and wood.
1 Middle and hind tibia with a ventroaplcal spur (Figs. 6b, vs); mesonotal sclerites long and
narrow (Fig. 7b) metanotum with heavily sclerotized plates Brachycentrus
1' Middle and hind tibia without a ventroapical spur (Fig. 22a); mesonotal sclerites short and
wide, metanotum with weakly sclerotized plates Micrasema
Fig. 22. Trichoptera. a. Hind leg of Micrasema b. Abdominal gill of Pycnopsyche c. Abdominal
gill of Limnephilus.
FAMILY LIMNEPHILIDAE
This is a very large and complex family. The larvae construct cases of many different types
and shapes. Materials used in the construction of cases varies from small sand grains and gravel
to cases of plant material. Larval habitats range from swift mountain streams to ponds and lakes.
The following key is modified from Flint (I960). It is meant for eastern U.S. forms alone and is
not complete even for this region.
1 All gills single, unbranched (Fig. 22b) 2
I1 Many gills with branches of 2 and more (Fig. 22c} V
2 (1) Legs with femora, tibia, and tarsi ringed with black (Fig. 23a) Psychoglyphia
2' Legs without such contrasting black annuli 3
3 (2") Anterior margin of mesonotum with a mesal rectangular emargination (Fig. 2a); cases of sand
and small gravel. Widespread in cold rapid streams Neophylax
3' Mesonotum without such a mesal emargination (Figs. 23b, c) 4
4 (31) Anterior metathoracic plate (»a 1) not present, represented only by a transverse row of hairs. .
Apatania
4' Anterior metathoracic plates prese'nt (Fig. 23b) 5
5 (41) Head brown, with inconspicuous muscle scars posteriorly . Pseudostenophylax
5' Head pale, with dark scars and blotches present , 6
6 (5') Second abdominal segment with a sclerotized ring ventrally, anterior metanotal plates fused on
the meson Hydatophylax
6' Second abdominal segment without a sclerotized ring ventrally, anterior metanotal plates
barely touching or separate Pycnopsyche
14
-------
Fig. 23. Trichoptera. a. Posterior view, mesothoracic leg of Psychoglyphia b. Dorsal view,
thorax of Frenesia . (s, setae; Sa 1, Sa 2, Sa 3, setal areas or plates; 1, prothorax; II, mesothorax;
3, metathorax). (after Flint).
7 (!') Some gills with 4 or more branches 8
7' Gills with 3 or less branches 10
8 (7) Some gills on basal abdominal segment with 4 branches Onocosmoecus
8' Most gills with 6 or more branches 9
9 (8') Gills on basal abdominal segment with about 6 branches Hesperophylax
9' Many gills with 10-15 branches Ironoquia
10 (71) Legs ringed with contrasting black (somewhat as Fig. 23a) Glyphopsyche
10' Legs not ringed with black 11
11 (10') Anterior margin of pronotum with long pale, blade-like setae, head almost uniformly brown
(Fig. 23c) Frenesia
11' Anterior margin of pronotum without such setae; head not uniformly brown 12
Fig. 24. Trichoptera. a. Anterior view, head of Nemotauliusb. Same of Limnephilus c. Same
of Asynarchus. (after Flint).
12 (II1) Head yellowish with a median dark stripe, and a U-shaped band on the genae (Fig. 24.a)
Nemotaulius
12' Head mostly darkened, or marked with either spots and infuscations or with a dark V-shaped
band on the genae 13
13 (12') Head yellow with many small distinct dark dots; larvae up to 30 mm in length. . .Grammotaulius
13' Head brown, or a few larger, indistinct, dark blotches and infuscations; larvae smaller than
above . . 14
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14 (13') Prosternal horn between the base of the front legs extending beyond apices of fore coxae
Platy c e nt r opu s
14' Prosternal horn not extending beyond apices of fore coxae 15
15 (14') Head mostly pale with some dark spots and infuscations 16
15' Head mostly dark or with a distinctive dark pattern (Fig. 24b) 17
16 (15) Length 18 mm or more, head anteriorly with dark infuscations Anabolia
16' Length 13 mm, head anteriorly with only a band along the frontal suture. Lenarchulus
17 (15') Case roughly horn shaped, composed of plant material arranged obliquely; head pro- and
metanotum dark, except for 3 pale spots on the fronto-clypeus between the eyes (Fig. 24c). . . .
Asynarchus
17' Case cylindrical, composed of plant material arranged longitudinally or transversely; head
marked as above or with a dark central stripe anteriorly and a V-shaped band on the genae. . . .
Limnephilus
FAMILY LEPIDOSTOMATIDAE
Two genera are known in North America. The largest genus is Lepidostoma andcontainsaround
30 species. The immature stages of the other genus, Theliopsyche,are apparently limited to the eastern
U. S. andareunknown. The larvae of the genus Lepidostoma occupy a variety of habitats ranging from
springs and small streams to rivers and ponds.
FAMILY CALAMOCERATIDAE
Only two genera are found in the eastern and southern portions of the U. S. This key omits the
southwestern genus Notiomyia. All members are found in rapid streams or springs. The larval
cases are composed of plant materials. The genus Anisocentropus is confined to the southeast.
1 Anterior corner of pronotum produced downward into sharp curved hooks. (Fig. 25a)
Anisocentropus
I1 Pronotum almost rectangular, its anterior corners not as above Heteroplectron
/I J_
Fig. 25. Trichoptera. a. Dorsal view, prothorax of Anisocentropus b. Same of Psilotreta
c. Same of Mar ilia, (a and c, redrawn from Ross).
FAMILY HELICOPSYCHIDAE
Larvae of this family are very easy to distinguish by their spiral cases resembling a snail shell.
There is only one genus, Helicopsyche, which is fairly widespread in streams and cool springs over
much of the U. S.
FAMILY ODONTOCERIDAE
A small family with only two eastern genera. The larvae are generally found in swift, cold,
mountain streams. The cases are cylindrical and composed of small, neatly arranged stones.
1 Anterolateral corner of pronotum produced into sharp points (Fig. 25b) Psilotreta
1' Anterolateral corner of pronotum not as above, evenly rounded (Fig. 25c) Marilia
16
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FAMILY SERICOSTOMATIDAE
Is represented in North America by a single genus, Sericostoma. Larvae construct cases com-
posed of small stones in rapid mountain streams.
FAMILY LEPTOCERIDAE
Ecologically this is a very diverse family of caddisflies. The larvae occur in lakes, ponds, and
streams and build a variety of cases out of a variety of materials.
1 Case a translucent silk cone, second tarsus bent (Fig. 26a) Leptocerus americanus
1' Case generally not transparent, tarsus straight 2
Z (I1) Maxillary palps nearly as long as stipes, mandibles long, sharp at apex (Fig. 26f) cases conical,
composed of sand or plant material Oecetis
2' Maxillary palps only about 1/2 as long as stipes, mandibles shorter, blunt, at apex in lateral
view (Fig. 26d) * 3
3 (21) Head with two suture like pale areas paralleling the epicranial arms (Fig. 26e). . . . Athripsodes
3' Head without above areas, only the epicranial arms present 4
4 (31) Mesonotum membranous except for a pair of sclerotized, narrow, curved bars (Fig. 5c); cases
composed of sand grains, with or without lateral flanges Athripsodes
4' Mesonotum without such bar s 5
Fig 26 Trichoptera. a. Middle leg of Leptocerus b. Hind leg of Leptocella c. Same of
Mystacides "d. Lateral view, head of Leptocella e. Anterior view, head of Athripsodes f. Lateral
view, head of Oecetis. (ea, epicranial arm; m, mandible; mp, maxillary palp; st, stipes; ta,
tarsus), (a. b. c. d. , and f, after Ross).
17
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5 (41) Hind tibia with a break near the middle which appears to divide the tibia into two sclerotized
segments (Fig. 26c), abdomen with some gills 6
5' Hind tibia without such a break in the middle, entire tibia sclerotized (Fig. 26b), abdomen
without gills Leptocella
6 (5) Hind tibia with a regular fringe of long hairs (Fig. 26b); case of plant material arranged in a
spiral pattern Triaenodes
6' Hind tibia with only irregularly placed hairs (Fig, 26c), case elongate, made of various
material Mystacides
FAMILY MOLANIDAE
This is a small family composed of a single genus Molanna in most of North America. The
genus Molanodes is found in Alaska and the Palearctic realm.
FAMILY BERAEIDAE
Only one genus Berae is found in North America. The genus contains 3 species. Larvae make
a cornucopia-shaped case of sand grains.
18
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Ill SELECTED REFERENCES
Denning, D. G. 1956. Trichoptera, p. 237-270. _InR. L. Usinger (ed.).
Aquatic insects of California. Univ. California Press, Berkeley.
Flint, O. S. , Jr. I960. Taxonomy and biology of Nearctic Limnephilid
larvae (Trichoptera} with special reference to species found in Eastern
United States. Entomol. Amer. 40:1-117.
Flint, O. S. , Jr. 1962. The immature stages of Matrioptila jeanae (Ross)
(Trichoptera: Glossosomatidae). J. N. Y. Ent. Soc.7\): 64-67.
Flint, O. S. , Jr. 1962. Larvae of the caddis fly genus Rhyacophila in
Eastern North America. (Trichoptera: Rhyacophilidae). Proceed.
U. S. Nat'l. Mus. 113: 465-493.
Flint, O. S. , Jr. 1963. The immature stages of Paleagapetus celsus Ross
(Trichoptera: Hydroptilidae). Bull. Brook. Ent. Soc. 57: 40-44.
Flint, O. S. , Jr. 1944. Notes on some Nearctic Psychomyiidae with
special reference to their larvae (Trichoptera). Proceed. U. S.
Nat'l. Mus. 115: 467-481.
Ross, H. H. 1944. The caddisflies, or Trichoptera, of Illinois. Bull.
Illinois Nat. Hist. Survey. 23; 1-326.
Ross, H. H. 1959. Trichoptera, p. 1024-1049. _In W. T. Edmondson,
Fresh-water biology. John Wiley and Sons, New York.
19
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CHIRONOMIDAE
William M. Beck, Jr.
I INTRODUCTION
Notes On Chironomid Taxonomy
The material accompanying this memorandum was prepared to assist
biologists in water quality investigations in the Southeast. The chironomids
have been subjected to some 165 years of confusion of taxonomic concepts
and constitute at present one of the most difficult groups of insects with
which to work. A few remarks regarding some of the fundamental problems
may be helpful.
As with most groups of insects, taxonomy of the chironomids is based
largely on adult morphology. Those of us in the applied field need knowledge
of the identification and distribution of larvae. Such knowledge has lagged
far behind adult taxonomy, I have personally worked with chironomids for
seventeen years and am not at all proud of the present state of our know-
ledge. Let me enlarge on several points.
1. We have an estimated 400 species of chironomids in Florida. Of
these, roughly 275 species of adults can be named. Known larvae
number fewer than 200. Much remains to be done.
2. My wife and I have published two papers dealing with taxonomic diffi-
culties. The first of these was given at the First International
Symposium of Chironomid Research in Ploen, West Germany, in
1964 and was basically a plea for international cooperation. Such
international cooperation is now functional. The second paper, pre-
sented at the Second International Symposium of Chironomid
Research in Helsinki, Finland, in 1967 was a discussion of a major
dichotomy in taxonomic viewpoints. In this, the continental
Europeans have held one set of views and the British and Americans
another set. At the present time, only four North American
specialists are following the concepts of the continental Europeans.
3. Most of you are aware of the fact that the very common genus
Chironomus has been called Tendipes. Some original genera of
chironomids were based on a paper by the German, Meigen, pub-
lished in 1803. This paper proposed.the genera Chironomus,
T any pus, etc. Some years later it was discovered that Meigen in
-------
1800 had published an article in a very obscure journal using the
terms Tendipes (for Chironomus) and Pelopia (for Tanypus).
According to the international rules of zoological nomenclature,
the 1800 names had priority and, consequently, were the correct
ones. Most of the midge specialists tended to ignore this, feel-
ing that most of the world's literature used the 1803 names and
that use of the names would only compound the confusion. Then
•in 1963 the International Commission for Zoological Nomenclature
(Opinion 678) officially suppressed the Meigen terminology in
favor of the 1803 paper. Thus, Chironomus and Tanypus are now
the correct generic names. The main confusion--other than the
above--has resulted from a lack of coordination and cooperation
among specialists. As an example, the following is a partial list
of taxonomic battering inflicted on a single species of'European
midge.
Cryptochironomus pseudotener Goetghebuer 1922
Chironomus (Cryptochironomus) pseudotener (Goetgh. )
Goetgh. 1928
Chironomus (Chironomus) pseudotener (Goetgh.) Edwards 1929
Chironomus (Parachironomus) pseudotener (Goetgh.) Pagast
1931
Harnischia (Harnischia) pseudotner (Goetgh. ) Townes 1945
Chironomus (Cryptochironomus) pseudotener (Goetgh. )
S. and S. 1965
Parachironomus pseudotener (Goetgh,) Fittkau £t alii 1967
Such problems as this are the property of the chironomid specialist -
-not yours. They are discussed here in order to demonstrate why
there is not more usable material for the non-specialist.
4. It was suggested in the planning stages of this course that sig-
nificant publications in the field be listed. Unfortunately, most
publications covering this group are either extremely regional
(our own) or are out of date before the ink dries (Roback, 1957).
Most of the older works have long been out of print, but some are
available as photocopies (Johannsen, 1937a. 1937b). Most of the
larger European papers are expensive, of limited use here, and
generally in a foreign language. An annotated list of publications
is offered, but perhaps there is a way out of this difficulty. An
illustrated key is attached. This is as thorough (for the Southeast)
as it can be made. Rearing a single species of an unknown larva
can ruin at least one part of the key. If, however, we have a list
of all individuals possessing a copy of the key, then the key could
be updated periodically by replacing one or more pages. In this
way, the key would remain as nearly up-to-date as is possible.
-------
The subfamily Orthocladiinae is badly in need of revision on a world-
wide basis. Until such genera as Qrthocladius, Spaniotoma, and
Hydrobaenus are placed in proper perspective, work with this group will
remain difficult. In the present handling, the genus Orthocladius will be
recognized, right or wrong.
The genus Crjcotopus has been split into a number of genera by
European workers. For the present, we are recognizing Cricotopus and
Rheocricotopus (=Trichocladius in part) only.
The same may be said of Metriocnemus, and no attempt will be made
to break this down now.
Several groups are under revision at present, and greater taxonomic
subtlety must await publication of these revisions. Among these are:
Tanytarsini (Dr. Sublette), Polypedilum (a graduate student at the Univer-
sity of Minnesota), and Tanypodinae (Dr. Roback). In addition, regional
studies are under way. Dr. Fittkau of Germany is working up the entire
family for Amazonia; Drs. Oliver, Hamilton, and Saether are studying the
fauna of Canada; and a number of state workers are studying local faunas.
The deplorable lack of knowledge of the midges of the West Indies (and
other Latin American areas) makes understanding of relationships most
difficult. It will require great cooperation, and I am pleased to relate that
such cooperation now exists.
Making Slide Mounts of Chironomid Larvae
In order to identify chironomid larvae properly, slide mounts must
generally be prepared. Although either permanent or temporary mounts
may be made, only permanent mounting methods will be discussed here.
It takes virtually as long to make a temporary mount as it does a perma-
nent one. More will be said about this below.
The method selected should be the one that best satisfies your needs,
time being a major consideration. Since most of the readers of this
discussion will be in some field of applied biology, time and expense come
close to being synonymous.
The first necessary action is to develop a full understanding of just
what these preparations should show. Perhaps the most difficult part of
slide mounting is learning to position the larvae properly before adding
the cover slip and some maneuvering after the cover slip has been added.
Generally, an entire larva may be mounted under one cover slip. In
-------
the case of larger larvae, it is frequently necessary to mount the head
capsule under one slip and the posterior three or four abdominal segments
under another. The center portion of the larva is descarded. Certain
recalcitrant genera with smaller larvae require the same treatment. With
these, you simply have to learn as you go.
The most important part of the larva for identification purposes is
the head capsule. Whether dissected free of the body or still attached, it
is mounted the same way--ventral side up. This (after one learns to
apply enough pressure to the cover slip to spread the parts, but not enough
to break the cover slip) exposes most of the structures used for identifica-
tion.
Second in importance is the posterior portion of the body bearing
such structures as the posterior prolegs, supra-anal papillae, supra-anal
bristles, anal gills and blood gills. Gentle pressure on the cover slip is
desirable here also.
The abdominal segments themselves are important, despite what was
said above about discarding the middle portion of the body of very large
larvae. Such things as lateral hair fringes, large setae, hair pencils, or
special integument characteristics are of interest.
A. Materials
1. Slides - Little need be said of these except that standard one by
three inch slides are recommended--ground edges, pre-cleaned.
2. Cover glasses - I have found 12 mm circular cover glasses, No. 2
grade to be most satisfactory.
3. Labels - This seems to be a trivial item to list, but it can make a
lot of difference when one is making large numbers of slides. I
have found 3/4 Magic Transparent Tape very satisfactory. You
can write on it (preferably with pencil); erase; and it has held its
adhesive qualities for the four years I have been using it. It will
soak off easily in water.
4. Slide ringing - The use of asphaltum varnish to ring permanent
slides is recommended by some workers. It is especially recom-
mended for use with semi-permanent mounting media such as
glycerine jelly, PVA-lacto-phenol, or CMC-10*. Although I do not
use glycerine jelly, I have found ringing to be unnecessary with the
* This does not constitute an endorsement by any governmental agency.
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last two. It is very time-consuming.
B. Mounting Media
1. Canada Balsam - The old faithful! This is hard to beat but has the
disadvantage of taking a great deal of time per slide. Its advantage
lies in its permanence and the fact that so many modifications have
been developed for the method.
2. Euparol - Many of the European -workers prefer this. Somewhat
faster than Balsam; still too slow for routine use.
3. The Hamilton Method
a. Place larvae in hot (near boiling) 5 °/o KOH for 10 minutes.
b. Transfer to glacial acetic acid for at least 10 minutes.
c. Transfer to absolute ethyl alcohol for 10 minutes.
d. Transfer to absolute ethyl alcohol layered over cedarwood oil
for 10 minutes.
e. Transfer to cedarwood oil for 10 minutes. Any necessary
dissecting should be done here.
f. Mount in Canada Balsam and allow to set for a few minutes.
Add a small drop of zylene and place on cover slip.
g. This technique is not too time-consuming if properly set up.
It results in excellent, permanent slides and very transparent
mounts.
4. Others - There are, of course, numerous other media and methods.
CMC-10, discussed below, is my favorite for larval work. Since
my job involves a combination of office, laboratory, and field work ,
it is necessary to pick a mounting medium that can tolerate erratic
scheduling. Like everyone else, I have my own personal likes and
dislikes. I do not like to use absolute ethyl alcohol because it re-
mains absolute so briefly. I do not like the phenol media because
of the hazards involved. These hazards include skin burns and the
systemic hazard of prolonged contact. Many factors must be con-
sidered when selecting a mounting medium for, hopefully, routine
use.
C. The CMC-10 Technique
1. Place alcohol specimens in water 10 minutes (or until they sink).
2. Use clean slides.
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3. Add drop of CMC-10 (learn on the way).
4.- Use needle to pick up larva from water and place in medium.
5. Remove all bubbles with tip of needle.
6. Position with needle.
a. Be sure that head is bottom side up.
7. Add cover slip. Use forceps. Do not drop, but let down gently.
8. Use tip of forceps to apply pressure to both head end and posterior
end. Considerable pressure needed to spread mouthparts, antennae,
posterior prolegs.
9. Label.
10. Place flat in trays to dry.
11. Check daily and fill any air spaces with a thinner of solution of
CMC-10.
12. Larvae may be viewed under a microscope in about 24 hours.
13. Remove any CMC-10 from the top of the cover slip with a small
scalpel. This can best be done after about 48 hours.
14. Do not stand slides on edge for at least 5 days.
15. Ring with asphaltum if desired.
D. Special Problems
1. Large larvae
a. Same technique basically as above.
b. Use two drops of mounting medium.
fc. Pinch off head and last three abdominal segments with dissecting
needle.
d. Mount head in one drop and posterior segments in other.
Discard middle segments of body.
2. Recalcitrant larvae - Cryptochironomus and some related genera
have the head placed on the body at an odd angle. The head can-
not be managed properly. Use double mounting with head under one
cover slip and body under the other.
3. Certain species of Tanytarsus tend to effervesce in an acid medium
(such as CMC-10). This will be obvious immediately. Simply
wait until all action ceases', and mount in another drop on another
slide.
4. Bad slides - Some larvae will tend to change position while the
medium hardens. Place the slides in a covered Petri dish of
distilled water overnight. Lift off the cover slip the next morn-
ing and transfer the larva to a drop of medium on another slide and
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remount carefully. I know of no time limitation on this.
E. General Advice
1. Seeking Help with Identification
a. Always contact the person selected ahead of time. Ask if
he will either check your identifications or will identify for
you (depending on your particular need).
b. If he will perform this service for you, find out how he wishes
to receive it--in alcohol or mounted. Do not hesitate to let
him know if you are able to make decent slides.
c. Be patient. He has a job also and will get to your material
as soon as he possibly can. Give him some idea of your need
time--wise. Bear in mind that he is probably as anxious to see
your material as you are to have it identified.
d. Do not expect too many identifications to species. The greater
the distance between you, the lower will be the percentage of
specific identifications.
2. Selecting the Proper Technique
a. Evaluate your time carefully. If you are pressed for time,
use a rapid technique such as CMC-10 or PVA-lacto-phenol.
Many people do not like CMC-10 (especially museum personnel)
because it is not supposed to be permanent. I have used it
several years and get good permanent mounts with it. The
balsam, euparol and Hamilton methods are probably much
more satisfactory but are very time-consuming.
b. I cannot make any statement about the permanence of the tape
labels. Mine have given no trouble in over three years of use.
It will stand erasures but will not take many kinds of ink.
F. General Remarks
1. Larval Mounts
It would be nice, indeed, if you could make a slide and assume that
all the characters you need to see would be clearly visible. Un-
-------
. fortunately, such is not generally the case. For example, it is
surprising how seldom both larval antennae are completely visi-
ble, or that paralabial plates will be in precisely the same plane
so that all the characteristics will be equally visible on both plates.
For that reason, I generally make a minimum number of three
slides of each species.
2. Fractionating Samples
There will be times when a generalized collection will contain
hundreds of chironomid larvae. It would be ridiculous to
attempt to make slides of each one of them. It (is possible, how-
ever, with practice to select a representative series and mount only
those. The following list of characters to look for has proven
of value to me:
a. Size - get a representative series.
b. Color - some color does persist in alcohol in some species.
c. General body appearance - the head of Cryptochironomus is
attached to the body at an odd angle.
d. Relative size and position of the eye spots.
e. Posterior margin of head capsule, darkened or not.
f. Gula, darkened or not.
g. Relative distinctness of body segmentation.
h. Size and color of pre-anal papillae.
i. Presence or absence of blood gills.
j. Shape of head capsule. This will become obvious very rapidly.
Keying Instructions
A. Of Keys in General
There are basically three different kinds of keys.
1. Keys without illustrations. This type is the least satisfactory
because many features are almost impossible to describe with
words alone.
2. Keys with illustrations. This is more helpful, but still falls short
of the ideal.
3. This third type has the added advantage of permitting you--by means
of written descriptions--to determine whether or not this organism
which has suddenly acquired a name deserves that name. It should
8
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be pointed out that any organism put into a key will have to come
out with a name, even though it may not even belong in that group.
Most people writing keys would prefer to make them as simple as pos
sible. A dichotomous key with a single alternative per couplet would be
ideal. Unfortunately, this is not always possible.
When using a key, never volunteer any information! Answer only the
questions asked in couplet individually. This is very important. For ex-
ample, a genus we are working on at present has nine species. Five of
these species have on the posterior prolegs claws bearing spines on the
inner edges. In the key, however, this character appears with regard to
one species only. Volunteering this information could result in mistaken
identification of the other four species.
There is no way to prepare you for aberrant specimens. Such things
do occur, and you will gradually come to recognize them.
B. Of the Present Keys
The keys following have resulted to a major extent from unabashed
theft. Fortunately, the same may be said of most chironomid keys in
use today. The present keys are a synthesis of the works of Thienemann,
Fittkau, Roback, Hilsenhoff, Lenz, and Johannsen, I am grateful to Mr.
William T. Mason, Jr. for his Figures 1 through 4, use of which saved me
many hours.
The present key is as complete as I can make it at this time. As is
mentioned elsewhere, there are many revisions being made in chironomid
taxonomy. Each revision is almost certain to render useless certain parts
of existing keys. Learning to identify the larva of a presently unknown
species of Ablabesmyia may render useless our entire key to that genus.
Consequently, the keys are done in loose-leaf form. At irregular intervals
certain parts of the keys will be revised and pages replaced.
Concurrent with learning to use a key is the process of forgetting it.
This may sound like a strange statement--but it is a true one. You will
almost immediately start looking for, and finding, short-cuts that will en-
able you to by-pass larger and larger segments of the keys. For example,
you will very quickly eliminate any need for the key to subfamilies. A
tanypodine looks like a tanypodine.
There are a number of intentional omissions in the following keys.
The subfamily Podonominae is apparently not present in the Southeast. The
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clunionine are marine inter-tidal midges and have been omitted. Midges
confined to highly specialized habitats (such as pitcher plants and
bromeliads) have been ignored since they are not of general interest. No
genera of the subfamily Diame^inae
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mandible will have a darkened area that might be mistaken for a tooth
unless examined carefully.
Synonyms:
Used here Some authors
pre mandible tor ma
sensory pit (r antenna) ring organ
labial plate hypostomial plate
11
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Fig. 1. Schematic Drawing of a Chironimid Larva
1. Antenna
2 . Head Capsule
3. Thoracic segments
4. Abdominal segment
5. Caudo-lateral process
of 10th segment
6. Freanal papilla
with setae
7 Anal Rill
8 Posterior proleg
9. Claws or spines of the
posterior proleg
10. Ventral gill
11 Lateral hair fringe
12. Hair pencil
13. Anterior proleg
14. Eye spot
15. Mandible
Fig. 2. Schematic head capsule diagram of the
Subfamily Tanypodinae (ventral view).
1. Paralabial comb (may be absentl
2. Labium
3. Sense vesicles of labrum
4. Clavate bristles of labrum
5. Labrum
6. Maxillary palpus
7. Mandible
8 Ring organ of antenna
9. Antenna (retractile)
10. Eye spot
11. Lingua of hypopharynx
12. Super lingua
13. Suspensorium of hypopharynx
12
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10
20
Fig. 3. Schematic head capsule diagram of
the Subfamily Chironominae (ventral view).
1.
2.
3.
Striate paralabial plate
Labial plate
Mandible (note the dark lateral and light
dorsomesal teeth)
Mandibular brush
Preapical mandibular comb
Antenna! tubercle with spur
(Tanytarsini only)
Antenna on tubercle
Lauterborn organ on long petiole
(Tribe Tanytarsini)
Papilla of labrum
Antennal blade
Labrum
Accessory tooth of mandible
13. Epipharynegeal plate
14. Premandible
15. Eye spot
4.
5.
6.
9.
10
11.
12
Fig. 4. Schematic head capsule diagram
of the Subfamilies Diameriinae and
Orthocladiinae (ventral view).
1. Non-striate paralabial plate (may be
absent or vestigial)
t, Paralabial hairs (beard)
3 . Labial plate
4. Mandible
5. Concavity of mandible
6. Mandibular serration
7. Ring organ of antenna
8. Antenna
9. Annulated third antennal segment
(Diamesinae only)
10. Antennal blade
11. Labral bristle
12. Labral spine
13. Lauterborn organ of antenna
14. Labrum
15. Mandibular brush
16. Mandibular crenulations
IV. Finger processes of epipharynx
18. Premandible
19. Hypopharynegeal hair
20. Eye spot
13
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II' KEY TO CHIRONOMID LARVAE OF THE SOUTHEASTERN UNITED STATES
Key t o . Sub f ami lie s
1 Antennae retractile (Fig. 2) Tanypodinae
1' Antennae not retractile (Fig. 3) -2
2 (I1) Third antennal segment annulate (Fig. 5a) Diamesinae
2" Third antennal segment not annulate 3
3 (21) Striated paralabial plates present (Fig. 3) Chironominae
3' Paralabial plates, if present, not striated, but may be bearded (Fig. 4) Orthocladiinae
Key to Groups of Tanypodinae
1 Larvae with slender abdominal segments, no hair fringe (Fig. 1); no paralabial comb (Fig. 2). -
Pentaneurini
1" Larvae with broad segments, usually with hair fringe (Fig. 1) ; labrum with paralabial comb
(Fig. 2) or free chitin points in row 2
2 (I1) Antennae at least half as long as head; a row of free chitin points (Fig. 2} Coelotanypodini
2' Antennae at mos 1/3 as long as head; paralabial comb present 3
3(2') Mandible with thick bulging basal part (Fig. 5b) Tanypus
3' Mandible not as above, slenderer (Fig. 5c). . 4
4 (3') Lingua (Fig. 2) with four yellow teeth of equal length .Psectrotanypus
4' Lingua with five teeth 5
5(4") Lingua with black teeth; supralingua (Fig. 2) scale-like with toothed edge Procladius
5' Lingua with yellowish or reddish teeth; supralingua two-pointed 6
6 (51) Mandible with large two-pointed tooth (Fig. 5d); paralabial comb with 13 teeth. Anatopynia
6' Mandible with two small teeth close together; paralabial comb at most eight teeth
Apsectrotanypus and Macropelopia
Fig. 5.
Genera of Coe lotanypodini
1 Mandible hook-like (Fig. 8a) Clinotanypus
1' Mandible curved (Fig. 5c); a pair of small, chitinized processes on third abdominal segment. . .
Coelotanypus
Key to Genera of Pentaneurini (except Natar sia)
1 Only one basal palpal segment (Fig. 2) 2
1' More than one basal palpal segment (Fig. 2) Ablabesmyia
2 (1) Black or brown claws present on posterior prolegs (Fig. 5e) 3
2' No black or brown claws present on posterior prolegs 6
14
-------
3 (2) Four more or less brown claws on posterior prolegs; body with scattered hairs. . Conchapelopia
3" Three or fewer dark claws on posterior prolegs 4
4 (31) None of claws of posterior proleg toothed or spined on inner edge; one dark claw; supra-anal
bristles set in distinct papillae Pentaneura
4" At least one claw toothed or spined on inner edge (Fig. 6a) 5
5 (41) Three short dark claws; AR 5 or more Guttipelopia
5' One dark claw with three teeth, two short yellow claws with long teeth on inner edge; AR less
than 4 (Fig. 6a) Monopelopia (in part) (boliekae)
6 (21) One claw bifid on posterior proleg (Fig. 6b) 7
6' No claws bifid 8
7 (6) First laterals shorter than median tooth (Fig. 6d) Labrundinia
7' First laterals not shorter than median tooth (Fig. 6c) Zavrelimyia
8 (6') One short yellow claw with two small teeth on inner margin (Fig. 6a)
Monopelopia (in part) (tillandsxa)
8' Otherwise 9
9 (8') Part of head capsule dark .Paramerina
9' Head capsule entirely pale 10
10 (9') Median tooth longer than first laterals; very small species (Fig. 6c) Nilotanypus
10' Median tooth not longer than first laterals 11
11 (101) First lateral tooth out-turned; body with scattered hairs Conchapelopia, Arctopelopia
11' First lateral tooth not out-turned Larsia
Key to Ablabesmyia Larvae
1
I1
2 (!•)
2'
One claw of posterior proleg dark yellow, none brown; AR 5. 8; all teeth of lingua dark yellow. .
philosphagnos
At least one claw of posterior proleg brown or black 2
A large dark brown rectangle ventrally at apex of head capsule; five or six palpal segments;
AR 5.1; one short dark claw, one longer claw slightly darkened (Fig. 6e) hauberi
No dark brown rectangle at apex of head capsule 3
Fig. 6.
3 (21) Maxillary palpus with more than three basal segments 7
3' Maxillary palpus with two or three basal segments 4
4 (31) Three basal palpal segments (most basal one very small); AR 4. 5-1; two dark claws, the shorter
one darker (Fig. 7a) ianta
4' Only two basal palpal segments 5
5 (41) Second palpal segment distinctly longer than first (20:26); AR 5.4-6; two dark claws about
equally dark peleensis
5' Palpal segments approximately subequal; AR not over 5 6
15
-------
6 (51) AR 4. 5; sensory pit at . 62 from base of first antennal segment; anal papillae gray, two times
long as wide rhamphe
6' AR 5; sensory pit at . 50 from base of first antennal segment; anal papillae three times long
as wide americana
7 (2') All teeth of lingua dark; inner laterals distinctly shorter than outer laterals; one short dark
claw, one longer claw may also appear very slightly darkened (Fig. 7b) aspera
7' Tips of three median teeth of lingua pale; at least two distinctly darkened claws on posterior
proleg (Fig. 7c) °
8 (71) Inner lateral teeth of lingua almost as long as outers, median smaller; two dark claws, one of
which is longer auriensis
8' Inner lateral teeth of lingua distinctly shorter than outer laterals 9
9 (8') Three dark claws (one of which is lighter than the other two) (Fig. 7d) mallochi
9' Two dark claws ornata
Key to Labrundinia
1
1'
2 (1)
2'
Head capsule distinctly marked with black
Head capsule not distinctly marked with black
Head nodulate, posterior fourth black ................................ • ........... floridana
Head not nodulate, a black band across middle of head capsule .................... johannseni
3 (I1) Median tooth of lingua distinctly longer than outer laterals; posterior legs with Corynoneura-
like spur with 6-8 spines basally (Fig. 7e) neopilosella
3' Median tooth of lingua not longer than outer laterals; spur of posterior prolegs with only 1-3
fine spines basally (Fig. 7f) 4
4 (31) Head capsule darkened apically pilosella
Head capsule not darkened apically, a pale green larva
virescens
O
a
Fig. 7.
Key to Larsia Larvae
1 Inner laterals of lingua distinctly shorter than outer laterals.
1> Inner laterals of lingua about as long as outer laterals
berneri. indistincta
lurida
Subfamily O r t h o c 1 a d i i n a e
1 Twelfth body segment ending in four globose anal gills (Fig. 8b) Smittia
1' Posterior prolegs well developed
i U') Small species; under 5 mm long; antennae at least half as long as head, generally longer 3
Antennae shorte r than above
Z'
3 (2)
Antennae 4-segmented, about 1/3 longer than head Corynoneura
Antennae 5-segmented, more than 1/2 as long as head Thienemanniella
16
-------
4(2') Labial plate truncated apically with several clear, even teeth across apex ; body haired (Fig.
^c* Epoicocladius
41 Labial plate not as above 5
5 '4') Outer edge of mandibles crenulated (Fig. 9a); labial plate with 11 or 13 teeth if 11 first
laterals bifid ....
5'
6 (51)
7'
9 (8)
9'
10 (9)
10'
_. Cricotopus
Outer edge of mandibles not crenulated ^~T
Labial plate with 11 teeth; middle tooth broadly truncated (Fig. 9b); labrum without pectinate
or toothed plates; hypopharyn* with distally projecting haira; larva 8-10 mm long, yellow dusky
a fa on
Cardiocladius
g reen.
Not as above
.7
7 (6') Body with hair pencils on abdominal segments (Fig. 1); premandibles short and blunt; antennae
very short .-. .
„ , Lricotopus
Body without hair pencils; may have scattered hairs —g
8(7') Mandible with inner margin with fine, or long filament-like serrations (Fig. 9c) 9
Mandible without serrations on inner margin 12
Labial plate with an even number of teeth.
Labial plate with an odd number of teeth. .
,10
11
Labial plate with 8 o* 10 rounded teeth (Fig. 9d) (Footnote 1) Stenochironomus
Labial plate with 12 teeth . . .Nanocladius
Fig. 9.
11 (91) Labial plate with 11 teeth, median peaked (Fig. lOa), body with coarse hairs Eukiefferiella
11' Body without coarse hairs .NanocladiuT
12 (8') Preanal papillae generally at least twice as long as broad; premandibles generally bifurcate
(Fig. lObl 13
12' Preanal papillae shorter or lacking; premandibles simple (Fig. lOc) or bifurcate 14
13 (12) Antenna slightly curved; labial plate dark with small middle tooth recessed between large first
laterals (Fig. lOd) Brillia
13' Antenna generally straight; labial plate with an even number of teeth Metriocnemus
Footnote 1. This actually belongs in the Chironomini, but absence of striated paralabial plates
could lead to the wrong subfamily. It is placed in both keys.
17
-------
14 (121) Paralabial plates present, some time difficult to see; if absent, labial plate with two wide,
clear middle teeth, peaked mesally (Fig. lOe). 15
14' Paralabial plates absent 17
-
Fig. 10.
15 (14) Labial plate with 14 fairly even teeth; premandibles short bifurcate Diplocladius
15' Teeth of labial plate not even; premandibles simple; preanal papillae generally rugose or with
spurs (Fig. lla) 16
16 (151) Middle teeth of labial plate generally clear and wide; if darker they are still each peaked
mesally and always very narrowly separated (Fig. lOe); preanal papillae generally with spurs.
Psectrocladius
16' Middle teeth of labial plate not as above; may be long and narrow or widely separated and
palmate (Fig. lib) Rheocricotopus
17 (14') Labial plate with 13 , 14 or 21 teeth. Orthocladius
17' Labial plate with 9-12 teeth 18
18 (17') Labial plate with an even number of teeth 19
18" Labial plate with an odd number of teeth Nanocladius
19 (18) Labial plate with 10 or 12 teeth; middle pair may be elongated; always longer than first laterals
(Fig. llcj Nanocladius
19' Labial plate not as above 20
Fig. 11.
20 (19') Labrum with a pair of short broad plates and one pair of longer narrower plates with serrate
distal margins; middle pair of labial teeth shorter than laterals Orthocladius
20' Labrum with a pair of digitate bristles; mandibular brush with numerous fine branches on
margins; antennal blade longer than terminal segments combined Limnophyes
Tribes of Chironominae
1 Antennae set on definite peduncles (Fig. 12a) Tanytarsini
I1 Antennae not on peduncles Chironomini
Genera of Tanytarsini
1 Paralabial plates well separated at midline (Fig. 12b) 2
Paralabials bar-like and almost touching at midline 3
2 (1) Peduncle with simple spur-like projection; lauterborn organs on each end of 2nd antennal seg-
ment (Fig. 12a) Zavrelia
Peduncle with complex, finger-like projections; lauterborn organs opposite each other on
distal end of 2nd antennal segment (Fig. 12c) Stempellina
18
-------
3 (I1) Peduncle with a spur—may be minute (Fig. 12a). Micropsectra
3' Peduncle without spur 4
Fig. 12.
4(3') Large, almost sessile lauterborn organs (Fig. 13a) Cladotanytarsus
4' Lauterborn organs on longer petioles ....: 5
5 (4') Small lauterborn organs on petioles shorter than distal 3 antennal segments.. . . Rheotanytarsus
5' Petioles longer than distal 3 antennal segments (Fig. 13b) Tanytarsua
Key to Chironomini
1 Seven antennal segments , Demicryptochironomus
1' Six or fewer segments 2
2 (I1) Six antennal segments 3
2' Five antennal segments 9
3 (2) Labium with a pale, toothless median portion (Fig. 13c) Paralauterborniella nigrohalterale
3' Labium fully toothed 4
Fig. 13.
4(3') Labium with pale median teeth. . 5
4" Labium without pale median teeth 7
5 (4) Labium with 4 pale median teeth Paratendipes
5' Labium with 2 (sometimes 3) pale median teeth 6
19
-------
6 (5')
6'
7 (4')
7'
8 (7')
8'
9 (2')
9'
10 (9)
10'
11 (101)
11'
12 (91)
12'
13 (12)
-
Paralabials as in Fig. 16e. Small species Paralauterborniella elachista
Paralabials not as in Fig. I6e. Larger species Microtendipes
Blood -gill -like appendages ............................................... Lauterborniella
No such appendages [[[ E
Labial plate with 16 teeth, median 2 recessed ............................. Stictochironomus
Labial plate with 14 teeth, first laterals fused ................................ Omisus pica
Blood gills present
B lood gills lacking
1
A single pair of blood gills .......................................... Einfeldia. Kiefferulus
Two pair of blood gills .................................. • ............................. U
Anterior pair of gills forked (Fig. 14a) ....................... Goeldichironomus holoprasinus
Neither pair forked [[[ Chironomus
Labial plate with a pale toothless median portion (Fig. 14b) .
Labial plate otherwise
-
-
Pale toothless portion of labial plate much wider than first laterals combined
.Cryptochironomus
Median paler portion of labial plate no wider than first laterals combined, median only
slightly paler; three minute teeth on mandible Nilothauma bicornis
14 (12') Labial plate with 8 or 10 teeth, paralabial striations not visible Stenochironomus
14' More than 10 teeth
15 (14') Labial plate as in Fig. 14c. Penultimate or ultimate tooth projecting forward Harnischia
15' Labial plate otherwise 16
16 (15') Labial plate as in Fig. 14 d Chironomini sp. A(Roback)
16' Labial plate otherwise 17
17 (161) Labial plate as in Fig. 14e Polypedilum
17' Labial plate otherwise 18
18 (17') Paralabials bar-like, almost touching at mid-line. Pseudochironomus
18' Paralabials well separated
19 (181) Labial teeth relatively even like the teeth of a saw (Fig. 14f) 20
19' Teeth otherwise 21
I
Fig. 14.
20 (19) Paralabials as in Fig. 15a Polypedilum fallax
20' Paralabials as in Fig. 15b Pedionomus beckae
-------
22 (21) Labial teeth 12 .Phaenopsectra
22' Labial teeth 16 23
I •
'-
Fig. 15.
23 (22') Median teeth fused at base, appearing almost as a split tooth (Fig. 16a) Endochironomus
23' Median teeth distinctly separated (Fig. 15c)
Tribelos
24 (21') Labial plate with a single tooth (double or notched in pectinatellae - (Fig. 16b> and 6 or 7
laterals, all more or less pointed and progressively reduced in size outward; the penultimate
may project beyond the teeth on either side (Fig. 16c) Parachironomus
24' Another combination of characters
25
^
Fig. 16
25 (24') Median labial tooth broad, rounded and dome-like (Fig. 15d) Cryptotendipes
25' Another combination of characters 26
26 (25') Labial plate with 15 teeth, alternating large and small; mature larva may lack teeth on
mandible Xenochir onomus
26' Another combination of characters 27
27 (26') Paralabials more than 2 1/2 times as wide as long Glyptotendipes
27' Paralabials less than 2 1/2 times as wide as long Dicrotendipes
21
-------
HI SELECTED REFERENCES
Beck, William M. , Jr. and Elisabeth C. Beck. 1966. Chironomidae
(Diptera) of Florida I. Pentaneurini (Tanypodinae). Bull. Fla.
State Mus. 10(8): 305-379.
Curry, LaVerne L. 1958. Larvae and pupae of the species of
Cryptochironomus (Diptera) in Michigan. Limnol. Oceanogr. ,
3(4): 427-442.
Darby, Rollo E. 1962. Midges associated with California rice fields
with special reference to their ecology. (Diptera: Chironomidae).
Hilgardia 32(1): 1-206. Calif. Agric. Exp. Sta., Univ. of Calif.,
Berkeley.
Johannsen, O. A. 1937a. Aquatic Diptera. Part III. Chironomidae:
Subfamilies Tanypodinae, Diamesinae and Orthocladiinae. N. Y.
Agr. Exp. Sta. Mem. 205: 1-84.
1937b. Aquatic Diptera. Part IV. Chironomidae:
Subfamily Chironominae. N. Y. Agr. Exp. Sta. Mem. 210: 1-80.
Mason, William T., Jr. 1968. An introduction to the identification of
chironomid larvae. Fed. Water Poll. Cont. Adm. , 1015 Broadway,
Cincinnati, Ohio - 45202.
Roback, Selwyn S. 1957. The immature tendipedids of the Philadelphia
area. Acad. Nat. Sci. Phila. Monog. 9: 1-152.
The publications of Johannsen are out of print. Photocopies may be pur-
chased from: University Microfilms, Inc. , Ann Arbor, Michigan.
The possibility of Xerox copies of these publications should be investigated.
22
-------
FRESHWATER FISHES
John S. Ramsey
Fishes are coldblooded vertebrates which breathe with gills and
whose paired appendages are fins. There are several hundred fresh-
water species in eastern U. S. , with about 30 known undescribed species.
Identification of individuals using existing keys is difficult for the
novice due to the e? ..stence of numerous similar species, undetected
geographic variation, and because useful literature is scattered,
particularly for the southeastern states.
The remarks here will cover (1) collection of fishes, (2) process-
ing and museum maintenance, (3) study equipment, fish morphology,
and use of dichotomous keys for identification, and (4) the relationship
of fishes to water quality studies.
Collection of Freshwater Fishes
Preservation. -- Preserve fishes alive in 10 to Z0°/o formalin. Color
and form are distorted if specimens are allowed to asphyxiate or remain
unpreserved for any length of time, and identification becomes difficult.
Larger specimens (over 7") must be slit to ensure good internal fix-
ation. The slit should be made horizontally along the lower right side,
opening the body cavity from below the pectoral fin to above the vent. If
many large specimens are preserved, the formalin solution is likely to
become bloody. Bloody formalin seems to be less effective in preserva-
tion, so it may be desirable to change the solution after a few hours. If
only a few small specimens are collected, add water until a strength of
about 10°/o is reached.
Number to preserve. -- Take as many specimens as is possible. If
population structure data are needed, preserve the entire sample or be
certain of field identification if specimens are discarded. In any event,
try to preserve 20 or more individuals of each small species encountered,
and as many of larger specimens as can be placed in available containers.
-------
Labelling. -- Each collection should be labelled immediately on comple-
tion to avoid possible mixup. Use only high rag content paper, as for-
malin almost dissolves low grade paper. If labels are printed, allow
space for the following categories: State, County, Locality (including
name of stream, distance and direction from nearest mapped town, and
township, range and section, if available), Date, Collection Number, and
Collectors. Data should be listed in waterproof ink. Pencil may be
used, but tends to wear from label paper.
Seining. -- Small streams and shallows of ponds can be sampled effectively
with small seines(10 to 15 feet), especially at night. Seining is one of the
fastest techniques available, as a sample can be completed in about one
hour. When many samples must be made in a day, the time-saving feature
of seining can be important. Another major advantage of seining is that
individual habitat features can be discerned.
We have found a 12' x 5' nylon seine with 3/16" mesh about the best
for general-purpose, two-man collecting. The netting is loosely mount-
ed on 5' wooden or metal brails. The-small mesh size is most efficient
for capturing fry and small species, especially darters. Other seine
types include a 5 to 6 foot seine, which one man can use in small streams,
and larger bag seines (25 to 50.'), which are useful in ponds and pools of
streams where there are few snags.
Equipment for general seining includes (1) seine (2) supply of wide-
mouth jars containing proper amount of formalin (3) canvas carrying bag
for jar (4) waders or tennis shoes and bathing suit (5) headlamp and
battery for night collecting (6) detailed maps.
It is important to sample each stream microhabitat thoroughly when
seining. Techniques used vary with each type of flow pattern and sub-
strate: (1) Riffles--set the seine with brails moderately close together,
kick vigorously from above to overturn rubble or gravel; sample up and
down fastest and slowest current at greatest and least depths (2) Pools--
seine upstream onto riffle just to side of current, or downstream in
current. Many cyprinids will school along the edge of the fast current just
below a riffle. A deep pool cannot be sampled effectively with a seine,
but some work above and below riffles gives an indication of what species
are present. (3) Backwaters--still water at the edge of fast current
can be productive for some rarer species. Sample this habitat thoroughly
by seine sweeps and by kicking detritus into the net. (4) Ponds--surround
vegetation and kick detritus into the seine.
Comparison of a vigorous seining sample with those taken through
other techniques indicates almost 100%> success in obtaining all species
present. Riffle collecting with a seine is probably the most effective
-------
technique for obtaining darters (Percidae) which appear to be among the
first fishes to succumb to environmental contamination. As they are
less mobile than other fishes, their absence might indicate sporadic
pollution in an otherwise healthy-appear ing environment.
Poisoning. -- Small rivers and long pools in smaller streams may be
sampled effectively. All poison samples should be performed with the
knowledge and cooperation of state conservation agencies. There should
be many persons on the pickup crew, as some forms surface only once,
and do not reappear. Three main fish toxicant types are used: Rotenone--
ChemFish Collector, NoxFish, and ProNoxFish are some of the derris
derivatives used in fish collecting. These products are generally ineffective
at water temperatures below 65° F. , and are most potent at 80° F. or above.
When using rotenone, block nets may be set above and below the sample
area. Add the rotenone at a rate of about one quart for a stream having
10 cfs of flow, preferably on a riffle for complete mixing. Mark the head
of the rotenone slug with a dye so that it may be followed. When the slug
reaches the end of the sample area, again preferrably on a riffle, begin
mixing potassium permanganate to neutralize the rotenone. The water
should be stained a moderate purple color. About 5 Ibs. of potassium
permanganate should neutralize a quart of rotenone after it has diffused
in a pool of about 100 feet in length. Continue neutralizing until fish have
stopped surfacing in the sample area. Preserve specimens as they are
captured. Use fine-meshed dipnets to capture even smaller species.
Cresol. -- Also known as black disinfectant, cresol is a highly toxic
substance best handled with extreme care. It is used routinely in sainpling
trout waters, where water temperature is too low for rotenone sampling.
It is used in other areas during the winter. There are no exact standards
to follow for use of this chemical, as results have varied each time it is
applied. Too strong an application in a river will kill fishes for miles,
while too weak a concentration will not kill anything. The manufacturer
recommends 4 oz. of cresol (phenol coefficient 6) per 12 gallons of water
for general disinfecting purposes. Probably half of this would be suitable
for fish collecting. Good results on a large river were obtained by adding
one quart of cresol per foot-second of river flow. Preserve fishes as
they are recovered. Use fine-mesh dipnets to ensure representative
occurrence of species in the sample.
Sodium cyanide. -- When a fast-flowing large river is to be sampled,
perhaps the best technique is to use this chemical. While extremely toxic
to humans (and to be handled with absolute caution), sodium cyanide merely
stuns fishes. Some darters which inhabit the deepest, strongest currents
among boulders may be taken using this poison.
-------
Shocking1. -- Boat shockers and stream shockers are useful in lakes and
small streams, but sometimes are ineffective where water hardness is
low. Conductivity in small streams may be altered by putting a salt block
above the sample area, but generally this approach is not especially
practical. In hard-water rivers of moderate size, shocking is very high
in efficiency for collecting small riffle-dwellers, especially darters.
Netting. -- Gill nets, trammel nets, pound nets, and other commercial
fishing devices may be used, but it must be recognized that these
techniques are selective for larger, actively moving fishes.
In summary, the best collecting means is determined by the habitat
represented by a suggested sample area.
Processing of Collections
Replace formalin soon after time of capture if the larger specimens
have bled much. Leave in formalin for at least a week (two weeks if
there are many large fishes). While specimens may be maintained in-
definitely in 10°/o formalin, they tend to become depigmented and the
calcium is leached from osseous structures if not buffered. Also, it is
unpleasant at best to work with formalin specimens in subsequent
identification, and some persons develop an acute formalin allergy.
Thus it is desirable to soak the formalin from fish specimens. Pour
off and discard the original preservative, rinse, and soak in water.
Change the water twice daily until no strong formalin fumes are present.
Add alcohol (45%> isopropyl or 70°/o ethyl) well over the volume of fish
present. If the collection jar is full of specimens, change the alcohol
several days later.
Sorting. -- An important aspect of fish identification is the proper sorting
of a collection. It may take a little time to develop an "eye" for differences
in similar species, but with practice one becomes more skillful at detect-
ing subtle differentiae. At most ichthyological laboratories collections are
rough-sorted by technicians, and are checked and corrected by experts.
Almost every family of freshwater fishes in eastern North America
contains many "look-alikes". To detect possible polyspecific groupings
in rough-sorted collections, the best technique is to arrange all speci-
mens in rows, and examine each carefully for consistent differences in
the following: (1) eye size relative to snout length (2) body shape (3) fin
placement and shape (4) mouth placement and (5) details of pigmentation
on body and fins, including chromatophore size and distribution. Satisfy
yourself that possible differences do not represent sexual dimorphism and
-------
dichromatism or age difference.
Generally, especially in cyprinids and percids, if the specimens
look a little different they probably are a different species. This may be
checked through use of keys. It is better to have a species represented
twice in a sorted collection than to have two or more listed as one,
particularly for water quality work.
Once sorted, the specimens ideally should be placed in museum jars,
fully labelled -with one species to a jar. However, space limitations of
many laboratories make it desirable to place all species together again in
the original collection jar. All collections are valuable to fish
systematists, and if it becomes necessary to discard some series, it
would be useful to contact an established ichthyological museum to deter-
mine interest in depositing survey materials there.
Identification of Fishes
Equipment. -- Items essential in examination of fishes for identification
include:
Dissecting microscope--low power of about 7x, and higher, either
rotary or stereozoom type of binocular microscope. A substage mirror
is essential.
Light source--very high illumination -is required. Many favor a
gooseneck lamp with 100 W. lightbulb, others the smaller lamp types
projecting a concentrated beam of light. The important aspect is to
bring the light as close to the subject as is comfortable.
Long forceps--for removing specimens from jars.
Fine-pointed forceps--be certain the forceps points meet at the tip
for proper grasping of fins in small fishes and for removal of pharyngeal
teeth in small cyprinids.
Divider--a fine-pointed divider is useful for measuring body propor-
tions. A dial caliper is used by many.
Rule--a stainless steel rule (metric) is used in conjunction with a
divider when obtaining actual measurements.
Dissecting kit--internal examination frequently is required, for which
routine dissecting tools are useful.
Morphology. -- Each text-book type of key for identification typically in-
cludes a section on how to make counts and measurements. More specific
research papers typically refer to standards suggested by C. L. Hubbs
and K. F. Lagler (1958. Fishes of the Great Lakes Region, Cranbrook
Inst. Sci. Bull. 26, rev. ed.). Definitions given below follow the criteria
of Hubbs and Lagler. It is assumed that the student is familar with gross
fish morphology.
-------
Spines - -unsegmented, unbranched, usually stiff and pungent fin
supports. Denoted by Roman numerals in fin-ray formula.
Soft rays--segmented, usually flexible and branched fin supports.
Denoted by Arabic numerals in fin-ray formula.
Fin-ray formula--denotes nature and placement of radial fin support
elements. Examples for the various fin types follow: (1) Dorsal fin; D.
8 indicates that there are eight principal soft rays in the dorsal fin.
Principal soft-rays are those reaching the fin margin, usually including
one unbranched ray anteriorly. The last two soft rays are counted as
one because they share a. single basal element. D. XII, 10 signifies that
there are 12 spines and 10 soft rays in the dorsal fin, and that the spinous
and soft portions are continuous in one fin. D. XII-10 indicates that the
spinous and soft dorsal fins are separated, there being 12 spines and 10
soft rays. (2) Anal fin: A. 7 means there are seven principal soft
rays in the fin. The last two rays are counted as one as they share the
same basal element. A. Ill, 7 indicates three spines and seven soft rays
in the anal fin. (3) Pectoral fin: Pj I, 13 means that there is one spine
and 13 soft rays in the fin. All elements are counted. (4) Pelvic fin:
P£ 8 indicates eight soft rays in the pelvic fin. All elements are count-
ed. (5) Caudal fin: C. 20 indicates there are 20 principal rays in the
caudal. The small procurrent rays in advance of the principal rays
are not counted.
B ranchipstegal rays - -slender bones in the gill membranes. All
elements are counted.
Scales--terms applied to scale character include (1) Cycloid; having
a smooth exposed scale margin. (2) Ctenoid; scale margin roughened
by comb-like ctenii. (3) Embedded (or imbedded): small cycloid scales
entirely or largely covered by skin, detectable by scraping gently with
point of forceps on skin from which excess moisture has been blotted.
Lateral-line scales--number of scales along the side, usually bearing
pores of the lateral-line sensory system. Counted anteriorly from the
hypural plate edge (detected by flexing tail and noting where no lateral
movement occurs on the posterior caudal peduncle) to the upper edge of
the opercle. The lateral line is incomplete in many forms (the scales
are unpored posteriorly). The formula 11s 20 + 12 = 32 indicates that
there are 32 lateral-line scales, of which 20 are pored and 12 are un-
pored.
Scales above the lateral line - - counted downward and posteriorly
from side of dorsal fin origin (anterior base of dorsal fin).
Scales below the lateral line--counted upward and anteriorly from
side of anal fin origin.
Predorsal scales--scale rows crossing the nape midline (region
between occiput and dorsal fin origin).
Cheek scales--number of rows crossing a diagonal from the eye to
the angle of the preopercle.
Circumferential scales--scale rows around the body just in advance
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of dorsal fin. Sometimes a formula is useful: Circ. Scales 13+2+11=
26 indicates 13 longitudinal rows above the lateral line, two lateral-
line rows, and 11 rows below the lateral line, total 26 scale rows.
Caudal peduncle scales--the least number of longitudinal scale rows
around the caudal peduncle. May be expressed as a formula.
Pharyngeal teeth--number and arrangement of teeth on the
pharyngeal bones are important in identifying minnows (Cyprinidae).
Generally there are one or two rows of teeth on each arch, there being
a row of four or five large teeth in the major row and two to zero very
small teeth in the minor row. One or more teeth may be missing,
but can be detected by presence of a socket on the pharyngeal bone.
Usually expressed as a formula, for example 2,4-4,2 signifies that there
are two rows of teeth on each arch, and that there are four teeth in the
major row and two in the minor row on each bone. A count of 0,4-5,0
indicates one row of teeth on each, four teeth in the major row of the
left arch and five on the right arch.
Pyloric caecae--number of tips or bases (stipulate which is used)
of pyloric caecae, gut diverticula at the junction of stomach and intestine.
Gill rakers--each distinct element is counted, although often there
is confusion on -what rudimentary anterior gill rakers to count. The count
is made on the first gill arch, the formula GR 3+15=18 indicating that
there are 18 gill rakers, three on the upper limb and 15 on the lower limb.
If a raker is placed immediately on the angle of the gill arch, it is in-
cluded with those on the lower limb.
Proportional measurements--each measurement is made in a
straight line from point to point.
Total length--from the anteriormost projection of the head (snout
or lower jaw) to the tip of the tail when the caudal lobes are squeezed to-
gether.
Standard length- -distance from the snout tip to the hypural flexure
(base of the caudal fin).
Body depth--the greatest vertical dimension of the body.
Head length--distance from the snout tip to the fleshy margin of the
opercle.
Eye length--greatest dimension (may be diagonal) of the exposed
portion of the eye.
Snout length--from the tip of the snout or upper jaw to the anterior
edge of the orbit (bony eye socket).
Most taxonomic keys are arranged in couplets (dichotomous keys),
however some older keys use triplets or up to six choices. Be aware
of the structure of the key being used. Some rules for key use are:
Use more than one specimen. -- have several examples before you
when using the key. Check features mentioned on each to determine
range of variation involved, if any.
Read and understand both couplets, --a first couplet may seem to
describe the specimen at hand when actually the second choice is better.
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Study illustrative figures. -- most general keys provide helpful
illustrations covering characters not well-defined in words.
Mark doubtful couplets. -- since many key characters are split on
a degree basis, frequently it is impossible to determine what the author
means. Mark these points of indecision, and try both routes. In any
event be wary of accepting identifications based on doubtful character
description.
Check species identification. -- once a tentative species name has
been reached in a key, it is important to confirm or reject the determin-
ation through several means: (1) Compare characteristics of the
specimens with data listed in the discussion of each species. (2) Deter-
mine if the correct geographic range is involved. (3) Compare with
photographs and drawings in the key and from other sources. (4)
Compare with specimens identified by a specialist.
If there is any doubt in species determination, it is better to list
the genus only than to mention an incorrect species name, particularly
in publication. The specimens may be sent to an ichthyologist for verifi-
cation. A sample containing a number of individuals should be sent,
as most specialists will provide identification in exchange for part of the
series.
Useful Modern References for Identification of
Eastern Fishes
North America
Bailey, R; M. , et al. I960. A list of common names and scientific
names of fishes from the United States and Canada. Am. Fish.
Soc. Spec. Publ. 2, 102p.
Eddy, S. 1957. How to know the freshwater fishes. Brown Co. ,
Dubuque. 2 53 p.
Moore, G. A. 1968. Fishes, p. 22-165. to W. F. Blair, et al. ,
Vertebrates of the United States (second edition). McGraw-Hill, N. Y.
Alabama
Smith-Vaniz, W. In Press. Keys to fishes of Alabama. Ala. Agr. Exp.
Sta. Spec. Publ.
Arkansas
See North America—no recent lists or keys.
Delaware
See North America—no recent list or keys.
8
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Florida
Carr, A. , and C. J. Coin. 1955. Guide to the reptiles, amphibians,
and fresh water fishes of Florida. Univ. of Florida Press,
Gainesville. 341 p.
Georgia
See North America and Alabama--no recent state list.
Illinois
Eddy, S. , and T. Surber. 1961. Northern fishes with special reference
to the upper Mississippi Valley (second edition). Univ. of
Minnesota Press, Minneapolis.
Indiana
Gerking, S. D. 1955. Key to the fishes of Indiana. Invest. Indiana
Lakes and Streams 4(2): 49-86.
Iowa
Bailey, R. M. 1951. A checklist of the fishes of Iowa with keys for
identification, p. 187-238. In Harlan, J. R. , and E. B. Speaker.
Iowa fish and fishing. Iowa State Conservation Cornm.
Kansas
Cross, F. B. 1967. Fishes of Kansas. State Biological Survey and
Univ. of Kansas Museum of Natural History, Lawrence, 357p.
Kentucky
Clay, W. M. 1962. A field manual of Kentucky fishes. Kentucky Dept.
Wildlife Res., 147p.
See also North America.
Louisiana
Douglas, N. H. , and J. T. Davis. 1967. A checklist of the freshwater
fishes of Louisiana. Louisiana Wildlife and Fisheries Comm. , p. ?•
29.
See also North America.
Maryland
Elser, H. J. 1950. The common fishes of Maryland: how to tell them
apart. Maryland Board of Natural Resources, Dept. of Research
and Education., 45p.
See also North America.
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Michigan
Hubbs, C. Li., and K. F. Lagler. 1958. Fishes of the Great Lakes region
(second edition). Bull. Cranbrook Inst. Sci. 26: 1-186.
Minnesota
See Illinois.
Mississippi
Cook, F. A. 1959. Freshwater fishes in Mississippi. Miss. Game and
Fish Comm., 239p.
See also North America.
Missouri
Pflieger, W. L. In Preparation. Fishes of Missouri.
See also North America.
Nebraska
See Kansas, North America, South Dakota.
New England
Bailey, J. R. , and J. A. Oliver. 1939. The fishes of the Connecticut
watershed, p. 150-189. In Biological survey of the Connecticut
watershed. New Hampshire'Fish and Game Dept. Survey Rept. IV.
Bailey, R. M. 1938. The fishes of the Merrimack watershed. In
Biological survey of the Merrimack watershed, p. 149-185. New
Hampshire Fish and Game Dept. Survey Rept. III.
Everhart, W. H. 1950. Fishes of Maine. Maine Dept. Inland Game and
Fish, 53p.
Scott, W. B. 1967. Freshwater fishes of eastern Canada (second edition).
Univ. of Toronto Press, 137p.
New Jersey
See North America.
New York
Greeley, J. R. 1927 to 1940. (Watershed survey reports on fishes of New
York rivers published as Supplements to the 16th through 29th Ann.
Repts. of the New York State Cons. Dept.)
See also North America, New England, Michigan, Ohio.
10
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North Carolina
See North America.
North Dakota
See North America, South Dakota, Illinois.
Ohio
Trautman, M. B. 1957. The fishes of Ohio. Ohio State Univ. Press,
Columbus, 683p.
Oklahoma
Moore, G. A. 1952. A list of the fishes of Oklahoma. Okla. Game
and Fish Dept.
See also Kansas, North America.
Pennsylvania
See Ohio, Illinois, Michigan, North America.
South Carolina
See North America.
South Dakota
Bailey, R. M. , and M. O. Allum. 1962. Fishes of South Dakota. Misc.
Publ. Mus. Zool. Univ. of Michigan 119, 131p.
Tennessee
Kuhne, E. R. 1939- A guide to the fishes of Tennessee and the Mid-
South. Tenn. Dept. Cons. , Div. Game and Fish.
See also North America, Kentucky.
Texas
Hubbs, Clark. 1957. Distributional^patterns of Texas fresh--water fishes.
Southwestern Nat. 2: 89-104.
. 1961. A checklist of Texas fresh-water fishes. Texas
Fish and Game Comm. , Div. Inland Fisheries, IF Ser. 3 rw. , 14p.
See also North America.
Virginia
Raney, E. C. 1950. Freshwater fishes, p. 151-194. In The James River
Basin past, present and future. Virginia Acad. Sci. , Richmond.
See also North America.
11
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West Virginia
See North America.
Wisconsin
Greene, C. W. 1935. The distribution of Wisconsin fishes.
Wisconsin Cons. Comm. , Madison. 235p.
See also Illinois, Michigan, Iowa, North America.
Nature £f Stream Fishes Relative t£ Water Quality
Some general references on fish distribution relative to presence
or absence of pollution include P. Dondoroff (1957. Biological indices
of water pollution, with special reference to fish populations, p. 144-
163. In C. M. Tarzwell (ed.), Biological problems in water pollution.
R. A. T aft Sanitary Engineering Center, Cincinnati) and F. T. K.
Pentelow and R. E. Johnson (Chairmen. 1965. Environmental require-
ments of fishes and wildlife, p. 145-194. In C. M. Tarzwell (ed. ),
Biological problems in water pollution, third seminar. R. A. Taft
Sanitary Engineering Center, Cincinnati.
There are no data on tolerance levels or ecological requirements
for the vast majority of freshwater fishes. An attempt presently is
being made to determine such aspects using 20 representative species at
the FWPCA National Water Quality Laboratory in Duluth, Minnesota.
The species being investigated include some of fairly wide range in east-
ern U. S. , or of special sport fishery interest.
Fishes being tested against all pollutants at the Duluth Laboratory in-
clude Dorosoma petenense (threadfin shad), Salvelinus fontinalis (brook
trout), Salmo gairdneri (rainbow trout), Esox lucius (northern pike),
Notropis atherinoides (emerald shiner), Pimephales promelas (fathead
minnow), Catostomus commersoni (white sucker), Ictalurus. punctatus .
(channel catfish), Roccus chrysops (white bass), Lepomis macrochirus
(bluegill), Micropterus salmoides (largemouth bass), and Perca
flavescens (yellow perch).
Species being tested for reaction to special types of pollutants include
Oncorhynchus kisutch (coho calmon), Salvelinus namaycush (lake trout),
Coregonus artedii (cisco), Pros opium williamsoni (mountain whitefish),
Osmerus mordax (American smelt), Micropterus dolomieui (smallmouth
bass), and Stizostedion vitreum (walleye)
The goldfish (Carassius auratus) is serving as an all-purpose experi-
mental standard species, or "white rat" among freshwater fishes.
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Results of these studies should provide criteria for estimating
extent or type of pollution involved in an area. Until such time as
total information becomes available, only general observations might
be made.
Species indicating clean water. -- Many native fishes would serve as
indicators of undisturbed habitat, particularly in the families Percidae
(darters) and Cyprinidae (minnows). Unfortunately for pollution bio-
logists, their habitat requirements have led to distributional or ecologic
limitation, and none is especially widespread or common. Refarence
to species discussions in the literature suggested above frequently will
show that a species is "restricted to clear flowing streams". Thus
clean water "indicator" species among fishes vary from drainage to
drainage and from one physiographic province to another. When work-
ing in an area, it might be well to compile a listing of species known
from the drainage, then determine if absence at a locality is due to
pollution or to natural habitat limitation.
Pollution indicator species. -- Possibly the only species which consis-
tently does well in polluted waters in central and southern U. S. is the
mosquitofish, Gambusia affinis. The species is widespread, but gen-
erally is rare where many other fishes occur. Typically it is limited
to shallow backwaters of streams, but becomes more abundant in
swampy, heavily organic conditions. When less tolerant species are
extirpated by pollution, Gambusia often becomes the dominant species,
occurring throughout the stream habitat. Thus it is a facultatively dom-
inant form in many types of polluted water. Dr. Denzel Ferguson
(Mississippi State University) has published several papers demonstrating
that the mosquitofish can adapt genetically to withstand pesticide runoff
in cotton-raising areas.
In the southern states, three species seem to adapt to or tolerate
a variety of pollutants that eliminate other fishes, especially in small
streams. These species are the mosquitofish, the green sunfish
(Lepomis cyanellus). and the bluegill (Lepomis macrochirus). In some-
what larger streams the fathead minnow (Pimephales promelas) also
' survives. If only one or a combination of these four species occurs,
pollution may be indicated.
Population structure change. --In some instances data are available on
prior occurrence of species in a stream. Comparison of percent com-
position of each species with present population structure might lead to
useful criteria for analysis of pollution problems.
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Sedentary species absent. -- Quite frequently a stream locality appears
healthy in every respect, has good dissolved oxygen level, clear water,
and good vegetation cover on the substrate, and a seemingly good fish
fauna. However, analysis of species composition indicates that there
is an absence or unusual scarcity of species of sedentary habit. In southern
rocky or gravelly areas, darters of the genera Percina and Etheostoma
should be present always. Above the Coastal Plain, sculpins of the
genus Cottus likewise should be present on hard substrate. Other fish
families or genera largely non-vagile in habit are the lampreys
(Petromyzontidae), genus Noturus of the catfishes (Ictaluridae), mud-
minnows (Umbridae), and swampfishes (Amblyopsidae). Some pre-
liminary observations on movements of these forms indicate that they
tend to move upstream during periods of environmental stress. Thus
they are extirpated rapidly by a contaminant slug.
Other fish groups, and particularly larger species, have the
ability or predisposition to run downstream from pollutants, outracing
a slug to the mouth of an unpolluted tributary where they seek refuge.
Many fish' kills are prevented or diminished in intensity by the
availability of such a refugium to fleeing fishes. The presence of such
tributaries should be detected in analyzing populations comprised mostly
of vagile species.
Sedentary fishes normally are absent or rare in large muddy rivers
with sluggish flow. It is important to analyze the habitat thoroughly to
determine significance of species absence.
Extremely vagile species include most minnows and suckers. Some
centrarchids also are quick to move upstream when pollution abates,
especially blue gill and green sunfish. Gizzard shad (Dorosoma cepedianum),
goldfish, and carp (Cyprinus carpio) are among the first to move upstream
when conditions become favorable.
Heavy plant growth on rubble. -- One indication of periodic pollution is
the growth of long strands of green algae (Spyrogira, Cladophora) and
river weed (Podosternum) on rocks in riffle areas. Normally grazing
fishes, especially stoneroller minnows (Campostoma anomalum), are
active enough to prevent extraordinary luxuriance of such vegetation.
Although many vagile fishes be present, this condition may indicate
periodic extended downstream retreat from pollution.
Sculpins only present. -- In certain rare instances, a Cottus species may
be the only fish present in an area. Usually this condition is seen below
dams where sudden discharge of very cold water occurs. Apparently
14
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Cottus, especially C_. bairdi, are tolerant to sudden drops in water temper
ature. Other fishes appear much less tolerant.
In summary, complete survey of fishes in an area is desirable for
proper pollution analysis. Knowledge of the normal habitat and natural
fish limitation is essential. With increasing accumulation of data on
normal specific requirements, better understanding of habitat-species
interaction will be available.
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