New distributional records and rediscovery of three rare freshwater mussels (Bivalvia, Unionidae) in the Sequatchie River, Tennessee

Abstract

We present new drainage records for five freshwater mussels in the Sequatchie River, a tributary of the Tennessee River. We also report the rediscovery of Purple Lilliput, Toxolasma lividum Rafinesque, 1831, Tennessee Pigtoe, Pleuronaia barnesiana (Lea, 1838), and the federally endangered Slabside Pearlymussel, Pleuronaia dolabelloides (Lea, 1840), and we provide information on other mussel species found in our survey. In the Sequatchie River, T. lividum was last seen in 1957 and P. barnesiana and P. dolabelloides were last seen in 1980. The discovery of five new drainage records and rediscovery of three rare species highlights the need for additional mussel surveys in the Sequatchie River and the importance of surveys in conservation efforts.

Full text

NOTES ON GEOGRAPHIC DISTRIBUTION
© The authors. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original author and source are credited.
Check List 19 (4): 485–503.
https://doi.org/10.15560/19.4.485
4
19
New distributional records and rediscovery of three rare freshwater
mussels (Bivalvia, Unionidae) in the Sequatchie River, Tennessee
G R. D1*, B J. D2, H D. F2, R T. E2,
B M. M2
1 McClung Museum of Natural History and Culture, University of Tennessee, Knoxville, Tennessee, USA • gdinkins@utk.edu
2 Dinkin s Biological Cons ulting, LL C, Powell, Tennessee, USA • BJD: bd inki ns@dink insbiologica l.com • HDF: hfaust@d inki nsbiological.
com • RTE: reldridge@dinkinsbiological.com • BMM: bmize@dinkinsbiological.com
* Corresponding author
Abstract. We present new drainage records for ve freshwater mussels in the Sequatchie River, a tributary of the
Tennessee River. We also report the rediscovery of Purple Lilliput, Toxolasm a lividum Ranesque, 1831, Tennessee
Pigtoe, Pleuronaia barnesiana (Lea, 1838), and the federally endangered Slabside Pearlymussel, Pleuronaia dola-
belloides (Lea, 1840), and we provide information on other mussel species found in our survey. In the Sequatchie
River, T. lividum was last seen in 1957 and P. barnesiana and P. dolabelloides were last seen in 1980. e discovery
of ve new drainage records and rediscovery of three rare species highlights the need for additional mussel surveys
in the Sequatchie River and the importance of surveys in conservation eorts.
Keywords. Conservation easements, endangered, endemic mussels, extirpated species
Academic editor: Igor Christo Miyahira
Received 23 January 2023, accepted 28 June 2023, published 12 July 2023
Dinkins GR, Dinkins BJ, Faust HD, Eldridge RT, Mize BM (2023) New distributional records and rediscover y of three rare freshwa-
ter mussels (Bivalvia, Unionidae) in the Sequatchie River, Tennessee. Check List 19 (4): 485–503. https://doi.org/10.15560/19.4.485
Introduction
North America has the highest diversity of freshwater
mussels in the world, and the freshwater and terrestri-
al gastropod fauna is among the richest (Johnson et al.
2013; Williams et al. 2017; Bouchet and Rocroi 2005).
Interest in the taxonomy, distribution, and conserva-
tion of freshwater mussels (order Unionida, families
Margaritiferidae and Unionidae) of the USA and Can-
ada has increased over the last 50 years, due in part to
the passage of the U.S. Endangered Species acts of 1966,
1969, and 1973 and the Canadian Species at Risk Act of
2002 (Williams et al. 2017). Recent research has shown
approximately 74% of freshwater gastropods in these
two countries are imperiled (Johnson et al. 2013), and
the rate of imperilment in freshwater mussels is nearly
identical (Jim Williams, U.S. Geological Survey, retired,
unpubl. data). Within the USA, Alabama and Tennes-
see have the richest mussel faunas with approximately
190 species currently recognized in Alabama (Williams
et al. 2008) and 141 species recognized in Tennessee (G.
Dinkins unpubl. data). ese two states have lost the
most mussel species to extinction (Alabama—22 spe-
cies, Tennessee—16 species) (Williams et al 2008; Par-
malee and Bogan 1998) and have the greatest number
of mussels on the federal list of threatened and endan-
gered species (Alabama—67, Tennessee—51) (U.S. Fish
and Wildlife Service 2023).
With 104 species of freshwater mussels, the Tennes-
see River system is the most diverse in North Ameri-
ca (Haag 2012). e Tennessee River begins in eastern
Tennessee at the conuence of the French Broad and
Holston Rivers and ows southwest into Alabama
before turning west and northward and owing into
the Ohio River in western Kentucky. Its largest tribu-
taries include the Clinch, Powell, Emory, Little, Little
Tennessee, Hiwassee, Sequatchie, Paint Rock, Elk, Buf-
falo, and Duck Rivers (Fig. 1).
e earliest collection of mussels in the Sequatchie
River drainage was by Ortmann (1925) who reported

486 Check List 19 (4)
a total of 12 species from three locations on the main
channel, one location on the Little Sequatchie River,
and one location in an unnamed tributary. Hatcher
and Ahlstedt (1982) reported 11 species at 10 sites in
the lower reaches of the main channel. Gordon (1991)
found 18 species at sites on the main channel and sev-
eral tributaries and described the channel as being
heavily silted and impacted by poor land-use practices.
Gordon (1991) also found the river to be nearly devoid
of mussels from km 72 to 128, with several species pres-
ent only as relict shells or represented by only one or
two living individuals. Since 1990, the Tennessee Valley
Authority (TVA) has monitored water quality and the
benthic macroinvertebrate community at eight xed
sites in the Sequatchie River between river km 11.4
and 179.1. Dead mussel shells found at these sites have
occasionally been retained (Je Simmons, TVA, pers.
comm.) and most are housed at the University of Ten-
nessee’s McClung Museum of Natural History and Cul-
ture (MMNHC).
In 2018, a 73-ha tract of land bordering 1.7 km of
the right descending bank of the Sequatchie River
between river km 23.6 and 25.3 was placed into a per-
manent conservation easement. We were tasked with
documenting the aquatic biodiversity in the wetlands
and open water bodies on the parcel and in the main
channel of the Sequatchie River bordering the conser-
vation easement property. Herein, we report the results
of a survey of a short reach of the Sequatchie River, dis-
cuss ve new drainage records and the rediscovery of
three rare species, and provide recommendations for
future research.
Study Area
e Sequatchie River drains parts of Bledsoe, Cum-
berland, Grundy, Marion, Sequatchie, and Van Buren
counties and originates from Head of Sequatchie
Spring in Devilstep Hollow. From its source, the riv-
er ows southwest for 293 km to the conuence with
the Tennessee River a few kilometers downstream of
Walden Gorge, a geographic feature long recognized
to be a distributional barrier to numerous mussel
species (Ortmann 1918, 1925). e Sequatchie Valley
remains narrow throughout its length (averaging less
than 8 km wide) and divides Walden Ridge from the
southern part of the Cumberland Plateau. Because of
the narrow valley the Sequatchie River ows through,
all tributaries are third order or smaller, except
for the Little Sequatchie River, and most are small,
spring inuenced, and have a high to medium gradi-
ent. ere are three low-head dams on the Sequatchie
Figure 1. Map of the Tennessee River drainage in Tennessee, Virginia, North Carolina, Georgia, Alabama, Mississippi, and Kentucky.
Signicant rivers are as follows: A = Powell, B = Clinch, C = Holston, D = French Broad, E = Little, F = Tennessee, G = Emory, H = Little
Tennessee, I = Hiwassee, J = Sequatchie, K = Paint Rock, L = Elk, M = Bualo, and N = Duck.

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 487
River, otherwise the main channel is free-owing
except for the lower 7.2 km which are impounded by
Guntersville Reservoir. e towns of Pikeville, Dun-
lap, and Whitwell each have a permitted Wastewa-
ter Treatment Plant discharging to the Sequatchie
River at river km 202.9, 113.8, and 59.5, respectively.
ere are several permitted mining facilities in the
watershed, but all have been inactive for many years
(Craig Walker, Oce of Surface Mining, retired, pers.
comm.). e Tennessee Department of Environment
and Conservation (TDEC) considers the Sequatchie
River between its conuence with the Tennessee Riv-
er and the mouth of the Little Sequatchie River, along
with several tributaries, to be “Exceptional Tennes-
see Waters” as dened by Rule Chapter 0400-40-3-
06-4(a)3. However, this is because the lower reach of
the Sequatchie River is designated as critical habitat
for one or more populations of federally listed threat-
ened or endangered aquatic animals, not because of
exceptional water quality. In fact, TDEC considers
segments of the Sequatchie River and several tributar-
ies to be impaired by point and non-point source sedi-
mentation, stream-side habitat alteration, high levels
of Escherichia coli, and mercury (Hg) levels in sh tis-
sue (TDEC 2023).
Methods
On 7 July 2021 we investigated the Sequatchie River
between Ketner Mill (river km 27.4) to the upstream
boundary of the conservation easement property at
river km 25.3 (Fig. 2). e purpose of the trip was to
identify access points, assess depths, and determine
equipment necessary for a subsequent and more sub-
stantial survey using a larger eld crew. During this
reconnaissance, fresh dead shells lying along the shore-
line and on exposed surfaces were gathered. On 28 and
29 July 2021, we returned and conducted a series of
searches for freshwater mussels in the Sequatchie River
from km 24.7 to 25.3. In this reach, maximum depth
was 4 m and the wetted width of the channel averaged
30 m. Substrates were dominated by gravel and cobble,
with sand and boulders present. Underwater visibility
averaged 2 m and ow averaged 5.1 m3/sec at the U.S.
Geological Survey gage (No. 03571000) near Whit-
well, Tennessee, approximately 15 river km upstream.
Deeper areas (generally in the middle of the channel)
were visually searched by two divers spaced 5–10 m
apart using a surface supplied air system. Shallow mar-
gins were visually searched by a person on each side
of the channel using a mask and snorkel. As the sur-
vey team progressed upstream, live mussels and dead
Figure 2. Map showing the segment of Sequatchie River, Marion County, Tennessee surveyed for mussels in this study. Survey
segment began at Ketner Mill, river km 27.4 and extended downstream to river km 24.7.

488 Check List 19 (4)
shells were removed from the substrate and tempo-
rarily held underwater in mesh bags. e survey team
moved in unison and stopped periodically to identify
and count live mussels and dead shells. Live mussels
were measured to the nearest millimeter (long axis).
Photographs were taken of live mussels before they
were carefully reinserted into the substrate. Fresh dead
shells were dened as those having traces of so tissue
remaining inside the shell or had lustrous nacre and an
intact periostracum. Weathered dead and relict shells
were combined and were dened as those without trac-
es of so tissue inside the shell, and with chalky or non-
lustrous nacre and the periostracum mostly or entirely
eroded. Most of the fresh dead shells and some relict
shells encountered in the survey were cleaned, labeled,
and catalogued at MMNHC. Additional photographs
were taken in the museum of the species representing
new drainage records. We follow the nomenclature of
Williams et al. (2017), Watters (2018), and the Fresh-
water Mollusk Conservation Society checklist of names
(2021), except we combined Lampsilis cardium Ran-
esque 1820, Plain Pocketbook and Lampsilis ovata (Say,
1817), Pocketbook into a single taxon (L. ovata) for the
reasons given by Williams et al. (2008). Fieldwork for
this survey was conducted under permits issued to
Gerald Dinkins (Tennessee Wildlife Resources Agen-
cy, Scientic Collecting Permit 1837, and U.S. Fish and
Wildlife Service, Native Endangered and reatened
Species Recovery Permit TE069754-6).
To assess the historical record of mussels in the
Sequatchie River, we searched les and the mollusk
database at MMNHC, and we conferred with our col-
leagues at the U.S. Fish and Wildlife Service (USFWS),
TVA, and the Tennessee Wildlife Resources Agency
(TWRA). We utilized the InvertEBase website (https://
invertebase.org/portal/) to query other mollusk col-
lections for records from the Sequatchie River, and we
contacted the collection manager at e Ohio State
University Museum of Biological Diversity (OSUM)
and the North Carolina State Museum of Natural Sci-
ences (NCSMNS) for information in their respective
collections not available through InvertEBase. We pre-
sumed all Sequatchie River specimens in these databas-
es are correctly identied.
Results
In our survey of a short reach of the Sequatchie River,
we found 438 live mussels and 464 dead shells repre-
senting 22 species from one order, Unionida, and one
family, Unionidae (Table 1, Fig. 3). Dead shells were
common on exposed surfaces between river km 25.3
and 27.4; most appeared to have been killed by musk-
rats. Between river km 24.7 and 25.3, live mussels and
dead shells were evenly distributed and were present in
all habitats.
T
Class Bivalvia Linnaeus, 1758
Order Unionida Gray, 1854
Family Unionidae Ranesque, 1820
Amblema plicata (Say, 1817)
reeridge
Fig ure 3A
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1299°N, –85.5235°W; river km 25.1; 28.VII.2021;
G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T. Eldridge,
B.M. Mize leg.; 3 sex indeterminate (indet.), 45 mm
MMNHC 20948.
Identication. We identied three dead Amblema pli-
cata based on the dark periostracum, white nacre, solid
and rounded shell outline, and medium size. Important
diagnostic characters include the prominent beak and
deep beak cavity. e exterior surface has several gen-
erally parallel ridges or folds emanating from the center
of the shell and extending posteriorly. e pseudocardi-
nal teeth are large, rough, and thick, the lateral teeth are
moderately long and straight. Amblema plicata can be
distinguished from Megalonaias nervosa (Ranesque,
1820), Washboard, by its more rounded shape and the
lack of sculpturing anteriorly to the umbo.
Table 1. Freshwater mussels found in the Sequatchie River,
river km 24.7–27.4, Marion County, Tennessee, 7 and 28 July
2021. Number of live individuals followed by the number of
fresh dead in parentheses and the combined number of relict
and weathered dead shells in brackets. P = proposed; LE =
Listed endangered.
Species Number collected Federal status
Amblema plicata (1) [ 2]
Cambarunio iris 5 (42) [55]
Cyclonaias pustulosa 27 (6) [25]
Cyclonaias tuberculata 292 (32) [22]
Ellipsaria lineolata (1) [ 1]
Elliptio crassidens 13[9]
Eurynia dilatata 1 (1)
Lampsilis fasciola 6 (4) [14]
Lampsil is ovata 18 (2) [2]
Lasmigona costata 4 (1)
Leaunio vanuxemensis 4 (27) [46]
Ligumia recta [3]
Megalonaias nervosa 3[1]
Obliquaria reexa 2 (4) [2]
Pleurobema cordatum 1
Pleuronaia barnesiana 3 (14) [1] P
Pleuronaia dolabelloides 8 (1) [3] LE
Potamilus alatus 5 (3) [3]
Ptychobranchus fasciolaris 33 (8) [9]
Theliderma metanevra 1
Toxolasma lividum 12 (53) [61]
Tritogonia verrucosa (5)
Total found: 438 (205) [259]

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 489
Figure 3. Freshwater mussels collected from Sequatchie River between river km 27.4 and 24.7. A. Amblema plicata. B. Cambarunio
iris (male). C. Cambarunio iris (female). D. Cyclonaias pustulosa. E. Cyclonaias tuberculata. F. Ellipsaria lineolata. G. Elliptio crassidens.
H. Eurynia dilatata. I. Lampsilis fasciola (male). J. Lampsilis fasciola (female). Scale bars = 25 mm [continued on next page].

490 Check List 19 (4)
Figure 3 [continued]. Freshwater mussels collected from Sequatchie River between river km 27.4 and 24.7. K. Lampsilis ovata
(male). L. Lampsilis ovata (female). M. Lasmigona costata. N. Leaunio vanuxemensis (male). O. Leaunio vanuxemensis (female). P.
Ligumia recta. Q. Megalonaias nervosa. R. Obliquaria reexa. Scale bars = 25 mm [continued on next page].

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 491
Figure 3 [continued]. Freshwater mussels collected from Sequatchie River between river km 27.4 and 24.7. S. Pleurobema cor-
datum. T. Pleuronaia barnesiana. U. Pleuronaia dolabelloides. V. Potamilus alatus. W. Ptychobranchus fasciolaris. X. Theliderma
metanevra. Y. Toxolasma lividum. Z. Tritogonia verrucosa. Scale bars = 25 mm.

492 Check List 19 (4)
Geographical distribution. Amblema plicata is widely
distributed throughout the Mississippi River basin and
its distribution extends northward into the Hudson Bay
and Great Lakes (Dawley 1947; Burch 1975) and in the
Gulf drainages from the Choctawhatchee River to the
Nueces River (Williams et al. 2008). In Tennessee, A.
plicata has been reported from nearly every major trib-
utary to and the mainstem of the Tennessee and Cum-
berland Rivers and several of the direct tributaries to
the Mississippi River. Gordon (1991) reported relict
shells of A. plicata from ve locations in the Sequatchie
River and a single live individual from one location.
e species typically occurs in gravel and sand sub-
strates in shoals and pools of large creeks and rivers and
can be found in reservoirs where there is current and
rm substrates (Parmalee and Bogan 1998; Williams et
al. 2008). Based on scarcity of live individuals found by
Gordon (1991) and the lack of live individuals in our
survey eort, the status of A. plicata in the Sequatchie
River is uncertain.
Comments. Two relict single valves were not retained
or measured due to their degraded condition.
Cambarunio iris (Lea, 1829)
Rainbow
Figure 3B, C
Material examined. UNITED STATES OF AMER-
ICA – Tennessee • Sequatchie River, Marion Coun-
ty; 35.1267°N, –85.5244°W; river km 24.7–25.3;
28.VII.2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust,
R.T. Eldridge, B.M. Mize leg.; 26 ♂ 52–65 mm, 3 ♀
41–45 mm, MMNHC 18653; 35.14067°N, –85.52226°W;
river km 25.3–27.4; 7.VII.2021; B.J. Dinkins, H.D. Faust
leg.; 30 ♂ 41–74 mm, 7 ♀ 39–48 mm, MMNHC 18645.
Identication. We identied ve live and 97 dead Cam-
barunio iris based on the small, thin shell that is elon-
gate and compressed, and broadly rounded posterior
and sharply rounded anterior ends, and straight to con-
vex ventral margin. Important diagnostic characters
include punctuated rays emanating from the beak and
extending to or nearly to the ventral margin. Important
internal shell characters include pseudocardinal teeth
that are small and compressed, and lateral teeth that
are thin and moderately short. e nacre color is vari-
able. e species is distinguished from young Ptycho-
branchus fasciolaris (Ranesque, 1820) by the thin shell
and delicate lateral teeth.
Geographical distribution. e range of Cambarun-
io iris was revised by Watters (2018). It is reported to
occur in tributaries to the Great Lakes, upper Ohio
River basin, and the Tennessee River system above Tus-
cumbia, Alabama. In the Sequatchie River, Hatcher
and Ahlstedt (1982) reported Villosa taeniata (Conrad,
1834) from two locations, and Gordon (1991) reported
Villosa nebulosa from six locations. We assume spec-
imens of V. taeniata reported by Hatcher and Ahlst-
edt (1982) and specimens of V. nebulosa reported by
Gordon (1991) represent C. iris based on their similar-
ity in appearance.
Comments. Numerous relict specimens of C. iris were
not retained due to their degraded condition.
Cyclonaias pustulosa (L ea, 18 31)
Pimpleback
Figure 3D
Material examined. UNITED STATES OF AMER-
ICA – Tennessee • Sequatchie River, Marion Coun-
ty; 35.1267°N, –85.5244°W; river km 24.7–25.3;
28.VII.2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust,
R.T. Eldridge, B.M. Mize leg.; 51 sex indet., 41–52 mm,
MMNHC 20949; 35.14067°N, –85.52226°W; river km
25.3–27.4; 7.VII.2021; B.J. Dinkins, H.D. Faust leg. 7 sex
indet., 30–52 mm, MMNHC 18651.
Identication. We identied 27 live and 31 dead
Cyclonaias pustulosa based on the solid, inated, pus-
tulose shell combined with the full, rounded beaks that
exceed the shell outline. e periostracum is smooth
and light brown. On small to medium-sized individ-
uals, a squarish green bar expands ventrally from the
beak. Important internal shell characters include heavy,
triangular pseudocardinal teeth, short, curved later-
al teeth, exceptionally deep beak cavity, and a pearly
white nacre. Cyclonaias pustulosa is distinguished from
Cyclonaias tuberculata (Ranesque, 1820) by its white
nacre and the presence of a green bar emanating from
the beak.
Geographic distribution. Cyclonaias pustulosa is
widely distributed from the eastern reaches of the Great
Lakes, Lake St. Clair and Lake Erie, and through the
Mississippi River Basin from western New York west to
South Dakota (Parmalee and Bogan 1998; Williams et
al. 2008) and south to Louisiana (Howells et al. 1996;
Vidrine 1993). A recent genetic analysis by Johnson et
al. (2018) expanded the range of C. pustulosa to include
the Gulf Coast rivers from the Pascagoula River sys-
tem in Mississippi west to the Nueces River system in
southwest Texas. In Tennessee, C. pustulosa occurs
in most medium-sized to large rivers (Parmalee and
Bogan 1998). e species was not reported from the
Sequatchie River by Hatcher and Ahlstedt (1982). Gor-
don (1991) reported nding relict shell of C. pustulosa
at two locations. Our survey is the rst to report live C.
pustulosa in the Sequatchie River. Multiple size classes
were observed.
Comments. Numerous fresh dead specimens of C. pus-
tulosa were not retained because of the large number
encountered.
Cyclonaias tuberculata (Ra nesque, 1820)
Purple Wartyback
Figure 3E
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 493
Eldridge, B.M. Mize leg.; 292 sex indet., 26–82 mm,
MMNHC 18625; 35.14067°N, –85.52226°W; river km
25.3–27.4; 7.VII.2021; B.J. Dinkins, H.D. Faust leg. 22
sex indet., 28–60 mm, MMNHC 18661.
Identication. We identied 292 live and 54 dead
Cyclonaias tuberculata based on the solid, somewhat
compressed, pustulose shell combined with rounded
beaks that barely exceed the shell outline. e perio-
stracum is semi-glossy, light brown, and unrayed.
Important internal shell characters include heavy, tri-
angular pseudocardinal teeth, short, straight lateral
teeth, exceptionally deep beak cavity, and a deep-pur-
ple nacre. Cyclonaias tuberculata is distinguished from
C. pustulosa by its deep-purple nacre and the absence of
a green bar emanating from the beak.
Geographic distribution. Cyclonaias tuberculata oc-
curs in parts of the Great Lakes basin and is widespread
in the upper and middle Mississippi River basin (Clarke
1981; Parmalee and Bogan 1998). In Tennessee, the spe-
cies is found in the main channels of the Tennessee and
Cumberland Rivers and in most of the major tributar-
ies (Parmalee and Bogan 1998). e species was not re-
ported by Hatcher and Ahlstedt (1982). Gordon (1991)
reported relict shells of C. tuberculata at three loca-
tions and a live but very old individual at one location.
Cyclonaias tuberculata was the most common species
found in our survey and was represented by numerous
size classes.
Comments. Numerous dead specimens of C. tuber-
culata were not retained because of the large number
encountered.
Ellipsaria lineolata (Ranesque, 1820)
Buttery
Figure 3F
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 2 sex indet., 2 ♂ 68, 70 mm,
MMNHC 18664.
Identication. We identied two dead Ellipsaria
lineolata based on the heavy, compressed, subtriangu-
lar shell, light brown periostracum, presence of faint
chevrons emanating from the beaks and terminating at
the ventral margin, sharp posterior ridge, and medium
size. Important diagnostic characters include the lack
of a prominent beak and shallow beak cavity. e pseu-
docardinal teeth are triangular and heavy, the lateral
teeth are short and curved, and the beak cavity is mod-
erately deep. Ellipsaria lineolata can be distinguished
from Elliptio crassidens (Lamarck, 1819) by its less elon-
gated shell, sharp posterior ridge, presence of chevrons,
and white nacre.
Geographic distribution. Ellipsaria lineolata is wide-
spread in the Mississippi River basin, from Pennsylva-
nia to Minnesota south to Ohio River basin (Simpson
1900; Parmalee and Bogan 1998) and in the Mobile
River basin in Alabama, Georgia, and Mississippi (Wil-
liams et al. 2008; Jones et al. 2021). In Tennessee, E. lin-
eolata is widespread in the Tennessee and Cumberland
Rivers and in several of their major tributaries. e
species was not found by Hatcher and Ahlstedt (1982)
and Gordon (1991) found only a single relict valve at
one location. We found one relict valve and one fresh
dead specimen, indicating the species is extant in the
Sequatchie River but very rare.
Elliptio crassidens (Lamarck, 1819)
Elephantear
Figure 3G
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 22 sex indet., 96–140 mm,
MMNHC 20950.
Identication. We identied 13 live and nine dead
Elliptio crassidens based on the heavy, unrayed, sub-
triangular shell, dark brown to blackish periostracum,
and medium to large size. Important internal shell
characteristics include a shallow beak cavity, beaks that
do not interrupt the shell outline, heavy pseudocardi-
nal and lateral teeth, and faint to dark purple nacre.
Elliptio crassidens can be distinguished from Eurynia
dilatata (Ranesque, 1820) by its slightly more inat-
ed and heavier shell, more robust pseudocardinal teeth,
and darker nacre.
Geographic distribution. Elliptio crassidens is wide-
spread in the Mississippi River basin, south to Louisi-
ana (Watters at al. 2009; Williams et al. 2008; Vidrine
1993). e species occurs in Gulf Coast drainages in
Mississippi, Louisiana, Alabama, Georgia, and Florida
(Jones et al. 2021; Williams et al. 2008; Vidrine 1993;
Williams et al. 2014). In Tennessee, E. crassidens occurs
in the Tennessee and Cumberland River drainages, and
their larger tributaries, and in the Loosahatchie River
in West Tennessee (Parmalee and Bogan 1998). In the
Sequatchie River, the species was not found by Hatcher
and Ahlstedt (1982), and Gordon (1991) found only a
single relict valve at one location. We found 13 live indi-
viduals and nine relict shells. All were large individuals
indicating the species may not be reproducing in the
reach we surveyed.
Eurynia dilatata (Ranesque, 1820)
Spike
Figure 3H
Material examined. UNITED STATES OF AMER-
ICA – Tennessee • Sequatchie River, Marion Coun-
ty; 35.1267°N, –85.5244°W; river km 24.7–25.3;
28.VII.2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust,
R.T. Eldridge, B.M. Mize leg.; 2 sex indet., 59–65 mm,
MM NHC 20951.
Identication. We identied one live and one dead E.
dilatata based on the compressed shell with a slight-

494 Check List 19 (4)
ly convex ventral margin, pointed posterior margin,
and rounded anterior margin. Important diagnostic
characters include lack of prominent beaks, and dark,
cloth-like periostracum. Eurynia dilatata can be dis-
tinguished from Ligumia recta (Lamarck, 1819) by its
more compressed shell and purple nacre.
Geographical distribution. Eurynia dilatata is distrib-
uted from the Great Lakes basin and St. Lawrence Riv-
er, and in the Mississippi River basin south to northern
Louisiana (Parmalee and Bogan 1998; Vidrine 1993).
In Tennessee, the species occurs in small to large rivers
throughout the Tennessee and Cumberland River sys-
tems (Parmalee and Bogan 1998). Live E. dilatata were
found at multiple locations in the Sequatchie River by
Hatcher and Ahlstedt (1982) and Gordon (1991).
Lampsilis fasciola Ranesque, 1820
Wavyrayed Lampmussel
Figure 3I, J
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 13 ♀ 51-60 mm MMNHC
18646; 35.14067°N, –85.52226°W; river km 27.4; 7.VII.
2021; B.J. Dinkins, H.D. Faust; leg.; 2 ♂ 58, 59 mm, 2 ♀
51, 65 mm MMNHC 18647.
Identication. We identied six live and 18 dead Lamp-
silis fasciola based on the thin shell, medium size, glossy
periostracum densely patterned with ne wavy lines
that are not interrupted at the annual growth lines, and
rounded beaks that break the shell outline. Important
internal diagnostic characters moderate beak cavity,
widely diverging pseudocardinal teeth, short, curved
lateral teeth, and white or bluish-white nacre. Lampsilis
fasciola can be distinguished from Lampsilis ovata (Say,
1817) by the presence of the wavy rays on the periostra-
cum and the more rounded beak.
Geographic distribution. Lampsilis fasciola occurs
in parts of the Great Lakes basin. e species occurs
throughout the Ohio River basin but does not occur
west of the Mississippi River (Watters et al. 2009). In
Tennessee, L. fasciola occurs in small creeks to medi-
um-sized rivers in the Tennessee and Cumberland Riv-
er systems (Parmalee and Bogan 1998). Hatcher and
Ahlstedt (1982) reported a single live L. fasciola and
Gordon (1991) found relict shells at two locations and
an unreported number of live individuals at one loca-
tion. We found dead L. fasciola representing numerous
size classes.
Lampsilis ovata (Say, 1817)
Pocketbook
Figure 3K, L
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 20 sex indet.; 35.14067°N,
–85.52226°W; river km 25.3–27.4; 7.VII.2021; B.J. Din-
kins, H.D. Faust leg. 1 ♂ 111 mm, 1 ♀ 100 mm, MMN-
HC 18652 .
Identication. We identied 18 live and four dead L.
ovata based on the glossy yellow periostracum, thin
and oval shell outline, convex ventral margin, inat-
ed beaks, dened posterior ridge, and medium to large
size. Important internal shell characters include well
developed pseudocardinal teeth, short, curved later-
al teeth, open and deep beak cavity, and white nacre.
Lampsilis ovata can be distinguished from L. fasciola by
the lack of rays on the periostracum and a higher, more
full inated beaks.
Geographical distribution. Lampsilis ovata occurs in
most of the Ohio River basin (Strayer and Jerka 1997;
Cummings and Mayer 1992; Williams et al. 2008). In
Tennessee, the species is found throughout the Tennes-
see and Cumberland River systems and in the direct
tributaries to the Mississippi River (Parmalee and
Bogan 1998). Live, fresh dead, or relict Lampsilis ovata
were reported by Hatcher and Ahlstedt (1982) at sever-
al locations in the Sequatchie River, and Gordon (1991)
reported relict shells of L. cardium/ovata at four loca-
tions. We found live individuals of L. ovata represent-
ing several size classes.
Lasmigona costata (Ranesque, 1820)
Flutedshell
Figure 3M
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 4 sex indet., 100–130 mm,
MMNHC 20952.
Identication. We identied four live and one dead
Lasmigona costata based on the medium-sized, com-
pressed shell with greenish periostracum, beaks that do
not break the shell outline, and distinct plications radi-
ating from the posterior ridge to the posterior margin.
Lasmigona costata can be distinguished from Tritogo-
nia verrucosa (Ranesque, 1820) by the lack of sculp-
turing on the shell anterior to the posterior ridge, lack
of a sulcus, and by having a posterior ridge that is not
inated ventrally.
Geographical distribution. Lasmigona costata is wide-
spread, occurring in the Great Lakes basin and Hud-
son River system, and the entire Mississippi River basin
from Minnesota south to Arkansas (Clarke 1985). In
Tennessee, it occurs in small to medium-sized tribu-
taries to, and the main channel of, the Tennessee and
Cumberland Rivers (Parmalee and Bogan 1998). e
species was not found in the Sequatchie River by Hatch-
er and Ahlstedt (1982), and Gordon (1991) found only
relict valves at ve locations.

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 495
Leaunio vanuxemensis (Lea, 1838)
Mountain Creekshell
Figure 3N, O
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 6 ♂ 48–65 mm MMNHC
18662; 35.14067°N, –85.52226°W; river km 25.3–27.4; 7.
VII.2021; B.J. Dinkins, H.D. Faust leg. 11 ♂ 43–58 mm,
9 ♀ 41–57 mm MMNHC 18666.
Identication. We identied four live and 73 dead L.
vanuxemensis based on the dark periostracum, elon-
gate/elliptical shell outline, and small size. Important
diagnostic characters include the presence of faint, thin
rays on the posterior half of the shell, lack of a promi-
nent beak, shallow beak cavity, and bronze to purple
nacre. e pseudocardinal teeth are small and trian-
gular and the lateral teeth are thin, short, and straight.
Leaunio vanuxemensis is strongly dimorphic. Female
shells are more inated and have a biangulate posterior
margin, while male shells have a narrowly rounded pos-
terior margin. e species can be distinguished from
Eurynia dilatata by its more inated and thinner shell,
and its strong dimorphism. Leaunio vanuxemensis can
be distinguished from C. iris by having rays restricted
to the posterior half of the shell, darker periostracum,
and bronze to purple nacre.
Geographical distribution. Leunio vanuxemensis is
widely distributed in the Tennessee, Duck, and Cum-
berland River systems of Virginia, North Carolina,
Tennessee, Georgia, Alabama, Mississippi, and Ken-
tucky (Parmalee and Bogan 1998; Williams et al. 2008;
Watters 2018; Jones et al. 2021). In Tennessee, L. vanux-
emensis is found in small creeks to medium rivers,
although it is more common in headwaters (Parmalee
and Bogan 1998). Hatcher and Ahlstedt (1982) reported
a single live individual at one main channel location in
the Sequatchie River, and Gordon (1991) found live and
relict valves of L. vanuxemensis at three locations each
in the main channel of the Sequatchie River.
Taxonomic remarks. Leaunio vanuxemensis is cur-
rently the subject of range-wide molecular analysis to
determine its relationship and distribution relative to
other species of Leaunio, especially Leaunio ortmanni
(Walker, 1925) (Kuehnl 2009; Watters 2018; Jess Jones,
USFWS, pers. comm.).
Comments. Numerous dead specimens of L. vanuxe-
mensis were not retained because of the large number
encountered.
Ligumia recta (Lamarck, 1819)
Black Sandshell
Figure 3P
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.2021;
G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T. Eldridge,
B.M. Mize leg.; 2 ♂, 120, 130 mm, MMNHC 18634.
Identication. We identied three dead Ligumia rec-
ta based on the dark periostracum, solid and elongate/
elliptica l shell outline, and medium to large size. Impor-
tant diagnostic characters include the lack of a promi-
nent beak and shallow beak cavity. e pseudocardinal
teeth are triangular, the lateral teeth are elongate and
straight, and the pallial line is impressed anteriorly.
Ligumia recta can be distinguished from Eurynia dila-
tata by its more inated shell, thicker pseudocardinal
teeth, and white nacre.
Geographical distribution. Ligumia recta is widely
distributed throughout the Mississippi River basin and
its distribution extends northward into the St. Law-
rence River system (Parmalee and Bogan 1998). On the
Gulf Slope, L. recta occurs in the Mobile River Basin of
Alabama and Mississippi and the Pearl River basin in
Mississippi and Louisiana (Williams et al. 2008; Jones
et al. 2021). In Tennessee, L. recta has been reported
from nearly every major tributary to and the main-
stem of the Tennessee and Cumberland Rivers and
has been reported from the Tennessee River a few km
downstream of the mouth of the Sequatchie River (Par-
malee and Bogan 1998). e species typically occurs in
medium-sized to large rivers where there is strong cur-
rent and coarse sand and gravel with cobble and depths
from a few centimeters to two or more meters (Par-
malee and Bogan 1998). We retained two single valves
of this species and catalogued them at the MMNHC
collection. Based on the lack of live individuals in our
survey eort, the status of L. recta in the Sequatchie
River is uncertain.
Comments. Length of two relict le valves in Figure 18
is estimated due to posterior tip missing in both speci-
mens; a third relict valve (sex indet.) was not measured
or retained due to its degraded condition.
Megalonaias nervosa (Ra nesque, 1820)
Washbo a rd
Figure 3Q
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1298°N, –85.5233°W; river km 24.9; 28.VII.2021;
G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T. Eldridge,
B.M. Mize leg.; 4 sex indet., 113–140mm; 1 single valve
sex indet., 137 mm.
Identication. We identied three live and one dead
M. nervosa based on the dark periostracum, solid and
quadrate shell outline, and large size. Important diag-
nostic characters include the shell surface which is most-
ly covered with nodulous plications and the beaks which
are narrow and do not exceed the outline of the hinge
line. ere are two heavy pseudocardinal teeth and two
slightly curved lateral teeth in the le valve of the relict
specimen we found. e species is distinguished from
Amblema plicata by its more quadrate shape and the
presence of sculpturing anteriorly to the umbo.

496 Check List 19 (4)
Geographical distribution. Megalonaias nervosa is
widespread throughout the Mississippi River basin and
inhabits the Gulf drainages from the Ochlockonee Riv-
er west to the Rio Grande River (Parmalee and Bogan,
1998). In the Tennessee River system, M. nervosa ranges
from eastern Tennessee downstream to the conuence
with the Ohio River (Parmalee and Bogan 1998; Haag
and Cicerello 2016). e species can inhabit large creeks
but is more common in large rivers and can be found
at depths approaching 20 m (Williams et al. 2008). e
presence of at least two size classes in the live individu-
als we found suggests the species is rare but reproduc-
ing in the Sequatchie River.
Obliquaria reexa (Ranesque, 1820)
reehorn Wartyback
Figure 3R
Material examined. UNITED STATES OF AMER-
ICA – Tennessee • Sequatchie River, Marion Coun-
ty; 35.1267°N, –85.5244°W; river km 24.7–25.3;
28.VII.2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust,
R.T. Eldridge, B.M. Mize leg.; 4 sex indet. 27–37
mm; 35.14067°N, −85.52226°W; river km 25.3–27.4;
7.VII.2021; B.J. Dinkins, H.D. Faust leg. 4 sex indet.
39–48 mm MMNHC 18656.
Identication. We identied two live and six dead
Obliquaria reexa based on the solid, somewhat inat-
ed, oval shell with dark, cloth-like periostracum and
full beaks that break the outline of the shell. Important
diagnostic characters include a sharp posterior ridge
usually having a series of parallel, subtle plications, and
a row of 3–5 large knobs emanating from the beak to
the ventral margin; the knobs on one valve alternate in
position with the knobs on the other valve. e nacre is
pearly white. Obliquaria reexa is distinguished from
eliderma metanevra (Ranesque, 1820) by the dark
periostracum, lack of knobs on the posterior ridge, and
presence of knobs on the central part of the shell that
alternate between the valves.
Geographical distribution. Obliquaria reexa occurs
in Lake Erie and its tributaries and is widespread in the
Mississippi River basin from Minnesota south to Lou-
isiana (Williams et al. 2008). e species also occurs
in several Gulf Coast drainages from Florida to Texas
(Williams et al. 2008). In Tennessee, O. reexa occurs
throughout the Tennessee and Cumberland River sys-
tems (Parmalee and Bogan 1998). e species was not
found in the Sequatchie River by Hatcher and Ahl stedt
(1982) or Gordon (1991). ere is only one previous
record of the species from the Sequatchie River: seven
specimens collected August 1957 at Ketner Mill (Har-
vard University Museum of Comparative Zoology, Cat-
alog Number 236180).
Pleurobema cordatum (Ranesque, 1820)
Ohio Pigtoe
Figure 3S
Material examined. UNITED STATES OF AMERICA
– Tennessee • Sequatchie River, Marion County;
35.1299°N, –85.5235°W; river km 25.1; 28.VII.2021;
G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T. Eldridge,
B.M. Mize leg.; 1 sex indet., 93 mm.
Identication. We identied one live Pleurobema cor-
datum based on the semi-dark and cloth-like perios-
tracum, heavy and smooth shell with subtriangular
outline, and bluntly pointed anterior shell margin. e
individual had a wide, shallow sulcus anterior to the
broad posterior ridge. Important diagnostic charac-
ters include the cloth-like shell surface and the round,
full beaks which break the shell outline and are angled
anteriorly. Pleurobema cordatum is distinguished from
Pleuronaia barnesiana (Lea, 1838) and P. dolabelloides
(Lea, 1840) by the high, full umbos, wide and shallow
sulcus, and dark, unrayed periostracum.
Geographical distribution. Pleurobema cordatum
occurs in the upper Mississippi and St. Lawrence River
basins (Parmalee and Bogan 1998; Watters et al. 2009).
e species is found in medium-sized to large rivers,
where it occurs in owing water with substrates com-
posed of mixtures of sand and gravel (Williams et al.
2008). We found one live individual at the upper end
of our study reach at 1 m depth in the center of the
channel indicating the species is present but rare in the
Sequatchie River.
Taxonomic remarks. Pleurobema cordatum, P. clava
(Lamarck , 1819), P. plenum (Lea, 1840), and P. rubrum
(Ranesque, 1820) are currently the subject of range-
wide molecular analysis to determine their relationship
and distribution (Nathan Johnson, U.S. Geological Sur-
vey, pers. comm.). Ortmann (1925) reported specimens
of Pleurobema clava (Lamarck, 1819) in the Bryant
Walker collection from the Sequatchie River at Jasper.
Parmalee and Bogan (1998) reported P. clava formerly
occurred in the Sequatchie River although this appears
to be based on Ortmann’s record, as we could nd no
specimens of this species in any of the collections we
queried. Based on these ndings, we do not consider
P. clava to have historically occurred in the Sequatchie
River.
Pleuronaia barnesiana (Lea, 1838)
Tennessee Pigtoe
Figure 3T
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize 12 sex indet., 39–43 mm, MMN-
HC 18655; 35.14067°N, –85.52226°W; river km 25.3–
27.4; 7.VII.2021; B.J. Dinkins, H.D. Faust, 6 sex indet.,
33–45 mm, MMNHC 18654.
Identication. We identied three live and 15 dead P.
barnesiana based on the semi-glossy and light brown
periostracum, umbos that do not break t he shell outline,
and its quadrate outline. Important diagnostic charac-
ters include pseudocardinal teeth that are compressed

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 497
and nearly parallel. Most individuals we encountered
had distinct or faint greenish rays. ere is no attened,
plate-like area ending at the posterior ridge, and live
individuals have a creamy white or tan foot.
Geographical distribution. Pleuronaiabarnesiana is
endemic to the Tennessee River drainage (Simpson
1914) where it occurs in medium-sized creeks and rivers
in eastern and middle Tennessee (Parmalee and Bogan
1998). e species typically occurs in moderate current
at depths less than 1 m, and in substrate composed of
coarse sand, silt, and gravel. Based on the number of
live and fresh dead shells encountered in our survey, the
species is reproducing in the Sequatchie River down-
stream of Ketner Mill.
Pleuronaia dolabelloides (Lea, 1840)
Slabside Pearlymussel
Figure 3U
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1299°N, –85.5235°W; river km 25.1; 28.VII.2021;
G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T. Eldridge,
B.M. Mize 12 leg.; sex indet. 35–81 mm, MMNHC
18793
Identication. We identied eight live and four dead P.
dolabelloides based on the semi-glossy and light brown
periostracum, full umbos that slightly break the shell
outline, and the presence of broad, interrupted green-
ish rays extending from the umbos diagonally to the
ventral margin of the shell. ere is a attened, plate-
like area ending at the posterior ridge. Important inter-
nal shell characters include triangular pseudocardinal
teeth bordered by a broad interdentum, shallow beak
cavity, and pearly white nacre. Pleuronaia dolabelloi-
des can be distinguished from P. barnesiana and Pleu-
robema oviforme (Conrad, 1834) by its ventrally curved
posterior ridge which forms the posterior border of a
attened plate and by its bright orange foot (Williams
et al. 2008).
Geographical distribution. Pleuronaia dolabelloides
is endemic to the Cumberland and Tennessee river
drainages (Parmalee and Bogan 1998; Williams et al.
2008). Historically, the species occurred in large creeks
to large rivers in shoal habitat consisting of sand, ne
gravel, and cobble substrates (Parmalee and Bogan
1998). Based on the number of live and fresh dead shells
encountered in our survey, the species is common and
reproducing in the Sequatchie River downstream of
Ketner Mill.
Potamilus alatus (Say, 1817)
Pink Heelsplitter
Figure 3V
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 8 sex indet. 28–117 mm,
MMNHC 20953; 35.14067°N, –85.52226°W; river km
25.3–27.4; 7.VII.2021; B.J. Dinkins, H.D. Faust leg. 1 sex
indet. 101 mm, MMNHC 18658.
Identication. We identied ve live and six dead P.
alatus based on the moderately thick, compressed,
and ovate shell having a straight ventral margin, high
posterior wing, and small beaks that do not break the
shell outline. e periostracum is light to dark brown.
Important internal shell characters include sharp, tri-
angular pseudocardinal teeth, long, slightly curved lat-
eral teeth, shallow beak cavity, and a dark purple nacre.
Potamilus alatus is distinguished from Lampsilis ova-
ta by its more compressed shell, dark brown periostra-
cum, presence of a high wing, and purple nacre.
Geographical distribution. Potamilus alatus occurs in
the Great Lakes basin and St. Lawrence River system,
throughout the Mississippi River basin south to Arkan-
sas and Tennessee (Parmalee and Bogan 1998; Williams
et al. 2008). In Tennessee, the species is widespread,
occurring widely in the main channel of the Tennes-
see and Cumberland Rivers and in medium-sized to
large tributaries (Parmalee and Bogan 1998). We found
the species to be common throughout our survey reach
with numerous age classes represented indicating the
species is common and reproducing in the Sequatchie
River downstream of Ketner Mill.
Ptychobranchus fasciolaris (Ranesque, 1820)
Kidneyshell
Figure 3W
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1267°N, –85.5244°W; river km 24.7; 28.VII.2021;
G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T. Eldridge,
B.M. Mize leg.; 4 sex indet. 53–73 mm, MMNHC 18660;
35.14067°N, –85.52226°W; river km 24.9; 7.VII.2021;
B.J. Dinkins, H.D. Faust leg.; 33 sex indet. 12–103 mm,
MMN HC 18657.
Identication. We identied 33 live individuals and 17
dead P. fasciolaris based on the solid, elongate, elliptical,
and compressed shell combined with a bluntly pointed
posterior end and a rounded anterior end, and umbos
that do not exceed the shell outline. e periostracum
is light brown and most of the specimens we encoun-
tered had wide, interrupted rays. Important internal
shell characters include heavy, triangular pseudocar-
dinal teeth, short, straight lateral teeth, exceptionally
shallow beak cavity, and a pearly white nacre. Ptycho-
branchus fasciolaris is distinguished from Eurynia dila-
tata by its more inated shell, brownish periostracum,
and white nacre.
Geographical distribution. Ptychobranchus fasciolar-
is occurs in the Ohio River basin and the Great Lakes
basin (Watters et al. 2009). In the Tennessee River, the
species historically occurred downstream to the conu-
ence with the Ohio River (Parmalee and Bogan 1998;
Haag and Cicerello 2016). e species occurs in small

498 Check List 19 (4)
to large rivers, typically in habitats with owing water
where there is sand and gravel (Williams et al. 2008). In
the main channel of the Tennessee River, P. fasciolaris
can be found at depths exceeding 6 m (Williams et al.
2008). We found the species to be common throughout
our survey reach with numerous age classes represent-
ed indicating the species is reproducing downstream of
Ketner Mill.
eliderma metanevra (R anesque, 1820)
Monkeyface
Figure 3X
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1290°N, –85.5231°W; river km 24.9; 28.VII.2021;
G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T. Eldridge,
B.M. Mize 1 leg.; sex indet., 86 mm.
Identication. We identied one live T. metanevra
based on the solid, inated, and square-shaped shell,
and umbos that slightly exceed the shell outline. e
periostracum is brown, smooth, and unrayed. Impor-
tant diagnostic characters include an inated posterior
ridge that extends diagonally from the umbos toward
the posterior ventral margin and the presence of sev-
eral large, elevated knobs. eliderma metanevra can
be distinguished from eliderma cylindrica (Say, 1817)
by its square-shaped shell, inated posterior ridge, and
presence of large, elevated knobs.
Geographical distribution. eliderma metanevra
occurs in the upper and middle Mississippi River
basin south to the Ouachita River in Louisiana (Wil-
liams et al. 2008; Vidrine 1993). e species is found
in medium-sized to large rivers in owing water, in
substrates comprised of sand and gravel (Williams et
al. 2008). e collection of a live individual in our sur-
vey indicates the species is present but very rare in the
Sequatchie River downstream of Ketner Mill.
Toxolasma lividum Ranesque, 1831
Purple Lilliput
Figure 3Y
Material examined. UNITED STATES OF AMERI-
CA – Tennessee • Sequatchie River, Marion County;
35.1290°N, –85.5235°W; river km 24.7–25.3; 28.VII.
2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust, R.T.
Eldridge, B.M. Mize leg.; 7 ♂ 24–45 mm, 4 ♀ 33–42
mm, 1 sex indet., MMNHC 18665; 35.14067°N,
–85.52226°W; river km 25.3–27.4; 7.VII.2021; B.J. Din-
kins, H.D. Faust; leg.; 5 ♂ 27–35 mm, 4 ♀ 26–30 mm,
MM NHC 18 663.
Identication. We identied 12 live and 114 dead
Toxolasma lividum based on the dark, cloth-like and
unrayed periostracum, small shell size, rounded shell
anterior, and nearly straight ventral shell margin.
Males are characterized by the short and elliptical shell
outline, while females are distinctly inated. Important
internal shell characters include a bright purple nacre
and erect, triangular pseudocardinal teeth and nearly
straight lateral teeth. Tox ola sma lividum can be distin-
guished from Tox ola sma parvum (Barnes, 1823) by its
heavier shell and purple nacre.
Geographical distribution. Toxolasma lividum occurs
in the Mississippi River basin only in the Ouachita and
Ozark highlands (Haag and Cicerello 2016) and in the
Ohio River basin (Parmalee and Bogan 1998; Watters et
al. 2009). is diminutive species is found in medium-
sized rivers in mud, sand, and gravel substrates but is
most common in small to medium-sized streams (Haag
and Cicerello 2016, Watters 2009). Like several other
species of Toxol a s m a , it is oen found along stream
margins and in depositional areas (G. Dinkins, per-
sonal observation) and may live 12 years (Watters et al.
2009). Our collection of numerous live and fresh dead
T. lividum represented by several size classes indicates
the species is abundant and reproducing downstream
of Ketner Mill.
Comments. In addition to the 44 fresh dead T. lividum
found between river km 25.3 and 27.4, we collected 61
relict specimens that were not retained.
Tritogonia verrucosa (R anesque, 1820)
Pistolgrip
Figure 3Z
Material examined. UNITED STATES OF AMER-
ICA – Tennessee • Sequatchie River, Marion Coun-
ty; 35.1267°N, –85.5244°W; river km 24.7–25.3;
28.VII.2021; G.R. Dinkins, B.J. Dinkins, H.D. Faust,
R.T. Eldridge, B.M. Mize leg.; 5 sex indet., 85 mm,
MMNHC 20954.
Identication. We identied ve dead T. verruc osa
based on the solid, elongate shell sculptured with numer-
ous nodules and plications across both valves, a distinct,
elevated posterior ridge, and a greenish/brown perio-
stracum. Important internal shell characters include a
pearly white nacre, moderately deep beak cavity, thick
pseudocardinal teeth, and short, straight lateral teeth.
Tritogonia verrucosa can be distinguished from elider-
ma metanevra by its elongate shell, lack of large knobs on
the posterior ridge, and greenish periostracum.
Geographical distribution. Tritogonia verrucosa is
widely distributed throughout the Mississippi River
basin, from the upper reaches of the Ohio River basin
south to Louisiana (Watters et al. 2009; Williams et al.
2008; Vidrine 1993). In Tennessee, the species occurs
statewide, except for the upper Tennessee River system
(Parmalee and Bogan 1998). In the Sequatchie River,
T. verrucosa was not reported by Hatcher and Ahlstedt
(1982), and Gordon (1991) found only a relict valve at a
single location. Based on the lack of live individuals in
our survey, the status of T. verru cosa in the Sequatchie
River downstream of Ketner Mill is uncertain.
Comments. In addition to the one fresh dead specimen
collected and retained between river km 24.7–25.3, we
collected four fresh dead specimens from this reach
that were not retained or measured.

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 499
Discussion
A search of the InvertEBase website (https://inverte
base.org/portal) for mussels found in the Sequatchie
River revealed 29 records representing 23 species, all
collected prior to the late 1950s and all from Sequatchie
and Marion counties (Table 2). ese records are in
the collections at the Denver Museum of Nature and
Science, Florida Museum of Natural History, Harvard
University Museum of Comparative Zoology, NCS-
MNS, and the University of Michigan Museum of Zool-
ogy. An additional 18 records from the Sequatchie River
between 1909 to 1991 but not available in InvertEBase
were provided to us by NCSMNS, and the online mol-
lusk database at OSUM contains four records repre-
senting three species collected between 1965 and 1981.
In the mollusk collection at MMNHC there are 30
records representing 12 species collected between 1973
and 2017. Based on current taxonomy, these museum
records document a total of 39 mussel species histori-
cally occurring in the Sequatchie River drainage.
Herein we report new drainage records for Ligumia
recta, Megalonaias nervosa, Pleurobema cordatum, Pty-
chobranchus fasciolaris, and eliderma metanevra. All
ve species were known to historically occur in the Ten-
nessee River near the conuence with the Sequatchie
River. Ligumia recta was recorded in the early 1900s
from the Tennessee River at Bridgeport, approximately
13 km downstream of the Sequatchie River (UMMZ
098316). Megalonaias nervosa was recorded in 1980
from the Tennessee River near the downstream end of
Burns Island, approximately 3.1 km downstream from
the Sequatchie River (MMNHC 5456). Pleurobema cor-
datum was recorded in 1999 from the Tennessee Riv-
er approximately 2 km upstream from the Sequatchie
River (Illinois Natural History Survey 24596, NCS-
MNS 47689). Ptychobranchus fasciolaris was recorded
in 1999 in the Tennessee River approximately 2 km
upstream from the Sequatchie River (Illinois Natural
History Survey 24599; NCSMNS 47709). eliderma
metanevra was recorded in 1999 in the Tennessee River
approximately 2 km upstream from the mouth of the
Sequatchie River (NCSMNS 86003).
We also report the presence of three rare species in
the Sequatchie River: Pleuronaia barnesiana, P. dolabel-
loides, and Tox o l a s ma lividum. Pleuronaia barnesiana
was collected in the Sequatchie R iver in 1980 (MMNHC
17118), and the species was found in the Sequatchie Riv-
er in the early 1900s (UMMZ 092869, UMMZ 092795).
We found three live and 12 fresh dead P. barnesiana,
the rst report of this species in the Sequatchie River
in over 40 years. Pleuronaia barnesiana has been extir-
pated from most of the streams it once occurred in,
including the main channel Tennessee River, and it is
estimated to occupy approximately 25% of its former
Table 2. Historical summary of freshwater mussels in Sequatchie River drainage, Tennessee. Sources: X = this study; 1 = Ortmann
(1925); 2 = Hatcher and Ahlstedt (1982); 3 = Gordon (1991); 4 = Tennessee Valley Authority – unpublished data; 5 = McClung
Museum of Natural History and Culture; 6 = North Carolina State Museum of Natural Sciences; 7 = Delaware Museum of Natural
History; 8 = Florida Museum of Natural History; 9 = Harvard University Museum of Comparative Zoology; 10 = University of Michi-
gan Museum of Zoology; 11 = Carnegie Museum of Natural History; 12 = Illinois Natural History Survey.
Species Source
Margaritiferidae
Margaritifera monodonta (Say, 1829) 1, 3, 4, 5
Unionidae
Actinonaias pec torosa (Conrad, 1834) 1, 10
Alasmidonta viridis (Ranesque, 1820) 11
Amblema plicata (Sa y, 1817 ) X, 3, 10, 11, 12
Cambarunio iris (Lea, 1829) X, 1, 2, 3, 4, 6, 11
Cyclonaias pustulosa (Le a, 18 31) X, 3
Cyclonaias tuberculata (Ranesque, 1820) X, 3, 4, 10
Ellipsaria lineolata (Ranesque, 1820) X, 3
Elliptio crassidens (Lamarck, 1819) X, 3, 5, 11
Epioblasma biemarginata (Lea, 1857) 10
Epioblasma capsaeformis (Lea, 1834) 2, 6, 10
Epioblasma triquetra (Ranesque, 1820) 3, 6
Eurynia dilatata (Ranesque, 1820) X, 2, 3, 4, 5, 10, 12
Fusconaia co r (Conrad, 1834) 10
Fusconaia cuneolus (Lea, 184 0) 2, 10
Lampsilis cardium/ovata 1, 2, 3, 4, 5, 10
Lampsilis fasciola Ranesque, 1820 X, 1, 3, 5, 8, 10
Lasmigona costata (Ranesque, 1820) X, 13, 5, 9, 12
Lasmigona holstonia (Lea, 18 38) 3, 6
Species Source
Leaunio vanuxemensis (Lea, 1838) X, 1, 2, 3, 4, 11, 12
Lemiox rimosus (Ranesque, 1831) 6
Ligumia recta (Lamarck, 1819) X
Megalonaias nervosa (Ranesque, 1820) X
Obliquaria reexa (Ranesque, 1820) X, 9
Obovaria subrotunda (Ranesque, 1820) 1, 3, 5, 6, 9, 10, 11
Pleurobema cordatum (Ranesque, 1820) X
Pleurobema oviforme (Conrad, 1834) 3, 5, 10
Pleuronaia barnesiana (Lea , 1838) X, 1, 2, 5, 10
Pleuronaia dolabelloides (Lea, 18 40) X, 2, 6
Potamilus alatus (Sa y, 1817) X, 1, 3, 5, 9, 10, 11
Potamilus fragilis (Ranesque, 1820) 1, 11
Ptychobranchus fasciolaris (Ranesque, 1820) X
Pyganodon grandis (Say, 1829) 6
Theliderma cylindrica (S ay, 1817) 1, 7, 10
Theliderma metanevra (Ranesque, 1820) X
Toxolasma cylindrellus (Lea, 18 68) 6
Toxolasma lividum Ranesque, 1831 X, 6
Tritogonia verrucosa (Ranesque, 1820) X, 3, 6, 9, 10
Venustaconcha trabalis (Conrad, 1834) 3, 6

500 Check List 19 (4)
range (Fitzgerald et al 2021). e USFWS was peti-
tioned by the Center for Biological Diversity (CBD
2010)to listP.barnesianaas threatened or endangered
under the Endangered Species Act and, in response to
that petition, a survey for its occurrence across most of
its historical range was conducted. However, the sur-
vey for P. barnesiana did not include the Sequatchie
River because the species was considered extirpated in
the drainage (Fraley and Dinkins 2020, Andrew Hen-
derson, USFWS, pers. comm.). While the Clinch, Pow-
ell, and Holston River systems in the upper Tennessee
River drainage represent strongholds for P. barnesiana,
the status of populations in those watersheds varies due
to localized threats associated with mining and agri-
cultural land uses (USFWS 2020a).Remaining popula-
tions in the middle and lower Tennessee River drainage
are highly fragmented due to hydrologic alteration and
urban development, and as a result, natural recoloniza-
tion potential in many tributaries is limited (USFWS
2020a). A decision on its listing by USFWS is expect-
ed in 2023 (Andrew Henderson, USFWS, pers. comm.).
Presently, P. barnesiana occupies a fraction of its his-
torical range and we agree the species deserves protect-
ed status.
We collected eight live and four fresh dead P. dol a-
belloides representing the rst live individuals of this
species found in the Sequatchie River. e only pre-
vious record of P. dolabelloides from the Sequatchie
River was a complete specimen collected 11 August
1957 at Ketner Mill (NCSMNS 1022032) and a single
valve collected 26 June 1980, 3.2 km north of Dunlap,
Sequatchie County (Hatcher and Ahlstedt 1982). Pleu-
ronaia dolabelloides was widespread in the Tennessee
River drainage, occurring from the upper Clinch and
Powell rivers (Virginia) downstream to the Duck and
Bualo rivers (Tennessee). In the Cumberland River
drainage, the species occurred from about the Red Riv-
er upstream to the vicinity of the Caney Fork (Haag and
Cicerello 2016). In Kentucky, Tennessee, Alabama, Mis-
sissippi, and Virginia 25 populations have been identi-
ed, but only 17 are still extant, all in the Tennessee
River drainage (Kristin Womble, Tennessee Techno-
logical University, pers. comm.). e population clos-
est to the Sequatchie River is in the lower Paint Rock
River, approximately 127 river km downstream of the
Sequatchie River. Pleuronaia dolabelloides is listed as
Endangered under the Endangered Species Act (USF-
WS 2013). e lower 12.9 km of the Sequatchie River
has been designated as critical habitat for P. dolabel-
loides, although the species was considered extirpated
from this reach (Andy Ford, USFWS, pers. comm.).
We collected 12 live and 114 fresh dead T. lividum,
representing the rst live individuals of this species
reported from the Sequatchie River. e only previ-
ous collection of T. lividum from the Sequatchie River
was on 11 August 1957 when two dead specimens (one
paired specimen and one single valve) were collect-
ed immediately below Ketner Mill (NCSMNS 62878).
In 2010, USFWS was petitioned by the CBD to list T.
lividum as reatened or Endangered under the Endan-
gered Species Act, but USFWS found listing was unwar-
ranted (USFWS 2020b). Tox olasma lividum is very rare
if not extirpated in Ohio (Watters et al. 2009) and is
now in danger of disappearing completely in Kentucky
(Haag and Cicerello 2016). e species has declined in
Alabama although Garner et al. (2004) designated T.
lividum a species of low conservation concern in the
state. USFWS considers T. lividum to be extant in nine
states (Alabama, Arkansas, Illinois, Indiana, Kentucky,
Michigan, Missouri, Ohio, and Tennessee), extirpated
from two states (North Carolina, Georgia), and possi-
bly extirpated from two more (Oklahoma and Virgin-
ia) (USFWS 2020b). Historically there were 272 known
populations, with 146 remaining today. Of those, 87
are small populations, conned to a limited area, with
no evidence of young mussels or mussels of multiple
ages (USFWS 2020b). Despite these declines, USFWS
found the species had not met the threshold for pro-
tection under the ESA (USFWS 2020c). Prior to our
survey, USFWS considered T. lividum to be extirpated
from the Sequatchie River. e nearest extant popula-
tion to the Sequatchie River is in the lower Paint Rock
River, a direct tributary to Tennessee River in north-
eastern Alabama (Paul Johnson, Alabama Department
of Natural Resources, pers. comm.). e Paint Rock
River is approximately 127 river km downstream from
the Sequatchie River and the lower reach of both rivers
is impounded by reservoirs on the main channel Ten-
nessee River.
e most common species found in our survey
were Cyclonaias tuberculata, Ptychobranchus fascio-
laris, Cyclonaias pustulosa, Lampsilis ovata, Elliptio
crassidens, and T. lividum representing 76.8% of all live
mussels found. e following species were uncommon
in our survey, each represented by more than two but
less than eight live individuals: P. dolabelloides, Lamp-
silis fasciola, Potamilus alatus, Cambarunio iris, Lasmi-
gona costata, Leaunio vanuxemensis, Obliquaria reexa,
Megalonaias nervosa, and P. barnesiana. A single live
individual was found of Eurynia dilatata, Pleurobema
cordatum, eliderma metanevra, and Tritogonia ver-
rucosa indicating these species are extant but rare in
the Sequatchie River downstream of Ketner Mill. We
found three species (Amblema plicata, Ligumia recta,
and Ellipsaria lineolata) only as dead, weathered single
valves. ese species may no longer be extant between
river km 24.7 and 25.3 or are very rare. Prior to our sur-
vey, L. vanuxemensis had been documented numerous
times in the Sequatchie River and as recently as 2014
(MMNHC lot no. 6437). Leaunio vanuxemensis was
described by Lea from the Cumberland River system
and this species’ relationship with Leaunio ortmanni
(Walker, 1925), Kentucky Creekshell, has been the sub-
ject of recent and ongoing taxonomic analyses (Kuehnl
2009; Watters 2018; Jess Jones, USWFW, unpubl. data).
In general, the mussel fauna of the Sequatchie Riv-
er has largely been understudied presumably because
of water quality issues related to coal mining and

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 501
wastewater discharge. e only comprehensive sur-
vey for mussels in the Sequatchie River was conducted
in 1991 and the results indicated the fauna was “quite
depauperate” (Gordon 1991). is may explain the gen-
eral lack of interest in the Sequatchie River over the last
30 years compared to other rivers in the Tennessee Riv-
er system, such as the Clinch (Ahlstedt 1991), Powell
(Johnson 2011; Johnson et al. 2010), Little (Schilling et
al. 2017), Hiwassee (Parmalee and Hughes 1994), Little
Tennessee (Parmalee and Klippel 1984), Elk (Ahlstedt
1983), Paint Rock (Fobian et al. 2014), Duck (Ahlstedt
et al. 2017; Schilling and Williams 2002), and Bualo
(Reed et al. 2019). e Sequatchie River, while not par-
ticularly remote, has few bridge crossings and is dif-
cult to access and sample except at bridge crossings.
e entire length of the main channel is bounded on
both banks by private property and access to the river
is restricted. In the lower 27.4 km of the main channel,
there are only four bridge crossings, and at one of these
(Interstate Highway 24), parking on the road shoul-
der is illegal which hinders river access. Further, there
is little wadable habitat in the lower Sequatchie Riv-
er (especially downstream of Ketner Mill) and in this
lower reach depths typically range from 2–4 m dur-
ing normal ows. Even though our survey eort was
restricted to only a short reach of the river, we were the
rst to include an underwater examination of pool hab-
itat using diving gear. Based on museum records and
conversations with colleagues at several state and fed-
eral regulatory agencies, our survey eort produced the
single largest collection of live mussels and dead shells
to date from the Sequatchie River. e discovery of ve
new drainage records and rediscovery of To xolasma liv-
idum, Pleuronaia barnesiana, and P. dolabelloides dem-
onstrates the need for additional survey work using
underwater gear throughout the main channel of the
Sequatchie River. Our survey also highlights the value
of documenting biodiversity and setting aside areas for
conservation easement.
Acknowledgements
We thank Ornstein–Schuler Investments, LLC for
coordinating the survey eorts and Heritage Preserva-
tion Trust, Inc. for providing access to the Sequatchie
River via the conservation easement parcel. We also
thank Jamie Smith and Art Bogan (NCSMNS), Nate
Shoobs (OSUM), and Tim Pearce (Carnegie Museum)
for providing collection records. We thank Je Sim-
mons (TVA), Andrew Henderson (USFWS), and Jess
Jones (USFWS) for information on the distribution and
status of several species, Todd Amacker (TVA) for pho-
tographing specimens, and to Craig Walker (Oce of
Surface Mining, retired) for information on coal min-
ing in the Sequatchie River drainage. Robert Butler
(USFWS, retired), Je Garner (Alabama Department of
Conservation and Natural Resources), and two anony-
mous reviewers reviewed an earlier dra of this man-
uscript and provided numerous useful comments and
edits. Finally, we thank Dr. Igor Miyahira of the Uni-
versidade Federal do Estado do Rio de Janeiro for his
patient guidance and editorial advice.
Author’s Contributions
Conceptualization: GRD, BJD, RTE. Funding acquisi-
tion: BJD. Investigation: GRD, BJD, HDF, RTE, BMM.
Methodology: GRD, BJD, HDF, RTE, BMM. Project
administration: BJD. Validation: GRD, HDF. Visu-
alization: GRD, BJD. Writing – original dra: GRD.
Writing – review and editing: GRD.
References
Ahlstedt SA (1983) e molluscan fauna of the Elk River in
Tennessee and Alabama. American Malacological Bulle-
tin 1: 43–50.
Ahlstedt SA (1991) Twentieth century changes in the fresh-
water mussel fauna of the Clinch River (Tennessee and
Virginia). Walkerana 5: 73–122.
Ahlstedt SA, Powell JR, Butler RS, Fagg MT, Hubbs DW,
Novak SR, Palmer SR, Johnson PD (2017) Historical
and current examination of freshwater mussels (Bival-
via: Margaritiferidae: Unionidae) in the Duck River basin
Tennessee, U.S.A. Malacological Review 45: 1–163.
Bouchet P, Rocroi J (2005) Classication and nomenclature
of gastropod families. Malacologia 47: 1–397.
Burch JB (1975) Freshwater unionacean clams (Mollusca:
Pelecypoda) of North America. Revised edition. Malaco-
logical Publications, Hamburg, Michigan, USA, 204 pp.
Center for Biological Diversity (2010) Petition to list 404
aquatic, riparian, and wetland species from the South-
eastern United States as threatened or endangered under
the Endangered Species Act. Letter to USA Secretary of
the Interior, USA Secretary of Commerce, and Regional
Director of the USA Fish and Wildlife Service, Southeast
Region. April 20, 2010.
Clarke AH (1981) e freshwater molluscs of Canada.
National Museums of Canada, Ottawa, Canada, 446 pp.
Clarke AH (1985) e tribe Alasmidontini (Unionidae: Ano-
dontinae). Part II: Lasmigona and Simpsonaias. Smithso-
nian Contributions to Zoology 399: 1–101.
Cummings KS, Mayer CA (1993) Field guide to freshwater
mussels of the Midwest. Illinois Natural History Survey,
Manual 5: 1–194.
Dawley C (1947) Distribution of aquatic mollusks in Minne-
sota. e American Midland Naturalist 38 (3): 671–697.
https://doi.org/10.2307/2421686
Fitzgerald DB, Henderson AR, Maloney KO, Freeman
MC, Young JA, Rosenberger AE, Kazyak DC, Smith DR
(2021) A Bayesian framework for assessing extinction risk
based on ordinal categories of population condition and
projected landscape change. Biological Conservation 253:
108866. https://doi.org/10.1016/j.biocon.2020.108866
Fobian TB, Buntin ML, Holield JT, Tarpley TA, Garner
JT, Johnson PD (2014) Freshwater mussels (Unionidae)
in the Paint Rock River (Jackson, Madison, and Marshall
Counties), Alabama. Southeastern Naturalist 13 (2): 347–
366.

502 Check List 19 (4)
Fraley SJ, Dinkins GR (2020) A survey for Pleurobema ovi-
forme and Pleuronaia barnesiana throughout their his-
torical range. Report prepared for the Southeastern
Association of Fish and Wildlife Agencies, October 2020.
Freshwater Mollusk Conservation Society (2021) e
2021 checklist of freshwater bivalves (Mollusca: Bival-
via: Unionida) of the United States and Canada. Consid-
ered and approved by the Bivalve Names Subcommittee
December 2020. Freshwater Mollusk Conservation Soci-
ety. https://molluskconservation.org/MServices_Names-
Bivalves.html. Accessed on 2022-11- 30.
Garner JT, Blalock-Herod H, Bogan AE, Butler RS, Haag
WR, Harteld PD, Herod JJ, Johnson PD, McGre-
gor SW, Williams JD (2004) Freshwater mussels and
snails. In: Mirarchi RA (Eds.) Alabama Wildlife. Volume
1. A checklist of vertebrates and selected invertebrates:
aquatic mollusks, shes, amphibians, reptiles, birds, and
mammals. e University of Alabama Press, Tuscaloosa,
Alabama, USA, 13–58.
Gordon M (1991) Survey of the aquatic Mollusca of the
Sequatchie River and Battle Creek drainages, Tennessee.
Report to Tennessee Wildlife Resources Agency, Nash-
ville, Tennessee, USA, 21 pp.
Haag WR (2012) North American freshwater mussels: nat-
ural history, ecology, and conservation. Cambridge Uni-
versity Press, New York, USA, 505 pp.
Haag WR, Cicerello RR (2016) A distributional atlas of the
freshwater mussels of Kentucky. Scientic and Technical
Series Number 8, Kentucky State Nature Preserves Com-
mission, Frankfort, USA, 299 pp.
Hatcher R, Ahlstedt SA (1982) Survey of endangered and
threatened mollusks in Tennessee streams. Report to Ten-
nessee Wildlife Resources Agency, Nashville, Tennessee,
26 pp.
Howells RG, Neck RW, Murray HD (1996) Freshwater
mussels of Texas. Texas Parks and Wildlife Department,
Inland Fisheries Division, Austin, Texas. 218 pp.
Johnson MS (2011) A quantitative survey of the freshwa-
ter mussel fauna in the Powell River of Virginia and Ten-
nessee, and life history study of two endangered species,
Quadrula sparsa and Quadrula intermedia. M.S. the-
sis, Virginia Polytechnic Institute and State University,
Blacksburg, Virginia, USA, 171 pp.
Johnson MS, Neves RJ, Henley WF (2010) Status of the
freshwater mussel fauna in the Powell River, Virginia and
Tennessee. Unpublished report to U.S. Fish and Wildlife
Service. Virginia Cooperative Fish and Wildlife Research
Unit, Blacksburg, Virginia, USA, 77 pp.
Johnson NA, Smith CH, Pfeier JM, Randklev CR, Wil-
liams JD, Austin JD (2018) Integrative taxonomy resolves
taxonomic uncertainty for freshwater mussels being con-
sidered for protection under the U.S. Endangered Species
Act. Scientic Reports 8: 15892. https://doi.org/10.1038/
s41598-018-33806-z
Johnson PD, Bogan AE, Brown KM, Burkhead NM, Cord-
eiro JR, Garner JT, Harteld DA, Lepitzki AW, Mackie
GL, Pip E, Tarpley TA, Tiemann JS, Whelan NV, Strong
EE (2013) Conservation status of freshwater gastropods
of Canada and the United States. Fisheries 38: 247–282.
Jones RL, Wagner MD, Slack WT, Peyton S, Harteld P
(2021) Guide to the identication and distribution of
freshwater mussels (Bivalvia: Unionidae) in Mississippi.
Second edition. Mississippi Department of Wildlife, Fish-
eries, and Parks, Jackson, Mississippi, USA, 344 pp.
Kuehnl KF (2009) Exploring levels of genetic variation in
the freshwater mussel genus Villosa (Bivalvia: Unionidae)
at dierent spatial and systematic scales: implications for
biogeography, taxonomy, and conservation. Doctoral dis-
sertation, e Ohio State University, Columbus, Ohio,
USA, 261 pp.
Ortmann AE (1918) e nayades (freshwater mussels) of the
upper Tennessee drainage. With notes on synonymy and
distribution. Proceedings of the American Philosophical
Society 57: 521–626.
Ortmann AE (1925) e naiad-fauna of the Tennessee River
system below Walden Gorge. e American Midland Nat-
uralist 9 (7): 321–372. https://doi.org/10.2307/2992763
Parmalee PW, Bogan AE (1998) e freshwater mussels of
Tennessee. University of Tennessee Press, Knoxville, Ten-
nessee, USA, 328 pp.
Parmalee PW, Hughes MH (1994) Freshwater mussels
(Bivalvia: Unionidae) of the Hiwassee River in east Ten-
nessee. American Malacological Bulletin 11 (1): 21–27.
Parmalee PW, Klippel WE (1984) e naiad fauna of the
Tellico River, Monroe County, Tennessee. American Mal-
acological Bulletin 3 (1): 41–44.
Reed MP, Dinkins GR, Ahlstedt SA (2019) Freshwater mus-
sels (Bivalvia: Margaritiferidae and Unionidae) of the
Bualo River drainage, Tennessee. Southeastern Natural-
ist 18 (2): 346–372.
Schilling EM, Williams JD (2002) Freshwater mussels
(Bivalvia: Margaritiferidae and Unionidae) of the low-
er Duck River in middle Tennessee: a historic and recent
review. Southeastern Naturalist 1 (4): 403–414.
Schilling DE, Phipps AT, Jones JW, Hallerman EM (2017)
A survey of freshwater mussels (Unionidae) in Little Riv-
er, Blount County, Tennessee. Southeastern Naturalist 16
(1): 105–116.
Simpson CT (1900) Synopsis of the naiades, or pearly
fresh-water mussels. Proceedings of the United States
National Museum 22 (1205): 501–1044. https://doi.
org/10.5479/si.00963801.22-1205.501
Simpson CT (1914) A descriptive catalogue of the naiades,
or pearly fresh-water mussels. Parts I–III. Bryant Walk-
er, Detroit, Michigan, USA, xii + 1540 pp. https://doi.
org/10.5962/bhl.title.10910
Strayer DL, Jirka KJ (1997) e pearly mussels of New York
state. New York State Museum Memoir 26: 1–113, 27 pls
Tennessee Department of Environment and Con-
servation (2023) List of impaired and threatened
waters in Tennessee. https://ww w.tn.gov/content/
dam/tn/enroment/water/watershed-planning/wr_
wq_303d-2022-nal.xlsx. Accessed on: 2023-04-23.
U.S. Fish and Wildlife Service (2013) Endangered and
threatened wildlife and plants; endangered status for
the Fluted Kidneyshell and Slabside Pearlymussel and
designation of critical habitat. Federal Register 78 (82):
25041–25044. https://www.govinfo.gov/content/pkg/FR-
2013-04-29/pdf/2013-09975.pdf. Accessed on: 2023-07-
04.

Dinkins et al. | Three rare freshwater mussels in the Sequatchie River, Tennessee 503
U.S. Fish and Wildlife Service (2020a) Species status assess-
ment for three freshwater mussels from the Tennessee and
Cumberland River basins (Medionidus conradicus, Pleu-
robema oviforme, and Pleuronaia barnesiana), version
1.1. Asheville Ecological Services Field Oce, Asheville,
North Carolina, USA.
U.S. Fish and Wildlife Service (2020b) Species status assess-
ment report for the Purple Lilliput (Toxolasma lividum),
version 1.0. Asheville Ecological Field Oce, North Car-
olina, USA, 158 pp.
U.S. Fish and Wildlife Service (2020c) Endangered and
threatened species: 12–month nding for Purple Lilli-
put; Longsolid and Round Hickorynut and designation of
Critical Habitat. 75 pp. https://www.govinfo.gov/content/
pkg/FR-2020-09-29/pdf/2020–17015.pdf. Accessed on:
2023-07-04.
U.S. Fish and Wildlife Service (2023) Environmental Con-
servation Online System. https://www.ecos.fws.gov/ecp.
Accessed on: 2023-04-23.
Vidrine MF (1993) e historical distributions of freshwater
mussels in Louisiana. Gail Q. Vidrine collectibles, Eunice,
Louisiana, USA, 225 pp.
Watters GT (2018) A preliminary review of the nominal
genus Villosa of freshwater mussels (Bivalvia, Unionidae)
in North America. Visaya, Supplement 10: 1–140.
Watters GT, Hoggarth MA, Stansbery DH (2009) e fresh-
water mussels of Ohio. e Ohio State University, Colum-
bus, Ohio, USA, 421 pp.
Williams JD, Bogan AE, Garner JT (2008) e freshwater
mussels of Alabama and the Mobile Basin in Georgia,
Mississippi, and Tennessee. University of Alabama Press,
Tuscaloosa, Alabama, USA, 908 pp.
Williams JD, Butler RS, Warren GL, Johnson NA (2014)
Freshwater mussels of Florida. University of Alabama
Press, Tuscaloosa, Alabama, USA, 498 pp.
Williams, JD, Bogan AE, Butler RS, Cummings KS, Gar-
ner JT, Harris JL, Johnson NA, Watters GT (2017) A
revised list of the freshwater mussels (Mollusca: Bivalvia:
Unionida) of the United States and Canada. Freshwater
Mollusk Biology and Conservation 20: 33–58.