Biota of Freshwater Ecosystems
Identification Manual No. 11
FRESHWATER UNIONACEAN CLAMS (MOLLUSCA:PELECYPODA) OF NORTH AMERICA
by
J. B. Burch
Museum and Department of Zoology
The University of Michigan
Ann Arbor, Michigan 48104
for the
ENVIRONMENTAL PROTECTION AGENCY
Project # 18050 ELD
Contract # 14-12-894
March 1973
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402. Price: $4.10, domestic postpaid; $3.75, GPO Bookstore
Stock Number 6501-00688
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EPA Review Notice
This report has been reviewed by the Environ-
mental Protection Agency, and approved for
publication. Approval does not signify that
the contents necessarily reflect the views
and policies of the EPA, nor does mention of
trade names or commercial products constitute
endorsement or recommendation for use.
WATER POLLUTION CONTROL RESEARCH SERIES
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Inquiries pertaining to Water Pollution Control Research Reports
should be directed to the Chief, Publications Branch (Water), Research
Information Division, R§M, Environmental Protection Agency, Washington,
D.C. 20460.
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FOREWORD
"Freshwater Unionacean Clams (Mollusca: Pelecypoda) of North
America" is the eleventh of a series of identification manuals
for selected taxa of invertebrates occurring in freshwater
systems. These documents, prepared by the Oceanography and
Limnology Program, Smithsonian Institution for the Environ-
mental Protection Agency, will contribute toward improving
the quality of the data upon which environmental decisions
are based.
Additional manuals will include but not necessarily be limit-
ed to, freshwater representatives of the following groups:
dryopoid beetles, branchiuran crustaceans (Argulus), amphipod
crustaceans (Gammaridae), isopod crustaceans (Asellidae),
decapod crustaceans (Astacidae), leeches (Hirudinea), poly-
chaete worms (Polychaeta), freshwater nematodes (Nematoda),
freshwater planarians (Turbellaria), and freshwater clams
(Sphaeriacea).
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ABSTRACT
Bivalved mollusks of the superfamily Unionacea (Order Schizodonta) are
represented in North America by three families, 46 genera, and, as
treated in this key, 221 species. The primitive Margaritiferidae are
represented by two genera and four species, the Amblemidae by eight
genera and 25 species, and the very large family Unionidae by 36 genera
and 192 species. Systematics are not well worked out in many groups,
which makes a definitive listing of species somewhat arbitrary at this
time. The present key in most instances reflects a conservative
approach to the lower taxa and, although it omits many nominal species
of doubtful validity, the key nevertheless represents most of the bio-
logical species.
Characters of soft anatomy are used to separate the families, subfamilies
and, in a few cases, genera. Species are separated by shell characters.
The main feature of this publication is an illustrated taxonomic key
using both soft anatomy and shell characters for the identification of
the North American Unionacea.
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CONTENTS
Section Page
I Introduction 1
Identification 5
II Species List and Ranges 11
III Key to Families of North American Unionacea 25
Key to Species of Margaritiferidae 26
Key to Species of Amblemidae 29
Key to Subfamilies of Unionidae 44
Key to Species of Pleurobeminae 45
Key to Species of Popenaidinae 70
Key to Species of Anodontinae 72
Key to Species of Lampsilinae 93
IV Acknowledgements 155
V References 157
VI Glossary 163
VII Index to Scientific Names 171
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FIGURES
Shell terminology-
Shell terminology-
Shell shapes
Beak sculpture
Animal, external view
Mantle margins of freshwater mussels
Gills of gravid female mussels
Cumberlandia monodonta
Margaritifera hembeli
M. mavgaritifera3 M. faloata
Gonidia angulata
Quadrula intermedia
Tritogonia verrucosa3 Quadrula cylindrica
Elliptoideus sloatianus
Quincuncina in furcata3 Q. burkei
Megalonaias giganteus
Amblema neislerii
A. perplicata3 A. costata
Plectomerus dombeyanus
Quadrula metccnerra3 Q. quadrula
Q. nodulata3 Q. pustulosa
Q. archeri3 Q. aurea
Fusconaia flava undata
F. ebenus3 F. subrotunda
F. cor3 F. succissa
Median sulcus on right valves
F. cuneolus3 F. flava flava
Gills in the Unionidae
Cyclonaias tuberculata
Plethobasus cooperianus3 P. cyphus
Uniomerus tetralasmus
Hemistena lata
Pleurobema (Lexingtonia collina)
P. (L.) dolabelloides
P. (L.) masoni
P. cordatum pyramidatum
P. marshalli3 P. altwn
P. cordatum cordatum
P. showalterii3 P. altum
P. clavam, P. curtum
P. decisum3 P. chattanogaense
P. cordatum pauperculum3 P. cordatum coccineum3 P. oviforme,
P. verum3 P. irrasum3 P. nux, P. perovatum3 P. reclusum
Outlines of shells of Pleurobema
Outlines of shells of Pleurobema
Elliptio (Canthyria) spinosa
E. shepardiana
E. crassidens crassidens3 E. crassidens downiei
Shells of Elliptio in end view
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FIGURES - continued
Elliptic/ dilatata3 E. fraterna
E. nigella3 E. arctata
E. lanceolata3 E. ohipolaensis
E. oomplanata3 E. ioterina
E. jayensis3 E. hopetonensis
E. ohipolaensis, E. jayense
E. oongaraea
E. waooamawensis
E. dariensis
Cyrtonaias berlandierii
Popenaias popei3 P. buckleyi
Anodonta suborbioulata
A. imbeoiIlus
A. peggae3 A. couperiana
A. gibbosa3 S. grandis aorpulenta
A. grandis grandis
A. kennerlyi
Beak sculpture; Strophitus undulatus
Anodontoides ferussaoianus} Anodonta grandis simpsoniana
Anodonta implieata, A. oataraota
A. dejeeta
A. wahlamentensis3 A. ealiforniensis
A. beringiana
A. oregonensis
Alasmidonta variaosa3 Anodontoides radiatus
Alasmidonta marginata3 A. rax>eneliana
Simpsoniconeha ambigua3 Strophitus subvexa
Arcidens confragosus
Arkansia wheeleri
Alasmidonta (Pegias) fabula
A. araula
A. ealaeolus
A. wrightiana3 A. triccngulata
A. heterodon
A. undulata
Lasmigona eomplanata3 L. oostata
L. holstonia L. oompressa
L. subviridis
Ptychobranahus subtentum
P. foremanianum3 P. fasciolare
P. greenij P. oooidentalis
Obliquaria reflexa
Cyprogenia alberti3 C. irrorata
Dromus drornus
Lemiox eaelata
Medionidus mcglamerae3 M. penicillatus
M. oonradicus3 M. aoutissimus
Glebula rotundata
Ellipsaria lineolata
Carunoulina parva3 C. pulla
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FIGURES - continued
Lampsilis anodontoides
L. 3ubangulata, L. jone si
Ligumia nasuba, L. recta
Obovaria retusa3 0. olivaria
0. subrotunda
0. rotulata, 0. unicolor
0. jacksoniana
Dysnomia
D. flexuosa
D. lewis si
D. stewardsoni
D. toruloses.
D. triquebra
D. brevidens
D. metastriata
D. lenior
D. penita
D, haysiana
D. sulcata
D. turgidula
D. archaeformis
D. biemarinata
D. propinqua
D. personata
D. oapsaeformis
D. florenbina
Tvuncilla truncata
T. macvodon, T. donaciformis
Lampsilis dolabraeformis
L. ezcaoata, L. ovata ovata
L. perpasta
L. binominata3 L, splendida
Leptodea
L. leptodoHj L. amphichaena
L. fragilisj L, laevissima
Proptera alata
Inflated shell; Beak sculpture
P. capax3 P. purpurata
Actinonaias pectorosa, A. ellipsifomds
A. carinata carinata3 A, carinata gibba
Mantle margins of Villosa3 Lampsilis and Carunculina
Villosa iris, V. vibex
V. lienosa3 V. oonstvicta, V. trabalis
Lampsilis anodontoides3 L. subangulata
L. splendida, L. jonesi
L. streakeri
L. altilis3 L. bracteata
L. australiss L. radiata siliquoidea
L. hydiana3 L. radiata radiata
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FIGURES - continued
148 Lampsilis dolabraeformis 148
149 L. exoavata3 L. ovata ovata 148
150 L. orbiaulata} L. stvaminea 149
151 Lampsilis umbos 150
152 L. ovata ventricosa, L. fasciola 150
153 L. oaviosa3 L. pevipasta 152
154 L. binominata, L. ochracea 153
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SECTION I
INTRODUCTION
The richest unionacean fauna (freshwater mussels) in the world is found
in North America and has been the subject of much species-naming since
the time of C. S. Rafinesque in the early 19th century. However, indepth
studies of these animals have been few, and investigations mainly have
centered around faunal distributions and nomenclature. (A notable ex-
ception is the work of A. E. Ortmann.) Therefore, while distributions
are rather well known for most of the nominal species, systematic rela-
tionships at all levels within the North American Unionacea are rather
poorly understood. For that reason, systematics of our freshwater
mussels have been the subject of considerable controversy in the past
and at present, with much of the controversy still unresolved. Neverthe-
less, the taxonomy of unionacean clams of a few geographic regions has
been rather thoroughly studied recently (e.g., see Johnson, 1970, 1972;
Clarke, 1973), and those publications have been especially helpful in
preparing the present key. But producing a finite, unified key for
identification of freshwater mussels for all of North America is very
difficult at this time. In spite of this, however, one may construct a
workable key to the traditionally recognized taxa which probably repre-
sent most of the species. A more precise key must await further study,
although it is improbable that many of our freshwater mussels will ever
be adequately studied because of their extinction by pollution and the
past and present destruction of their natural habitats by stream canal-
ization and impoundments made by hydroelectric and other dams.
The Unionacea of North America (north of Mexico) as described in this
publication consist of 221 species, grouped into 46 genera and 3 families.
The systematic arrangement of the higher categories (i.e., the families
and subfamilies) follows Heard and Guckert (1970) and reflects an inter-
pretation of phylogenetic relationships based on reproductive features
of the animals, rather than on shell characters. Such an organization
rests largely on the highly regarded anatomical studies of A. E. Ortmann
(see references), which are widely known and considered important by
recent malacologists, but previous to Heard and Guckert's publication
were either not used or interpreted only superficially. Following these
latter authors, it seems logical "that a system based on aspects of
reproduction, with parallelism in the shell features, more accurately
reflects natural, evolutionary affinities than does a system which re-
verses the emphasis [i.e., one that is based only or mainly on shell
characters]." But, to follow such a natural system with a group which
shows parallel development of shell characters in several different
major phylogenetic lines, means that a key to shells alone is extremely
difficult to construct. For that reason, if one only has shells to be
identified (without the soft parts), it may be necessary to try the
specimens with the several individual keys of the different families (or
in the case of the Unionidae, with the 4 subfamilies). Although such a
procedure may require a little more time, nevertheless it should cause
only a minor inconvenience.
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Below is a list of the families, subfamilies and genera according to the
taxonomic scheme used in this key. (The genera under each subfamily are
arranged alphabetically. In the Lampsilinae (Unionidae), the genera are
first arranged according to the marsupial characteristics of the gills,
then alphabetically.)
MARGARITIFERIDAE
AMBLEMIDAE
MARGARITIFERINAE
CUMBERLANDINAE
AMBLEMINAE
UNIONIDAE
GONIDEINAE
MEGALONAIADINAE
PLEUROBEMINAE
POPENAIADINAE
ANODONTINAE
Margaritifera
Cwnberlandia
Amblema
Elliptoideus
Fusaonaia
Pleotomevus
QuadruZa
Quinaunaina
Tritogonia
Gonidea
Megalonaias
Cyclonaias
Elliptic*
Hemistena
Plethobasus
Pleuvobema
Uniomevus
Cyrtonaias
Popenaias
Alasmidonta
Anodonta
Anodontoides
Aroidens
Arkansia
Lasmigona
Simpsoniaonaha
Strophitus
LAMPS ILINAE (het erogenae)Aotinonaias
Carunoulina
Dysnomia
Ellipsaria
Glebula
Lampsilis
Lemiox
Leptodea
Ligumia
Medionidus
Obovavia
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LAMPSILINAE (continued) Proptera
Tvunoilla
Villosa
(mesogenae) Cyprogenia
Obliquaria
(eschatigenae) Drorrns
(ptychogenae) Ptyckobranehus
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Ligament
Posterior slope
DORSAL
Major rest lines
Posterior ridge
POSTERIOR
Beak (umbo)
Growth lines
ANTERIOR
Pustules
a
to
N
d
o
w
0)
r—f
o
§
s
Beak (umbo)
Ligament
Posterior
pedal
retractor
Posterior
adductor
POSTERIOR
Left valve
Lateral teeth
Interdentum
Pseudocardinal
teeth
Hinge
Anterior
adductor
Anterior pedal J,
retractor
Pedal
protractor
Pallial line
ANTERIOR
W
u
cd
Q
W
CD
(—4
u
m
3
Fig. 1- Morphology of a freshwater mussel shell (Cyolonaias tubevaulata)
illustrating shell terminology: a- exterior of right valve; b- interi-
or of left valve.
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IDENTIFICATION
Characters of the shell of unionacean clams (freshwater mussels) are
especially important in species recognition and often for generic
placement. The shell consists of two halves or "valves" held together
at the dorsal margin by a tough elastic ligament. The two valves are
basically mirror images of each other and are articulated just below the
ligament at the dorsal margin by a hinge, which in most cases is fur-
nished with interlocking "teeth" (Fig. 1). These teeth or lamellae are
projections in one valve which fit into corresponding depressions at the
same point in the opposing valve (Fig. 2) and function in stabilizing
the two valves against shearing forces. Those teeth immediately below
or anterior to the beaks or umbos (the raised part of the dorsal margin
of each valve) are called "pseudocardinal teeth", and those teeth pos-
terior to the beaks are called "lateral teeth". The pseudocardinal
teeth are usually short and jagged, and the lateral teeth are usually
long and lamellar. In a few of the freshwater mussels (e.g., species of
Anodonta), the hinge teeth are completely lacking, and in others (e.g.,
Strophitus) they are only rudimentary. In general, characteristics of
the hinge teeth are rather uniform within each genus, and often differ
from one genus to another. Therefore, in the taxonomic keys in the
sections to follow, the hinge teeth are illustrated for at least one
species of each genus.
Pseudocardinal teeth
Lateral teeth,
Right valve
ANTERIOR
POSTERIOR
Left valve
Fig. 2- Articulation of hinge teeth as seen by a ventral view
through the gaping valves (Cyolonaias tubevoulata). (Modified
from Clarke, 1973)
The overall shape of the shell, as well as the shape or degree of de-
velopment of particular regions of the shell, are widely used in iden-
tification. Related characters are those of shell dimensions, such as
the ratio of length to height and the relative width. The more common
shell shapes are shown in Figure 3. However, among the many species of
freshwater clams are found various shapes intermediate to those shown
here, and some common, wide-ranging species are rather polymorphic in
shell shape.
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503-367 0-73-2
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b
c
a
d
f
e
h
i
g
Fig. 3- Shell shapes: a- rhomboidal; b- triangular; c- round; d-
quadrate; e- oval; £- oval; g- elliptical; h- posterior ridge convex,
i.e., bowed upward; i- posterior ridge concave, i.e., bowed downward.
On the exterior of the shell, the presence or absence of pustules or
corrugations, the fine sculpture of the beaks (Fig. 4), the degree of
development of the posterior ridge and posterior slope, and the color
and glossiness of the periostracum are characters frequently used in
classification. Characters of the inner surface of the valves useful in
identification are color of the nacre, relative depth of the beak cavity,
and especially characteristics of the hinge teeth.
Characters of the soft anatomy are important in classification, but are
significant almost entirely at taxonomic levels above the species, i.e.,
subgenera (occasionally), genera, subfamilies and families. Of special
importance is the basic structure and characteristics of the gills as
they relate to the marsupial function in females (e.g., see Fig. 7).
Color of the gills (in the living condition) is also sometimes signifi-
cant. Characters of the posterior siphonal area can distinguish the
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Fig. 4- Beak sculpture: a- concentric; b- double-looped; c- major
ridges relatively fine; d- major ridges relatively coarse; Scale = 1 mm.
Outer right
demibranch
Inner right
demibranch
Mantle margin
Right valve
Left valve
mantle
(folded
mantle
Anterior
adductor
muscle
Right labial
palp
Fig. 5- Animal, with right valve and right mantle lobe folded back,
exposing the foot, labial palp and demibranchs of the right gill.
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Anus
Excurrcnt
"" chamber
Mantle
Incurrent
chamber
Foot
Mantle margin
Supra-anal openings
Anus
Excurrent chamber
Thickened
mantle margin
Mantle
Incurrent chamber
-Right mantle margin
Foot
Left mantle margin
b
Fig. 6- Mantle margins of freshwater mussels: a- Margaritifera mavgari-
tifera; b- Amblema oostata.
Margaritiferidae from the other two North American unionacean families
(Fig. 6), and peculiarities of the mantle margin around the incurrent
opening will distinguish such genera as Caruneulinas lampsilis and
Villosa (see Fig. 139).
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Mantle lobe
Gill demibranchs
b
a
Fig. 7- Cross sections of gravid female mussels (shell re-
moved) : a- all four demibranchs swollen and serving as marsupia
(.Amblema costata - Amblemidae); b- only outer two demibranchs
swollen and serving as marsupia (EZliptto - Unionidae).
(Modified from Heard, 1968)
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SECTION II
SPECIES LIST AND RANGES
Family MARGARITIFERIDAE
Subfamily MARGARITIFERINAE
Genus Margaritifera Schumacher, 1817
Margaritifera falcata (Gould, 1850). Pacific drainage in western North
America from Alaska to New Mexico.
Margaritifera hembeli (Conrad, 1838). Escambia River system in Alabama
and in a tributary to Bayou Cocdrie, Louisiana.
Margaritifera margarn.tifeva (Linnaeus, 1758). Widespread from Pennsyl-
vania north to Newfoundland and Labrador in eastern North America.
Subfamily CUMBERLANDINAE
Genus Cumbevlandia
Cumberlandia monodonta (Say, 1829). Cumberland and Tennessee River
systems; Ohio, Illinois, Indiana and ?Nebraska.
Family AMBLEMIDAE
Subfamily AMBLEMINAE
Genus Amblema Ortmann, 1912
Amblema oostata Rafinesque, 1820. Mississippi drainage from western
New York to Minnesota, eastern Kansas and Texas. Alabama River
drainage, the St. Lawrence drainage, Red River of the North, Sas-
katchewan River and Lake Winnipeg.
Amblema neislevii Lea, 1858. Apalachicola River system; Flint River,
Georgia.
Amblema perplicata (Conrad, 1841). Gulf drainage rivers from central
Texas to the Yellow River of Florida and north from Texas to river
systems in Arkansas and Mississippi.
Genus Elliptoideus Frierson, 1927
Elliptoideus sloatianus (Lea, 1840). Apalachicola and Ochlockonee River
systems.
Genus Fusconaia Simpson, 1900
Fu8conaia cor (Conrad, 1834). Alabama River system and the Flint River,
Georgia.
Fusconaia cuneolus (Lea, 1840). Tennessee River system.
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Fusaonaia ebenus (Lea, 1831). Mississippi drainage generally and the
Alabama and Tombigbee Rivers.
Fusaonaia flava flava (Rafinesque, 1820). In the Ohio-Mississippi River
systems from Arkansas and Tennessee to North Dakota and Pennsylvania.
Present in the Great Lakes system from Wisconsin to central New
York and southern Ontario.
Fusaonaia flava undata (Barnes, 1823). All of the Mississippi drainage;
Coosa River in Alabama; Michigan and the upper St. Lawrence drain-
age.
Fusaonaia subrotunda (Lea, 1831). Ohio, Cumberland and Tennessee River
systems.
Fusaonaia suaoissa (Lea, 1852). Choctawhatchee, Yellow and Escambia
River systems (Florida west to Alabama).
Genus Pleatomerus Conrad, 1853
Pleatomerus dombeyanus (Valenciennes, 1833). Gulf drainage rivers and
streams from Alabama River to eastern Texas and north in the Mis-
sissippi systems to northwest Tennessee.
Genus Quadrula Rafinesque, 1820
Quadrula araheri Frierson, 1905. Tallapoosa River, Alabama.
Quadrula aurea (Lea, 1859). Texas.
Quadrula aylindriaa (Say, 1817). Ohio, Cumberland and Tennessee River
systems west to Nebraska and south to Arkansas.
Quadrula inteimedia (Conrad, 1836). Tennessee River system.
Quadrula metanevra Rafinesque 1820. Northern portion of the Mississippi
drainage south to the Tennessee and Arkansas Rivers.
Quadrula nodulata (Say, 1834). All of the Ohio, Cumberland and Tennes-
see River systems; Mississippi; Mississippi drainages from south-
eastern Minnesota to Louisiana, west to southeastern Kansas and
northeastern Texas.
Quadrula pustulosa (Lea, 1831). Mississippi drainage, Michigan and Lake
Erie.
Quadrula quadrula (Rafinesque, 1820). Most tributaries of the Missis-
sippi River, Great Lakes drainage, Alabama River system and some
streams of eastern and central Texas.
Genus Quinauncina Ortmann, 1922
Quincundna burkei (Walker, 1922). Choctawhatchee River system.
Quinaunaina infurioata (Conrad, 1834). Suwannee River west to the
Apalachicola River system.
Genus Tritogonia Agassiz, 1852
Tritogonia verrucosa (Rafinesque, 1820). Generally in the Mississippi
drainage and in Gulf draining streams from the Alabama River sys-
tem west to central Texas.
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Subfamily GONIDEINAE
Genus Gonidea Conrad, 1857
Gonidea angulata (Lea, 1838). Central California north to British
Columbia and east to Idaho.
Subfamily MEGALONAIADINAE
Genus Megalonaias Utterback, 1915
Megalonaias giganteus (Barnes, 1823). Throughout the Mississippi River
system and the Tombigbee River of Alabama.
Family UNIONIDAE
Subfamily PLEUROBEMINAE
Genus Cyolonaias Pilsbry, 1922
Cyolonaias tvberoulata (Rafinesque, 1820). Throughout the Mississippi
drainage, Lake St. Clair drainage and Lake Erie and in the Ohio
River drainage.
Genus Elliiptio Rafinesque, 1820
Subgenus Elliptio s.s.
Elliiptio aratata (Conrad, 1834). Alabama-Coosa, Escambia and Apalachi-
cola River systems. Savannah River system of South Carolina,
Catawba River and lower Cape Fear River system of North Carolina.
Elliptio crassidens crassidens (Lamarck, 1819). Generally in the Mis-
sissippi drainage, the Alabama-Coosa River system and the Amite
River of Louisiana east to the St. Marys River system of Florida.
Elliptio crassidens downiei (Lea, 1858). Satilla River system of
Georgia.
Elliptio ohipolaensis (Walker, 1905). Chipola River, Florida.
Elliptio oomplanata (Lightfoot, 1786). Apalachicola River system,
Altamaha River system of Georgia north to St. Lawrence River system
of Canada and in the Interior Basin west to Lake Superior and parts
of the Hudson Bay drainage.
Elliptio congaraea (Lea, 1831). Ogeechee River system of Georgia north
to the Cape Fear River system of North Carolina.
Elliptio dccciensis (Lea, 1842). St. Johns River system and peninsular
Florida and in the Altamaha River system of Georgia.
Elliptio dilatata (Rafinesque, 1820). Entire Mississippi drainage, St.
Lawrence system, Alabama River system southeast into Florida and
southwest to Guadalupe River, Texas.
Elliptio fratema (Lea, 1852). Choctawhatchee River system of Florida,
the upper Chattahoochee River, Georgia and the upper Savannah
13
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River system of South Carolina.
Elliptic) hopetonensis (Lea, 1838). Lower Altamaha River system of
Georgia.
Elliptio iaterina (Conrad, 1834). Escambia River system to the St. Marys
River system of Georgia, peninsular Florida and the Altamaha River
system of Georgia north to the White Oak River, North Carolina.
Elliptio jayensis (Lea, 1838). Suwannee River system, St. Marks River
system and peninsular Florida.
Elliptio lanoeolata (Lea, 1820). Discontinuous in the Escambia River
system east to the Apalachicola River system, Satilla River system
of Georgia and in Altamaha River system of Georgia north to the
Juanita River of the Susquehanna River system of Pennsylvania.
Elliptio nigella (Lea, 1852). Apalachicola River system.
Elliptio shepardiana (Lea, 1834). Altamaha River system of Georgia.
Elliptio waoaamawensis (Lea, 1863). Waccamenaw River system of North
Carolina.
Subgenus Canthyria Swainson 1840
Elliptio (Canthyria) spinosa (Lea, 1836). Altamaha River system of
Georgia.
Genus Hemistena Rafinesque, 1820
Eemistena lata (Rafinesque, 1820). Ohio, Cumberland and Tennessee River
systems.
Genus Plethobasus Simpson, 1900
Plethobasus oooperianus (Lea, 1834). Ohio, Cumberland and Tennessee
River systems.
Plethobasus ayphus (Rafinesque, 1820). Ohio, Cumberland and Tennessee
River systems and the Mississippi River system west to Iowa and
north to Minnesota.
Genus Pleurobema Rafinesque, 1820
Subgenus Pleurobema s.s.
Pleurobema aldriohianum Goodrich, 1931. Conasauga River, Tennessee.
Pleurobema altum (Conrad, 1854). Alabama River system.
Pleurobema amabile (Lea, 1865). Butler, Taylor Co., Georgia.
Pleurobema avallana Simpson, 1900. Cahaba River, Alabama.
Pleurobema bulbosum (Lea, 1857). Ocmulgee and Flint Rivers of Georgia.
Pleurobema ohattanogaense (Lea, 1858). Alabama River system.
Pleurobema clava (Lamarck, 1819). Ohio, Cumberland and Tennessee River
systems; Maumee Basin; Iowa City, Iowa; St. Peter's River, Minne-
sota and Nebraska.
Pleurobema coradatum oooaineum (Conrad, 1836). Upper Mississippi River
14
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from southwestern New York to Kansas and Iowa, north to Wisconsin,
south to Alabama and in the St. Lawrence River drainage.
Pleurobema oordatum oordatvm (Rafinesque, 1820). Ohio, Cumberland and
Tennessee River systems, Illinois west to the Mississippi River and
at Claiborne, Alabama.
Pleurobema covduvum pauperaulum (Simpson, 1900). Lake Erie, Lake St.
Clair and the Niagara River.
Pleurobema oordatum pyramidatum (Lea, 1834). Upper Mississippi River
drainage from western Pennsylvania, north to upper Wisconsin, west
to Kansas and Nebraska and south to Arkansas.
Pleurobema ourtum (Lea, 1859). Tombigbee River, Mississippi.
Pleurobema deoisum (Lea, 1831). Alabama and Tombigbee River systems.
Pleurobema favosum (Lea, 1856). Alabama River system.
Pleurobema flavidulum (Lea, 1861). Tombigbee River, Mississippi.
Pleurobema furvum (Conrad, 1834). Black Warrior River, Alabama.
Pleurobema hagleri Frierson, 1900. North and Black Warrior Rivers of
Alabama.
Pleurobema hanleyamm (Lea, 1852). Coosa River drainage of Georgia and
Alabama.
Pleurobema harperi (Wright, 1899). Altamaha and Flint Rivers of Georgia
and the Suwannee River of Florida.
Pleurobema irrasum (Lea, 1861). Coosa River system.
Pleurobema johannis (Lea, 1859). Alabama River system.
Pleurobema marshalli Frierson, 1927. Tombigbee River, Alabama.
Pleurobema meredithii (Lea, 1858). Tennessee River system and the Black
Warrior River, Alabama.
Pleurobema modicum (Lea, 1857). Chattahoochee River of Georgia.
Pleurobema murrayense (Lea, 1868). Coosa River system.
Pleurobema nuoleopsis (Conrad, 1849). Coosa River system.
Pleurobema nux Lea, 1852. Alabama River system.
Pleurobema oviforme (Conrad, 1834). Tennessee.
Pleurobema perovatum (Conrad, 1834). Prairie Creek, Marengo Co., Ala-
bama and small stream in Greene Co., Alabama.
Pleurobema pyviforme (Lea, 1857) . Suwannee River west to the Apalachi-.
cola River system.
Pleurobema reolusum (Wright, 1898). Ochlockonee River, Florida.
Pleurobema rubellum (Conrad, 1834). Black Warrior and Cahawba Rivers of
Alabama.
Pleurobema showalterii (Lea, 1860). Coosa River, Alabama.
Pleurobema simulans (Lea, 1871). Black Warrior and Cahawba River of
Alabama and Pine Barren Creek, Escambia Co., Florida.
Pleurobema stabile (Lea, 1861). Coosa River, Alabama.
Pleurobema striatum (Lea, 1840). Chattahoochee River of Georgia.
Pleurobema strodeanum (Wright, 1898). Choctawhatchee and Escambia
Rivers of Florida and southern Alabama.
Pleurobema tombigbeanum Frierson, 1908. Tombigbee and Alabama Rivers.
Pleurobema troschelianum (Lea, 1852). Alabama River system.
Pleurobema verum (Lea, 1860). Black Warrior and Cahawba Rivers of
Alabama.
15
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Subgenus Lexingtonia Ortmann, 1914
Pleuvobema (Lexingtonia) oollina (Conrad, 1837). James River system of
Virginia and the Tar River of the Pamlico River system of North
Carolina.
Pleuvobema (Lexingtonia) dolabelloides (Lea, 1840). Tennessee River
drainage.
Pleuvobema (Leoringtonia) masoni (Conrad, 1834). Ogeechee River system
of Georgia north to the James River system of Virginia.
Genus Uniomevus Conrad, 1853
Uniomevus tetvalasmus (Say, 1831). Mississippi drainage north to the
Ohio River. Alabama-Coosa River system and the Apalachicolan region
east to the Suwannee River and peninsular Florida. Altamaha River
system north to Chowan River system of North Carolina.
Subfamily POPENAIADINAE
Genus Popenaias Frierson, 1927
Popenaias buckleyi (Lea, 1843). Peninsular Florida.
Popenaias popei (Lea, 1857). Southern Texas and northeast Mexico.
Genus Cyvtonaias Crosse § Fischer, 1893
Cyvtonaias bevlandievii (Lea). Southern Texas.
Subfamily ANODONTINAE
Genus AlasrrtCdonta Say, 1818
Subgenus Alasmidonta s.s.
Alasmidonta aveula (Lea, 1836). Altamaha River system, Georgia.
Alasmidonta oaloeolus (Lea, 1830). Upper Mississippi drainage; Ohio,
Cumberland, and Tennessee Rivers; Lower and Middle St. Lawrence
system.
Alasmidonta hetevodon (Lea, 1830). Atlantic draining rivers. Petitcadiac
River system, New Brunswick, Canada south to the Neuse River system,
North Carolina.
Alasmidonta majcginata Say, 1819. In the Upper Mississippi drainage, the
Ohio, Cumberland and Tennessee River systems, Michigan and the Upper
St. Lawrence drainage.
Alasmidonta vadiatus (Conrad, 1834). Small streams in southern Alabama.
Alasmidonta vaveneliana (Lea, 1834). Tennessee and Cumberland River
systems.
Alasmidonta tviangulata (Lea, 1858). Apalachicola River system: Flint,
Chattahoochee, Ogeechee and Savannah River drainages in Georgia;
Apalachicola and Chipola drainages in Florida; Cooper-Santee River
system in South Carolina.
16
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Alasmidonta undulata (Say, 1817). Lower St. Lawrence drainage south to
North Carolina.
Alasmidonta varicosa (Lamarck, 1819). Lower St. Lawrence drainage and
Atlantic draining streams south to South Carolina.
Alasmidonta wrightiana (Walker, 1901). Restricted to the Ochlockonee
River, Florida.
Subgenus Pegias Simpson, 1900
Alasmidonta (Pegias) fabula (Lea, 1836). Cumberland and Tennessee River
systems.
Genus Anodonta Lamarck, 1799
Anodonta beringiana Middendorff, 1851. Kamchatka, Alaska.
Anodonta califomiensis Lea, 1852. Rivers in California east to Utah and
Arizona.
Anodonta cataracta Say, 1817. Alabama-Coosa River system; Choctawhatchee
and upper Apalachicola River systems. Atlantic drainage: Altamaha
River system of Georgia north to the St. Lawrence River system of
Canada and westward to Michigan.
Andonta couperiana Lea, 1842. Apalachicola, Ochlockonee and St. Marys
River systems. Peninsular Florida and the Atlantic draining Alta-
maha River of Georgia north to the Cape Fear River system of North
Carolina.
Anodonta dejecta Lewis, 1875. Southeastern California and northwestern
Mexico; Arizona.
Andonta gibbosa Say, 1824. Altamaha River system of Georgia.
Anodonta grandis corpulenta Cooper, 1834. Missouri River and the Upper
Mississippi Drainage east to Indiana.
Anodonta grandis grandis Say, 1829. Throughout Mississippi-Missouri
River drainage, the St. Lawrence drainage and Canadian Interior
Basin from western Ontario to Alberta and in the Gulf drainages of
Louisiana and Texas.
Anodonta grandis simpsoniana Lea, 1861. Hudson Bay drainage areas of
Quebec, Ontario, northern Manitoba, Saskatchewan and Alberta and
from the Arctic drainage area of northern Alberta and Northwest Ter-
ritories in the Mackenzie River system north to the Mackenzie River
Delta.
Anodonta implicata Say, 1829. St. Lawrence drainage north to New Bruns-
wick and Nova Scotia, Canada and south to the Potomac River in Mary-
land.
Anodonta kennerlyi Lea, 1860. Oregon to British Columbia, Canada.
Anodonta oregonensis Lea, 1838. Washington, Oregon, northern California
and eastward to the Great Salt Lake.
Anodonta peggyae Johnson, 1965. Withlacoochee and Hillsborough River
systems of peninsular Florida. Choctawhatchee River system east to
the Suwannee River system.
Anodonta suborbiculata Say, 1931. Mississippi drainage in Nebraska, Iowa,
Illinois and south to Louisiana.
17
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Anodonta wahlametensis Lea, 1838. Wahlamat River near the Columbia
River junction.
Genus Anodontoides Simpson, 1898
Anodontoides ferussacianus (Lea, 1834). Ohio-Mississippi River system.
St. Lawrence River system and the Great Lakes, the Ottawa River,
the Albany River and areas drained by the Nelson River.
Anodontoides vadiatus (Conrad, 1834). Alabama-Coosa River system,
Escambia River system and the Apalachicola River system.
Genus Aroidens Simpson, 1900
Aroidens oonfvagosus (Say, 1829). In the Mississippi River drainage
from southern Ohio west to eastern Kansas, north to southern Wis-
consin and south to eastern Texas and into Louisiana.
Genus Arkansia Ortmann § Walker, 1912
Arkansia wheetevi Ortmann § Walker, 1912. Ouachita River, Arkansas and
Arkansas River in Oklahoma.
Genus Lasmigona Rafinesque, 1831
Lasmigona oomptanata (Barnes, 1823). Upper Mississippi River drainage
southwest to Arkansas, the Ohio River system, upper St. Lawrence
system north to the Mackenzie River.
Lasmigona compressa (Lea, 1829). Interior Basin, Hudson Bay, Canada,
the Upper Mississippi, Ohio and St. Lawrence River systems extend-
ing from Saskatchewan to Nebraska and eastward to Vermont and north
on the Atlantic Slope to the Hudson River.
Lasmigona oostata (Rafinesque, 1820). Generally in Mississippi River
drainage, generally the St. Lawrence River system, Hudson Bay drain-
age in the Red and Winnipeg River systems and in the Tombigbee
River of Mississippi.
Lasmigona svibviridis (Conrad, 1835). New and Greenbrier Rivers, Virginia
and West Virginia. Upper Savannah River system of South Carolina
north to the Hudson River system and westward through Mohawk River,
Erie Canal to the Genesee River of New York.
Genus Simpsonioonoha Frierson, 1914
Simpsoniooneha arribiqua (Say, 1825). Ohio River system extending south
to Arkansas, west to Iowa, north to Michigan and east to Tennessee.
Genus Strophitus Rafinesque, 1820
Strophitus subvexus (Conrad, 1834). Alabama-Coosa and Apalachicola
River systems.
18
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Strophitus undalatus (Say, 1817). Mississippi and Ohio River drainages,
ranging from central Texas to Lake Winnipeg, Canada. Atlantic drain-
age, upper Savannah River tributary of South Carolina north to the
St. Lawrence River system.
Subfamily LAMPSILINAE
Genus Aotinonaias Crosse § Fischer, 1893
Aotinonaias carinata carinata (Barnes, 1823). Ohio-Mississippi River
drainage, St. Lawrence drainage in tributaries from Lake Michigan
drainage; to Lake Ontario, New York and Minnesota to Arkansas.
Actinonaias carinata gibba (Simpson, 1900). Ohio River and southward.
Aotinonaias ellipsiformis (Conrad, 1836). Upper Mississippi Valley,
western New York and southern Michigan.
Aotinonaias pectorosa (Conrad, 1834). Tennessee and Cumberland River
systems.
Genus Carunculina Simpson, 1898
Carunculina parva (Barnes, 1823). Throughout Mississippi drainage from
western New York to Minnesota and south to Texas, Arkansas and Flor-
ida. On the Atlantic Slope it occurs in Black Creek, northern Flor-
ida.
Carunculina pulla (Conrad, 1838). Altamaha River of Georgia north to the
Neuse River system of North Carolina.
Genus Dysnomia Agassiz, 1832
Dysnomia arcaefomris (Lea, 1831). Tennessee and Cumberland River systems.
Dysnomia biemarginata (Lea, 1857). Tennessee River drainage.
Dysnomia brevidens (Lea, 1834). Tennessee River drainage.
Dysnomia capsaeformis (Lea, 1834). Tennessee River drainage.
Dysnomia flexuosa (Rafinesque, 1820). Ohio River drainage.
Dysnomia florentina (Lea, 1857). Tennessee River drainage and the Cum-
berland River.
Dysnomia haysiana (Lea, 1833). Tennessee and Cumberland River drainage.
Dysnomia lenior (Lea, 1840). Stones River, Tennessee and Paint Rock
River in Alabama.
Dysnomia lewisii (Walker, 1910). Holston and Clinch Rivers of Tennessee
and Cumberland River in Kentucky.
Dysnomia metastriata (Conrad, 1840). Black Warrior River and Woodville,
Alabama.
Dysnomia penita (Conrad, 1834). Lower Alabama and Tombigbee River drain-
age.
Dysnomia pevsonata (Say, 1829). Ohio River drainage.
Dysnomia propinqua (Lea, 1857). Tennessee and Cumberland River drainage.
Dysnomia stewardsoni (Lea, 1852). Tennessee River.
Dysnomia sulcata (Lea, 1830). Ohio River drainage.
Dysnomia torulosa (Rafinesque, 1820). Ohio River drainage and into Mich-
igan.
19
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Dysnomia tviquetva (Rafinesque, 1820). Ohio River drainage, western New
York to southern Ontario west to Wisconsin, Iowa and eastern Ne-
braska to Oklahoma and east to West Virginia, Tennessee and north-
ern Alabama.
Dysnomia turgidula (Lea, 1858). Cumberland River, Alabama.
Genus Ellipsaria Rafinesque, 1820
Ellipsaria lineolata (Rafinesque, 1820). Mississippi River drainage
south into Arkansas, west into eastern Iowa and Kansas and Texas and
in the Tombigbee and Alabama River systems.
Genus Glebula Conrad, 1853
Glebula rotundata (Lamarck, 1819). Eastern Texas east to the Alabama-
Coosa, Escambia and Apalachicola River systems.
Genus Lampsilis Rafinesque, 1820
Lampsilis altilis (Conrad, 1834). Alabama River drainage.
Lampsilis anodontoides (Lea, 1834) . All of the Mississippi drainage
north to eastern South Dakota. All of the Gulf drainage from With-
lacoochee River, Florida west to the Rio Grande and into Mexico.
Lampsilis australis Simpson, 1900. Choctawhatchee and Escambia River
systems.
Lampsilis binominata (Simpson, 1900). Chattahoochee and Flint Rivers of
Georgia (upper Apalachicola River system).
Lampsilis bvaoteata (Gould, 1855). Llanos, Guadalupe and Colorado Rivers
of Texas.
Lampsilis cariosa (Say, 1817). Atlantic drainage from Georgia to the
lower St. Lawrence system.
Lampsilis dolabraeformis (Lea, 1838). Altamaha River system of Georgia.
Lampsilis excavata Lea, 1857. Extends from the Escambia River system of
Alabama and western Florida to the Pearl River of Mississippi.
Lampsilis fasciola Rafinesque, 1820. Scattered in the Great Lakes and
their drainages.
Lampsilis hydiana (Lea, 1838). Eastern Texas, Oklahoma, Arkansas and
east to Alabama.
Lampsilis jonesi van der Schalie, 1934. In the Choctawhatchee River sys-
tem of Alabama and Florida.
Lampsilis ochvaoea (Say, 1817). Atlantic drainage from Nova Scotia south
to the Savannah River system of Georgia.
Lampsilis orbioulata (Hildreth, 1828). Ohio and Cumberland Rivers west
to the Mississippi River.
Lampsilis ovata ovata (Say, 1817). Interior Basin, Ohio and Mississippi
drainages, St. Lawrence drainage, Hudson Bay drainage and introduced
into the Potomac River system in Maryland.
Lampsilis ovata ventvioosa (Barnes, 1823). All of the Mississippi drain-
age, the St. Lawrence system and the Hudson Bay drainages.
20
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Lampsilis perpasta (Lea, 1861). Coosa River of Alabama and the Swamp
Creek, Georgia.
Lampsilis vadiata vadiata (Gmelin, 1792). St. Lawrence drainage, Mani-
toba, Atlantic Slope south to South Carolina.
Lampsilis vadiata siliquoidea (Barnes, 1823). All of the Mississippi
valley and all of Canada east of the Rocky Mountains.
Lampsilis splendida (Lea, 1838). Altamaha River system of Georgia north
to the Cooper-Santee River system of South Carolina.
Lampsilis stvaminea (Conrad, 1834). Southern Alabama and southern Mis-
sissippi.
Lampsilis stveckeri Frierson, 1927. Little Red River, Arkansas and in
Travis Co., Texas.
Lampsilis subangulata (Lea, 1840). Ochlockonee River of Georgia west
to the Choctawhatchee River of Alabama.
Genus Lerrtiox Rafinesque, 1831
Lemiox caelata (-Conrad, 1834). Tennessee River drainage.
Genus Leptodea Rafinesque, 1820
Leptodea amphichaena Frierson, 1898. Saline River, Texas.
Leptodea fvagilis (Rafinesque, 1820). All of the Mississippi drainage.
New York to Kansas and south to Texas, Mississippi and Alabama,
north to Wisconsin and Minnesota. In the St. Lawrence River drain-
age and the Hudson River.
Leptodea laevissima (Lea, 1830). Entire Mississippi drainage from New
York to Minnesota and south to eastern Texas and Louisiana.
Leptodea leptodon (Rafinesque, 1820). Upper Mississippi River drainage
south to the Tennessee River; Buffalo, New York; southern Michigan
and the Souris River, Manitoba.
Genus Ligumia
Ligumia nasuta (Say, 1817). James River of Virginia north to the St.
Lawrence River system, west to Lake Erie, Ohio and Michigan.
Ligumia recta (Lamarck, 1819). Throughout Mississippi drainage; Alabama
River drainage, north to Minnesota and Manitoba and the St. Lawrence
system.
Genus Medionidus Simpson, 1900
Medionidus aautissimus (Lea, 1831). Alabama River system.
Medionidus convadicus (Lea, 1834). Tennessee River drainage and the Ala-
bama River system.
Medionidus mcglameviae van der Schalie, 1939. Tombigbee River.
Medionidus penicillatus (Lea, 1857) . From the Suwannee River of Florida
west to the Chipola River, Alabama.
21
i03-367 0-73-3
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Genus Obovaria Rafinesque, 1819
Obovaria Qaaksoniana Frierson, 1912. Pearl and Yalabusha Rivers of Mis-
sissippi.
Obovaria olivcacia (Rafinesque, 1820). Western Pennsylvania and New York
to Missouri, Iowa and Kansas, south to Alabama and Arkansas and
north to Minnesota, Michigan, Ontario and Quebec.
Obovaria retusa (Lamarck, 1819). Ohio, Cumberland and Tennessee River
systems.
Obovaria rotulata (Wright, 1899). Escambia River, Florida.
Obovaria subrotimda (Rafinesque, 1820). Ohio, Tennessee and Cumberland
River systems, southeastern Louisiana and the Tombigbee drainage,
north to Michigan and the St. Lawrence drainage.
Obovaria unioolor (Lea, 1845). Gulf flowing streams of Mississippi and
Alabama.
Genus Proptera Rafinesque, 1819
Proptera alata (Say, 1817). Throughout the Mississippi drainage south to
Arkansas; Tennessee and northern Alabama in the St. Lawrence drain-
age and in parts of the Red River of the North and Winnipeg River.
Proptera oapax (Green, 1832). Lower Ohio River drainage south to St.
Francis River in Arkansas and north to eastern Iowa.
Proptera purpurata (Lamarck, 1819). Eastern Texas north to Kansas and
southern Missouri, western Tennessee to the Alabama River drainage.
Genus Trunailla Rafinesque, 1819
Trunailla donaciformis (Lea, 1828). Generally in the Mississippi drain-
age from western Pennsylvania to eastern Kansas, north to Minnesota
and south to eastern Texas and east to Louisiana and Alabama.
Trunailla maarodon (Lea, 1859). Eastern Texas northward into Oklahoma.
Trunailla trunaata Rafinesque, 1820. Throughout the Mississippi River
drainage from western Pennsylvania to Michigan and Minnesota, south
to Iowa, eastern Kansas and Texas, northern Alabama and Tennessee.
Genus Villosa Frierson, 1927
Villosa concestator (Lea, 1857). North Carolina to Louisiana and Texas.
Villosa oonstriata (Conrad, 1838). James River system of Virginia south
to the Catawba River, North Carolina.
Villosa delvmbis (Conrad, 1834). Altamaha River system of Georgia north
to the Neuse River system of North Carolina.
Villosa fabalis (Lea, 1831). Ohio River drainage and the Rouge River in
Michigan.
Villosa iris (Lea, 1830). St. Lawrence River system in the Lake Huron t
Lake Ontario drainages and in Ohio, Tennessee and upper Mississippi
River systems.
Villosa lienosa (Conrad, 1834). Alabama-Coosa River system to the Apa]
chicolan region; in the lower Mississippi River drainage north to
22
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the lower Ohio and Wabash Pavers and east to southwest Georgia and
peninsular Florida.
Villosa nebulosa (Conrad, 1834). Cumberland and Tennessee River systems,
Green River of Kentucky, the Tombigbee and Alabama River systems and
at Columbus, Georgia and Wolfville, North Carolina.
Villosa ortmanni (Walker, 1925). Green and Barren Rivers and probably
other streams in Kentucky.
Villosa piota (Conrad, 1834). Tennessee and Duck Rivers and the upper
Cumberland Basin.
Villosa propria (Lea, 1865). Found in Walker Co., Georgia and the Clinch
River of Virginia.
Villosa trabalis (Conrad, 1834). In streams of the upper Cumberland
Basin and in the Clinch River of Virginia.
Villosa vanuxemensis (Lea, 1838). Cumberland and Tennessee River systems
and headwaters of the Coosa River.
Villosa vibex (Conrad, 1834). Alabama-Coosa River system and Apalachi-
colan region. The Pearl River system of Mississippi east to the
Suwannee River system of Florida. Altamaha River system of Georgia
north to the Cape Fear River system of North Carolina.
Villosa villosa (Wright, 1898). Apalachicola River system east to the
St. Marys River system of Georgia and in peninsular Florida.
Genus Cyprogenia Agassiz, 1852
Cyprogenia aberti (Conrad, 1850). Southeastern Kansas, southern Missouri,
eastern Oklahoma and Arkansas.
Cyprogenia irrorata (Lea, 1830). Ohio, Cumberland and Tennessee River
systems.
Genus Obliquaria Rafinesque, 1820
Obliquaria reflexa Rafinesque, 1820. Entire Mississippi drainage from
western Pennsylvania north into Ontario, Canada, southwest to east-
ern Kansas and Oklahoma and east into Georgia.
Genus Dromus Simpson, 1900
Dromus dromus (Lea, 1834). Tennessee and Cumberland River systems.
Genus Ptyohobranohus Simpson, 1900
Ptyohobranohus fasoiolare (Rafinesque, 1820). Ohio, Tennessee-and Cum-
berland River systems, lower Michigan, Kansas, Arkansas, Oklahoma
and Louisiana.
Ptyohobranohus foremanianum (Lea, 1842) Coosa River, Alabama.
Ptyohobranohus greeni (Conrad, 1834). Black Warrior River, Alabama.
Ptyohobranohus oooidentalis (Conrad, 1836). Current and Little Red
Rivers, Arkansas.
Ptyohobranohus subtentum (Say, 1825). Tennessee and Cumberland River
systems.
23
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SECTION III
KEYS TO THE FAMILIES OF NORTH AMERICAN UNIONACEA
The key below for separating the three families of North American
Unionacea (Margaritiferidae, Amblemidae and Unionidae) is based on
characters of the animal following Heard and Guckert (1970), rather than
on characters of the shell. As these authors point out, as well as others
before them, such features of the soft anatomy seem more liable to
accurately reflect natural, evolutionary taxonomic units than does a
system based on the shell. Inasmuch as many specimens for identification
will consist of only shells, it may be necessary initially to do some
scanning of pictures, or to actually try identification of the specimens
with the keys to each of the three families. However, since the
Margaritiferidae are represented by only several species, this reduces
the preliminary keying procedure to essentially only two families, the
Amblemidae (with eight genera) and the very large Unionidae (with 36
genera).
1 Posterior mantle margins not united dorsally to form separate
anal opening; posterior medial mantle margins not thick-
ened or exhibiting any tendency toward forming distinct
siphons (Fig. 6a): MARGARITIFERIDAE (page 26)
Posterior mantle margin forming one or more separate open-
ings (supra-anal openings) dorsally; mantle border area
thickened at point between branchial (incurrent) open-
ing and anal (excurrent) opening, indicating tendency
to form distinct siphons (Fig. 6b) 2
2(1) All 4 demibranchs serve as marsupia, i.e., appear swollen
in gravid females (Fig. 7a): AMBLEMIDAE (page 29)
Only the 2 outer demibranchs serve as marsupia and
appear swollen in the gravid female condition
(Fig. 7b): UNIONIDAE (page 44)
25
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KEY TO SPECIES OF MARGARITIFERIDAE
Shell thin and fragile, narrow dorsoventrally; pseudocardinal
teeth greatly reduced, that of right valve pointed, nearly
picklike (Fig. 8): Cumberlandia monodonta
Shell more sturdy, deeper dorsoventrally; pseudocardinal
teeth broad, well-developed. Genus Margaritifera ., 2
b
Fig. 8- Cumberlandia monodonta: a- right valve; b-
hinge plate of right valve (arrow points to pseudocardinal
tooth); c- hinge of left valve. Scale = 1 cm.
26
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2(1) Posterior slope corrugated (Fig. 9)
Posterior slope smooth
Margar-Ctifeva hembeli
3
3(2) East of the Continental Divide; nacre white, except in head-
waters of Missouri, where specimens have purple nacre;
pseudocardinal teeth of left valve have well-developed
anterior and posterior cusps, although they occasionally
may be unequal in size; sexes separate (Fig. 10a):
Mavgaritifera mavgaritifera
Pacific drainage; nacre typically or usually purple, some-
times salmon or pink, rarely white; pseudocardinal teeth
of left valve with anterior cusp usually very much reduced
in size or obsolete; hermaphroditic. (Fig. 10b)
Margavitifeva falcata
Fig. 9- Margavitifeva hembeli: right valve. Scale = 1 cm.
27
-------
Fig. 10- Margaritifera : a- M. margcwit-ifera3 right valve and hinge
plate of left valve; b- M. falaata. Scale = 1 cm
28
-------
KEY TO SPECIES OF AMBLEMIDAE
Hinge teeth well-developed • 2
Hinge teeth lacking. Restricted to Pacific Coast drainage
(Fig. 11): Gonidea angulata
Fig. 11- Gonidia angulata: right valve and hinge plate
of left valve. Scale = 1 cm.
2(1)
3(2)
4(3)
Shell surface with distinct corrugations on posterior
slope
Shell surface without distinct corrugations on posterior
slope
Shell surface with distinct pustules, usually covering a
considerable area
Shell surface without distinct pustules
12
4
6
Shell round or roundly-oval (Fig. 12)
Shell elongate, rhomboidal
Quadrula intermedia
5
29
-------
5(4) Posterior ridge well-developed; shell without diagonal row
of large pustules; nacre purple or purplish-pink
(Fig. 13a): Tritogonia verrucosa
Posterior ridge low; shell with diagonal row of large pustules
anterior and ventral to posterior ridge; nacre white
(Fig, 13b): Quadrula aylindriaa
6(3) Shell elongate, rhomboidal, with truncate posterior end;
nacre purple, especially in lower half of shell. Con-
fined to the Ochlockonee and Apalachicola River systems
in Georgia and Florida (Fig. 14): Elliptoideus sloatianus
Shell elongate, oval or round; nacre white 7
Fig. 12- Quadrula intermedia: right valve.
Scale = 1 cm.
30
-------
b
Fig. 13a- Tritogonia verrucosa} right valve and hinge plate of left
valve; b- Quadrula oylindrioa3 right valve. Scale = 1 cm.
31
-------
7(6) Shell small (usually less than 6 cm); shell corrugations
relatively fine. Confined to Gulf drainage from
Suwannee to Choctawhatchee River, Florida. Genus
Quincunoina 8
Shell large (often up to 13 cm in length and sometimes
18 cm), corrugations heavy 9
8(7) Shell nearly as high as long, truncately oval in outline
(Fig. 15a): Quinoundna infuraata
Shell elongate (Fig. 15b): Quineuncina burkei
Fig. 14- Elliptoideus sloatianus: right valve and hinge
plate of left valve. Scale = 1 cm.
32
-------
Fig. 15- Quinounaina: a- Q. infureata3 right valve and hinge plate of
left valve; b- Q. burkeis right valves. Scale = 1 cm.
33
-------
9(7) Shell sculpture extending anterior to beaks (Fig. 16):
Megalonaias giganteus
Shell sculpture not extending anterior to beaks. Genus
Amblema 10
10(9) Large, equal-sized, parallel undulations extended across
posterior ridge; shell very inflated (Fig. 17):
Amblema ne-islern-i
Large, but not necessarily equal-sized undulations fan out
from beak to shell margins; undulations on posterior
ridge more or less follow ridge, rather than crossing it;
shell moderately inflated or flattened 11
Fig. 16- Megalonaias giganteus: right valve of a rather
young adult, and hinge plate of left valve. Scale = 1 cm.
34
-------
Fig. 17- Amblema ne-Lslerii: right valve, hinge plate of left valve
and outline of medial cross-section. Scale = 1 cm.
35
-------
11(10) Shell round or roundly-oval, moderately inflated, its
ventral margin typically rounded (Fig. 18a): Amblema perplioata
Shell elongated, typically flattened, sometimes moderately
inflated; ventral margin of shell typically nearly
straight and more or less parallel to dorsal margin
(Fig. 18b): Amblema costaba
k- \
Fig. 18- Amblema: a- A. pevplioata, right valve; b- A. costata, right
valve and hinge plate of left valve. Scale = 1 cm.
36
-------
12(2) Shell rhomboidal, with raised and relatively sharp posterior
ridge (Fig. 19): Pleotomerus dombeyanus
Shell round, oval or triangular 13
13(12) Shell surface pustulose. Genus Quadrula in part 14
Shell surface smooth .... Genus Fusoonaia 21
14(13) Shell twice as long as high (Fig. 13b): Quadrula oylindrica
Shell less than twice as long as high 13
15(14) Shell with green chevron-shaped markings 16
Shell lacking chevron-shaped color markings 17
16(15) Shell moderately inflated; posterior ridge high and
usually having 3-5 very large swellings or raised
pustules (Fig. 20a): Quadrula metanevra
Shell compressed; posterior ridge low and rounded and with
pustules similar to those found on other parts of shell
(Fig. 12): Quadrula intermedia
Fig. 19- Plectomerus dombeyanus: right valve and hinge
plate of left valve. Scale = 1 cm.
37
503-367 O - 73 - 4
-------
17(15) Shell with median sulcus on surface which extends from umbo
to ventral margin; shell usually moderately to heavily
pustulose, but pustules occasionally may be lacking
(Fig. 20b): Quadrula quadrula
Shell lacking median sulcus on disc and umbonal region;
shell with or without pustules 18
18(17) Umbonal region highly inflated, with beak extending well
above hinge plate; commonly pustulose 19
Umbonal region only slightly inflated; beak does not extend
noticeably above hinge plate; commonly lacking pustules . 20
Fig. 20- Quadrula: a- Q. metanevras right valve; b- Q. quadralas right
valve and hinge plate of left valve. Scale = 1 cm.
38
-------
19(18) Pustules on disc arranged in 2 divergent rows; shell without
green rays on umbonal region (Fig* 21a): Quadrula nodulata
Pustules on disc more evenly scattered over shell surface;
umbonal region commonly with wide green ray (Fig. 21b):
Quadrula pustulosa
20(18) Shell nearly circular in outline; shell nearly as high as
long (Fig. 22a) : Quadrula areheri
Shell rectangular to broadly elliptical in outline; shell
clearly longer than high (Fig. 22b) Quadrula aurea
Fig. 21- Quadrula3 right valves: a- Q. nodulata; b- Q. pustulosa.
Scale = 1 cm.
39
-------
21(13) Beaks very high: the umbonal region extremely inflated.
continuing full, high and round onto disc below the
umbo 22
Beaks not especially high; umbonal region not extremely
inflated 24
22 (21) Posterior ridge angular (Fig. 23): Fusaonaia flava undata
Posterior ridge angular and smooth 23
Fig. 22- Quadrula3 right valves: a- Q. avcnevi; b- Q. auvea. Scale =
1 cm.
40
-------
23(22) Disc inflated from umbo
down to ventral margin
of shell (Fig. 24a):
Fusconaia ebenus
Disc inflated only on
upper half of shell
valve (Fig. 24b):
Fusaonaia subvotunda
24(21) Shell as high as long, or
very nearly so 25
Shell length exceeds
height 26
Fig. 23- Fusaonaia flava undata: right
valve. Scale = 1 cm.
a
b
Fig. 24- Fuseonaia3 right valves: a- F. ebenusj b- F. subrotunda.
Scale. = 1 cm.
41
-------
25(24) Shell with median sulcus; shell typically with many dark
green rays (Fig, 25a): Fusoonaia cot
Median sulcus absent; shell without color rays (Fig. 25b):
Fusoonaia suooissa
Fig. 25- Fusoonaia3 right valves: a- F. oov; b- F. suooissa. Scale
1 cm.
Fig. 26- Median sul-
cus on right valves:
a- sulcus extending
up onto umbonal region;
b- sulcus not extending
into sulcus region.
42
-------
26(24) Shell's posterior slope from posterior ridge to dorsal-
posterior margin, short and steep; shell with median
sulcus 27
Shell's posterior slope long and gently descending; shell
without median sulcus (Fig, 25b): Fusaonaia suoaissa
27(26) Wide shallow median sulcus on disc extends up onto umbonal
region (Fig. 26a), giving umbonal region flattened
appearance (Fig. 27a); Fusaonaia owieolus
Wide shallow median sulcus of disc does not extend into
umbonal region (Fig. 26b), leaving umbonal region with
full round appearance (Fig. 27b): Fusaonaia fLava ftava
Fig. 27- Fusaonaia: a- F. ouneolus, right valve; b- F. flava flava3
right valve and hinge plate of left valve. Scale = 1 cm.
43
-------
KEY TO SUBFAMILIES OF UNIONIDAE
1 In gills of gravid females, secondary septa which are more or less
perpendicular to primary septa (except in Stroph-itus) divide
each water tube into 3 tubes (Fig. 28a) (glochidia contained
only in middle tube of each set); glochidia with hooks:
ANODONTINAE (page 72)
In gills septa and water tubes undivided; glochidia without hooks
(except in Pvoptera, which has axehead-shaped glochidia) 2
2(1) Marsupium filling entire outer pair of gills, forming smooth pads
(Fig. 28b); shell not sexually dimorphic 3
Marsupium confined to restricted regions of outer demibranchs
(Fig. 28c,d,e,f); marsupia not forming smooth pads but marked
externally by sulci; shell generally exhibiting sexual
dimorphism: LAMPSILINAE (page 93)
3(2) Animals bradytictic, i.e., long-term breeders, retaining develop-
ing glochidial larvae in their gills except in Nearctic summer:
POPENAIADINAE (page 70)
Animals tachytictic, i.e., short-term breeders, carrying glochidia
in their gills only during Nearctic summer:PLEUROBEMINAE (page 45)
SWt
mwt
in
no
iinr
b
Fig. 28 - Marsupial gills in gravid female unionid clams: a- cross-section
of gill of Lasmigona (glochidia shown in only one main water tube); b-
Elliptio dilatata; c- Ptyohobranchus fasoiolare (ptychogenae); d- Obliquaria
veflexa (mesogenae); e- Dvomus dromus (eschatigenae); f- Lampsilis fasaiota
(heterogenae). f = foot; id = inner demibranch; lm = left mantle lobe; lb =
labial palp; mwt = main water tube; od = outer demibranch; P = placenta; ps
= primary septum; rm = right mantle lobe, folded back to expose gills; ss =
secondary septum; swt = secondary water tube.
44
-------
KEY TO SPECIES OF PLEUROBEMINAE
1 Shell surface sculptured with pustules 2
Shell surface without pustules 4
2(1) Shell rounded in shape; nacre purple (Fig. 29):
Cyclonaias tubevoulata
Shell irregularly oval in shape; nacre white, sometimes with
slight pinkish tinge. Genus Plethobasus 3
Fig. 29- Cyclonaias tubevoulata
valve. Scale = 1 cm.
right valve and hjnge plate of left
45
-------
3(2) Pustules over entire posterior half of shell surface
(Fig. 30a) Plethobasus eooperianus
Pustules arranged in central median row, absent from anterior
and posterior shell surface (Fig. 30b); Plethobasus ayphyus
i\A
Fig. 30- Plethobasus: a- P. eooperianus; right valve; b- P, ayphyuss
right valve and hinge plate of left valve. Scale = 1 cm.
46
-------
4(1) Pseudocardinal teeth rather poorly developed to obsolete ... 5
Pseudocardinal teeth well developed 6
5(4) Pseudocardinal teeth present, although poorly developed
(Fig. 31): Uniomevus tetvalasmus
Pseudocardinal teeth rudimentary or absent (Fig. 32):
HerrrLstena lata
?f
N
Fig. 31- Un-iomerus tetvalasmus: right valve and
hinge plate of left valve. Scale = 1 cm.
47
-------
6(4) Shell generally high, triangular, high-oval, roundly oval,
or occasionally elliptical; beaks generally high and
generally arched forward; nacre white or occcasionally
pinkish. Genus Pleuvobema 7
Shell elongate, rhomboidal (or if low-triangular, broadly
elliptical, or somewhat oval, nacre purple); beaks low,
not arched; nacre purple (usually), pink or iridescent.
Genus Elliptio 22
7(6) Placentae in gravid females deep orange or red. Subgenus
Lexingtonia 8
Placentae in gravid females grayish-white to pale brown.
Subgenus Pleiwobema s.s 11
8(7) Shell with spines on posterior ridge and slope (Fig. 33a)
Vtewpobema (Lexingtonia) oottina
Shell without spines 9
Fig. 32- Bemistena lata: right valve and hinge
plate of left valve. Scale = 1 cm.
48
-------
Fig. 33- Pleuvobema (Lexingtonia) aollina: a-
dorsal view of both valves (anterior end to right)
of a specimen with spines (after Boss and Clench,
1967); b- right valve of a specimen without spines.
Scale = 1 cm.
49
-------
9(8) Shell high, especially in adults; beaks prominent and arched
forward; color rays on shell especially prominent (Fig. 34):
Pleurobema (Lexingtonia) dolabelloides
Shell more elongate; beaks less prominent and not notice-
ably arched forward; color rays, when present, not
prominent . 10
10(9) Periostracum smooth and yellowish, without color rays or with
only slightest hint of some very narrow brownish rays
(Fig. 33b): Pteurobema (Lexingtonia) collina-
Periostracum rougher, satiny, due to fine periostracal growth
ridges; brownish to dark olive-green with dark green or
brown color rays (Fig. 35): Pteurobema (Lexingtonia) masoni
Fig. 34- Pteurobema (Lexingtonia) dolabelloides : right valves and hinge
plate of left valve. Scale = 1 cm.
50
-------
Fig. 35- Pleurobema (Lexingtonia) masoni: right valves and hinge plate
of left valve. Scale = 1 cm.
51
-------
11 (8) Shell distinctly higher than long 12
Shell height and width similar, or shell length exceeds
height 14
12(11) Height of shell and prominence of beaks greatly accentuated;
shell especially inflated in area below beaks (Fig. 36a);
beak cavities relatively deep (Fig. 36b):
Pleurohema cordatum pyramidatum
Height of shell and beaks not as pronounced; beak cavities
shallow 13
15(1) Shell nearly round to roundly oval (Fig. 37a):
Pleurohema marshalli
Shell triangularly oval (Fig. 37b): Pleurohema altum
14(11) Shell height and length nearly equal ...................... 15
Shell distinctly longer than high ......................... 17
15(14) Beak cavities very deep (Fig. 38): Pleurobema cordatum cordatum
Beak cavities shallow ..................................... 16
Fig. 36- Pleurohema cordatum pyramidatum: a- anterior end
showing both valves; b- right valve. Scale = 1 cm.
52
-------
Fig. 37- Pleui'obemaj right valves: a- P. marshalli; b- P. altwn.
Scale = 1 cm.
Fig. 38- Pleurobema cordatum aordatwv; right valve and hinge plate
left valve. Scale = 1 cm,
53
-------
16(15) Shell brown, dark brown or green-brown, especially dark on
disc below beaks (Tig- 39a): Pleurobema showalterii
Shell tan or straw-yellow (Fig. 39b): Pleicrobema altum
17(13) Shell strongly arched, beaks at extreme dorsal anterior
end 18
Shell not strongly arched, beaks may be far anterior, but
not at extreme dorsal anterior end 21
18(17) Shell with distinct lateral dorsoventral median sulcus
(Fig. 40a): Pleurobema olaoa
Shell without a distinct lateral dorsoventral median
sulcus 19
Fig. 39- Pleurobema3 right valves: a- P. showalterii; b- P. altum.
Scale = 1 cm.
54
-------
19fl8) Adult shell small, 4 cm or less in length, dark olive-brown
to green-black in color (Fig. 40b); Pleurobema curtum
Adult shell larger, 5 cm or more in length, dark tan to
straw-yellow in color 20
Fig. 40- Pleurobema, right valves: a- P. alava; b- P. auvtum. Scale
1 cm.
-------
20(19) Beaks high and prominent; shell deeply but narrowly inflated
just below the beaks (Fig. 41a): Pleurobema deoisum
Beaks lower, not as high and prominent; shell broadly
inflated below beaks (Fig. 41b): Pleurobema chattanogaense
21(17) Shell high, rounded, triangular or subtriangular (Fig. 42a-
d; 43): Pleurobema ssp.
Shell lower, oval, ovate-triangular, elliptical or sub-
rhomboidal (Fig. 42e-i; 44): Pleurobema ssp.
(No thorough study has been made of the genus Pleurobema
on a broad basis. The systematic status of many or most
of the nominal species is unknown or confused. Therefore,
a workable key at this time is impossible to construct.
Figures 42, 43 and 44 illustrate many of the named forms.
Their distributions, as far as known, are given in the
preceeding section "Species List and Ranges".)
Fig. 41- Pleurobema, right valves: a- P. deoisum; b- P. chattanogaense.
Scale = 1 cm.
56
-------
Fig. 42- Pleurobemcij right valves: a- P. cordatwn pauperaulnmj b-
P, aordatum ooacrineum; c- P. oviforme; d- P. verumj e,f- P. irpasimj
g- P. m^r; h- P. perovatum; i- P. realusxm. Scale = 1 cm.
57
-------
P. cordatum pauperculum
P. strodeanum
P. verum
P. oviforme
P. rubellum
Fig. 43- Outlines of shells of various nominal species of
Pleuvobema which are high, rounded-triangular or subtri-
angular in outline. Scale = 1 cm.
58
-------
P. aldrichianum
P. harperi
P. amabile
P. reclusum
P. hanleyanum
P. mux
P. flavidulum
P. perovatum
P. avellana
P. irrasum
P. pyriforme
P. bulbosum
P. troschelianum
P. murrayense
P. simulans
P. nmleopsis
P. favosum
P. meredithii
P. modicum
P. hagleri
P. stabile
Fig. 44- Outlines of shells of various nominal species of
Pleuroberna which are low, oval, ovate-triangular, elliptical
or subrhomboidal in outline. Scale = 1 cm.
59
-------
22(6) Shell with spines (Fig. 45): Elliptio (Canthyvia) spinosa
Shell without spines. Subgenus Elliptio s.s 23
23(22) Shell extremely elongate, length/height ratio 3.5 or greater
(Fig. 46): Elliptio shepardiana
Shell enlongate (but length/height ratio less than 3) to
relatively stubby 24
24(23) Shell subtriangular to subrhomboidal, rather heavy, generally
relatively high, somewhat arched forward 25
Shell generally more elongate, elliptical to rhomboidal, of
varying thickness (often thin) but not expecially heavy,
usually no or little indication of being arched forward .. 26
25(24) Shell especially heavy (Fig. 47a): Elliptio orassidens orassidens
Shell lighter, usually more elongate, and with more anteriorly
placed beaks. Restricted to Satilla River system of
Georgia (Fig. 47b): Elliptio orassidens downiei
Fig. 45- Elliptio
(Canthyria) spinosa:
right valve. Scale
1 cm.
m Fig. 46- Elliptio
/}} shepardiana: right
7/ valve. Scale = 1 cm
60
-------
b
Fig. 47- Elliiptio: a- E. arassidens crassidens, right valve and hinge
plate of left valve; b- E. arassidens downiei3 right valve. Scale = 1
cm.
61
-------
26(24) Shell flattened (Fig. 48a) 27
Shell inflated (Fig. 48b) 34
27(26) Posterior ridge relatively close to dorsal margin and bowed
upward (Fig. 49a) Elliptic) dilatata
Posterior ridge more median in position and nearly straight . 28
Fig. 48- Shells of Elliptio in
anterior end view: a- flattened
shell; b- inflated shell.
Fig. 49- Elliptic)3 right
valves: a- E. dilatata;
b- E. fraterna. Scale
= 1 cm.
.. : • -
•rjJ&Wi
nflu- W
b
62
-------
28(27) Posterior slope usually sculptured with wrinkles that radiate
dorsally from posterior ridge (Fig. 49b): Elliptic? fraterna
Posterior slope usually without wrinkles 29
29(28) Shell considerably higher posteriorly than anteriorly.
Apalachicola River system of Florida, Alabama and Georgia.
(Fig. 50a) : Elliptic? nigella
Shell height nearly same in posterior and anterior regions .. 30
Fig. 50- Elliptioj right valves: a- E. nigella; b- E, arotata.
Scale = 1 cm.
63
-------
30(29) Shell arcuate, i.e., bowed upwards medially, with ventral
margin curved concavely upward (Fig. 50b): Elliptic arotata
Shell not arcuate, ventral margin straight or convexly
curved downward 31
31(30) Shell lanceolate, i.e., especially elongated and usually
pointed posteriorly near midline (Fig. 51a):Elliptio lanoeolata
Shell rhomboidal to subelliptical 32
32(31) Shell subelliptical, ventral margin curved downward.
Apalachicola River system. (Fig. 51b): Elliptio ohipolaensis
Shell rhomboidal, ventral margin usually straight or only
slightly curved 33
Fig. 51- Elliptio, right valves: a- E. lanoeolata; b- E. ohipolaensis.
Scale = 1 cm.
64
-------
33(32) Shell rather uniformly trapezoidal, disc flattened;
periostracum not usually shiny, often rayed, yellowish-
green to black (Johnson, 1970) (Fig. 52a): Elliptio oomplanata
Shell subrhomboidal, often somewhat pointed, very variable as
to shape and degree of inflation; periostracum usually
subshiny to shiny, often rayed, yellowish to brownish
(Johnson, 1970) (Fig. 52b): Elliptio iotevina
34(26) Shell elongate, subelliptical or lanceolate; length/height
ratio nearly 2 or greater 35
Shell shorter, rhomboidal to sub-ovate; length/height ratio
1.75 or less 36
b
Fig. 52- Elliptio: a- E. oomplanata3 right valve and hinge plate of
left valve; b- E. iotevina. Scale = 1 cm.
65
-------
35(34) Shell generally dark and usually with numerous fine dark
green rays. St. Marks and Suwannee River systems and
peninsular Florida. (Fig. 53a; 54b): Elliptio jayensis
Shell greenish-yellow or olive (except very old specimens
which are dark), often with greenish color rays, but not
as numerous and fine as above. Atlantic slope, from
Susquehanna River system of Pennsylvania to Satilla
River system of Georgia; Apalachicolan region (Escambia
River system, east to Apalachicola River system)
(Fig. 51a): Elliptio lanoeolata
b
Fig. 53- Elliptioj right valves; a- E. jayensis; b- E. hopetonensis.
Scale = 1 cm.
66
-------
36(34) Posterior end broadly and bluntly truncate; dorsal margin
very long, joining posterior margin at an acute angle.
Lower Altamaha River system only. (Fig. 53b):
Ellipito hopetonensis
Posterior end not broadly truncate; dorsal margin short-
ened, joining posterior margin at a wider angle 37
37(36) Shell subovate to subelliptical 38
Shell rhomboidal, subrhomboidal, subtriangular or quadrate . 39
38(37) Shell epidermis chestnut brown, without color rays.
Apalachicola River system (Fig. 54a): Elliptic) chipolaensis
Shell epidermis dark or light green, or yellow-green,
usually with numerous fine dark green rays. St. Marks
and Suwannee River systems and peninsular Florida (Fig.
53a; 54b): Elliptio jayense
Fig. 54- Elliptio3 right valves: a- E. chipolaensis; b- E. jayensis.
Scale = 1 cm.
67
-------
39(37) Shell subtriangular or quadrate, moderately heavy. Southern
Atlantic drainage, from Cape Fear River system of North
Carolina to Ogeechee River system of Georgia. (Fig. 55):
Elliptio congaraea
Shell rhomboidal or subrhomboidal 40
40(39) Posterior ridge rounded or subangular. St. Marks and
Suwannee River systems and peninsular Florida. (Fig. 53a;
54b): Elliptic) jayensis
Posterior ridge usually acutely angular 41
41(40) Shell small, usually less than 6 cm in length. Restricted
to Waccamaw River system of North Carolina. (Fig. 56):
Elliptio waocamawensis
Shell large, up to or exceeding 13 cm in length. Altamaha
River system of Georgia and peninsular Florida. (Fig. 57):
Elliptio dariensis
Fig. 55- Elliptio congaraea: right valve. Scale =
1 cm.
68
-------
Fig. 56- Elliptic
waoaamawensis: right
valve. Scale = 1 cm.
lpl|i§e
Fig. 57- Elliptic dariensis: right valves. Scale = 1 cm
503-36? 0-73-6
-------
KEY TO SPECIES OF POPENAIADINAE
1 Shell elongate, length/height ratio 1.8 or greater. Genus
Popenaias 2
Shell high, length/height ratio 1.4 or less: Genus
Cyrtonaias (Fig. 58): Cyrtonaias berlandierii
2(1) Shell flattened; posterior slope broad and shallow;
periostracum dull (Fig. 59a): Popenaias popei
Shell inflated; posterior slope steep; periostracum
glossy (Fig. 59b): Popenaias buokleyi
Fig. 58- Cyrtonaias berlandierii: right valve and
hinge plate of left valve. Scale = 1 cm.
70
-------
Fig. 59- Popenaias: a- P. popei; b- P. buokleyi3 right valve and
hinge plate of left valve. Scale = 1 cm.
71
-------
KEY TO SPECIES OF ANODONTINAE
1 Hinge entirely without teeth, or teeth very reduced with
only pseudocardinal teeth present, and these represented
only by small rudiment; shell thin, fragile 2
Hinge teeth quite distinct, even though they may be rather
poorly developed in some species; shell of moderate
thickness, or if thin, not particularly fragile 30
2(1) Pseudocardinal teeth absent. Genus Anodonta, Anodontoides
in part, Strophitus in part 3
Pseudocardinal teeth present, but rudimentary 24
3(2) Species east of Continental Divide 4
Species in Pacific Drainage 17
4(3) Umbos do not extend above dorsal margin 5
Umbos extend above dorsal margin 8
5(4) Shell very flat, high, nearly round in outline (Fig. 60):
Anodonta suborbioulata
Shell more elongate, not especially flattened, often quite
inflated 6
6(5) Shell more elongate, length/height ratio approximately 2.0
(Fig. 61): Anodonta -tmbec-illus
Shell higher, length/height ratio approximately 1.5 7
7(6) Shell height greatest in posterior half; color pattern: straw-
yellow on blue-green background (Fig. 62a) Anodonta peggyae
Shell height greatest in median portion; color pattern: blue-
green on straw-yellow background (Fig. 62b) Anodonta oouperiana
Fig. 60- Anodonta
suborbioulata: right
valve. Scale = 1 cm.
72
-------
Fig. 61- Anodonta
imbeoillus: right
valve. Scale = 1 cm
Fig. 62- Anodonta, right valves: a- A. peggae; b- A. oouperiana.
Scale = 1 cm.
73
-------
8(4) Shell high, length/height ratio 1.6 or less 9
Shell elongate, length/height ratio greater than 1.6 10
9(8) Shell strikingly inflated in posterior region of disc and
posterior ridge, being inflated down to ventral shell
margin; nacre usually iridescent or white (Fig. 63a):
Anodonta gibbosa
Shell more evenly inflated, not being noticeably more
inflated in posterior region; nacre often coppery-pink
or salmon pink (Fig. 63b) : Anodonta grand-is corpulenta
i
b
Fig. 63- Anodontaj right valves: a- A. gi-bbosa; b- A. grandis
corpulenta. Scale = 1 cm.
74
-------
10(8) Shell strikingly inflated in posterior region of disc and
posterior ridge, being inflated down to ventral shell
margin (Fig. 63a): Anodonta gibbosa
Shell more evenly inflated, not being noticeably more
inflated in posterior region 11
11(10) Beak sculpture double-looped and nodulous (Fig. 64):
Anodonta gvandis gvandis
Beak sculpture single- or double-looped, but not nodulous
(i.e., each ridge of sculpture rather uniform in height).. 12
12(11) Beak sculpture with 7-10 ridges. East of Continental Divide
this species is known only from western Alberta, Canada
(Fig. 65): Anodonta kennevlyi
Beak sculpture with 3-6 ridges 13
13(12) Beak sculpture single-looped, or only faintly double-looped . 14
Beak sculpture double-looped, usually distinctly so 16
Fig. 64- Anodonta
grand-is gvandis: right
valve. Scale = 1 cm.
Fig. 65- Anodonta
kennerlyi: right valve.
Scale = 1 cm.
I 1
75
-------
¦
I 1
Fig. 66a- beak sculpture coarse; b- beak sculpture fine; c- Strophitus
undulatuSj right valve; d- S. undulatus3 hinge plate of left valve.
Scale = 1 cm.
Fig. 67a- Anodontoides ferussacianus3 right valve; b- Anodonta grandis
simpsoniana3 right valve. Scale = 1 cm.
76
-------
14(13) Major ridges of beak sculpture (Fig. 66a) relatively coarse
(Fig. 66c): Strophitus undulatus
Major ridges of beak sculpture relatively fine (Fig. 66b)... 15
15(14) Ridges of beak sculpture are not parallel to concentric
growth lines of beak, but cross them obliquely (Fig.
67a): Anodontoides ferussacianus
Ridges of beak sculpture run parallel to concentric growth
lines of beak; Hudson Bay drainage of Canada (Fig. 67b):
Anodonta grandis simpsoniana
16(13) Anterior ventral portion of shell below pallial line is
noticeably thickened; nacre often coppery-pink to salmon
pink (Fig. 68a): Anodonta implioata
Anterior ventral portion of shell below pallial line is not
thickened; nacre white or iridescent, never pink (Fig.
68b): Anodonta oataraota
Fig. 68- Anodonta : a- A. implioataj right valve; b- A. oataraota}
right valve and hinge plate of left valve. Scale = 1 cm.
77
-------
Fig. 69- Anodonta
dejecta: right valve
Scale = 1 cm.
Fig. 70- Anodonta} right valves: a- A. wahlametensis; b- A.
aaliforniensis. Scale = 1 cm.
-------
17(3) Height of posterior half of shell greater than height of
anterior half 18
Height of posterior half of shell nearly equal to height
of anterior half 20
18(17) Shell length/height ratio is 2 or greater; shell nearly
rhomboidal in outline (Fig. 69): Anodonta dejecta
Shell length/height ratio is 1.5 or less; shell broadly
ovate in outline 19
19(18) Shell with high conspicuous wing (Fig. 70a):Anodonta wahlametensis
Shell with wing of only moderate height (Fig. 70b):
Anodonta califomiensis
20(17) Shell inflated only over anterior half of shell (Fig. 71):
Anodonta beringiana
Shell inflated over median and/or posterior portion 21
21(20) Bars of beak sculpture uneven in height, making beak bumpy
or tuberculose (Fig. 64): Anodonta grandis grandis
Bars of beak sculpture even in height 22
22(21) Posterior end of shell truncate (Fig. 69): Anodonta dejecta
Posterior end of shell pointed 23
Fig. 71- Anodonta beringiana: right valve.
Scale = 1 cm.
79
-------
Fig. 72- Anodonta
ovegonensis: right
valve. Scale = 1 cm.
I 1
Fig. 73a- Atasmidonta variaosa, right valve; b- Anodontoides radiatus3
right valve and hinge plate of right valve. Scale = 1 cm.
80
-------
23(22) Shell narrowly elliptical, length/height ratio 2, shell
inflated primarily along posterior ridge (Fig. 65):
Anodonta kennerleyi
Shell typically less narrowly elliptical, length/height
ratio usually less than 2, shell inflated primarily
over median portion (Fig. 72) : Anodonta ovegonensis
24(2) Pseudocardinal teeth very thin, blade-like 25
Pseudocardinal teeth tubercular 26
25(24) Shell rhomboidal; posterior ridge prominent; posterior slope
with rather fine corrugated sculpture (Fig. 73a):
Alasmidonta varioosa
Shell long-ovate; posterior ridge absent; anterior slope
smooth (Fig. 73b): Anodontoides radiatus
26(24) Posterior slope with corrugated sculpture. Genus Alasmidonta 27
Posterior slope lacking corrugated sculpture 29
27(26) Posterior ridge angular (Fig. 74a): Alasmidonta marginata
Posterior ridge rounded 28
Fig. 74- Alasmidonta, right valves, a- A. marginata; b- A.
raveneliana. Scale = 1 cm.
81
-------
28(27) Shell surface relatively smooth, except for periodic rest
marks; ventral margin of shell typically without broad,
shallow indentation (Fig. 74b): Alasmidonta raveneliana
Shell surface with irregular undulations, giving it rough
appearance; ventral margin of shell typically with broad,
shallow indentation (Fig. 73a) Alasmidonta vavioosa
29(26) Shell elongate, length/height ratio about 2; posterior
ridge low, rounded, hardly noticeable (Fig. 75a):
Simpsonioonoha ambigua
Shell less elongate, length/height ratio 1.6 or less;
posterior ridge well developed (Fig. 75b): Stvophitus subvexus
1
b
Fig. 75a- Simpsonioonoha ambigua3 right valve and hinge plate of left
valve; b- Strophitus subvexus, right valve. Scale = 1 cm.
82
-------
30(1) Shell with large corrugations on disc and posterior slope,
or on both 31
Shell without large corrugations on either disc or post-
erior slope 32
31(30) Tubercles of beak sculpture extending beyond beaks; pseudo-
cardinal teeth compressed, laminate (Fig. 76):
Aroidens oonfvagosua
Tubercles of beak sculpture restricted to first 3 or 4 mm
of beaks; pseudocardinal teeth large and triangular,
not compressed (Fig. 77): Avkansia wheeleri
Fig. 76- Aroidens aonfragosus: right valve and
hinge plate of left valve. Scale = 1 cm.
83
-------
32(30) Beak sculpture concentric (see Fig. 4). Genus Alasmidonta .. 33
Beak sculpture double-looped (see Fig. 4). Genus Lasmigona . 43
33(32) Posterior end broadly truncate, with truncate slope running
anterioventrally; posterior end sometimes bifurcate at
shell margin (Fig. 78): Alasmidonta (Pegias) fabula
Posterior end rounded or pointed, or if truncate, truncate
slope runs anteriodorsally. Subgenus Alasmidonta s.s 34
34(33) Shell short and high, length/height ratio less than 1.5 35
Shell elongate, length/height ratio more than 1.5 38
35(34) Shell very high; posterior slope extremely steep, at an
angle of nearly 90° to disc (Fig. 79): Alasmidonta avoula
Shell height lower; posterior slope not so steep 36
Fig. 77- Arkansia wheeleri: right valve and hinge
plate of left valve. Scale = 1 cm.
84
-------
Fig. 78- Alasmidonta (Pegias) fabula:
and hinge plate of left valve. Scale
right valve
1 cm.
Fig. 79- Alasmidonta
araula: right valve.
Scale = 1 cm.
503-367 O - 73 - 7
-------
36(35) Posterior end flatly truncate; ventral margin of shell nearly
straight; growth lines sharp, giving periostracum rough
appearance (Fig. 80): Alaamidonta oaloeolus
Posterior end pointed or rounded; ventral margin of shell
rounded; periostracum may be irregular in places, but
basically smooth 37
37(36) Posterior slope strongly and rather coarsely corrugated;
beaks near center of shell (Fig. 81a): Alasmidonta wirightiana
Posterior slope either without corrugations, or if they are
present, they are minor and rather fine; beaks near
forward end of shell (Fig. 81b): Alasmidonta triangulata
Fig. 80- Alasmidonta oaloeolus: right valve and
hinge plates of left valve. Scale = 1 cm.
86
-------
b
Fig. 81- Alasmidonta: a- A. wrightianaj b- A. triangutata. Scale
1 cm.
87
-------
38(34) Right valve contains 2 lateral teeth (Fig. 82):
Alasmidonta heterodon
Right valve contains only 1 lateral tooth, which is often
rudimentary 39
39(38) Posterior ridge angular (Fig. 74a): Alasmidonta marginata
Posterior ridge rounded 40
40(39) Pseudocardinal teeth well-developed; tooth surface typically
rough, with ridges or bumps 41
Pseudocardinal teeth rather rudimentary; tooth surface
smooth 42
41(40) Pseudocardinal teeth large; ridges on beak large and heavy;
periostracum may be irregular in places, but basically
smooth (Fig. 83): Alasmidonta undulata
Pseudocardinal teeth relatively smaller; ridges on beak of
moderate size; growth lines sharp, giving periostracum
rough appearance (Fig. 80): Alasmidonta oaloeolus
Fig. 82- Alasmidonta hetevodon: right valve and
hinge plate of left valve. Scale = 1 cm.
88
-------
42(40) Ventral margin of shell gently rounded convexly when viewed
laterally; shell surface relatively smooth, except for
periodic rest marks (Fig. 74b): Alasmidonta raveneliana
Ventral margin rounded concavely when viewed laterally;
shell surface with irregular undulations, making surface
rough (Fig. 73a): Alasmidonta varicosa
43(32) Posterior ridge with undulations; hinge teeth
heavy and rough 44
Posterior ridge without undulations; hinge teeth smooth or
more delicate 45
I 1
Fig. 83- Alasmidonta undulata: right valve and hinge
plate of left valve. Scale = 1 cm.
89
-------
44(43) Shell roundly oval to nearly round, with prominent wing;
undulations on posterior slope gentle, not coarse
corrugation (Fig. 84a): Lasmigona oomplanata
Shell elongate, without wing; posterior slope strongly
corrugated (Fig. 84b): Lasmigona costata
45(43) Shell roundly oval to nearly round (Fig. 84a)-.Lasmigona oomplanata
Shell elongate 46
Fig. 84- Lasmigona: a- L. oomplanata, right valve and hinge plate of
left valve; b- L. costata3 right valve. Scale = 1 cm.
90
-------
46(45) Lateral teeth rudimentary (Fig. 85a):
Lateral teeth clearly developed
Lasmigona hotstonia
47
Fig. 85- Lasmigona: a- L. holstonicij right valve; b- L, compressa,
right valve and hinge plate of left valve. Scale s 1 cm.
91
-------
47(46) Major cusps of pseudocardinal teeth in left valve directly
below or posterior of beaks (Fig. 85b): Lasmigona aompressa
Major cusps of pseudocardinal teeth in left valve anterior
of beaks (Fig. 86): Lasmigona subviridis
Fig. 86- Lasmigona subviridis: right valve and
hinge plate of left valve. Scale = 1 cm.
92
-------
KEY TO SPECIES OF LAMPSILINAE
1 Entire ventral part of outer gill demibranch serving as
marsupium, its ventral edge folded (Fig. 28c). Genus
Ptyohobvanahus 2
(The shells of this genus are elongated, flattened and
with very low beaks which generally do not rise much
above the hinge line. The shells are straw-yellow in
color, with radiating green rays. Because of the color-
ing and general shape of their shells, species of
Ptyohobvanahus can be confused with certain species of
Aotinonaias (e.g., A. ellipsifovmis), but the lateral
teeth in Ptyohobvanahus are shorter, directed downward,
and are somewhat swollen posteriorly (see Fig. 88).)
Marsupium confined to either central or posterior part of
outer gill demibranch (Fig. 28d,e,f) 6
2(1) Posterior slope corrugated (Fig. 87): Ptyohobvanahus subtentum
Posterior slope not corrugated 3
3(2) Green rays on shell wide, broken into rectangular spots .... 4
Green rays on shell of fine continuous lines 5
Fig. 87- Ptyohobvanahus subtentum: right valve.
Scale = 1 cm.
93
-------
Fig, 88- Ptyahobranahus: a- P. foremanianim, right valve; b- P.
fasoiolare3 right valve and hinge plate of left valve. Scale = 1 cm.
94
-------
4(3) Color rays restricted mainly to upper half of shell; posterior
ridge straight (Fig. 88a): Ptyohobranohus foremanianum
Color rays usually well represented on lower half of shell;
posterior ridge arched upward (Fig. 88b).
Ptyohobranohus fasoiolare
5(3) Posterior ridge straight or bowed downward; posterior ridge
on beak angular (Fig. 89a): Ptyohobranohus greeni
Posterior ridge arched upward; posterior ridge on beak
rounded (Fig 89b): Ptyohobranohus oooidentalis
6(1) Marsupium confined to central part of outer gill demibranch
(Fig. 28d) 7
Marsupium confined to posterior part of outer gill demi-
branch (Fig. 28e,f) 9
1
b
Fig. 89- Ptyohobranohusj right valves : a- P. greeni; b- P. oooiden-
talis. Scale = 1 cm.
95
-------
7(6) Shell with single median row of large tubercles (Fig. 90):
Obliquaz>ia veflexa
Shell surface sculptured with numerous tubercles or nodules
of varying sizes or with radiating wrinkles, but without
single median row of large tubercles. Genus Cyprogenia . 8
8(7) Shell more triangular in outline, often with irregular
swellings on disc and posterior slope, but lacking high
round pustules (Fig. 91a): Cyprogenia aberti
Shell nearly round in outline, sculptured with round, high
pustules, usually abundant and distributed over nearly
entire shell surface (Fig. 91b): Cyprogenia irrorata
Fig. 90- Obliquaria reflexa: right valve and
hinge plate of left valve. Scale = 1 cm.
96
-------
Fig. 91- Cypvogenia: a- C. aberti3 right valve; b- C. irrorata,
right valve and hinge plate of left valve. Scale = 1 cm.
97
-------
9(6) Marsupium confined to lower part of posterior outer gill
demibranch (Figs 28e, 92) : Vvorrrus dromus
Marsupium contained in both upper and lower halves of post-
erior part of gill demibranch (Fig. 28f) (characteristic
of most of subfamily Lampsilinae, i.e. 15 genera) 10
Fig. 92- Dromus drornus: right valve and hinge
plate of left valve. Scale = 1 cm.
98
-------
10(9) Posterior slope transversely corrugated 11
Posterior slope smooth, or if corrugated, with radiating
corrugations only 15
11(10) Shell relatively high; sculpture on posterior half of disc
consisting of radiating grooves, which run to ventral
shell margin (Fig. 93) : Lerrriox oaelata
Shell elongate; not sculptured with radiating grooves.
Genus Medionidus 12
m
i 1
Fig. 93- Lemiox oaelata: right valve and hinge
plate of left valve. Scale = 1 cm.
99
-------
12(11) The posterior shell margin meets dorsal'margin at sharp
angle, forming wing (Fig. 94a): Medionidus maglamerae
Shell without wing 13
13(12) Shell shorter, length/height ratio 1.8 or less; disc below
umbo full and round (Fig. 94b): Medionidus penicillatus
Shell longer, length/height ratio 2.0 or greater; disc below
umbo flattened 14
Fig. 94- Medionidus: a- M. maglamerae3 right valve; b- M. penicillatus,
right valve and hinge plate of left valve. Scale = 1 cm.
100
-------
14(13) Rays on shell mostly continuous occurring on anterior third
of shell as abundantly as on median and posterior
portions; periostracum has satiny appearance due to
closely spaced microscopic ridges (Fig, 95a):
Medionidus conradiaus
Rays on shell broken mostly into streaks, blotches or chevron
designs, typically less abundant on anterior third of
shell; periostracum glossy (Fig. 95b): Medionidus aoutissimus
b
Fig. 95- Medionidus3 right valves: a- M. oonradiousj b- M. aoutissi-
mus. Scale = 1 cm.
101
503-367 O - 73 - 8
-------
15(10) Posterior half of pseudocardinal teeth divided into series
of parallel, vertical, rough, deeply divided lamellae
(Fig. 96): Glebula rotimdata
Posterior half of pseudocardinal teeth may be rough, but
they are not deeply lamellate 16
Fig. 96- Glebula votundata: right valve, hinge
plate of left valve and enlargement of pseudo-
cardinal tooth in left valve. Scale = 1 cm.
102
-------
16(15) Shell high, arced, flattened; posterior transverse slope
short, without trace of wing, and at 90° angle to disc;
hinge teeth very large and heavy CFig- 97):Ellipsaria lineolata
Shells without above combination of characters; if shell
is high it is generally not arced, and if so, it is
inflated, not flattened, and has less acute posterior
slope 17
Fig. 97- Elliipsavia lineolata: right valve and
hinge plate of left valve. Scale = 1 cm.
103
-------
Fig. 98- Carunaulina; a- C. parva3 right valve and hinge plate of left
valve; b- C. pulla, right valves. Scale = 1 cm.
104
-------
17(16) Females with well-developed caruncle on inner edge of each
side of mantle in front of branchial opening (see Fig.
139c); adults small, usually less than 40 mm in length:
Genus Carunculina (Fig- 98)
(A number of nominal species have been placed in the genus
Carunaulina. However, the systematics have not been well
worked out, although Johnson (1967) has spent the most
time analyzing Cavunculina shell characters and their
variation. He recognizes two species, C. pawa (Barnes)
and C. pulla (Conrad). According to Johnson, C. pulla
is restricted to the Altamaha River system of Georgia
north to the Neuse River system in North Carolina.
Cavunculina is not found north of the Neuse River on the
Atlantic slope. C. pawa is a very variable species
which is found throughout the Interior Basin, from
western New York to Minnesota, to Texas, Arkansas and
Florida (Johnson, 1967). It is found in the Atlantic
drainage in northern Florida in Black Creek.)
Females lack caruncles on inner edge of each side of mantle
in front of branchial opening; adults larger, usually
more than 40 mm in length 18
18(17) Shell elongate, length/height ratio 2.0 or greater 19
Shell shorter, length/height ratio less than 2.0 23
19(18) Posterior ridge high, near dorsal margin, and ending
posteriorly in point above dorsoventral midline (Fig. 99):
Lampsilis anodontoides
Posterior ridge lower, further from dorsal margin, and
ending posteriorly at or below dorsoventral midline 20
Fig. 99- Lampsilis anodontoides: right valve.
Scale = 1 cm.
105
-------
20(19) Posterior ridge concave (see Fig. 3), i.e. bowed downward
(Fig. 100a): Lampsilis subangulata
Posterior ridge straight or slightly convex (see Fig. 3).... 21
21(20) Posterior end of shell truncate (Fig. 100b): Lampsilis jonesi
Posterior end of shell bluntly pointed. Genus Ligumia 22
22(21) Posterior ridge extends to posterior margin of shell, and
is often angular near umbo; posterior slope typically
concave; posterior margin meets dorsal margin at angle,
forming low wing (Fig. 101a): Ligumia nasuta
Posterior ridge indistinct near posterior margin of shell,
and is broadly rounded near umbo; posterior slope
usually not concave; without wing where posterior and
dorsal margins meet (Fig. 101b): Ligumia recta
Fig. 100- Lampsilisright valves: a- L. subangulata; b- L. jonesi.
Scale = 1 cm.
106
-------
23(18) Shell round, or high-oval; teeth heavy. Genus Obovaria
Shell elongate or oval (if oval, teeth are not heavy) .
24
30
24(23) Beaks of shell high and arched strongly anteriorly 25
Beaks of shell lower and not strongly arched anteriorly ..... 26
Fig. 101- ligumia: a- L. nasuta, right valve and hinge plates of left
valve; b- L. recLa, right valve and hinge plates of left valves. Scale =
1 cm.
107
-------
Fig. 102- Obovca"ia3 right
valves: a- 0. retusa; b-
0. olivaria. Scale = 1 cm,
Fig. 103- Obovax>ia subro-
tunda: right valve and
hinge plate of left valve.
Scale = 1 cm.
108
-------
25(24) Nacre purple; typically rayless (Fig. 102a): Obovaria retusa
Nacre white; upper 1/3 of shell with green rays (Fig. 102b):
Obovaria olivaria
26(24) Beaks central, or nearly so 27
Beaks located anteriorly 29
27(26) Periostracum light-colored, often with color rays, especially
on disc (Fig. 103): Ohovaria subrotunda
Periostracum dark brown or black; color rays, if present,
limited to posterior slope 28
28(27) Shell almost circular in outline. Distribution limited to
Escambia River of Alabama and Florida (Fig. 104a):
Obovaria rotulata
Shell roundly elliptical or roundly ovate. Distribution
limited to the Alabama-Coosa River system (Fig. 104b):
Obovaria unioolor
Fig. 104- Obovaria3 right valves: a- 0. rotulata; b- 0. unioolor.
Scale = 1 cm.
109
-------
29(26) Shell ovate, nearly as high as long (Fig. 102b): Obovaria olivaria
Shell elliptical, clearly longer than high (Fig. 105):
Obovaria oacksoniccna
30(23) Shell showing strong sexual dimorphism. Genus Dysnomia 31
Shells of males and females only slightly sexually dimorphic,
if at all 61
31(30) Shell 3-pronged in outline (Fig. 106), strongly so in
females, due to greatly protruding posterior and median
ridges 32
Female shell not 3-pronged in outline; although shells of
males may be weakly 3-pronged in 3 species (Z?. biemarg-
inata, D. florintina and D. torulosa) 34
32(31) Median ridge greatly raised on at least half of disc, with
large swelling just prior to rest period lines (Fig. 107):
Dysonomia flexuosa
Median ridge not particularly raised on disc, swellings
before rest period lines are confined to protruding
portion of shell which projects beyond normal ventral
margin 33
Fig. 105- Obovaria jaoksoniccna: right valve.
Scale = 1 cm.
110
-------
Fig. 106- Dysnomia:
right valves showing 3-
pronged condition in fe
male (left) and male
(right).
dm
i
c
Fig. 107- Dysnomia flexuosa3 right valves: a- female; b- male; c- hinj
plate of left valve. Scale = 1 cm.
Ill
-------
Fig. 108- Dysnomia lewtsii3
1 cm.
I 1
b
right valves: a- female; b- male. Scale
112
-------
33(32) Rays inconspicuous on posterior ridge, typically obscured
on that portion of median ridge which protrudes beyond
normal ventral margin (Fig. 108): Dysnomia lewisii
Rays noticeable on posterior ridge, typically also on that
portion of median ridge which protrudes beyond normal
ventral margin (Fig. 109): Dysnomia stewardsoni
Fig. 109- Dysnomia stewavdsoni, right valves: a- female; b- male.
Scale = 1 cm.
113
-------
I 1
b
Fig. 110- Dysnomia torulosa, right valves: a- female; b- male. Scale
1 cm.
114
-------
34(33) Median ridge present on shell as well as posterior ridge;
with large swellings between rest period lines, making
high round knobs along median ridge (Fig. 110):
Dysnomia torulosa
Median ridge either present or absent; knobs absent on
disc 35
35(34) Rays discontinuous, especially on posterior ridge, giving
shell spotted, streaked or chevroned appearance 36
Rays continuous 38
36(35) Rays easily seen to be chevroned; posterior ridge very
¦ angular; posterior slope steep (Fig. Ill): Dysnomia triquetva
Rays not chevroned, or only minutely chevroned on small
local areas; posterior ridge not angular; posterior
slope not steep 37
Fig. Ill- Dysnomia triquetra3 right valves: a- female; b- male. Scale
= 1 cm.
115
-------
37(36) Rays typically conspicuous, appearing streaked on disc, but
becoming dot-like on posterior ridge and posterior slope;
disc immediately below umbo typically low and flattened;
shell typically ovate-elliptical; length/height ratio
1.5 or greater (Fig. 112): Dysnomia brevidens
Rays typically inconspicuous; disc immediately below umbo
typically high and rounded; shell often short and high;
length/height ratio 1.3 or less (Fig. 113) -.Dysnomia metastviata
Fig. 112- dysnomia brevidens, right valves: a- female; b- male. Scale
= 1 cm.
116
-------
38(35) Shell usually with color rays primarily on posterior ridge
and immediately adjacent areas, although immature shells
may be rayed occasionally over median portion of valve
as well
Color rays on shell not limited to region of posterior
ridge
Fig. 113- Dysnomia metastriata, right valves: a- female; b- male
Scale = 1 cm.
117
503-367 O - 73 - 9
-------
39(38) Shell typically pale ashy-green; shell elongate-elliptical
and small, rarely exceeding 3.75 cm in length (Fig. 114):
Dysnomia leniov
Shell not pale ashy-green, but rather yellow, brown, green
or olive 40
Fig. 114- Dysnomia leniov, right valves: a- female; b- male. Scale
= 1 cm.
118
-------
40(39) Upper margin of shell very broad and humped; color rays on
shell consisting of very fine, dark brown lines, arranged
very close together; minute chevroned spots often occur
between rays; posterior ridge occasionally furrowed along
rays (Fig. IIS): Dysnomia penita
Upper margin of shell narrower and not especially humped;
color rays on shell are broader and spaced wider apart ., 41
Fig. 115- Dysnomia penita* right valves: a- female; b- male. Scale
= 1 cm.
119
-------
41(40) Posterior ridge usually furrowed; periostracum glossy;
nacre usually lavender-purple (Fig. 116): Dysnomia haysiccna
Posterior ridge not furrowed, or only rarely furrowed
close to ventral margin on females; nacre usually white.. 42
Fig. 116- dysnomia haysiana^ right valves: a- female; b- male. Scale
1 cm.
120
-------
42(41) Periostracum very glossy; shell 2,5 cm in length or less
(Fig. 116): Dysnomia haysiana (juvenile)
Periostracum dull or with only low gloss 43
43(42) Shell high and inflated, especially in male; marsupial
extension on female shell is relatively narrow (Fig. 117):
Dysnomia sulcata
Shell only slightly inflated; marsupial extension on
female shell is relatively broad (Fig. 118): Dysnomia turgidula
Fig. 117- Dysnomia sulaata3 right valves: a- female; b- male. Scale =
1 cm.
121
-------
44(43) Shell greatly inflated; posterior ridge sharply angled;
posterior slope very steep and often with 1 or 2 minor
ridges. (Fig* 119): Dysnomia archaeformis
Shell not greatly inflated; posterior ridge round (except
in D. hiemcccginata and some specimens of D. flexuosa).... 45
Fig. 118- Dysnomia tuvgidula, right valves: a- female; b- male. Scale
= 1 cm.
122
-------
45(44) Median ridge high and with bumpy swellings just above growth
rest lines 46
Median ridge low and smooth, or absent 50
46(45) Posterior ridge strongly biangulate 47
Posterior ridge not strongly biangulate. 48
Fig. 119- Dysnomia arahaeformis, right valves: a- female; b- male.
Scale = 1 cm.
123
-------
47(46) Depression between median and posterior ridge on male wide;
on females marsupial extension is narrow and centrally
located (Fig. 107): Dysnomia flexuosa
Depression between median and posterior ridge relatively
narrow; on females marsupial extension is broad and
located posteriorly (Fig. 120): Dysnomia biemarginata
48(46) Posterior margin of shell long and curved, giving shell
characteristic shape; beaks greatly displaced anteriorly
(Fig. 121): Dysnomia propinqua
Posterior margin of shell shorter and more acutely curved;
beaks not greatly displaced anteriorly 49
Fig. 120- Dysnomia biemarginata3 right valves: a- female; b- male.
Scale = 1 cm.
124
-------
a b
Fig. 121- Dysnomia propinqua} right valves: a- female; b- male. Scale
= 1 cm.
Fig. 122- Dysnomia personata, right valves: a- female; b- male. Scale
= 1 cm.
125
-------
49(48) Umbos flattened, due to extension of depression between
posterior ridge and median ridge up onto umbo; shell
rather evenly colored over entire surface; rays obscure
(Fig. 107): Dysnomia flexuosa
Umbos round and full, depression between posterior and
median ridge not extending up onto umbo. Shell often
with bright green rays (Fig. 110): Dysnomia tovulosa
50(45) Median ridge low and smooth or absent 51
Median ridge absent 54
51(50) Umbos low and flattened due to depression between posterior
and median ridges extend up onto umbo (Fig. 109):
Dysnomia stewardsoni
Umbos round and full, depression between posterior and
median ridges not extending up onto umbo 52
52(51) Shell as high as long, or nearly so 53
Shell clearly longer than high (Fig. 110) : Dysnomia tovulosa
53(52) Umbos centrally placed, or nearly so (Fig. 122) -.Dysnomia personata
Umbos anteriorly placed (Fig. 117): Dysnomia sulcata
54(50) Shell as high as long, or nearly so 55
Shell clearly longer than high 56
55(54) Umbos centrally placed, or nearly so (Fig. 122) -.Dysnomia personata
Umbos anteriorly placed (Fig. 117): Dysnomia sulcata
56(54) Shell rayless, yellow and small (not exceeding 3 cm in
length) (Fig. 113): Dysnomia metastriata (immature)
Shell with rays 57
57(56) On left valve, interdentum clearly discemable as flat ledge
of about 2 mm width; pseudocardinal and lateral teeth
large and heavy; shell obscurely rayed (Fig. 108):
Dysnomia lewisii
On left valve interdentum inconspicuous; pseudocardinal and
lateral teeth not large and heavy (except in D. sulcata);
Shell typically distinctly rayed with dark green, but
occasionally obscurely rayed 58
58(57) Beak greatly displaced anteriorly; nacre often purple or
pink (although sometimes white); female shell with narrow
marsupial extension (Fig. 117): Dysnomia sulcata
Beak not greatly displaced anteriorly; nacre typically white;
female shell with broad marsupial extension 59
126
-------
59(58) Shell elliptical in outline, not inflated (Fig. 123):
Dysnomia aapsaeformis
Shell typically short and inflated 60
Fig. 123- dysnomia aapsaeformis> right valves: a- female; b- male
Scale = 1 cm.
127
-------
60(59) Beaks low (Fig. 124): Dysnomia florentina
Beaks higher, clearly extending well above upper anterior
and posterior margins (Fig. 118): Dysnomia turgidula
61(31) Posterior ridge angular. Genera Tvuncilla^Lampsilis (in
part) 62
Posterior ridge rounded or absent 70
Fig. 124- Dysnomia florentina, right valves: a- female; b- male.
Scale = 1 cm.
128
-------
62(61) Shell flattened laterally; beak cavities shallow; color rays
on shell with or without v-shaped markings. Genus
Truncilla 63
Shell inflated; beak cavities deep; color rays present (with-
out v-shaped markings) or absent. Genus Lampsilis (in
part) 65
63(62) Shell high, oval to subtriangular; posterior ridge sharp,
distinct down to ventral margin of shell; posterior slope
very short and very steep (Fig. 125): Truncilla truncata
Shell elongate, elliptical (juveniles sometimes oval);
posterior ridge angular, but becoming round and fading
out near ventral margin of shell 64
h
Fig. 125- Truncilla truncata: right valve and
hinge plate of left valve. Scale = 1 cm.
129
-------
Fig. 126- Tvuncilla, right valves:
Scale = 1 cm.
b
a- T. rrtaevodon; b- T, donaciformis.
m
Fig. 127- Lampsilis: a- L. dolabraefomiSj right valve; b- shell inflated
to ventral margin; c- shell inflated to upper half only. Scale = 1 cm.
130
-------
64(63) Color rays on shell generally narrow; shell typically quite
flattened; beak cavity generally very shallow (Fig. 126a):
Truncilla macro don
Color rays on shell generally broad; shell somewhat inflated;
beak cavity shallow, but clearly discemable (Fig. 126b):
Trunci I la cbnaciformis
65(62) Shell high, length/height ratio 1.4 or less 66
Shell more elongate, length/height ratio 1.5 or more 68
66(65) Posterior end rounded (Fig. 127a): Lampsilis dolabvaefovmis
Posterior end pointed 67
67(66) Shell inflated down to ventral margin (Fig. 127b; 128a):
Lampsilis exoccvata
Shell well inflated in upper half, but not down to ventral
margin (Fig. 127c; 128b): Lampsilis ovata ovata
<
t
Fig. 128- Lampsilis3 right valves:
Scale = 1 cm.
b
a- L. exoavata; b- L. ovata ovata.
131
-------
Fig. 129- Lampsilis
verpasta: right valve
Scale = 1 cm.
Fig. 130- Lampsilisj right valves: a- L. binominataj b- L. splendida.
Scale = 1 cm.
132
-------
68(65) Shell without color rays; posterior ridge convex (Fig. 129):
Lampsilis perpasta
Shell with color rays; posterior ridge straight or concave .. 69
69(68) Shell with only a few narrow (but sharply defined) color
rays (Fig. 130a): Lampsilis binominata
Shell with many color rays (Fig. 130b): Lampsilis splendida
70(61) Pseudocardinal teeth poorly developed. Genus Leptodea 71
Pseudocardinal teeth well developed 75
71(70) Shell elongate (length/height ratio 1.5 or more), with poorly
to only moderately developed wing 72
Shell higher (length/height ratio less than 1.5), with well
developed wing 73
Fig. 131- Leptodea shells, anterior view: a-
shell very flattened; b- shell inflated.
133
503-367 O - 73 - 10
-------
I 1
b
Fig. 132- Leptodeoij right valves: a- L. leptodon; b- L, amphiahaena.
Scale = 1 cm.
134
-------
72(71) Shell very flattened (Fig. 131a), with moderately developed
wing (Fig. 132a): Leptodea leptodbn
Shell inflated (Fig. 131b); wing absent or at most low and
poorly developed (Fig. 132b): Leptodea amphichaena
73(72) Ground color of periostracum straw-yellow to grey or grey-
brown; nacre white on adults, silvery and iridescent on
juveniles (Fig. 133a): Leptodea fragilis
Ground color of periostracum greenish-grey; nacre coppery-
pink on adults, silvery and iridescent on juveniles
(Fig. 133b): Leptodea laevissima
Fig. 133- Leptodea: a- L. fvagilis, right valve and hinge plate of
left valve; b- L. laevissima. Scale = 1 cm.
135
-------
Fig. 134- Proptera alat'a : right valve and hinge
plate of left valve. Scale = 1 cm.
/>•
a
Fig. 135a- extremely inflated shell, anterior end viewj b- fine beak
sculpture (e.g., Proptera aapax); c- coarse beak sculpture (e.g.,
Lampsilis ovata ventvioosa). Scale = 1 cm.
136
-------
74(70) Shell with well-developed wing (Fig. 134): Proptera alata
Wing usually lacking, but if present is very low and poorly
developed 75
75(74) Shell extremely inflated (Fig. 135a), with very fine beak
sculpture (Fig. 135b, 136a): Proptera eapax
Shell not extremely inflated (of if well inflated it has
coarse beak sculpture (Fig. 135c)) 76
76(75) Shell large (up to 11.5 cm) and with purple nacre (Fig. 136b):
Proptera purpurata
Shell without purple nacre, nacre usually white, or if
pinkish-purple, shell is small (less than 6 cm) 77
Fig. 136- Proptera3 right valves: a- P. capaxj b- P. purpurata. Scale
= 1 cm.
137
-------
77(76) Posterior mantle margin without papillate or ribbon-like
projections. Genus Aotinonaias
Posterior mantle margin area in front of branchial opening
modified to form extensions, either papillate projections
or ribbon-like flaps
78
81
78(77) Color rays on shell faint, but interrupted periodically by
dark blotches (Fig. 137a): Aotinonaias peotorosa
Color rays on shell more or less of continuous intensity ... 79
79(78) Periostracum rather dull, not glossy; shell elongate; post-
erior half of shell generally not higher than shell
anterior to beaks (Fig. 137b): Aotinonaias ellipsiformis
Periostracum glossy; shell higher; posterior half of shell
higher than shell anterior to beaks 80
80(79) Shell more elongate, elliptical in outline (Fig. 138a):
Aotinonaias oarinata oarinata
Shell less elongate, oval in outline (Fig. 138b):
Aotinonaias oarinata gibba
1
Fig. 137- Aotinonaias> right valves:
formis. Scale = 1 cm.
a- A. peotorosa; b- A. ellipsi-
138
-------
b
Fig. 138- Actinonaias: a- 4. aarinata oax*Lnata3 right valve and hinj
plate of left valve; b- A. aarinata gibha. Scale = 1 cm.
139
-------
81(79) Posterior mantle margins with long papillate projections
(Fig. 139a). Genus Villosa 82
(There are many nominal species that should be placed
in the genus Villosa. However, how many of these repre-
sent distinct biological species and which are synonyms
has not been adequately studied. According to Johnson
(1970) it is not yet possible to tell how many species
there are in Villosa. Therefore, the key below is only
to species complexes.)
Posterior mantle margins with ribbon-like flaps (Fig. 139b).
Genus Lampsilis 85
Excurrent
opening
Incurrent
opening
Flap
b
Excurrent
opening
Papillae7
a
Excurrent
chamber
Incurrent
chamber
Caruncle
C
Fig. 139- Posterior mantle margins: a- Villosa, with long papillate
projections; b- Lampsiliss with ribbonlike flaps; c- Caruneulina, with
caruncles. (Modified from Heard, 1968).
140
-------
82(81) Shell with either wide or narrow, but more or less continuous,
color rays 83
Shell with wide discontinuous color rays: Villosa iris complex
(This group includes the species V. iris (Fig. 140a),
V. ogeeohensis3 V. nebulosa and V. piota.)
83(82) Shell with broad color rays: Villosa villosa complex
(This group includes the species V. villosa, V. delnmbis,
V. piota and V. vibex (Fig. 140b).)
Shell with narrow color rays 84
SeSS^ry-v .• , ,y«>
HHP . - ^-->.^,7*®
r
• Jl
^prr!' - jstvj ¦ -
Fig. 140- Villosa: a- V. iris, right valve and hinge plate of left
valve; b- V. vibex} right valve. Scale = 1 cm.
141
-------
(—
Fig. 141- Villosaj right valves: a- V. lienosa; b- V. aonstriata; c-
V. tvabalis. Scale = 1 cm.
142
-------
84(83) Posterior end of shell truncate or very broadly rounded;
shell more or less rhoraboidal in outline: V. fabalis complex
(This group includes the species V. fabilis3 V. lienosa
(Fig. 141a) and V. propria.)
Posterior end of shell medially pointed; shell elliptical
in outline: Villosa vanuxemensis complex
(This group includes the species V. vanuxemensis3 V.
aonoestator3 V. oonstricta (Fig. 141b), V. ovtmanni3 and
V. trabalis (Fig. 141c).)
85(81) Shell elongate, length/height ratio 1.6 or more 86
Shell higher, less elongate, length/height ratio less than
1.6 96
86(85) Posterior ridge high, terminating in rather sharp point well
above midline of shell (Fig. 142a): Lampsilis anodontoides
Posterior ridge lower, terminating near midline of shell or
lower 87
87(86) Posterior ridge concave (Fig. 142b): Lampsilis subangulata
Posterior ridge convex 88
l 1
b
Fig. 142- Lampsilis3 right valves: a- L. anodontoides; b- L. subangu-
lata. Scale = 1 cm.
143
-------
88(87) Posterior ridge decidedly angular (Fig. 143a): Lampsilis splendida
Posterior rounded or only weakly angular 89
89(88) Posterior ridge weakly angular; shell small, 5.5 cm or less
in length (Fig. 143b): Lampsilis jonesi
Posterior ridge rounded, or, if weakly angular, adult shell
large, up to 11 cm or more in length 90
Fig. 143- Lampsilisj right valves: a- L. splendida; b- L. gonesi. Scale
1 cm.
*'r v-1
fSttMfi-."'-
=) /wss® - •
2Wr-
Fig. 144- Lampsilis
streokevi3 right valve.
Scale = 1 cm.
144
-------
90(89) Color rays on shell discontinuous, broken by many concentric
non-pigmented areas (Fig. 144): Lampsilis streckevi
Color rays on shell more or less continuous 91
91(90) Shell of adults small, 7.5 cm or less in length; color rays
on shell dark brown, green-brown or black; Alabama River
drainage and several rivers in Texas 92
Shell of adults large or small; color rays on shell some
shade of green, often bright or light green, although
they may be darker, with varying degrees of brown (species
with brown rays are large, adults more than 10 cm in
length) 93
92(91) Shell elliptical, with pointed posterior end. Alabama River
drainage. (Fig. 145a): Lampsilis altilis
Shell rhomboidal (usually oval in females), with broadly
rounded posterior end. Llanos, Guadalupe and Colorado
Rivers of Texas. (Fig. 145b): Lampsilis bvacteata
I
b
Fig. 145- Lampsilis, right valves: a- L. altilis; b- L. bracteata.
Scale = 1 cm.
145
-------
93(91) Shell elliptical, with pointed posterior end; beaks located
especially far anteriorly (Fig. 146a) Lampsilis australis
Shell rhomboidal (usually oval in females), with broadly
rounded or truncate posterior end 94
94(93) Color rays extend over entire shell; color rays usually
many, conspicuous, and extend to ventral margin without
becoming blurred or faded in color 95
Color rays nearly absent or limited to posterior slope, or
they become faded or blurred before reaching ventral
margin; females prominently swollen posteriorly (Fig.
146b): Lampsilis vadiata siliquoidea
Fig. 146- Lampsilis: a- L. australis3 right valve; b- L. vadiata
siliquoidea3 right valve and hinge plate of left valve. Scale = 1 cm.
146
-------
95(94) Shells of females prominently swollen posterioventrally
(Fig. 147a): Lampsilis hydiana
Shells of females not prominently swollen posterioventrally
(Fig. 147b): Lampsilis vadiata radiata
m—
V
X)'
-------
-------
95(94) Shells of females prominently swollen posterioventrally
(Fig. 147a): Lampsilis hydiana
Shells of females not prominently swollen posterioventrally
(Fig. 147b): Lampsilis radiata radiata
Fig. 147- Lampsiliss right valves: a- L. hydiana; b- L. radiata
radiata. Scale = 1 cm.
147
-------
Fig. 148- Lampsilis dola-
braeformiSj right valve.
Scale = 1 cm.
I
Fig. 149- Lampsiliss right valves:
Scale = 1 cm.
I 1
b
a- L. excavata; b- L. ovata ovata.
148
-------
96(81) Posterior ridge sharply angular 97
Posterior ridge rounded or only very weakly angular 100
97(96) Shell very high, with few or no color rays 98
Shell more elongate, with many color rays (Fig. 143a):
Lampsilis splendida
98(97) Posterior end pointed 99
Posterior end rounded (Fig. 148): Lampsilis dolabvaeformis
99(98) Shell inflated down to ventral margin (Fig. 149a):
Lampsilis exoavata
Shell well inflated in upper half, but not down to ventral
margin (Fig. 149b) : Lampsilis ovata ovata
I 1
b
Fig. 150- Lampsilis, right valves: a- L. orbioulata; b- L. stvaminea.
Scale = 1 cm.
149
503-367 O - 73 - 11
-------
Fig. 151- Lampsilis shells:
a- umbos high and protruding;
b- umbos relatively low.
Fig. 152- Lampsilisj right valves: a- L. ovata ventriaosa; b- L.
fasoiola. Scale = 1 cm.
150
-------
100(96) Shell very thick and heavy, with large thick hinge teeth;
median area of shell with series of spaced, parallel
undulations; beaks high, broad and arched forward
(Fig. 150a): Lampsilis orbiculata
Shell not especially thick or heavy; hinge teeth prominent,
but not especially large and thick; surface smooth or
with slight, irregular undulations; beaks may be low
or high, but not especially broad or arched forward ... 101
101(100) Many of shell growth lines rather evenly raised, giving
shell surface washboard-like appearance (Fig. 150b):
Lampsilis straminea
Shell surface without washboard-like appearance 102
102(101) Shell with high protruding umbos (Fig. 151a) 103
Shell with lower umbos (Fig. 151b) 105
103(102) Beak sculpture consisting of fine concentric ridges (Fig.
149a): Lampsilis exoavata
Beak sculpture having heavy concentric ridges 104
104(103) Color rays on shell absent or restricted to posterior
slope (or sometimes also being present in the area
of posterior ridge) (Fig. 152a): Lampsilis ovata ventricosa
Color rays on shell not restricted to only posterior slope
and posterior ridge regions. Known only from Altamaha
River system (Fig. 148): Lampsilis dolabraeformis
105(102) Shell more or less evenly covered with color rays; beaks
sculptured with small double-looped ridges (Fig. 152b):
Lampsilis faseiola
Shell with very few or without color rays, or if many
color rays present, beak sculpture consists of heavy
concentric or wavy ridges 106
106(105) Shell large, up to 12 cm or more in length, heavy; post-
erior ridge broadly rounded or absent; periostracum
yellow, glossy, minor growth lines indistinct, generally
without color rays, except occasionally on posterior
slope and rarely on disc (Fig. 153a): Lampsilis aariosa
Shell smaller, generally less than 8 cm in length, heavy
(L. perpasta) or light (L. binominata> L. oohraaea);
posterior ridge present and usually weakly angular;
periostracum glossy (L. binominata, L. perpasta) or
dull (L. oohraaea), with (L. binominata3 L. oohraaea)
or without (L. perpasta) color rays 107
151
-------
Fig. 153- LampsiliSy right valves: a- L. aariosa; b- L. perpasta.
Scale = 1 cm.
152
-------
107(106) Shell relatively thick and heavy; posterior ridge convex;
color rays absent (Fig. 153b): Lampsilis perpasta
Shell relatively thin and light; posterior ridge concave;
color rays generally present 108
108(107) Shell glossy; minor growth lines rather indistinct; color
rays few and widely spaced; pseudocardinal teeth thick
and directed downward (Fig. 154a): Lampsilis binominata
Shell rather dull; minor growth lines distinct; color rays
usually present and narrowly spaced, often only on
posterior half of shell; pseudocardinal teeth lamellar
and obliquely or nearly horizontal (Fig. 154b):
Lampsilis ochraaea
Fig. 154- Lampsilis, right valves: a- I. binominata; b- L. oehraoea.
Scale = 1 cm.
153
-------
SECTION IV
ACKNOWLEDGEMENTS
I wish to thank Mr John L. Tottenham for preparing most of the illustra-
tions, Ms P. A. Ayers for providing technical assistance, and Dr W. H.
Heard for advice regarding some of the key anatomical characters.
155
-------
SECTION V
REFERENCES
The bibliography below is not intended to be complete, but to bring to
the attention of the interested reader some of the more important publi-
cations dealing with North American freshwater mussels, as well as to
provide a good cross-section of the workers who have published on
unionid clams in the northern part of the Western Hemisphere. A complete
bibliography of the Unionacea of North America would take many pages,
and for those interested can be assembled from the references given in
the works cited below.
Athearn, H. D. and A. H. Clarke, Jr. 1962. The freshwater mussels of
Nova Scotia. National Museum of Canada Bulletin, No. 183:11-41.
Baker, Frank Collins. 1898. The Mollusca of the Chicago area. The
Pelecypoda. The Chicago Academy of Sciences. Bulletin of the
Natural History Survey, No. 3(1}:1-103, pis 1-27.
1922. The molluscan fauna of the Big Vermilion River, with special
reference to its modification as a result of pollution by sewage
and manufacturing wastes. Illinois Biological Monographs, 7(2):1-
126, pis 1-15.
1928. The fresh-water Mollusca of Wisconsin. Part II. Pelecypoda.
Bulletin of the Wisconsin Geological and Natural History Survey,
70(2):i-vi+l-495, pis 29-105.
Baker, H. B. 1964. Some of Rafinesque's unionid names. Nautilus, 77:
140-142.
Boss, K. J. and W. J. Clench. 1967. Notes on Pleurobema collina
(Conrad) from the James River, Virginia. Occasional Papers on
Mollusks, 3(37):45-52.
Call, Richard Ellsworth. 1900. A descriptive illustrated catalogue of
the Mollusca of Indiana. Twenty-fourth Annual Report of the
Indiana Department of Geology and Natural Resources, 1899, pp. 335-
1017, pis 1-78.
Clark, H. Walton and Charles B. Wilson. 1912. The mussel fauna of the
Maumee River. United States Bureau of Fisheries. Document, No. 757:
1-72.
Clarke, Arthur H. 1973. The freshwater molluscs of the Canadian Interior
Basin. Malacologia, 13(1/2):1-509.
Clarke, Arthur H. and Clifford 0. Berg. 1959. The freshwater mussels of
central New York. Ithaca N.Y., Cornell University, Agricultural
Experimental Station, New York State College of Agriculture, Memoir,
367, 80 pp.
Clench, William J. and Ruth D. Turner. 1956. Freshwater mollusks of
Alabama, Georgia, and Florida from the Escambia to the Suwannee
River. Bulletin of the Florida State Museum: Biological Sciences,
1(3):97-239.
Coker, Robert E. 1914. Water-power development in relation to fishes
and mussels of the Mississippi. Report of the United States
Commissioner of Fisheries, Appendix 8, pp. 1-28, pis 1-6.
157
-------
Conrad, T. A. 1853. A synopsis of the family of naiades of North America,
with notes, and a table of some of the genera of the family, accor-
ding to their geographical distribution, and descriptions of genera
and subgenera of the family. Proceedings of the Academy of Natural
Sciences of Philadelphia, 6:243-269.
Cvancara, Alan M. 1970. Mussels (Unionidae) of the Red River Valley in
North Dakota and Minnesota, U.S.A. Malacologia, 10(1^:57-92.
Dall, William H. 1910. Land and freshwater mollusks of Alaska and ad-
joining regions. Earriman Alaska Series of the Smithsonian
Institution, 13, xii+171 pp., pis 1 and 2.
Frierson, L. S. 1927. A classified and annotated check list of the
North American naiades. Baylor University Press, Waco, Texas.
Ill pp.
Fuller, Samuel L. H. 1971. A brief field guide to the fresh-water mussels
(Mollusca: Bivalvia: Unionacea) of the Savannah River System. ASB
(Association of Southeastern Biologists) Bulletin, 18(4):137-146.
Goodrich, Calvin. 1932. The Mollusca of Michigan. University of
Michigan, Ann Arbor, University Museums, Michigan Handbook Series,
No. 5, 120 pp., 7 pis.
Goodrich, Calvin and Henry van der Schalie. 1944. A revision of the
Mollusca of Indiana. American Midland Naturalist, 32(2):257-326.
Haas, F. 1969. Superfamilia Unionacea. Das Tierreich, Berlin, Lief.
88, x+663 pp.
Hannibal, Harold. 1912. A synopsis of the Recent and Tertiary freshwater
Mollusca of the California Province, based upon an ontogenetic
classification. Proceedings of the Malacological Society of London,
10:112-211, pis 5-8.
Heard, William, H. 1968. Mollusca. In: Parrish, Fred K. (Ed.) Keys to
Water Quality Indicative Organisms (Southeastern United States).
Federal Water Pollution Control Administration, U.S. Department of
the Interior, pp. Gl-26.
Heard, William H. and Richard H. Guckert. 1970. A re-evaluation of the
Recent Unionacea (Pelecypoda) of North America. Malacologia, 10(2):
333-355.
Henderson, Junius. 1924. Mollusca of Colorado, Utah, Montana, Idaho and
Wyoming. University of Colorado Studies, 13(2):65-223.
1929. The non-marine Mollusca of Oregon and Washington. University
of Colorado Studies, 17:47-190.
1936. Mollusca of Colorado, Utah, Montana, Idaho, and Wyoming.
Supplement. University of Colorado Studies, 23(2):81-145.
1936. The non-marine Mollusca of Oregon and Washington. Supplement.
University of Colorado Studies, 23(4):251-280.
Isely, F. B. 1925. The freshwater mussel fauna of eastern Oklahoma.
University of Oklahoma Bulletin, new series, No. 322:43-118.
Johnson, Richard I. 1967a. Illustrations of all the mollusks described
by Berlin Hart and Samuel Hart Wright. Occasional Papers on
Mollusks, 3:1-35.
1967b. Additions to the unionid fauna of the Gulf drainage of
Alabama, Georgia and Florida (Mollusca:Bivalvia). Breviora, No.
270:1-21.
1969. Illustrations of Lamarck's types of North American Unionidae
mostly in the Paris Museum. Nautilus, 83(2):52-61.
158
-------
Johnson, Richard I. 1970. The systematics and zoogeography of the
Unionidae (Mollusca:Bivalvia) of the southern Atlantic Slope region.
Bulletin of the Museum of Comparative Zoology at Harvard University3
140(6):263-449.
1972. Illustrations of all the Mollusks described by Lorraine
Screven Frierson. Occasional Papers on Mollusks3 3(41):]37-173.
La Rocque, Aurdle. 1967. Pleistocene Mollusca of Ohio. Bulletin of the
Geological Survey of Ohio3 62:vii-xiv+113-356, pis 1-8.
Latchford, F. R. 1882. Notes on the Ottawa Unionidae. Transactions of
the Ottawa Field Naturalist's Club3 3:48-57.
Lea, Issac. 1858. Descriptions of the embryonic forms of thirty-eight
species of Unionidae. Journal of the Academy of Natural Sciences of
Philadelphia3 series 23 4:43-50. pi. 5.
1863. Descriptions of the soft parts of one hundred and forty-three
species and some embryonic forms of Unionidae of the United States.
Journal of the Academy of Natural Sciences of Philadelphia3 series 23
5:401-456.
Marshall, William, B. 1890. Beaks of Unionidae inhabiting the vicinity of
Albany, New York. Bulletin of the New York State Museum3 2:169-189.
Matteson, M. P. 1955. Studies on the natural history of the Unionidae.
American Midland Naturalist3 53:126-145.
Meek, S. E. and H. Walton Clarke. 1912. The mussels of the Big Buffalo
Fork of the White River, Arkansas. Report of the United States
Commissioner of Fisheries for 19113 pp. 1-20.
Morrison, J. P. E. 1955. Family relationships in the North American
freshwater mussels. American Malacoloqical Union. Annual Report,
22:16-17.
Murray, Harold D. and A. Byron Leonard. 1962. Handbook of unionid mussels
in Kansas. University of Kansas Museum of Natural History3
Miscellaneous Publication3 No. 28:1-84, pis 1-45.
Neel, Joe Kendall and William Ray Allen. 1964. The mussel fauna of the
upper Cumberland Basin before its impoundment. Malacologia, 1(3):
427-459.
Ortmann, A. E. 1911. A monograph of the naiades of Pennsylvania. Pts 1
and 2. Memoirs of the Carnegie Museum3 4:279-374.
1913. The Alleghenian Divide and its influence upon the freshwater
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390.
1919. A monograph on the naiades of Pennsylvania. Pt. 3. Systematic
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1920. Correlation of shape and station in freshwater mussels.
Proceedings of the American Philosophical Society3 19:269-312.
1923-24. Notes on the anatomy and taxonomy of certain Lampsilinae
from the Gulf drainage. Nautilus3 37:56-60, 99-104, 137-144.
Ortmann, A. E. and Bryant Walker. 1922. On the nomenclature of certain
North American naiades. Occasional Papers of the Museum of Zoology3
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Parmalee, Paul W. 1967. The freshwater mussels of Illinois. Illinois
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Parodiz, J. J. 1967. Types of the North American Unionidae in the
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Rafinesque, C. S. 1819. Prodome de soixante-dix nouveaux genres d'
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Robertson, Imogene C. S. and Clifford L. Blakeslee. 1948. The Mollusca
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Simpson, C. T. 1900. Synopsis of the naiades, or pearly freshwater
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160
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758, pp. 1-52.
161
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SECTION VI
GLOSSARY
Alate - Having a "wing", i.e., a dorsal, thin, flat projection, as the
extension of the posterior slope of some freshwater mussels.
Anal opening or siphon - The dorsal posterior opening or siphon located
near the anus through which water leaves the mantle cavity of a mollusk
such as a freshwater mussel. Through it are carried excretory products
of the alimentary and renal systems. Also called the excurrent opening
or siphon.
Angular - Having an angle or having the tendency to form an angle, in
contrast to being round.
Anterior end - The shorter end of the shell (from the beaks) in fresh-
water mussels. The foot of the animal is directed toward this end.
Arched - In the form of an arch or curve; bending in a curved manner in
a particular direction.
Beak - The raised part on the dorsal margin of each of the bivalved shell
valves. The beaks are formed by the embryonic shell, around which the
later shell develops distally in a concentric manner. Also called umbo
(pi. umbos) .
Beak cavity - The cavity on the inside of each valve of a mussel shell
going into the beak. In some species the cavity is quite deep, in others
it is so shallow as to be hardly more than a weak depression.
Beak sculpture - The natural surface markings, other than those of color,
found on the beaks or umbos of mussel shells. Such markings are in some
cases characteristically different in the various taxa, and thereby
provide means of identification. They are sometimes considered important
in indicating phylogenetic relations between genera and higher taxonomic
groups.
Biangulate - Having two angles or corners.
Bifurcate - Divided into two branches.
Bivalve - A common or popular name referring to a member of the
molluscan class Pelecypoda or Bivalvia. The name refers to the
possession by the animal of two apposing plates or valves composed
mainly of calcium carbonate which enclose and protect the soft body of
the mollusk.
163
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Bradytictic - Refers to mussels that are long-term breeders, i.e., that
retain developing glochidial larvae in their gills throughout the year,
except in the Nearctic summer.
Branchial opening or siphon - The ventral posterior opening or siphon
through which water enters the mantle cavity of a mollusk such as a
freshwater mussel. After entering the mantle cavity the water flows
over and through the branchiae or gills, providing oxygen, and in
filter-feeders such as freshwater mussels, bringing microorganisms that
are trapped as food by the gill surface. Also called the incurrent
opening or siphon.
Caruncle - A fleshy elevation or outgrowth; a characteristic protuber-
ance on the inner edge of each side of the mantle in front of the
branchial opening of members of the lampsiline genus Carunculina.
Chevron-shaped - Shaped like a wide-angled V, normally positioned or
inverted .
Clam - A common or popular name for a bivalved mollusk of the class
Pelecypoda or Bivalvia.
Color ray - A more or less straight band of color, continuous or
discontinuous, contrasted to the ground color of the shell and radiating
from the umbonal area distally toward or to the peripherial margins of
the valve.
Concentric - Having the same center, e.g., the umbo, and expanding out-
ward in parallel (i.e., equidistant) lines, as in the lines of growth
of a mussel shell.
Compressed - Flattened or pressed together laterally, such as the
appearance of some freshwater mussels.
Corrugated - Wrinkled by alternating ridges and furrows.
Cusp - The highest elevations of the lateral and pseudocardinal teeth.
Demibranch - One-half of one of the paired gills of a lamellibranch
pelecypod; i.e., the two apposing rows of gill filaments on one side of
the gill; a half-gill. A vertical cross-section of one of the paired
lamellibranch gills is like a W pressed together. One-half of the W
is the demibranch. This peculiar type of ctenidium found in lamelli-
branchs apparently evolved by the elongation of the gill filaments on
each side of the gill axis, forming and inverted V, followed by the 1
bending back on itself of each filament forming a W.
Disc - The middle, central or main portion of the exterior of the valve
of a mussel as distinct from the posterior slope and other areas immedi-
ately adj acent to the marginal peripheries.
164
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Double-looped - Being in the form of two adjacent semicircles, i.e., end
to end with the openings oriented in the same direction. This is usu-
ally contrasted to single-looped, in which case there is only one semi-
circle. In regard to freshwater mussels, both terms refer to the
sculpturing of the umbo or beak of the shell.
Elliptical - Having the form of an ellipse.
Elongate - Lengthened; extending length-wise; especially longer than
high.
Excurrent opening or siphon - The dorsal posterior opening or siphon
through which water leaves the mantle cavity of a mollusk such as a
freshwater mussel. This opening or siphon is located near the anus and
nephridopores, and so also serves as an exit for excretory products.
Also called the anal opening or siphon.
Furrowed - Grooved or channelled.
Gill (Bronchia) - The platelike or filamentous outgrowth, usually lo-
cated within the mantle cavity, serving as the respiratory organ of
aquatic mollusks. In lamellibranch mollusks the gills are greatly enlarged,
serving not only the function of respiratory gaseous exchange, but also
in food gathering ("filter-feeding"). The basic structure of the
molluscan gill is characteristic throughout the phylum and is referred
to as a "ctenidium".
Gill filament - One of the leaflets of the gill.
Glochidium - The bivalved larva of freshwater mussels, generally para-
sitic on fish during this early stage in the life history.
Glossy - Smooth and shining; highly polished.
Gravid female - A female with marsupium filled with young embryos.
Ground color - The basic or background color of a shell, against which
any additional color markings are contrasted.
Growth lines - Minute lines on the outer shell surface indicating a
minor rest period during growth. Not to be confused with the major
"rest marks", caused by prolonged growth arrest (as during winter).
Einge - The stabilizing lamellae (pseudocardinal and lateral teeth) in
the dorsal part of each valve of a mussel shell. The opposing single
lamella in one valve articulates with a pair of complementary lamellae
in the opposing valve.
Einge plate - That part of the dorsal margin of the shell between and
including the pseudocardinal and lateral teeth.
165
503-367 0-73-12
-------
Incurrent opening or siphon - The ventral posterior opening or siphon
through which water enters the mantle cavity of a mollusk such as a
freshwater mussel. Also called the branchial opening or siphon. Water
flows through this opening to the gills or branchiae, where oxygen-carbon
dioxide exchange occurs, and in filter-feeders such as freshwater mussels,
where microorganisms are trapped as food.
Inflated - Swollen; expanded; distented.
Interdentum - The space on the hinge plate between the pseudocardinal
and lateral teeth.
InterZamellar connections - Connections of tissue joining the two
lamellae of a demibranch. Together with the interfilamental connections
(and at right angles to them) they are responsible for the formation of
ascending water tubes within the gill demibranch. Water enters the water
tubes by ostia in the interfilamental connections and flows upward to
the exhalent space at the top of the gill,, and thence to the outside of
the animal via the exhalant opening or siphon.
Iridescent - Prismatic coloration; exhibiting colors like the rainbow.
Lamella - A small thin plate, blade or scalelike structure.
Lamellate (Lamellar) - Formed in thin plates, composed of thin plates or
covered with them.
Lamina - A thin layer, blade or platelike extension.
Laminate - Consisting of plates or layers, one over another.
Lateral teeth - The elongated lamellae on the posterior half of the
hinge-plate.
Left valve - The shell half on the left side when the shell is placed
with the hinge up and the anterior end forward.
Length/height ratio - The number or quotient obtained by dividing the
greatest length of a clam shell by its greatest height. The more
elongate the clam, the higher will be the quotient; the shorter and
higher the shell, the lower will be the quotient.
Mantle - An extension of the dorsal body wall of mollusks as one or a
pair of folds, which usually secretes a shell and encloses a mantle
cavity, typically containing gills.
Mantle margin - The edge of the mantle or pallium, the characteristic
soft outer fold of integument covering the body of mollusks. In
gastropods, the mantle margin is adjacent to the shell aperture. In
pelecypods, the mantle margin is adjacent to the distal edge of the shell.
The mantle margin functions in shell deposition during new growth, and
in pelecypods it also serves a sensory function.
166
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Marsupial extension (on shell) - The bulge or ventral extension of the
shell on some female unionacean clams caused by new shell material being
laid down by the protruding mantle covering the swollen gravid gills
during shell growth. The marsupial extension on females results in
sexual dimorphism
Marsupium - The pouch used to contain young. In unionacean clams, in-
ternal spaces in the gills perform this service, and the type of modi-
fication of the gills to perform this protective function is important
in higher classification within the superfamily.
Median ridge - A dorsoventral ridge on the shell running from the region
of the umbos toward or to the ventral margin in some bivalves.
Mussel - A common or popular name for a bivalved mollusk of the class
Pelecypoda or Bivalvia.
Nacre - The white or iridescent inner layer of shell in many mollusks,
lying next to the mantle and often characteristically colored in many
unionacean clams.
Nodule - A small knot, lump or irregularly shaped mass, such as the
projections occurring on the shell surface of some freshwater mussels.
Nodulose (Nodular3 Nodulate) Having small knobs, nodules or projections.
Oblique - Slanting, as some ridges which are not parallel to the concen-
tric growth lines.
Obsolete - Obscure; not distinct; very rudimentary.
Oval - In the shape of the longitudinal section of a hen's egg, i.e.,
oblong and curvilinear, with one end narrower than than the other.
Pallial line - On the inside surface of abivalved shell that line of
attachment of the mantle to the shell, often marked by a depression or
scar.
Papillate - Having many small papillae or bumps on the surface.
Parallel - Spaced the same relative distance apart throughout the length,
even though the objects may be in the form of a curve, circle or spiral.
Periostracvm - The thin proteinaceous external layer covering most
mollusk shells.
Placentae - A name by which the branchial brood pouches (marsupia) of
unionacean clams are sometimes called.
167
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Posterior end - The longer end of the shell (from the beaks). This is
the end containing the siphonal (inhalant and exhalant) openings through
which water passes into and out of the mantle cavity. In most unionid
clams, this is the end sticking above the substratum in which the animal
is buried.
Posterior ridge - A ridge on the external surface of many mussel shells,
extending from the umbos posteroventrally toward or to the shell margin.
It is often used as a diagnostic character for species discrimination.
Posterior slope - The area on the external surface of a mussel shell
between the posterior ridge and the dorsal margin of the shell.
Pseudocardinal teeth - The usually compact lamellae on the anterior part
of the hinge plate.
Pustule - A blisterlike prominence, such as the projections found on the
shell surface of some freshwater mussels.
Pustulose (Pustular} Pustulate) - Having prominences resembling blisters.
Radiating - Proceeding outwardly (as, for example, lines) from a central
point, as color rays on a mussel shell.
Ray - A streak or linear mark. It may be continuous or interrupted at
intervals.
Rest mark - A darker or thicker part of the shell characteristically
formed during a major rest period in growth.
Rhomboidal - Having the shape of a rhomboid, i.e., quadrilateral with
opposite sides and angles equal, but neither equilateral nor equiangular.
Right valve - The shell half on the right side when the shell is placed
with the hinge up and the anterior end forward.
Rounded - Having a more or less evenly curved contour, in contrast to
being angular.
Rudimentary - Vestigial; not or barely functional in one species as
contrasted to being developed in others.
Sculpture - The natural surface markings, other than those of color,
usually found on mussel shells, and often furnishing identifying marks
for species recognition.
Septa - Partitions (formed by the interlamellar connections) separating
spaces occurring between the two lamellae of a eulamellibranch demi-
branch.
168
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Sexually dimorphic - Males and females of the same species being morpho-
logically different. In unionacean clams sexual dimorphism is usually
indicated by the marsupial extension on the shell. This extension is
caused by new shell material being laid down by the protruding mantle
covering the swollen gravid gills during shell growth.
Single-looped - Being in the form of one loop or semicircle, as contrasted
to being double-looped, i.e., consisting on two semicircles facing the
same direction and joined end-to-end. Refers to the condition of the
ridges on the umbo or beak of a mussel shell.
Siphon - A tubular or siphonlike structure formed by the opposing pos-
terior mantle margins in mussels; a pair are commonly present on bivalves,
providing restricted incurrent and excurrent openings to the mantle cavity.
Sulcus - A groove, furrow or channel.
Supra-anal opening - A dorso-posterior opening in the fused right and
left mantle margin in the anal region above the excurrent siphonal
opening. Present in the Amblemidae and Unionidae, but absent in the
Margaritiferidae.
Tachytictic - Refers to mussels that are short-term breeders, i.e., that
carry glochidial larvae in their gills only during the Nearctic summer.
Teeth - The opposing lamellae on the hinge plates of bivalved mollusks
which serve to stabilize the two valves against shearing forces. In the
Unionacea the anterior lamellae are called pseudocardinal teeth and the
posterior lamellae are called lateral teeth.
Transverse - In the same direction (i.e., parallel to) the growth lines
in a mussel shell; at right angles to radiating lines, which originate
at the beaks and run distally toward the shell periphery.
Truncate - Having the end cut off more or less squarely.
Tubercle - A nodule or small eminence, such as a solid elevation
occurring on the shell surface of some freshwater mussels.
Tuberculate (Tuberculoses Tubercled} Tubercular) - Covered with tubercles
or rounded knobs.
Umbo - The oldest part of the bivalved shell valve, formed by the em-
bryonic shell and around which the later shell is laid down distally in
a semi-concentric manner. The umbos can readily be identified as the
raised parts on the dorsal margin of each of the shell valves. Also
called "beak".
Undulation - A wavy form, resembling that of a wave or waves.
169
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Unionaoea (Unionoidea) - A superfamily of bivalved mollusks (class
Pelecypoda or Bivalvia, subclass Lamellibranchia, order Schizodonta)
living in freshwater and characterized by a schizodont hinge, the mantle
divided into two almost entirely separate flaps, a hatchet-shaped foot
and large leaflike gills behind the foot, which are used as marsupia to
brood eggs and larval young.
Valve - The single undivided shell of non-pelecypod mollusks, or one of
the opposing halves of the divided shell of a pelecypod mollusk. In
bivalved mollusks the two shell halves are held together at one margin
by an elastic ligament.
Wing - The dorsal, thin, flat extension of the posterior slope of some
freshwater mussels.
170
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SECTION VII
INDEX TO SCIENTIFIC NAMES
Aatinonaias, 2,19,138
oarinata oarinata3 19,138,139
oarinata gibba3 19,138,139
ellipsiformis, 19,138
pectorosa, 19,138
acutissimus, Medionidus3 21,101
alata3 Proptera3 22,136,137
Alasmidonta, Alasmidonta, 16,84
(Alasmidonta)3 2,16,81,84
aroula3 16,84,85
oaloeolus, 16,86,88,
heterodon3 16,88
marginata, 16,81,88
radiatus3 16,81
raveneliana3 16,81,82,89
triangulata3 16,86,87
undulata3 17,88,89
varioosa3 17,80,81,82,89
wrightiana, 17,86,87
(Pegias) fabula3 16,84,85
alberti, Cyprogenia, 23,96,97
aldriohianum3 Pleurobema, 14,59
altilis, Lampsilis, 20,145
alturn, Pleurobema, 14,52,53,54
amabile, Pleurobema, 14,59
ambiqua, Simpsonioonoha, 18,82
Amblema, 2, 11
oostata, 8,9,11,36
neislerii, 11,34,35
perplioata, 11,36
Amblemidae, 2,11,25
Ambleminae, 2,11
amphiehaena3 Leptodea, 21,134,135
angulata* Gonidea, 13,29
Anodonta3 2,5,17,72
beringiana, 17,79
californiensis 3 17,78,79
oataraota, 17,77
oouperiana3 17,72,73
degeota3 17,78,79
gibbosa3 17,74,75
grandis ocrpulenta, 17,74
grandis grandis, 17,75,79
grandis simpsoniana, 17,76,77
imbeoillus, 72,73
impliaata3 17,77
Anodonta kennerlyi, 17,75,81
oregonensis, 17,80,81
psggyae, 17,72,73
suborbioulata, 17,72
wahlametensis 3 18,78,79
Anodontinae, 2,16,44,72
Anodontoides, 2,18,72
ferussaaianus 3 18,76,77
radiatus, 18,80
anodontoides3 Lampsilis 3 20,105,143
aroaeformis3 Dysnomia3 19,122,123
araheri3 Quadrula3 12,39,40
Arcidens, 2,18
eonfragosuSj 18,83
arotata3 Wlliptio3 13,63,64
aroula3 Alasmidonta3 16,84,85
Arkansia, 2,18
wheeleri3 18,83,84
aurea3 Quadrula3 12,39,40
australis3 Lampsilis3 20,146
avallana, Pleurobema3 14,59
beringiana3 Anodontas 17,79
berlandierii3 Cyrtonaias 3 16,70
biemarginata3 Dysnomia3 19,110,124
binominata3 Lampsilis3 20,132,133,151,
153
braoteata3 Lampsilis3 20,145
brevidens 3 Dysnomia} 19,116
buokleyi3 Popenaias3 16,70,71
bulbosum3 Pleurobema, 14,59
bnrkei3 Quinouneina, 12,32,33
eaelata3 Lemiox, 21,99
oaloeolus 3 Alasmidonta3 16,86,88
aaliforniensis3 Anodonta3 17,78,79
Canthyria3 Elliptio, 14
oapax, Proptera, 22,136,137
oapsaeformis3 Dysnomia, 19,127
oarinata oarinata3 Aotinonaias3 19,
138,139
gibba, Aotinonaias, 19,138,139
oariosa3 Lampsilis3 20,151,152
Carunaulina3 2,6 ,19,105,140
parva3 19,104
pulla, 19,104,105
oataraota, Anodonta3 17,77
ohattanogaense3 Pleurobema3 14,56
171
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ohipolaensis 3 Elliptic*3 13,64,67
clax>a3 Pleurobema3 14,54,55
aollina3 Pleurobema (Lexingtonia)3
16,48,49,50
oomplanata3 Elliptic3 13,65
Lasmigona3 18,90
compressa3 Lasmigona3 18,91,92
eonaestator3 Villosa, 22,143
aonfragosusj AroidenSj 18,83
congaraea3 Elliptic)3 13,68
aonradious 3 Medionidus, 21,101
oonstriota3 Villosa3 22,142,143
eooperianuSj Plethobasus3 14,46
aor3 Fusconaia3 11,42
eordatum aoooinewn3 Pleurobema3 14,
57,58
aovdatvm, Pleurobemas 16,52,53
pauperculwn3 Pleurobema3 15,57,
58
pyramidatum3 Pleurobema3 15,52
aostata3 Amblema, 8,9,11,36
Lasmigona3 18,90
aouperiana3 Anodonta3 17,72,73
orassidens orassidens, Elliptio3
13,60,61
doimiei3 Elliptio3 13,60,61
Cumberlandia3 2,11
monodonta3 11,26
Cumberlandinae, 2,11
auneolus3 Fusaonaias 11,43
ourturn. Pleurobema3 15,55
Cyolonaias3 2,13
tuberaulata3 4,5,13,45
oylindrioa3 Quadrula3 12,30,31,37
ayphus3 Plethobasus3 14,46
Cyprogenia3 2,23,96
alberti, 23,96,97
ivrorata3 23,96,97
Cyrtonaias, 2,16,70
berlandierii3 16,70
dariensis 3 Elliptio 3 13,68,69
decision3 Pleurobema3 15,56
dejeata3 Anodonta3 17,78,99
delumbis, Villosa, 22,141
dilatata3 Elliptio3 13,62
dolabelloides3 Pleurobema (Lexing-
tonia) j 16,50
dolabraeformis3 Lampsilis, 20,130,
131,148,149,151
dombeyanus3 Pleotomerus, 12,37
donaoiformis, Trunoilla3 22,130,131
dromus3 Dromus3 23,98
Dromus3 2,23
dromus3 23,98
Dysnomia3 2,19,110,111
aroaefomie3 19,122,123
biemarginata3 19,110,124
brevidens3 19,116
aapsaeformis3 19,127
flexuosa3 19,110,111,122,124,126
florentina, 19,110,123
haysiana3 19,120,121
lenior3 19,118
lewisii3 19,112,112,126
metastriata, 19,116,117,126
penitas 19,119
personata3 19,125,126
propinqua3 19,124,125
stewardsoni3 19,113,126
sulcata3 19,121,126
torulosa3 19,110,114,115,126
triquetra3 20,115
turgidula, 20,121,122,128
ebenus, Fuseonaia3 12,41
Ellipsaria3 2,20
lineolata, 20,103
ellipsiformis, Aotinonaias3 19,138
Elliptio (Elliptio)3 2,9,13,48,62
arctata3 13,63,64
orassidens orassidens3 13,60,61
downiei3 13,60,61
ohipolaensis3 13,64,67
complanata3 13,65
aongax>aea3 13,68
dariensis3 13,68,69
dilatata, 13,62
fraterna3 13,62,63
hopetonensis, 14,66,67
ioterina, 14,65
jayensis, 14,66,67,68
laneeolata3 14,64,66
_nigella3 14,63
shepardiana3 14,60
waooamawensis3 14,68,69
Elliptio (Canthyria) spinosa3 14
Elliptio} Elliptio3 13,60
Elliptoideus, 2,11
sloatianus 3 11,30,32
exoavata3 Lampsilis, 20,131,148,149,
151
fabalis3 Villosa3 22,143
fabula3 Alasmidonta (Pegias)3 16,84,
85
172
-------
faloata3 Margaritifera3 11,27,28
fasaiola3 Lcanpsilis3 20,150,151
fasaiolare3 Ptyohobranohus3 23,94
favosum3 Pleurobema3 15,59
flava flava3 Fusaonaia3 12,43
undata3 Fusaonaia3 12,40
flavidulum, Pleuvobema3 15,59
flexuosa3 Dysnomia, 19,110,111,122,
124,126
florentina Dysnomia3 19,110,128
fovemanianum, Ptyahobranahus, 23,
94,95
fragilis, Leptodea3 21,135
fraterna3 Elliptic?3 13,62,63
furvum3 Pleuvobema, 15,59
Fusaonaia3 2,11,37
aor3 11,42
auneolus3 11,43
ehenus3 12,41
flava flava3 12,43
undata3 12,40
subrotunda3 12,41
sucaissa3 12,42,43
gibbosa3 Anodonta3 17,74,75
giganteus3 Megalonaias3 13,34
Glebula3 2,20
totundata3 20,102
Gonidea3 2,13
angulata3 13,29
Gonideinae, 2,13
gvandis aorpulenta3 Anodonta3 17,74
grandis3 Anodonta3 17,75,79
simpsoniana3 Anodonta3 17,76,77
greeni3 Ptyahobranahus} 23,95
hagleri3 Pleurobema3 15,59
hanleyanum3 Pleuvobema3 15,59
hai>peri3 Pleurobema3 15,59
haysiana, Dysnomia3 19,120,121
hembeli3 Margaritifera3 11,27
Hemistena3 2,14
latas 14,47,48
heterodon, Alasmidonta3 16,88
holstonia3 Lasmigona3 91
hopetonensis3 Elliptio3 14,66,67
hydiana3 Lampsilis3 20,147
iotevina3 Elliptio3 14,65
imbecillus3 Anodonta3 72,73
implicata, Anodonta3 11,11
infuriaata3 Quinaunoina3 12,32,33
intermedia3 Quadrula3 12,29,30,37
ivis3 Villosa3 22
ivrasum3 Pleuvobema3 15,57,59
irrorata3 Cyprogenia3 23,96,97
j aaksoniana3 Obovavia3 22, 110
jayensis3 Elliptio3 14,66,67,68
johcmnis3 Pleuvobema3 15,59
jonesi3 Lampsilis3 20,106,144
kennerlyi3 Anodonta3 17,75,81
laevissima, Leptodea3 21,135
Lampsilinae, 2,19,44,93
Lampsilis} 2,6,20,128,129,140,150
altilis3 20,145
anodontoides3 20,105,143
australis3 20,146
binominata3 20,132,133,151,153
br>aateata3 20,145
caviosa3 20,151,152
dolabraeformis3 20,130,131,148,
149,151
exaavata3 20,131,148,149,151
fasaiola, 20,150,151
hydiana3 20,147
jonesi3 20,106,144
oahvaaea3 20,151,153
orbioulata3 20,149,151
ovata ovata3 20,131,148,149
ventriaosa3 20,136,150,151
pevpasta3 21,132,133,151,152,153
vadiata radiata, 21,147
siliquoidea3 21,146
splendida3 21,132,133,144,149
straminea3 21,149,151
stveckevi3 21,144,143
subangulata3 21,106,143
lanceolata3 Elliptio3 14,64,66
Lasmigona3 2,18,84
aomplanata} 18,90
compressa3 18,91,92
aostata3 18,90
holstonia3 91
subviridis3 18,92
lata3 Hemistena3 14,47,48
Lemiox3 2,21
aaelata3 21,99
leniov3 Dysnomia3 19,118
Leptodea3 2,21,133
amphiahaena3 21,134,135
fvagilis3 21,135
laevissima3 21,135
leptodon3 21,134,135
leptodon3 Leptodea3 21,134,135
lewisii3 Dysnomia3 19,112,113,126
Lexingtonia3 Pleuvobema3 48
173
-------
lienosa, Villosa, 22,142,143
Ligumia, 2,21,106
nasuta, 21,106,107
recta, 21,106,107
lineolata, Ellipsaria, 20,103
macrodon, Truncilla, 2,22,128,129
Mccrgaritifera, 2,11,26
falcata, 11,27,28
hembeli, 11,27
margaritifera, 8,11,27,28
margaritifera, Margaritifera, 8
Margaritiferidae, 2,11,23,26
Margaritiferinae, 2,11
marginata, Alasmidonta, 16,81,88
marshalli, Fleurobema, 15,52,53
masoni, Fleurobema (Lexingtania),
16,50,51
mcglameriae, Medionidus, 21,100
Medionidus, 2,21,99
acutissimus, 21,101
conradieus, 21,101
mcglameriae, 21,100
penicillatus, 21,100
Megalonaiadinae, 13
Megalonaias, 2,13
giganteus, 13,34
meredithii, Pleurobema, 15,59
metanevra, Quadrula, 12,37,38
metastriata, dysnomia, 19,116,117,
126
modicum, Fleurobema, 15,59
monodonta, Cumberlandia, 11,26
rrrurrayense, Fleurobema, 15,59
nasuta, Ligumia, 21,106,107
nebulosa, Villosa, 23
neislerii, Amblema, 11,34,35
nigella, Elliptic, 14,63
nodulaba, Quadrula, 12,39
nucleopsis, Fleurobema, 15,59
mux, Fleurobema, 15,59
Obliquaria, 2,23
reflexa, 23,96
Obovaria, 2,22,107
jacksoniana, 22,110
olivaria, 22,108,109,110
retusa, 22,108,109
rotulata, 22,109
subrotunda, 22,108,109
unioolor, 22,109
occidentalis, Ptyohobranahus, 23,9
ochracea, Lampsilis, 20,151,153
olivaria, Obovaria, 22,108,109,110
orbiaulata, Lampsilis, 20,149,151
oregonensis, Anodonta, 17,80,81
ortmanni, Villosa, 23,143
ovata ovata, Lampsilis, 20,131,148,
149
ventriaosa, lampsilis, 20,136,150,
151
oviforme, Fleurobema, 15,57,58
parva, Carunoulina, 19,104
pectorosa, Aotinonaias, 19,138
peggyae, Anodonta, 17,72,73
Pegias, Alasmidonta, 17
penicillatus, Medionidus, 21,100
penita, Dysnomia, 19,119
pepovatum, Fleurobema, 15,57,59
perpasta, Lampsilis, 21,132,133,151,
152,153
perplicaba, Amblema, 11,36
personata, Dysnomia, 19,125,126
picta, Villosa, 23,141
Pleatomerus, 2,12
dombeyanus, 12,37
Flethobasus, 2,14,45
cooperianus, 14,46
ayphus, 14,46
Fleurobema, Fleurobema, 14,48
Fleurobema (Fleurobema), 2,14,48
aldrichianum, 14,59
altum, 14,52,53,54
amabile, 14,59
aoallana, 14,59
bulbosum, 14,59
chattanogaense, 14,56
clava, 14,54,55
cordatum coacineum, 14,57,58
cordatum, 15,52,53
pauperculum, 15,57,58
pyramidatum, 15,52
cur turn, 15,55
decision, 15,56
favosum, 15,59
flavidulum, 15,59
furvum, 15,59
hagleri, 15,59
hanleyamm, 15,59
haiperi, 15,59
irrasum, 15,57,59
johannis, 15,59
> marshalli, 15,52,53
meredithii, 15,59
174
-------
Pleurobema modicum,3 15,59
murrayense, 15,59
nucleopsis3 15,59
nux3 15,57,59
oviforme, 15,57,58
perovaturn, 15,57,59
pyriforme 15,59
reclusum3 15,57,59
rubellvm, 15,58
showalterii3 15,54
simulanSj 15,59
stabile, 15,59
striatum3 15
strodeamm3 15,58
tombigbeannm3 15
trosahelianum, 15,59
verum, 15,57,58
Pleurobema (Lexingtonia) collina,
16,48,49,50
do labelloid.es s 16,50
masoni, 16,50,51
Pleurobeminae, 2,13,44
popei3 Popenaias3 16,70,71
Popenaiadinae, 2,16,44,70
Popenaias3 2,16,70
buakleyi, 16,70,71
popei3 16,70,71
propinqua, Dysnomia3 19,124,125
propria3 ViIlosa, 23,143
Proptera3 2,22
alata., 22,136,137
capax, 22,136,137
purpurata, 22,137
Ptychobranahus3 2,23,93
fasaiolare3 23,94
foremaniamm, 23,94,95
greeni3 23,95
ocaidentalis 3 23,95
subtentum, 23,93
pulla3 Carunaulina3 19,104,105
purpurata3 Propteva3 22,137
pustulosa3 Quadrula3 12,39
pyriforme, Pleurobema3 15,59
Quadrula, 2,12,37
araheri, 12,39,40
aurea3 12,39,40
cylindriaa, 12,30,31,37
intermedia3 12,29,30,37
metanevra, 12,37,38
nodulata, 12,39
pustulosa3 12,39
Quadrula quadrula3 12,38
quadrula3 Quadrula3 12,38
Quincuncina3 2,12
burkei3 12,32,33
infuriaata, 12,32,33
radiata radiatas Lampsilis3 21,147
siliquoidea3 Lampsilis3 21,146
radiatus3 Alasmidonta^ 16,81
raveneliapia, Alasmidonta3 16,81,82,
89
reclusum3 Pleurobema3 15,57,59
recta, Ligumia3 21,106,107
reflexa, Qbliqua^ia3 23,96
retusa3 Obovaria, 22,108,109
rotulata, Obovaria, 22,109
rotundata, Glebula3 20,102
rubellum3 Pleurobema3 15,58
shepardiana3 Elliptio3 14,60
showalterii3 Pleurobema3 15,54
Sinrpsoniconcha, 2,18
ambiqua3 18,82
simulans, Pleurobema3 15,59
sloatianus3 Elliptaideus3 11,30,32
spinosa, Elliptic (Canthyria)3 14
splendida3 Lampsilis3 21,132,133,
144,149
stabile, Pleurobema3 15,59
stewardsoni3 Dysnomia3 19,113,126
straminea3 Lampsilis3 21,149,151
streckeri, Lampsilis3 21,144,145
striatum3 Pleurobema3 15
strodeanum3 Pleurobema3 15,58
Strophitus3 2,5,18,72
subvexus3 18,82
undulatus 3 19,76,77
subangulata3 Lampsilis3 21,106,143
suborbiculata3 Anodontas 17,72
subrotunda3 Pusaonaia3 12,41
Obovaria3 22,108,109
subtentum, Ptyahobranahus3 23,93
suhoexus3 Strophitus, 18,82
subviridus3 Lasmigona, 18,92
sucaissa3 Fusaonaia, 12,42,43
sulcata3 Dysnomia3 19,121,126
tetralasmus3 Uniomerus3 16,47
tombigbeanum, Pleurobema, 15
tovulosa3 Dysnomia3 19,110,114,115,
126
trabaliSj Villosa323,143
triangulata, Alasmidonta3 16,86,87
triquetra, Dysnomia3 20,115
175
-------
Tritogonia3 2,12
verrucosa, 12,30,31
troschelianum3 Pleurobema3 15,59
trunoata3 Trunailta3 22,129
Truneilla* 2,22,128,129
donaaiformis, 22,130,131,
macrodon, 22,130,131
tvunaata3 22,129
tubevaulata, Cyolonaias3 4,5,13,45
turgidula3 Dysnomia3 20,121,122,128
undulata.j A lasmidonta, 17,88,89
undulatus3 Strophitus, 19,76,77
uniaolor, Obovaria, 22,109
Uniomerus3 2,16
tetralasmus 3 16,47
Unionidae, 2,13,25,44
vanuxemensis3 ViIlosa3 23,143
varices a3 Alasmidonta3 17,80,81,82,
89
verrueosa3 Tritogonia, 12,30,31
verum3 Pleurobema, 15,57,58
vibex3 Villosa, 23,141
Villosa3 2,6,22,140
ocncestator3 22,143
constriata, 22.142,143
delwribiSj 22,141
fabatis, 22,143
iriss 22
lienosa3 22,142,143
nebulosa3 23
ortmanni3 23,143
piatas 23,141
propria3 23,143
trabalis, 23,142,143
vanuxemensis3 23,143
vibex3 23,141
villosa3 23,141
villosa, Villosa3 23,141
waccamawensis3 Elliptic3 14,68,69
wahlametensis3 Anodonta3 18,78,79
wheeleri3 Arkansia3 18,83,84
wrightiana3 Alasmidonta3 17,86,87
176
-------
SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
4. Tale BIOTA OF FRESHWATER ECOSYSTEMS IDENTIFICATION MANUAL
NO. 11 Freshwater Unionacean clams (Mollusca:Pelecypoda)
of North America,
A,ith.ir( a)
Burch, J. B.
9. Orgam-afion
Museum and Department of Zoology,
The University of Michigan,
Ann Arbor, Michigan
15. Sun I^menT^ry Na; cv
Project No.
18050 ELD
11. Comi&ci/Grant N
14-12-894
16 Abstract
Bivalved mollusks of the superfami'ly Unionacea (Order Schizodonta) are
represented in North America by three families, 46 genera, and,.as
treated in this key, 221 species. The primitive Margaritiferidae are
represented by two genera and four species, the Amblemidae by eight
genera and 25 species, and the very large family Unionidae by 36 genera
and 192 species. Systematics are not well worked out in many groups,
which makes a definitive listing of species somewhat arbitrary at this
time. The present key in most instances reflects a conservative approach
to the lower taxa and, although it omits many nominal species of doubt-
ful validity, the key nevertheless represents most of the biological
species.
Characters of soft anatomy are used to separate the families, subfamilies
and, in a few cases, genera. Species are separated by shell characters.
The main feature of this publication is an illustrated taxoriomic key using
both soft anatomy and shell characters for the identification of the
North American Unionacea.
17a. Descriptors
•Aquatic fauna, *Mollusks, *Pelecypods, *Mussels, Distribution
17 b. Identifiers
~Identification Manual, "Illustrated key, *Unionacea, *North America,
Species List
17c COWRR Field & Group
18. Availability
19.
SrCUTlt?
(Report)
run
Send To:
it
Secaritr Clasi.
fPufe)
2: Price
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U S DEPARTMENT OF THE INTERIOR
WASHINGTON, D C. 20240
ahstractor Burch, J.B. | institution The University of Michigan, Michigan
U S. GOVERNMENT PRINTING OFFICE • 1973 O - 503-367
------- |