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Freshwater Mollusk Biology and Conservation 20:33–58, 2017 Ó Freshwater Mollusk Conservation Society 2017 REGULAR ARTICLE A REVISED LIST OF THE FRESHWATER MUSSELS (MOLLUSCA: BIVALVIA: UNIONIDA) OF THE UNITED STATES AND CANADA James D. Williams1*, Arthur E. Bogan2, Robert S. Butler3,4, Kevin S. Cummings5, Jeffrey T. Garner6, John L. Harris7, Nathan A. Johnson8, and G. Thomas Watters9 1 Florida Museum of Natural History, Museum Road and Newell Drive, Gainesville, FL 32611 USA North Carolina Museum of Natural Sciences, MSC 1626, Raleigh, NC 27699 USA 3 U.S. Fish and Wildlife Service, 212 Mills Gap Road, Asheville, NC 28803 USA 4 Retired. 5 Illinois Natural History Survey, 607 East Peabody Drive, Champaign, IL 61820 USA 6 Alabama Division of Wildlife and Freshwater Fisheries, 350 County Road 275, Florence, AL 35633 USA 7 Department of Biological Sciences, Arkansas State University, State University, AR 71753 USA 8 U.S. Geological Survey, Wetland and Aquatic Research Center, 7920 NW 71st Street, Gainesville, FL 32653 USA 9 Museum of Biological Diversity, The Ohio State University, 1315 Kinnear Road, Columbus, OH 43212 USA 2 ABSTRACT We present a revised list of freshwater mussels (order Unionida, families Margaritiferidae and Unionidae) of the United States and Canada, incorporating changes in nomenclature and systematic taxonomy since publication of the most recent checklist in 1998. We recognize a total of 298 species in 55 genera in the families Margaritiferidae (one genus, five species) and Unionidae (54 genera, 293 species). We propose one change in the Margaritiferidae: the placement of the formerly monotypic genus Cumberlandia in the synonymy of Margaritifera. In the Unionidae, we recognize three new genera, elevate four genera from synonymy, and place three previously recognized genera in synonymy. We recognize for the first time two species (one native and one nonindigenous) in the Asian genus Sinanodonta as occurring in North America. We recognize four new species and one subspecies and elevate 21 species from synonymy. We elevate 10 subspecies to species status and no longer recognize four subspecies. We change common names for five taxa, correct spelling for eight species, and correct the date of publication of original descriptions for four species. KEY WORDS: Unionidae, Margaritiferidae, taxonomy, systematics, nomenclature, mussel scientific names, mussel common names INTRODUCTION During the past 50 yr, there has been considerable interest in freshwater mussels (order Unionida) in the United States *Corresponding Author: fishwilliams@gmail.com and Canada. Much of this interest was brought about by passage of the U.S. Endangered Species Acts of 1966, 1969, and 1973 and the Canadian Species at Risk Act of 2002. These legislative actions and the environmental movement that accompanied them focused conservation attention on all animals and plants, as well as their habitats. This in turn led 33 34 WILLIAMS ET AL. to assessment of species conservation status and the development of faunal lists for many states and provinces. The task of developing species lists was difficult for most invertebrates, including mussels, because so little attention had been given to the study of their biology, ecology, and systematics. In 1970, only six U.S. states had recent lists or books covering their mussel fauna. The first modern attempt to provide a comprehensive list of freshwater mussels of North America was published by Burch (1973, 1975). The first comprehensive list of freshwater mussels of the United States and Canada was compiled in Turgeon et al. (1988) and revised a decade later (Turgeon et al. 1998). Williams et al. (1993) was another important resource during this period; although mainly an assessment of species conservation status, this paper also provided a comprehensive and widely used species list similar to those of Turgeon et al. (1988, 1998). These lists standardized and provided taxonomic stability to mussel common and scientific names to an extent that was previously unavailable. However, systematic taxonomy of mussels was poorly known at that time, and classifications at all taxonomic levels were based largely on concepts from the early 1900s. Since publication of Turgeon et al. (1988, 1998) and Williams et al. (1993), many studies have refined our understanding of mussel systematic taxonomy. Several major publications have addressed systematic relationships within the class Bivalvia, including the order Unionida (Bieler et al. 2010; Carter et al. 2011; Bolotov et al. 2016; Araujo et al. 2017; Combosch et al. 2017). Major studies specific to the Unionida include Graf and Ó Foighil (2000), Hoeh et al. (2001, 2002, 2009), Roe and Hoeh (2003), Campbell et al. (2005), Walker et al. (2006), Graf and Cummings (2007, 2017), Cummings and Graf (2010), and Campbell and Lydeard (2012a, 2012b). In addition, many studies have examined systematic relationships at lower taxonomic levels (e.g., Serb et al. 2003; Jones et al. 2006; Lane et al. 2016). Together, this body of work depicts a view of mussel taxonomy that differs substantially from that of previous lists of the North American fauna. We present a revised classification and list of the freshwater mussels of the United States and Canada (Tables 1 and 2). The primary purpose of this revision is to provide in a single resource a comprehensive list and taxonomic classification that reflects recent refinement of mussel systematics. METHODS We used as a starting point the list of Turgeon et al. (1998). We revised this list and its taxonomic classification based on a review of peer-reviewed mussel taxonomic and nomenclatural literature produced since 1998, unpublished research by the authors, and discussions with other experts on mussel systematics. We also corrected the spelling of specific epithets and publication dates of original descriptions based on the International Code of Zoological Nomenclature (http://www. iczn.org/iczn/index.jsp). Species mentioned in the text, but not included in Table 2, have author and date of publication following the name. Author and date of publication for all other species are given in Table 2. Mussel common names follow Turgeon et al. (1998) with minor exceptions, but they are capitalized as is now the practice for many other animal groups (e.g., birds, reptiles, amphibians, fishes). Capitalization of common names helps avoid confusion by identifying standardized common names. For example, reference to a ‘‘fragile papershell’’ could apply to several thin-shelled species, but the capitalized ‘‘Fragile Papershell’’ is unambiguously recognized as the common name for Leptodea fragilis. We note and explain other instances where we changed common names from those of Turgeon et al. (1998) or where recognition of previously unrecognized species necessitated creation of a new common name. We provide a rationale for and discussion of all taxonomic changes in the following accounts for each family and genus and in Table 2. There is a degree of uncertainty and subjectivity in our revised list that is unavoidable given our still imperfect understanding of mussel systematics. We attempted to reconcile divergent views regarding mussel systematics based on our assessment of the strength of evidence for these views. In cases where evidence did not allow reconciliation, we attempted to provide a plausible conclusion based on our professional judgment and experience; these conclusions were based on consensus among the authors to the extent possible. Subspecies is a taxonomic category applied to populations that are morphologically distinct and geographically separated but that exhibit intergradation in contact zones (Mayr et al. 1953; Gilbert 1961). We evaluated morphological and molecular evidence relating to the status of subspecies recognized by Turgeon et al. (1998) and subsequent workers (Jones and Neves 2010). In most cases, recent evidence did not support recognition of subspecies but supported either subsuming subspecies under the nominal species or elevating subspecies to species status; we discuss this evidence for each case. However, strong evidence with which to evaluate their status was lacking for several, mostly extinct, subspecies (see Epioblasma). The designation of subspecies versus species is arbitrary and inconsistent for many animal groups (Huang and Knowles 2016), and this has historically been the case for mussels (e.g., Ortmann 1918, 1920). For subspecies that lacked strong evidence for synonymization or elevation, we recognize all as species to provide more consistent null hypotheses regarding potential diversity in these groups. This work has been registered with ZooBank and a copy has been archived at Zenodo.org. RESULTS Freshwater bivalve higher classification continues to evolve as more data are generated and new techniques are developed. Fossil and modern bivalve higher classification has REVISED LIST OF FRESHWATER MUSSELS Table 1. Higher classification of the Unionoidea present in the United States and Canada. CLASS Bivalvia Linnaeus, 1758 INFRACLASS Heteroconchia Hertwig, 1895 COHORT Uniomorphi Gray, 1854 [¼Paleoheterodonta] ORDER Unionida Gray, 1854 SUPERFAMILY Unionoidea Rafinesque, 1820 MARGARITIFERIDAE Henderson, 1929 Margaritifera Schumacher, 1816 UNIONIDAE Rafinesque, 1820 ANODONTINAE Rafinesque, 1820 Anodontini Rafinesque, 1820 Alasmidonta Say, 1818 Anodonta Lamarck, 1799 Anodontoides Simpson in Baker, 1898 Arcidens Simpson, 1900 Lasmigona Rafinesque, 1831 Pegias Simpson, 1900 Pyganodon Crosse and Fischer, 1894 Simpsonaias Frierson, 1914 Strophitus Rafinesque, 1820 Utterbackia Baker, 1927 Utterbackiana Frierson, 1927 Cristariini Lopes-Lima, Bogan, and Froufe, 2017 Sinanodonta Modell, 1945 GONIDEINAE Ortmann, 1916 Gonideini Ortmann, 1916 Gonidea Conrad, 1857 AMBLEMINAE Rafinesque, 1820 Amblemini Rafinesque, 1820 Amblema Rafinesque, 1820 Lampsilini Ihering, 1901 Actinonaias Crosse and Fischer, 1894 Cyprogenia Agassiz, 1852 Cyrtonaias Crosse and Fischer, 1894 Dromus Simpson, 1900 Ellipsaria Rafinesque, 1820 Epioblasma Rafinesque, 1831 Glebula Conrad, 1853 Hamiota Roe and Hartfield, 2005 Lampsilis Rafinesque, 1820 Lemiox Rafinesque, 1831 Leptodea Rafinesque, 1820 Ligumia Swainson, 1840 Medionidus Simpson, 1900 Obliquaria Rafinesque, 1820 Obovaria Rafinesque, 1819 Plectomerus Conrad, 1853 Potamilus Rafinesque, 1818 Ptychobranchus Simpson, 1900 Toxolasma Rafinesque, 1831 Truncilla Rafinesque, 1819 Venustaconcha Frierson, 1927 Villosa Frierson, 1927 35 Table 1, continued. Pleurobemini Hannibal, 1912 Elliptio Rafinesque, 1819 Elliptoideus Frierson, 1927 Eurynia Rafinesque, 1820 Fusconaia Simpson, 1900 Hemistena Rafinesque, 1820 Parvaspina Perkins, Gangloff, and Johnson, 2017 Plethobasus Simpson, 1900 Pleurobema Rafinesque, 1819 Pleuronaia Frierson, 1927 Quadrulini Ihering, 1901 Cyclonaias Pilsbry in Ortmann and Walker, 1922 Megalonaias Utterback, 1915 Quadrula Rafinesque, 1820 Theliderma Swainson, 1840 Tritogonia Agassiz, 1852 Uniomerus Conrad, 1853 AMBLEMINAE (incertae sedis) Disconaias Crosse and Fischer, 1894 Popenaias Frierson, 1927 Reginaia Campbell and Lydeard, 2012 recently been summarized by Carter et al. (2011), with standardized endings for higher taxa within Bivalvia. Recent evidence supports the order Unionida as a monophyletic clade (Combosch et al. 2017). There have been two recent assessments of the taxonomy for Margaritiferidae (Bolotov et al. 2016; Araujo et al. 2017). Higher level relationships within the Unionidae have recently been reviewed by LopesLima et al. (2017). Based on these publications, we provide our assessment of higher classification of the Unionida and its position in the class Bivalvia (Table 1). There is general agreement on the three subfamily divisions within the Unionidae in North America and seven subfamilies worldwide, but there remains some uncertainty regarding classification at lower levels. We adopted a subfamily-, tribe-, and generic-level classification for the United States and Canada based on recent phylogenetic research (Table 1). We recognize the Anodontinae as a subfamily with two tribes in the United States and Canada. We recognize the subfamily Gonideinae, containing the genus Gonidea. We recognize the subfamily Ambleminae as consisting of four tribes: Amblemini, Lampsilini, Pleurobemini, and Quadrulini. The placement of many genera within tribes in the Ambleminae is well supported and consistent among studies, but the placement of others is less certain and varies among studies (e.g., Plectomerus, Campbell et al. 2005). The Mexican and Central American genera Disconaias and Popenaias and North American Reginaia lack sufficient phylogenetic information to be confidently assigned to a classification, and we placed them in Ambleminae incertae sedis (Table 1). Our revised list includes many taxonomic changes at the 36 WILLIAMS ET AL. Table 2. List of Margaritiferidae and Unionidae of the United States and Canada. Currently recognized taxa are bolded. Taxa preceded by an asterisk and not bolded appeared in Turgeon et al. (1998) but are no longer recognized or reassigned to other genera. Scientific Name MARGARITIFERIDAE Henderson, 1929 *Cumberlandia Ortmann, 1912 *Cumberlandia monodonta (Say, 1829) Margaritifera Schumacher, 1816 Margaritifera falcata (Gould, 1850) Margaritifera hembeli (Conrad, 1838) Margaritifera margaritifera (Linnaeus, 1758) Margaritifera marrianae Johnson, 1983 Margaritifera monodonta (Say, 1829) UNIONIDAE Rafinesque, 1820 Actinonaias Crosse and Fischer, 1894 Actinonaias ligamentina (Lamarck, 1819) Actinonaias pectorosa (Conrad, 1834) Alasmidonta Say, 1818 Alasmidonta arcula (Lea, 1838) Alasmidonta atropurpurea (Rafinesque, 1831) Alasmidonta heterodon (Lea, 1829) Alasmidonta marginata Say, 1818 Alasmidonta mccordi Athearn, 1964 Alasmidonta raveneliana (Lea, 1834) Alasmidonta robusta Clarke, 1981 Alasmidonta triangulata (Lea, 1858) Alasmidonta undulata (Say, 1817) Alasmidonta varicosa (Lamarck, 1819) Alasmidonta viridis (Rafinesque, 1820) Alasmidonta wrightiana (Walker, 1901) Amblema Rafinesque, 1820 Amblema elliottii (Lea, 1856) Amblema neislerii (Lea, 1858) Amblema plicata (Say, 1817) Anodonta Lamarck, 1799 *Anodonta beringiana Middendorff, 1851 Anodonta californiensis Lea, 1852 *Anodonta couperiana Lea, 1840 *Anodonta dejecta Lewis, 1875 *Anodonta heardi Gordon and Hoeh, 1995 *Anodonta implicata Say, 1829 Anodonta kennerlyi Lea, 1860 Anodonta nuttalliana Lea, 1838 Anodonta oregonensis Lea, 1838 *Anodonta suborbiculata Say, 1831 Anodontoides Simpson in Baker, 1898 Anodontoides denigrata (Lea, 1852) Anodontoides ferussacianus (Lea, 1834) Anodontoides radiatus (Conrad, 1834) Arcidens Simpson, 1900 Arcidens confragosus (Say, 1829) Arcidens wheeleri (Ortmann and Walker, 1912) *Arkansia Ortmann and Walker, 1912 *Arkansia wheeleri Ortmann and Walker, 1912 Common Name Changes in Scientific and Common Names Spectaclecase Synonym of Margaritifera Reassigned to Margaritifera Western Pearlshell Louisiana Pearlshell Eastern Pearlshell Alabama Pearlshell Spectaclecase Reassigned from Cumberlandia Mucket Pheasantshell Altamaha Arcmussel Cumberland Elktoe Dwarf Wedgemussel Elktoe Coosa Elktoe Appalachian Elktoe Carolina Elktoe Southern Elktoe Triangle Floater Brook Floater Slippershell Mussel Ochlockonee Arcmussel Publication date corrected Coosa Fiveridge Fat Threeridge Threeridge Yukon Floater California Floater Barrel Floater Woebegone Floater Apalachicola Floater Alewife Floater Western Floater Winged Floater Oregon Floater Flat Floater Cumberland Papershell Cylindrical Papershell Rayed Creekshell Rock Pocketbook Ouachita Rock Pocketbook Ouachita Rock Pocketbook Reassigned to Sinanodonta Reassigned to Utterbackiana Synonym of Anodonta californiensis Reassigned to Utterbackiana Reassigned to Utterbackiana Reassigned to Utterbackiana Elevated from synonymy Reassigned from Arkansia Synonym of Arcidens Reassigned to Arcidens 37 REVISED LIST OF FRESHWATER MUSSELS Table 2, continued. Scientific Name Cyclonaias Pilsbry in Ortmann and Walker, 1922 Cyclonaias archeri (Frierson, 1905) Cyclonaias asperata (Lea, 1861) Cyclonaias aurea (Lea, 1859) Cyclonaias houstonensis (Lea, 1859) Cyclonaias infucata (Conrad, 1834) Cyclonaias kieneriana (Lea, 1852) Cyclonaias kleiniana (Lea, 1852) Cyclonaias mortoni (Conrad, 1835) Cyclonaias nodulata (Rafinesque, 1820) Cyclonaias petrina (Gould, 1855) Cyclonaias pustulosa (Lea, 1831) Cyclonaias refulgens (Lea, 1868) Cyclonaias succissa (Lea, 1852) Cyclonaias tuberculata (Rafinesque, 1820) Cyprogenia Agassiz, 1852 Cyprogenia aberti (Conrad, 1850) Cyprogenia stegaria (Rafinesque, 1820) Cyrtonaias Crosse and Fischer, 1894 Cyrtonaias tampicoensis (Lea, 1838) Disconaias Crosse and Fischer, 1894 Disconaias fimbriata (Frierson, 1907) *Disconaias salinasensis (Simpson, 1908) Dromus Simpson, 1900 Dromus dromas (Lea, 1834) Ellipsaria Rafinesque, 1820 Ellipsaria lineolata (Rafinesque, 1820) Elliptio Rafinesque, 1819 Elliptio ahenea (Lea, 1843) Elliptio angustata (Lea, 1831) Elliptio arca (Conrad, 1834) Elliptio arctata (Conrad, 1834) *Elliptio buckleyi (Lea, 1843) Elliptio chipolaensis (Walker, 1905) Elliptio cistellaeformis (Lea, 1863) Elliptio complanata (Lightfoot, 1786) Elliptio congaraea (Lea, 1831) Elliptio crassidens (Lamarck, 1819) Elliptio dariensis (Lea, 1842) *Elliptio dilatata (Rafinesque, 1820) Elliptio downiei (Lea, 1858) *Elliptio errans (Lea, 1856) Elliptio fisheriana (Lea, 1838) Elliptio folliculata (Lea, 1838) Elliptio fraterna (Lea, 1852) Elliptio fumata (Lea, 1857) *Elliptio hepatica (Lea, 1859) Elliptio hopetonensis (Lea, 1838) Elliptio icterina (Conrad, 1834) Common Name Tallapoosa Orb Alabama Orb Golden Orb Smooth Pimpleback Sculptured Pigtoe Coosa Orb Florida Mapleleaf Western Pimpleback Wartyback Texas Pimpleback Pimpleback Purple Pimpleback Purple Pigtoe Purple Wartyback Changes in Scientific and Common Names Elevated from synonymy Reassigned from Quadrula Reassigned from Quadrula Reassigned from Quadrula Reassigned from Quincuncina Elevated from synonymy Elevated from synonymy Species elevated from subspecies; reassigned from Quadrula Reassigned from Quadrula Reassigned from Quadrula Reassigned from Quadrula Reassigned from Quadrula Reassigned from Fusconaia Western Fanshell Fanshell Tampico Pearlymussel Fringed Mucket Salina Mucket Elevated from synonymy Synonym of Disconaias fimbriata Dromedary Pearlymussel Butterfly Southern Lance Carolina Lance Alabama Spike Delicate Spike Florida Shiny Spike Chipola Slabshell Box Spike Eastern Elliptio Carolina Slabshell Elephantear Georgia Elephantear Spike Satilla Elephantear Oval Elliptio Northern Lance Pod Lance Brother Spike Gulf Slabshell Brown Elliptio Altamaha Slabshell Variable Spike Synonym of Elliptio jayensis Reassigned to Eurynia Synonym of Elliptio icterina; publication date corrected Elevated from synonymy Synonym of Elliptio icterina WILLIAMS ET AL. 38 Table 2, continued. Scientific Name Elliptio jayensis (Lea, 1838) *Elliptio judithae Clarke, 1986 Elliptio lanceolata (Lea, 1828) *Elliptio lugubris (Lea, 1834) Elliptio marsupiobesa Fuller, 1972 Elliptio mcmichaeli Clench and Turner, 1956 Elliptio monroensis (Lea, 1843) Elliptio nigella (Lea, 1852) Elliptio occulta (Lea, 1843) Elliptio producta (Conrad, 1836) Elliptio pullata (Lea, 1856) Elliptio purpurella (Lea, 1857) *Elliptio raveneli (Conrad, 1834) Elliptio roanokensis (Lea, 1838) Elliptio shepardiana (Lea, 1834) Elliptio spinosa (Lea, 1836) *Elliptio steinstansana Johnson and Clarke, 1983 *Elliptio waccamawensis (Lea, 1863) *Elliptio waltoni (Wright, 1888) Elliptoideus Frierson, 1927 Elliptoideus sloatianus (Lea, 1840) Epioblasma Rafinesque, 1831 Epioblasma ahlstedti Jones and Neves, 2010 Epioblasma arcaeformis (Lea, 1831) Epioblasma aureola Jones and Neves, 2010 Epioblasma biemarginata (Lea, 1857) Epioblasma brevidens (Lea, 1831) Epioblasma capsaeformis (Lea, 1834) Epioblasma cincinnatiensis (Lea, 1840) Epioblasma curtisii (Frierson and Utterback, 1916) Epioblasma flexuosa (Rafinesque, 1820) Epioblasma florentina (Lea, 1857) *Epioblasma florentina aureola Jones and Neves, 2010 *Epioblasma florentina curtisii (Frierson and Utterback, 1916) *Epioblasma florentina florentina (Lea, 1857) *Epioblasma florentina walkeri (Wilson and Clark, 1914) Epioblasma gubernaculum (Reeve, 1865) Epioblasma haysiana (Lea, 1834) Epioblasma lenior (Lea, 1842) Epioblasma lewisii (Walker, 1910) Epioblasma metastriata (Conrad, 1838) Epioblasma obliquata (Rafinesque, 1820) *Epioblasma obliquata obliquata (Rafinesque, 1820) *Epioblasma obliquata perobliqua (Conrad, 1836) Epioblasma othcaloogensis (Lea, 1857) Epioblasma penita (Conrad, 1834) Epioblasma perobliqua (Conrad, 1836) Epioblasma personata (Say, 1829) Epioblasma propinqua (Lea, 1857) Epioblasma rangiana (Lea, 1838) Common Name Florida Spike Plicate Spike Yellow Lance Sad Elliptio Cape Fear Spike Fluted Elephantear St. Johns Elephantear Winged Spike Hidden Spike Atlantic Spike Gulf Spike Inflated Spike Carolina Spike Roanoke Slabshell Altamaha Lance Altamaha Spinymussel Tar River Spinymussel Waccamaw Spike Florida Lance Changes in Scientific and Common Names Common name changed from Flat Spike Synonym of Elliptio roanokensis Synonym of Elliptio icterina Elevated from synonymy Elevated from synonymy Elevated from synonymy Synonym of Elliptio icterina Reassigned to Parvaspina Synonym of Elliptio congaraea Synonym of Elliptio ahenea Purple Bankclimber Duck River Dartersnapper Sugarspoon Golden Riffleshell Angled Riffleshell Cumberlandian Combshell Oyster Mussel Ohio Riffleshell Curtis Pearlymussel Leafshell Yellow Blossom Golden Riffleshell Curtis Pearlymussel Yellow Blossom Tan Riffleshell Green Blossom Acornshell Narrow Catspaw Forkshell Upland Combshell Catspaw Catspaw White Catspaw Southern Acornshell Southern Combshell White Catspaw Round Combshell Tennessee Riffleshell Northern Riffleshell Described as new species Species elevated from subspecies Elevated from synonymy Species elevated from subspecies Described as new subspecies; elevated to species Subspecies elevated to species Nominotypical subspecies not required Subspecies elevated to species Species elevated from subspecies Nominotypical subspecies not required Subspecies elevated to species Species elevated from subspecies Species elevated from subspecies 39 REVISED LIST OF FRESHWATER MUSSELS Table 2, continued. Scientific Name Epioblasma sampsonii (Lea, 1861) Epioblasma stewardsonii (Lea, 1852) Epioblasma torulosa (Rafinesque, 1820) *Epioblasma torulosa gubernaculum (Reeve, 1865) *Epioblasma torulosa rangiana (Lea, 1838) *Epioblasma torulosa torulosa (Rafinesque, 1820) Epioblasma triquetra (Rafinesque, 1820) Epioblasma turgidula (Lea, 1858) Epioblasma walkeri (Wilson and Clark, 1914) Eurynia Rafinesque, 1820 Eurynia dilatata Rafinesque, 1820 Fusconaia Simpson, 1900 *Fusconaia askewi (Marsh, 1896) *Fusconaia barnesiana (Lea, 1838) Fusconaia burkei (Walker, 1922) Fusconaia cerina (Conrad, 1838) Fusconaia chunii (Lea, 1861) Fusconaia cor (Conrad, 1834) Fusconaia cuneolus (Lea, 1840) *Fusconaia ebena (Lea, 1831) Fusconaia escambia Clench and Turner, 1956 Fusconaia flava (Rafinesque, 1820) *Fusconaia lananensis (Frierson, 1901) Fusconaia masoni (Conrad, 1834) Fusconaia mitchelli (Simpson, 1895) Fusconaia ozarkensis (Call, 1887) Fusconaia subrotunda (Lea, 1831) *Fusconaia succissa (Lea, 1852) Glebula Conrad, 1853 Glebula rotundata (Lamarck, 1819) Gonidea Conrad, 1857 Gonidea angulata (Lea, 1838) Hamiota Roe and Hartfield, 2005 Hamiota altilis (Conrad, 1834) Hamiota australis (Simpson, 1900) Hamiota perovalis (Conrad, 1834) Hamiota subangulata (Lea, 1840) Hemistena Rafinesque, 1820 Hemistena lata (Rafinesque, 1820) Lampsilis Rafinesque, 1820 Lampsilis abrupta (Say, 1831) *Lampsilis altilis (Conrad, 1834) *Lampsilis australis Simpson, 1900 Lampsilis binominata Simpson, 1900 Lampsilis bracteata (Gould, 1855) Lampsilis brittsi Simpson, 1900 Lampsilis cardium Rafinesque, 1820 Lampsilis cariosa (Say,1817) Lampsilis dolabraeformis (Lea, 1838) Lampsilis fasciola Rafinesque, 1820 Common Name Wabash Riffleshell Cumberland Leafshell Tubercled Blossom Green Blossom Northern Riffleshell Tubercled Blossom Snuffbox Turgid Blossom Tan Riffleshell Spike Texas Pigtoe Tennessee Pigtoe Tapered Pigtoe Gulf Pigtoe Texas Pigtoe Shiny Pigtoe Finerayed Pigtoe Ebonyshell Narrow Pigtoe Wabash Pigtoe Triangle Pigtoe Atlantic Pigtoe False Spike Ozark Pigtoe Longsolid Purple Pigtoe Changes in Scientific and Common Names Subspecies elevated to species Subspecies elevated to species Nominotypical subspecies not required Species elevated from subspecies Elevated from synonymy Reassigned from Elliptio Synonym of Fusconaia chunii Reassigned to Pleuronaia Reassigned from Quincuncina Common name changed from Southern Pigtoe Elevated from synonymy Reassigned to Reginaia Synonym of Fusconaia chunii Reassigned from Quincuncina Reassigned to Cyclonaias Round Pearlshell Western Ridged Mussel Finelined Pocketbook Southern Sandshell Orangenacre Mucket Shinyrayed Pocketbook Described as new genus Reassigned from Lampsilis Reassigned from Lampsilis Reassigned from Lampsilis Reassigned from Lampsilis Cracking Pearlymussel Pink Mucket Finelined Pocketbook Southern Sandshell Lined Pocketbook Texas Fatmucket Northern Brokenray Plain Pocketbook Yellow Lampmussel Altamaha Pocketbook Wavyrayed Lampmussel Reassigned to Hamiota Reassigned to Hamiota Species elevated from subspecies 40 WILLIAMS ET AL. Table 2, continued. Scientific Name Lampsilis floridensis (Lea, 1852) *Lampsilis fullerkati Johnson, 1984 *Lampsilis haddletoni Athearn, 1964 Lampsilis higginsii (Lea, 1857) Lampsilis hydiana (Lea, 1838) Lampsilis ornata (Conrad, 1835) Lampsilis ovata (Say, 1817) *Lampsilis perovalis (Conrad, 1834) Lampsilis powellii (Lea, 1852) Lampsilis radiata (Gmelin, 1791) *Lampsilis radiata conspicua (Lea, 1872) *Lampsilis radiata radiata (Gmelin, 1791) Lampsilis rafinesqueana Frierson, 1927 Lampsilis reeveiana (Lea, 1852) *Lampsilis reeveiana brevicula (Call, 1887) *Lampsilis reeveiana brittsi Simpson, 1900 *Lampsilis reeveiana reeviana (Lea, 1852) Lampsilis satura (Lea, 1852) Lampsilis siliquoidea (Barnes, 1823) Lampsilis splendida (Lea, 1838) Lampsilis straminea (Conrad, 1834) *Lampsilis straminea claibornensis (Lea, 1838) *Lampsilis straminea straminea (Conrad, 1834) Lampsilis streckeri Frierson, 1927 *Lampsilis subangulata (Lea, 1840) Lampsilis teres (Rafinesque, 1820) Lampsilis virescens (Lea, 1858) Lasmigona Rafinesque, 1831 Lasmigona alabamensis Clarke, 1985 Lasmigona complanata (Barnes, 1823) *Lasmigona complanata alabamensis Clarke, 1985 *Lasmigona complanata complanata (Barnes, 1823) Lasmigona compressa (Lea, 1829) Lasmigona costata (Rafinesque, 1820) Lasmigona decorata (Lea, 1852) Lasmigona etowaensis (Conrad, 1849) Lasmigona holstonia (Lea, 1838) Lasmigona subviridis (Conrad, 1835) Lemiox Rafinesque, 1831 Lemiox rimosus (Rafinesque, 1831) Leptodea Rafinesque, 1820 Leptodea fragilis (Rafinesque, 1820) Leptodea leptodon (Rafinesque, 1820) Leptodea ochracea (Say, 1817) *Lexingtonia Ortmann, 1914 *Lexingtonia dolabelloides (Lea, 1840) *Lexingtonia subplana (Conrad, 1837) Ligumia Swainson, 1840 Ligumia nasuta (Say, 1817) Ligumia recta (Lamarck, 1819) Ligumia subrostrata (Say, 1831) Common Name Changes in Scientific and Common Names Florida Sandshell Waccamaw Fatmucket Haddleton Lampmussel Higgins Eye Louisiana Fatmucket Southern Pocketbook Pocketbook Orangenacre Mucket Arkansas Fatmucket Eastern Lampmussel Carolina Fatmucket Eastern Lampmussel Neosho Mucket Arkansas Brokenray Ozark Brokenray Northern Brokenray Arkansas Brokenray Sandbank Pocketbook Fatmucket Rayed Pink Fatmucket Rough Fatmucket Southern Fatmucket Rough Fatmucket Speckled Pocketbook Shinyrayed Pocketbook Yellow Sandshell Alabama Lampmussel Elevated from synonymy Synonym of Lampsilis radiata Reassigned to Obovaria Alabama Heelsplitter White Heelsplitter Alabama Heelsplitter White Heelsplitter Creek Heelsplitter Flutedshell Carolina Heelsplitter Etowah Heelsplitter Tennessee Heelsplitter Green Floater Species elevated from subspecies Reassigned to Hamiota Subspecies no longer recognized Nominotypical subspecies not required Subspecies no longer recognized Subspecies elevated to species Nominotypical subspecies not required Subspecies no longer recognized Nominotypical subspecies not required Reassigned to Hamiota Subspecies elevated to species Nominotypical subspecies not required Elevated from synonymy Birdwing Pearlymussel Fragile Papershell Scaleshell Tidewater Mucket Slabside Pearlymussel Virginia Pigtoe Eastern Pondmussel Black Sandshell Pondmussel Synonym of Fusconaia Reassigned to Pleuronaia Synonym of Fusconaia masoni 41 REVISED LIST OF FRESHWATER MUSSELS Table 2, continued. Scientific Name Medionidus Simpson, 1900 Medionidus acutissimus (Lea, 1831) Medionidus conradicus (Lea, 1834) *Medionidus mcglameriae van der Schalie, 1939 Medionidus parvulus (Lea, 1860) Medionidus penicillatus (Lea, 1857) Medionidus simpsonianus Walker, 1905 Medionidus walkeri (Wright, 1897) Megalonaias Utterback, 1915 Megalonaias nervosa (Rafinesque, 1820) Obliquaria Rafinesque, 1820 Obliquaria reflexa Rafinesque, 1820 Obovaria Rafinesque, 1819 Obovaria arkansasensis (Lea, 1862) Obovaria choctawensis (Athearn, 1964) Obovaria haddletoni (Athearn, 1964) *Obovaria jacksoniana (Frierson, 1912) Obovaria olivaria (Rafinesque, 1820) Obovaria retusa (Lamarck, 1819) *Obovaria rotulata (Wright, 1899) Obovaria subrotunda (Rafinesque, 1820) Obovaria unicolor (Lea, 1845) Parvaspina Perkins, Gangloff, and Johnson, 2017 Parvaspina collina (Conrad, 1836) Parvaspina steinstansana (Johnson and Clarke, 1983) Pegias Simpson, 1900 Pegias fabula (Lea, 1838) Plectomerus Conrad, 1853 Plectomerus dombeyanus (Valenciennes, 1827) Plethobasus Simpson, 1900 Plethobasus cicatricosus (Say, 1829) Plethobasus cooperianus (Lea, 1834) Plethobasus cyphyus (Rafinesque, 1820) Pleurobema Rafinesque, 1819 *Pleurobema altum (Conrad, 1854) Pleurobema athearni Gangloff, Williams, and Feminella, 2006 *Pleurobema avellanum Simpson, 1900 Pleurobema beadleianum (Lea, 1861) *Pleurobema bournianum (Lea, 1840) *Pleurobema chattanoogaense (Lea, 1858) Pleurobema clava (Lamarck, 1819) *Pleurobema collina (Conrad, 1836) Pleurobema cordatum (Rafinesque, 1820) Pleurobema curtum (Lea, 1859) Pleurobema decisum (Lea, 1831) Pleurobema fibuloides (Lea, 1859) *Pleurobema flavidulum (Lea, 1861) *Pleurobema furvum (Conrad, 1834) Pleurobema georgianum (Lea, 1841) Common Name Alabama Moccasinshell Cumberland Moccasinshell Tombigbee Moccasinshell Coosa Moccasinshell Gulf Moccasinshell Ochlockonee Moccasinshell Suwannee Moccasinshell Changes in Scientific and Common Names Synonym of Leptodea fragilis Washboard Threehorn Wartyback Southern Hickorynut Choctaw Bean Haddleton Lampmussel Southern Hickorynut Hickorynut Ring Pink Round Ebonyshell Round Hickorynut Alabama Hickorynut James Spinymussel Tar River Spinymussel Reassigned from Villosa Reassigned from Villosa Reassigned from Lampsilis Synonym of Obovaria arkansasensis Reassigned to Reginaia Described as new genus Reassigned from Pleurobema; publication date corrected Reassigned from Elliptio Littlewing Pearlymussel Bankclimber White Wartyback Orangefoot Pimpleback Sheepnose Highnut Canoe Creek Clubshell Considered a nomen dubium Described as new species Hazel Pigtoe Mississippi Pigtoe Scioto Pigtoe Painted Clubshell Clubshell James Spinymussel Ohio Pigtoe Black Clubshell Southern Clubshell Kusha Pigtoe Yellow Pigtoe Dark Pigtoe Southern Pigtoe Synonym of Pleurobema rubellum Synonym of Pleurobema clava Synonym of Pleurobema decisum Reassigned to Parvaspina Elevated from synonymy Synonym of Pleurobema perovatum Synonym of Pleurobema rubellum 42 WILLIAMS ET AL. Table 2, continued. Scientific Name *Pleurobema gibberum (Lea, 1838) *Pleurobema hagleri (Frierson, 1900) Pleurobema hanleyianum (Lea, 1852) Pleurobema hartmanianum (Lea, 1860) *Pleurobema johannis (Lea, 1859) Pleurobema marshalli Frierson, 1927 *Pleurobema murrayense (Lea, 1868) *Pleurobema nucleopsis (Conrad, 1849) Pleurobema oviforme (Conrad, 1834) Pleurobema perovatum (Conrad, 1834) Pleurobema plenum (Lea, 1840) Pleurobema pyriforme (Lea, 1857) Pleurobema riddellii (Lea, 1861) Pleurobema rubellum (Conrad, 1834) Pleurobema rubrum (Rafinesque, 1820) Pleurobema sintoxia (Rafinesque, 1820) Pleurobema stabile (Lea, 1861) Pleurobema strodeanum (Wright, 1898) Pleurobema taitianum (Lea, 1834) *Pleurobema troschelianum (Lea, 1852) Pleurobema verum (Lea, 1861) Pleuronaia Frierson, 1927 Pleuronaia barnesiana (Lea, 1838) Pleuronaia dolabelloides (Lea, 1840) Pleuronaia gibber (Lea, 1838) Popenais Frierson, 1927 Popenais popeii (Lea, 1857) Potamilus Rafinesque, 1818 Potamilus alatus (Say, 1817) Potamilus amphichaenus (Frierson, 1898) Potamilus capax (Green, 1832) Potamilus inflatus (Lea, 1831) Potamilus metnecktayi Johnson, 1998 Potamilus ohiensis (Rafinesque, 1820) Potamilus purpuratus (Lamarck, 1819) Ptychobranchus Simpson, 1900 Ptychobranchus fasciolaris (Rafinesque, 1820) Ptychobranchus foremanianus (Lea, 1842) Ptychobranchus greenii (Conrad, 1834) Ptychobranchus jonesi (van der Schalie, 1934) Ptychobranchus occidentalis (Conrad, 1836) *Ptychobranchus subtentum (Say, 1825) Ptychobranchus subtentus (Say, 1825) Pyganodon Crosse and Fischer, 1894 Pyganodon cataracta (Say, 1817) Pyganodon fragilis (Lamarck, 1819) Pyganodon gibbosa (Say, 1824) Pyganodon grandis (Say, 1829) Pyganodon lacustris (Lea, 1857) Common Name Cumberland Pigtoe Brown Pigtoe Georgia Pigtoe Cherokee Pigtoe Alabama Pigtoe Flat Pigtoe Coosa Pigtoe Longnut Tennessee Clubshell Ovate Clubshell Rough Pigtoe Oval Pigtoe Louisiana Pigtoe Warrior Pigtoe Pyramid Pigtoe Round Pigtoe Coosa Pigtoe Fuzzy Pigtoe Heavy Pigtoe Alabama Clubshell True Pigtoe Tennessee Pigtoe Slabside Pearlymussel Cumberland Pigtoe Changes in Scientific and Common Names Reassigned to Pleuronaia Synonym of Pleurobema rubellum Elevated from synonymy Synonym of Pleurobema perovatum Synonym of Pleurobema stabile Synonym of Pleurobema georgianum Elevated from synonymy Synonym of Pleurobema georgianum Elevated from synonymy Reassigned from Fusconaia Reassigned from Lexingtonia Reassigned from Pleurobema; spelling correction of species name Texas Hornshell Pink Heelsplitter Texas Heelsplitter Fat Pocketbook Inflated Heelsplitter Salina Mucket Pink Papershell Bleufer Common name changed from Alabama Heelsplitter Described as new species Kidneyshell Rayed Kidneyshell Triangular Kidneyshell Southern Kidneyshell Ouachita Kidneyshell Fluted Kidneyshell Fluted Kidneyshell Incorrect spelling of species name Spelling correction of species name Eastern Floater Newfoundland Floater Inflated Floater Giant Floater Lake Floater Publication date corrected Elevated from synonymy 43 REVISED LIST OF FRESHWATER MUSSELS Table 2, continued. Scientific Name Quadrula Rafinesque, 1820 Quadrula apiculata (Say, 1829) *Quadrula asperata (Lea, 1861) *Quadrula aurea (Lea, 1859) Quadrula couchiana (Lea, 1860) *Quadrula cylindrica cylindrica (Say, 1817) Common Name Southern Mapleleaf Alabama Orb Golden Orb Rio Grande Monkeyface Rabbitsfoot *Quadrula cylindrica strigillata (Wright, 1898) Quadrula fragosa (Conrad, 1835) *Quadrula houstonensis (Lea, 1859) *Quadrula intermedia (Conrad, 1836) *Quadrula kieneriana (Lea, 1852) *Quadrula metanevra (Rafinesque, 1820) Quadrula nobilis (Conrad, 1854) *Quadrula nodulata (Rafinesque, 1820) *Quadrula petrina (Gould, 1855) *Quadrula pustulosa mortoni (Conrad, 1835) Rough Rabbitsfoot Winged Mapleleaf Smooth Pimpleback Cumberland Monkeyface Coosa Orb Monkeyface Gulf Mapleleaf Wartyback Texas Pimpleback Western Pimpleback *Quadrula pustulosa pustulosa (Lea, 1831) Pimpleback Quadrula quadrula (Rafinesque, 1820) *Quadrula refulgens (Lea, 1868) Quadrula rumphiana (Lea, 1852) *Quadrula sparsa (Lea, 1841) *Quadrula stapes (Lea, 1831) *Quadrula tuberosa (Lea, 1840) *Quincuncina Ortmann, 1922 *Quincuncina burkei Walker, 1922 *Quincuncina infucata (Conrad, 1834) *Quincuncina mitchelli (Simpson, 1895) Reginaia Campbell and Lydeard, 2012 Reginaia apalachicola (Williams and Fradkin, 1999) Reginaia ebenus (Lea, 1831) Reginaia rotulata (Wright, 1899) Simpsonaias Frierson, 1914 Simpsonaias ambigua (Say, 1825) Sinanodonta Modell, 1945 Sinanodonta beringiana (Middendorff, 1851) Sinanodonta woodiana (Lea, 1834) Strophitus Rafinesque, 1820 Strophitus connasaugaensis (Lea, 1858) Strophitus subvexus (Conrad, 1834) Strophitus undulatus (Say, 1817) Theliderma Swainson, 1840 Theliderma cylindrica (Say, 1817) Theliderma intermedia (Conrad, 1836) Theliderma metanevra (Rafinesque, 1820) Theliderma sparsa (Lea, 1841) Theliderma stapes (Lea, 1831) Mapleleaf Purple Pimpleback Ridged Mapleleaf Appalachian Monkeyface Stirrupshell Rough Rockshell Tapered Pigtoe Sculptured Pigtoe False Spike Apalachicola Ebonyshell Ebonyshell Round Ebonyshell Changes in Scientific and Common Names Reassigned to Cyclonaias Reassigned to Cyclonaias Nominotypical subspecies not required; reassigned to Theliderma Subspecies no longer recognized Reassigned to Cyclonaias Reassigned to Theliderma Reassigned to Cyclonaias Reassigned to Theliderma Elevated from synonymy Reassigned to Cyclonaias Reassigned to Cyclonaias Subspecies elevated to species; reassigned to Cyclonaias Nominotypical subspecies not required; reassigned to Cyclonaias Reassigned to Cyclonaias Reassigned to Theliderma Reassigned to Theliderma Synonym of Theliderma metanevra Synonym of Fusconaia Reassigned to Fusconaia Reassigned to Cyclonaias Reassigned to Fusconaia Described as new genus Described as new species; reassigned from Fusconaia Reassigned from Fusconaia; spelling correction of species name Reassigned from Obovaria Salamander Mussel Yukon Floater Chinese Pondmussel Not previously reported from North America Reassigned from Anodonta Introduced and established in New Jersey Alabama Creekmussel Southern Creekmussel Creeper Rabbitsfoot Cumberland Monkeyface Monkeyface Appalachian Monkeyface Stirrupshell Elevated from synonymy Reassigned from Quadrula Reassigned from Quadrula Reassigned from Quadrula Reassigned from Quadrula Reassigned from Quadrula 44 WILLIAMS ET AL. Table 2, continued. Scientific Name Toxolasma Rafinesque, 1831 Toxolasma corvunculus (Lea, 1868) Toxolasma cylindrellus (Lea, 1868) Toxolasma lividum Rafinesque, 1831 Common Name Southern Purple Lilliput Pale Lilliput Purple Lilliput *Toxolasma lividus (Rafinesque, 1831) *Toxolasma mearnsi (Simpson, 1900) Toxolasma parvum (Barnes, 1823) *Toxolasma parvus (Barnes, 1823) Toxolasma paulum (Lea, 1840) *Toxolasma paulus (Lea, 1840) Toxolasma pullus (Conrad, 1838) Toxolasma texasiense (Lea, 1857) *Toxolasma texasiensis (Lea, 1857) Tritogonia Agassiz, 1852 Tritogonia verrucosa (Rafinesque, 1820) Truncilla Rafinesque, 1819 Truncilla cognata (Lea, 1860) Truncilla donaciformis (Lea, 1828) Truncilla macrodon (Lea, 1859) Truncilla truncata Rafinesque, 1820 Uniomerus Conrad, 1853 Uniomerus carolinianus (Bosc, 1801) Uniomerus columbensis (Lea, 1857) Uniomerus declivis (Say, 1831) Uniomerus tetralasmus (Say, 1831) Utterbackia Baker, 1927 Utterbackia imbecillis (Say, 1829) Utterbackia peggyae (Johnson, 1965) Utterbackia peninsularis Bogan and Hoeh, 1995 Utterbackiana Frierson, 1927 Utterbackiana couperiana (Lea, 1840) Utterbackiana hartfieldorum (Williams, Bogan, and Garner, 2009) Utterbackiana heardi (Gordon and Hoeh, 1995) Utterbackiana implicata (Say, 1829) Utterbackiana suborbiculata (Say, 1831) Venustaconcha Frierson, 1927 Venustaconcha ellipsiformis (Conrad, 1836) Venustaconcha pleasii (Marsh, 1891) Venustaconcha trabalis (Conrad, 1834) Purple Lilliput Western Lilliput Lilliput Lilliput Iridescent Lilliput Iridescent Lilliput Savannah Lilliput Texas Lilliput Texas Lilliput Venustaconcha troostensis (Lea, 1834) Villosa Frierson, 1927 *Villosa amygdala (Lea, 1843) Villosa amygdalum (Lea, 1843) *Villosa arkansasensis (Lea, 1862) *Villosa choctawensis Athearn, 1964 Villosa constricta (Conrad, 1838) Villosa delumbis (Conrad, 1834) Villosa fabalis (Lea, 1831) Cumberland Bean Changes in Scientific and Common Names Spelling correction of species name; parentheses unnecessary Incorrect spelling of species name Synonym of Toxolasma texasiense Spelling correction of species name Incorrect spelling of species name Spelling correction of species name Incorrect spelling of species name Spelling correction of species name Incorrect spelling of species name Pistolgrip Mexican Fawnsfoot Fawnsfoot Texas Fawnsfoot Deertoe Eastern Pondhorn Apalachicola Pondhorn Tapered Pondhorn Pondhorn Common name changed from Florida Pondhorn Elevated from synonymy Paper Pondshell Florida Floater Peninsular Floater Barrel Floater Cypress Floater Elevated from synonymy Reassigned from Anodonta Described as new species; reassigned from Anodonta Apalachicola Floater Alewife Floater Flat Floater Reassigned from Anodonta Reassigned from Anodonta Reassigned from Anodonta Ellipse Bleedingtooth Mussel Tennessee Bean Florida Rainbow Florida Rainbow Ouachita Creekshell Choctaw Bean Notched Rainbow Eastern Creekshell Rayed Bean Reassigned from Villosa; common name changed from Cumberland Bean Elevated from synonymy Incorrect spelling of species name Spelling correction of species name Reassigned to Obovaria Reassigned to Obovaria 45 REVISED LIST OF FRESHWATER MUSSELS Table 2, continued. Scientific Name Villosa iris (Lea, 1829) Villosa lienosa (Conrad, 1834) Villosa nebulosa (Conrad, 1834) Villosa ortmanni (Walker, 1925) *Villosa perpurpurea (Lea, 1861) Villosa sima (Lea, 1838) Villosa taeniata (Conrad, 1834) *Villosa trabalis (Conrad, 1834) Villosa umbrans (Lea, 1857) *Villosa vanuxemensis umbrans (Lea, 1857) Villosa vanuxemensis (Lea, 1838) *Villosa vanuxemensis vanuxemensis (Lea, 1838) Villosa vaughaniana (Lea, 1838) Villosa vibex (Conrad, 1834) Villosa villosa (Wright, 1898) Common Name Rainbow Little Spectaclecase Alabama Rainbow Kentucky Creekshell Purple Bean Caney Fork Rainbow Painted Creekshell Cumberland Bean Coosa Creekshell Coosa Creekshell Mountain Creekshell Mountain Creekshell Carolina Creekshell Southern Rainbow Downy Rainbow genus, species, and subspecies levels relative to previous lists. We recognize in total 298 freshwater mussel species from the United States and Canada. These comprise the families Margaritiferidae with one genus and five species and Unionidae with 54 genera and 293 species (Table 2). Turgeon et al. (1998) recognized in total 304 taxa: Margaritiferidae with two genera and five species and Unionidae with 49 genera, 286 species, and 13 subspecies. We summarize our changes to Turgeon et al. (1998) as follows. We recognize eight additional genera, including three recently described (Hamiota, Parvaspina, and Reginaia), four elevated from synonymy (Eurynia, Pleuronaia, Theliderma, and Utterbackiana), and one newly reported from North America (Sinanodonta). We place in synonymy four genera, including one in the Margaritiferidae (Cumberlandia) and three in the Unionidae (Arkansia, Lexingtonia, and Quincuncina). We recognize 25 additional species (all Unionidae), including four newly described species and 21 species elevated from synonymy. We place in synonymy 29 species and consider Pleurobema altum a nomen dubium, and we reassigned 41 species to other genera. We corrected the specific epithet spelling for eight species, corrected the date of publication for four, and changed the common names of five. Last, we recognized no subspecies, elevating 10 subspecies to species status and subsuming four subspecies into their nominal species (see Methods). Margaritiferidae Henderson, 1929 Turgeon et al. (1998) recognized two genera in Margaritiferidae, Cumberlandia (one species) and Margaritifera (four species). On the basis of shell morphology and soft anatomy, Smith (2001) placed Cumberlandia in Margaritanopsis and Margaritifera (in part) in Pseudunio, but this classification was not widely accepted. In a molecular phylogenetic analysis, Huff et al. (2004) considered Cumberlandia a junior synonym Changes in Scientific and Common Names Synonym of Venustaconcha trabalis Elevated from synonymy Reassigned to Venustaconcha Species elevated from subspecies Subspecies elevated to species Nominotypical subspecies not required of Margaritifera, and this classification was followed by some subsequent authors (e.g., Graf and Cummings 2007, 2017; Cummings and Graf 2010), but others continued to recognize the genus as valid (e.g., Williams et al. 2008; Watters et al. 2009; Haag 2012). A more comprehensive phylogeny of the Margaritiferidae that included eight of 13 currently recognized species (three from North America) retained the use of Cumberlandia (Bolotov et al. 2015). However, based on more recent evidence (Bolotov et al. 2016; Araujo et al. 2017), we consider Cumberlandia a junior synonym of Margaritifera. Cumberlandia Ortmann, 1912.—Turgeon et al. (1998) recognized one species, Cumberlandia monodonta. We place Cumberlandia in the synonymy of Margaritifera (see Margaritiferidae). Margaritifera Schumacher, 1816.—Turgeon et al. (1998) recognized four species of Margaritifera. Placement of Cumberlandia in the synonymy of Margaritifera brings the number of recognized species to five (see Margaritiferidae). Unionidae Rafinesque, 1820 Turgeon et al. (1998) recognized 49 genera, 286 species, and 13 subspecies in Unionidae. We recognize 54 genera, 293 species, and no subspecies. We provide support for and discussion of these changes in the following assessments of genera. Actinonaias Crosse and Fischer, 1894.—Turgeon et al. (1998) recognized two species, Actinonaias ligamentina and Actinonaias pectorosa. Molecular analyses (e.g., Campbell et al. 2005; Zanatta and Murphy 2006) found that the two species of Actinonaias together did not represent a monophyletic grouping, but the position of each of these lineages within the Lampsilini was unresolved. The type locality for Actinonaias is central Mexico, and 10 recognized species are restricted to this region (Graf and Cummings 2017), but no species 46 WILLIAMS ET AL. attributable to Actinonaias occur between Mexico and the range of ligamentina and pectorosa in the central United States and southern Canada. No phylogenetic research has examined relationships among Mexican Actinonaias and ligamentina and pectorosa, but it is unlikely they are closely related considering the disjunct distribution and lack of precedent for such a geographical pattern in other freshwater taxa (e.g., Miller et al. 2005). Actinonaias ligamentina and pectorosa require placement in two different genera, but at this time we retain these two species in the genus Actinonaias pending the outcome of further phylogenetic research. Alasmidonta Say, 1818.—Turgeon et al. (1998) recognized 12 species, and recent evidence supports no changes to this classification. Amblema Rafinesque, 1820.—Turgeon et al. (1998) recognized three species, and recent evidence supports no changes to this classification. Anodonta Lamarck, 1799.—Turgeon et al. (1998) recognized 10 species. Mock et al. (2004) and Zanatta et al. (2007) found Anodonta to be polyphyletic, with eastern North American species forming a monophyletic clade distinct from the one that includes the type species (Anodonta cygnea, which occurs in Eurasia) and western North American Anodonta. Without discussion, Graf and Cummings (2007) and Cummings and Graf (2010) placed Anodonta couperiana, A. heardi, and A. suborbiculata in Utterbackia, and A. implicata in Pyganodon. Because no supporting evidence was provided, we do not recognize these changes. The next available genus for the eastern North American clade (A. couperiana, A. heardi, A. suborbiculata, and A. implicata) identified as distinct by Mock et al. (2004) is Utterbackiana. Anodonta hartfieldorum Williams, Bogan, and Garner, 2009, was described subsequently and also belongs to Utterbackiana (see Utterbackiana). In a phylogenetic analysis of western North American Anodonta, Chong et al. (2008) found A. beringiana to be more closely related to the Asian species Sinanodonta woodiana than to North American species. Based on this evidence, we reassign beringiana to Sinanodonta (see Sinanodonta). We retain the remaining four western North American species within Anodonta (A. californiensis, A. kennerlyi, A. nuttalliana, and A. oregonensis) based on their phylogenetic affinity to Eurasian Anodonta (Mock et al. 2004; Zanatta et al. 2007; Chong et al. 2008). Anodonta dejecta was recognized by Turgeon et al. (1998), Graf and Cummings (2007), and Cummings and Graf (2010). This species is treated as a synonym of A. californiensis by Bequaert and Miller (1973) and the Arizona Game and Fish Department (2017). We do not recognize A. dejecta, which is here placed in synonymy of A. californiensis. Anodontoides Simpson in Baker, 1898.—Turgeon et al. (1998) recognized two species. One additional species, Anodontoides denigrata, was recognized without discussion by Neves et al. (1997) and Cicerello and Schuster (2003). Haag and Cicerello (2016) recognized A. denigrata on the basis of molecular data showing that upper Cumberland River drainage populations were distinct from A. ferussacianus (Bogan and Raley 2013), and we recognize this species for the same reason. Bogan and Raley (2013) referred to A. denigrata as A. argenteus (Lea, 1840), for which the type locality is Stones River, Tennessee. The Stones River is a tributary of the middle Cumberland River and well downstream of the putative distribution of A. denigrata and other species considered endemic to the upper Cumberland River drainage upstream of the hypothesized original location of Cumberland Falls (Haag and Cicerello 2016). Until further research delineates this species’ distribution more precisely, we use A. denigrata, for which the type locality is in the upper Cumberland River drainage (Clear Fork, Campbell County, Tennessee; see Ortmann 1918). Ahlstedt et al. (2016) reported a possibly distinct Anodontoides species from the Powell River, Virginia, but further work is needed to determine its validity and taxonomy. Arcidens Simpson, 1900.—Turgeon et al. (1998) recognized one species, Arcidens confragosus. Clarke (1981) considered Arkansia (see Arkansia) a junior synonym of Arcidens (see also Graf and Cummings 2007), and this classification was supported by morphological and molecular data (Inoue et al. 2014). We recognize two species of Arcidens. Arkansia Ortmann and Walker, 1912.—Arkansia was described as a monotypic genus including A. wheeleri, which was recognized by Turgeon et al. (1998). We place Arkansia in the synonymy of Arcidens (see Arcidens). Cyclonaias Pilsbry in Ortmann and Walker, 1922.— Turgeon et al. (1998) recognized Cyclonaias, which has long been considered a monotypic genus for C. tuberculata. Cyclonaias tuberculata has been aligned with the Quadrulini based on morphological (e.g., Frierson 1927; Modell 1964) and protein polymorphism data (Davis and Fuller 1981). Heard and Guckert (1971) placed Cyclonaias in the Pleurobemini based on its ectobranchous brooding (see also Graf and Cummings 2007). However, it appears that ectobranchy arose multiple times (Davis and Fuller 1981; Graf 2002; Roe and Hoeh 2003), meaning that this trait does not necessarily exclude Cyclonaias from the Quadrulini, and some female C. tuberculata brood glochidia in all four gills (Frierson 1927). Recent molecular studies consistently supported inclusion of Cyclonaias in the Quadrulini, but they further show that it is a member of a monophyletic clade including Q. pustulosa and related species (Campbell et al. 2005; Campbell and Lydeard 2012b). Serb et al. (2003) did not support this relationship, but these results were later attributed to an error in sample labeling (Campbell and Lydeard 2012b). However, Serb et al. (2003) as well as Campbell et al. (2005) and Campbell and Lydeard (2012b) support the monophyly of the Quadrula pustulosa clade and its distinctiveness from other species of Quadrula (see Quadrula and Theliderma). In addition to Cyclonaias tuberculata, the Quadrula pustulosa clade identified by these studies includes the following species recognized by Turgeon et al. (1998): Q. asperata, Q. aurea, Q. houstonensis, Q. nodulata, Q. petrina, Q. pustulosa, and Q. refulgens, as well REVISED LIST OF FRESHWATER MUSSELS as Fusconaia succissa and Quincuncina infucata (see Fusconaia and Quincuncina). The name Quadrula is not available for the Q. pustulosa clade because the type species, Q. quadrula, is a member of another distinct, monophyletic clade (see Quadrula). Graf and Cummings (2007) elevated the generic name Amphinaias Crosse and Fischer, 1894, for the Q. pustulosa clade. The type species for Amphinaias (by original designation) is Unio couchianus Lea, 1860, which has a quadrate shell and sulcus (but lacks pustules) similar to the Q. quadrula clade. This morphology is very different from the rounded, pustulose shells of the Q. pustulosa clade. Quadrula couchiana is considered extinct and genetic data are unavailable; however, we do not consider Amphinaias an available name for the Q. pustulosa clade because of the strongly divergent morphology of the type species. Campbell and Lydeard (2012b) proposed Rotundaria Rafinesque, 1820, as a name for the Q. pustulosa clade, presuming its availability based on statements in Valenciennes (1827). However, Valenciennes noted that Rafinesque had confused two species, one for which he kept Rafinesque’s name Unio verrucosa and named the other Unio tuberculosa [sic]. As such, Valenciennes’s statement cannot be accepted as a subsequent designation of Obliquaria tuberculata Rafinesque, 1820, as the type species of Rotundaria (P. Bouchet, Muséum National d’Histoire Naturelle, Paris, personal communication), and Herrmannsen (1848) later designated Obliquaria subrotunda Rafinesque, 1820, as the type species of Rotundaria. Rafinesque did not select a type species for Rotundaria and because more than one species was included by him in the genus, the type species cannot be fixed by monotypy. Therefore, Rotundaria is not available for the Q. pustulosa clade. Frierson (1927) erected the subgenus Bullata for Q. pustulosa but realized this was preoccupied and created the replacement name Pustulosa with the same type species. Thus, Cyclonaias becomes the oldest available name for this group. Of the 10 species discussed above as members of Cyclonaias, three were not recognized by Turgeon et al. (1998) (C. archeri, C. kieneriana, and C. kleiniana), and one was considered a subspecies (C. mortoni, as Quadrula pustulosa mortoni). Graf and Cummings (2007) elevated Q. archeri from synonymy with Q. asperata, but they provided no justification for this change. The distinctiveness of C. archeri was recognized by Williams et al. (2008) based on its morphology, absence of intergrades, and isolated and restricted distribution. We recognize C. archeri. The distinctiveness of C. kieneriana was recognized by Williams et al. (2008) based on shell morphology; however, it was not supported by molecular data (Serb et al. 2003), but that study included only one specimen of this putative taxon. We recognize C. kieneriana until additional information becomes available (see Williams et al. 2008). Cyclonaias kleiniana was synonymized under Quincuncina infucata by Clench and Turner (1956), but molecular studies supported the distinctiveness of these species and their inclusion in Cyclonaias (Lydeard et al. 2000; Campbell and Lydeard 2012b). 47 Molecular data supported the distinctiveness of C. mortoni from C. pustulosa (Serb et al. 2003). In summary, we recognize Cyclonaias as including 14 species: C. tuberculata, seven species recognized by Turgeon et al. (1998) under Quadrula, one subspecies recognized by Turgeon et al. (1998) but now elevated to species status (C. mortoni), two species recognized by Turgeon et al. (1998) in different genera (C. infucata and C. succissa), and three species elevated from synonymy (C. archeri, C. kieneriana, and C. kleiniana). Cyprogenia Agassiz, 1852.—Turgeon et al. (1998) recognized two species. Subsequent molecular data suggested cryptic species diversity in the genus (Serb and Barnhart 2008; Grobler et al. 2011). The most recent molecular analysis of Cyprogenia identified three independent evolutionary lineages: C. aberti in the Ozark drainages of Arkansas, Missouri, and Kansas; C. stegaria in the Ohio River Basin; and a third lineage in the Ouachita River drainage in Arkansas (Chong et al. 2016). Confusion regarding the type locality of Unio lamarckianus Lea, 1852, requires resolution to determine whether that name is available for the Ouachita River drainage population. We recognize the distinctiveness of this species but defer including it in our list until a specific epithet can be designated. Cyrtonaias Crosse and Fischer, 1894.—Turgeon et al. (1998) recognized one species, Cyrtonaias tampicoensis, and recent evidence supports no changes to this classification. Five other species are recognized, all of which occur in Mexico or Central America (Graf and Cummings 2017). Disconaias Crosse and Fischer, 1894.—Turgeon et al. (1998) recognized one species, Disconaias salinasensis Simpson in Dall, 1908, which was subsequently placed in the synonymy of Disconaias fimbriata by Graf and Cummings (2007). Five other species are recognized, all of which occur in Mexico (Graf and Cummings 2017). We recognize Disconaias fimbriata as the only species of the genus occurring in the United States (Rio Grande drainage). Dromus Simpson, 1900.—Turgeon et al. (1998) recognized one species, Dromus dromas, and recent evidence supports no changes to this classification. Ellipsaria Rafinesque, 1820.—Turgeon et al. (1998) recognized one species, Ellipsaria lineolata, and recent evidence supports no changes to this classification. Elliptio Rafinesque, 1819.—Turgeon et al. (1998) recognized 36 species, making it the largest unionid genus in the United States and Canada, but species concepts within this group remain mostly untested, and their highly variable shell morphology precludes traditional approaches for species diagnosis. Recent molecular studies have largely supported the monophyly of Elliptio with two exceptions (Campbell et al. 2005; Campbell and Lydeard 2012b; Perkins et al. 2017). Elliptio dilatata, which is morphologically and anatomically similar to many Elliptio, is not a member of this group; we recognize reassignment of this species to Eurynia (Campbell and Lydeard 2012b). We also recognize reassignment of Elliptio steinstansana to Parvaspina based on molecular data (Perkins et al. 2017). It is important to note that phylogenetic 48 WILLIAMS ET AL. affinities remain unknown for most species that we currently recognize under Elliptio and some may prove to be members of other genera (e.g., Eurynia; Elderkin et al. 2008; Campbell and Lydeard 2012b). Because of our poor understanding of species diversity within Elliptio, we largely retain the classification of Turgeon et al. (1998) with the following exceptions. We stress that this classification is provisional and meant to provide a stable, working hypothesis for diversity within the genus. We elevate from synonymy four species of Elliptio: E. fumata (from E. complanata), E. occulta and E. pullata (from E. icterina), and E. purpurella (from E. arctata and E. strigosa); these changes are based primarily on differences in shell morphology (Brim Box and Williams 2000; Williams et al. 2008, 2011, 2014). We place eight species into synonymy. Four Atlantic Slope species (E. errans, E. hepatica, E. lugubris, and E. raveneli) were recognized by Turgeon et al. (1998) based on Davis and Mulvey (1993). The research by Davis and Mulvey (1993) was confined almost exclusively to the Savannah River drainage and has no context within the greater Atlantic Coast region. The validity of these species has not been evaluated further. We return these species to synonymy following Johnson (1970) as follows: E. errans is synonymized under E. complanata; and E. hepatica, E. lugubris, and E. raveneli are synonymized under E. icterina. We place Elliptio waccamawensis into the synonymy of E. congaraea based on molecular data (McCartney et al. 2016). We place the following species into synonymy based on examination of shell type material by Clarke (1992) and Williams et al. (2011, 2014): E. waltoni (synonymized under E. ahenea), E. judithae (synonymized under E. roanokensis), and E. buckleyi (synonymized under E. jayensis). After these changes, we recognize 30 species of Elliptio, and it remains the largest unionid genus in the United States and Canada. Turgeon et al. (1998) listed the common names Flat Spike and Florida Shiny Spike for Elliptio jayensis and E. buckleyi, respectively. We follow the recommendation of Williams et al. (2014) that the common name of E. jayensis be changed to Florida Spike because the species is largely endemic to that state and is neither consistently flat nor shiny. Elliptoideus Frierson, 1927.—Turgeon et al. (1998) recognized one species, Elliptoideus sloatianus, and recent evidence supports no changes to this classification. Epioblasma Rafinesque, 1831.—Turgeon et al. (1998) recognized 20 species and five subspecies. Our changes to this classification involve recognition of two newly described cryptic species, elevating one species from synonymy, and elevating subspecies to species status. We recognize Epioblasma ahlstedti Jones and Neves, 2010, a cryptic species formerly included within E. capsaeformis, and we recognize and elevate to species status Epioblasma aureola Jones and Neves, 2010, formerly identified as E. florentina walkeri but described as E. florentina aureola Jones and Neves, 2010. Epioblasma cincinnatiensis was not recognized by Turgeon et al. (1998), and it has been considered a synonym (e.g., Parmalee and Bogan 1998) or a subspecies (e.g., Morrison 1942) of Epioblasma torulosa. Williams et al. (2008) elevated this species from synonymy based on examination of shell type material. Watters et al. (2009) also recognized this taxon but placed it in the synonymy of Epioblasma phillipsii (Conrad, 1835). However, E. phillipsii is considered a synonym of Obliquaria reflexa (see Williams et al. 2008). We follow Williams et al. (2008) in recognizing E. cincinnatiensis. Turgeon et al. (1998) recognized eight subspecies of Epioblasma in three nominal species: florentina (three), obliquata (two), and torulosa (three). A conclusive assessment of the taxonomic status of these taxa may be impossible at this time because half are considered extinct (E. florentina florentina, E. f. curtisii, E. torulosa torulosa, and E. t. gubernaculum). Cummings and Berlocher (1990) found no evidence of intergradation between E. t. torulosa and E. t. rangiana and both taxa co-occurred at many sites; based on this evidence, we elevate these subspecies to species status. Epioblasma aureola and E. walkeri represent morphologically and genetically distinct sister taxa (Jones and Neves 2010, as E. florentina aureola and E. florentina walkeri). These taxa appear to be restricted to two different river systems (Tennessee and Cumberland, respectively); based on the low probability of exchange between these populations and their distinctiveness, we recognize and elevate to full species status E. aureola and E. walkeri. There is little information with which to assess the taxonomic status of E. florentina florentina, E. florentina curtisii, E. obliquata obliquata, E. obliquata perobliqua, and E. torulosa gubernaculum, but all have distinctive shell morphology or occupy distinct geographical regions and we recognize all these taxa as distinct species (see Methods). We recognize 28 Epioblasma species, making it the second largest unionid genus in the United States and Canada. Eurynia Rafinesque, 1820.—Eurynia was not recognized in Turgeon et al. (1998). Eurynia was elevated from synonymy by Campbell and Lydeard (2012b) to accommodate Elliptio dilatata, which consistently falls outside the Elliptio clade in molecular analyses (see also Perkins et al. 2017). We consider Eurynia monotypic at this time, but more inclusive molecular studies may identify other species that belong to this genus, including some now assigned to Elliptio (Elderkin et al. 2008; Campbell and Lydeard 2012b). Fusconaia Simpson, 1900.—Turgeon et al. (1998) recognized 13 species. Several studies showed that the genus Fusconaia as portrayed by Turgeon et al. (1998) was polyphyletic (Lydeard et al. 2000; Serb et al. 2003; Campbell et al. 2005; Campbell and Lydeard 2012a, 2012b; Pfeiffer et al. 2016). Based on these results, we reassign three species recognized by Turgeon et al. (1998) to other genera: F. succissa to Cyclonaias, F. barnesiana to Pleuronaia, and F. ebenus to Reginaia. Pleuronaia was resurrected to accommodate F. barnesiana, along with two other species in the clade (Williams et al. 2008; Campbell and Lydeard 2012a, 2012b; see Pleuronaia). Reginaia was described to accommodate F. REVISED LIST OF FRESHWATER MUSSELS ebenus and two other species (Campbell and Lydeard 2012a; see Reginaia). These studies also showed that several species assigned to other genera belonged in Fusconaia. Based on these results, Quincuncina is a junior synonym of Fusconaia, and we reassign Q. burkei and Q. mitchelli to Fusconaia (Lydeard et al. 2000; Serb et al. 2003; Campbell et al. 2005; Pfeiffer et al. 2016; see Cyclonaias, Quadrula, and Quincuncina). Lexingtonia was placed in the synonymy of Fusconaia when its type species, L. subplana, was determined a junior synonym of Fusconaia masoni based on molecular data (Bogan et al. 2003). Fusconaia chunii was not recognized by Turgeon et al. (1998), but they recognized two other Fusconaia from Texas: F. askewi and F. lananensis. Subsequent molecular data showed that all Fusconaia in Texas drainages from the Sabine River west belonged to a single species (Burlakova et al. 2012). However, Unio chunii Lea, 1861, has priority over Unio askewi Marsh, 1896, and Quadrula lananensis Frierson, 1901, so we place F. askewi and F. lananensis in the synonymy of F. chunii. We adopt the former common name for F. askewi, Texas Pigtoe, for F. chunii because it is descriptive of the species’ range. Turgeon et al. (1988) listed the common name Gulf Pigtoe for Fusconaia cerina, but it was changed to Southern Pigtoe in Turgeon et al. (1998) without comment. However, Turgeon et al. (1998) also used Southern Pigtoe as the common name of Pleurobema georgianum. We designate the common name Gulf Pigtoe for F. cerina. In summary, we recognize 11 species of Fusconaia, including eight species recognized by Turgeon et al. (1998) under Fusconaia, two species recognized by Turgeon et al. (1998) in other genera, and one species elevated from synonymy. Glebula Conrad, 1853.—Turgeon et al. (1998) recognized one species, Glebula rotundata, and recent evidence supports no changes to this classification. Gonidea Conrad, 1857.—Turgeon et al. (1998) recognized one species, Gonidea angulata, and recent evidence supports no changes to this classification. Hamiota Roe and Hartfield, 2005.—Hamiota was described subsequent to Turgeon et al. (1998) to accommodate a monophyletic clade of four species that produce superconglutinates (Roe et al. 2001). They were previously recognized under Lampsilis: L. altilis, L. australis, L. perovalis, and L. subangulata (Roe and Hartfield 2005). We recognize all four of these species under Hamiota. Hemistena Rafinesque, 1820.—Turgeon et al. (1998) recognized one species, Hemistena lata, and recent evidence supports no changes to this classification. Lampsilis Rafinesque, 1820.—Turgeon et al. (1998) recognized 28 species and four subspecies. Molecular data indicated that Lampsilis, as presented by Turgeon et al. (1998), is polyphyletic (Graf and Ó Foighil 2000; Campbell et al. 2005). There are likely unrecognized taxa in the genus Lampsilis (e.g., in Arkansas; Harris et al. 2009). The genus 49 Hamiota was described to accommodate a monophyletic clade of four species, Lampsilis altilis, L. australis, L. perovalis, and L. subangulata (Roe and Hartfield 2005), and we recognize reassignment of these species from Lampsilis to Hamiota. We also recognize reassignment of Lampsilis haddletoni to Obovaria (Williams et al. 2008; see Obovaria). In addition to Hamiota, molecular data suggested the existence of at least two other paraphyletic clades within Lampsilis as recognized by Turgeon et al. (1998). Lampsilis cardium, L. ornata, and L. ovata formed a monophyletic clade sister to Hamiota, and L. siliquoidea and L. teres were members of a clade sister to the latter two groups; however, these groupings were not consistently or strongly supported, and the analyses did not include other species of putative Lampsilis (Campbell et al. 2005). Additional generic-level changes regarding Lampsilis will likely occur in the future, but we retain traditional use of this genus for all species except those reassigned to Hamiota and Obovaria. Lampsilis floridensis was not recognized by Turgeon et al. (1998), and formerly it was recognized as a subspecies (Clench and Turner 1956) or synonym (Burch 1975) of Lampsilis teres. We recognize L. floridensis as a full species based on shell morphology, unpublished molecular data, and its allopatric distribution (Williams et al. 2008). Turgeon et al. (1998) recognized nominal Lampsilis reeveiana along with two subspecies, L. r. brevicula and L. r. brittsi. Molecular data showed that brittsi populations from the Missouri River drainage formed a well-supported monophyletic clade separate from nominal reeveiana, but there was no morphological or genetic distinction between nominal L. reeveiana and L. r. brevicula (Harris et al. 2004). Based on these data, we follow McMurray et al. (2012) in recognizing L. brittsi and L. reeveiana as species and placing L. reeveiana brevicula into the synonymy of L. reeveiana. Turgeon et al. (1998) recognized nominal Lampsilis radiata and one subspecies, L. r. conspicua. However, molecular and shell morphology data did not support the distinctiveness of L. r. conspicua (Stiven and Alderman 1992), and we place this taxon into the synonymy of Lampsilis radiata. Turgeon et al. (1998) also recognized Lampsilis fullerkati, but we recognize placement of that species into the synonymy of L. radiata based on molecular data (McCartney et al. 2016). Turgeon et al. (1998) recognized nominal Lampsilis straminea and one subspecies, L. s. claibornensis. Lampsilis straminea straminea is restricted to the Black Belt Prairie region of Alabama and Mississippi and is characterized by a profusion of fine, concentric ridges on the shell, which are absent in L. s. claibornensis. However, concentric ridges are present in some other mussels inhabiting streams in the Black Belt Prairie region and are most likely environmentally induced and not due to genetic differences (Williams et al. 2008). We do not recognize the taxonomic validity of these shell forms and place L. s. claibornensis in the synonymy of Lampsilis straminea. The common name of Lampsilis s. straminea, Rough Fatmucket (Turgeon et al. 1998), is 50 WILLIAMS ET AL. descriptive of individuals in only a small portion of its range (i.e., the Black Belt Prairie). Therefore, we retain the common name for L. straminea claibornensis, Southern Fatmucket, for L. straminea. In summary, we recognize 24 species of Lampsilis including one species elevated from synonymy and two species elevated from subspecies. Lampsilis is the third largest genus in the family Unionidae following Elliptio (30) and Epioblasma (28). Lasmigona Rafinesque, 1831.—Turgeon et al. (1998) recognized six species and one subspecies. Williams et al. (2008) elevated Lasmigona complanata alabamensis to species status based on examination of museum shell material, and molecular data supported the distinctiveness of this taxon (King et al. 1999). Williams et al. (2008) also recognized Mobile Basin populations of Lasmigona holstonia as a distinct species based on unpublished molecular data and the occurrence of these populations in two different river systems. They resurrected from synonymy Lasmigona etowaensis to refer to Mobile Basin populations and retained L. holstonia to refer to Tennessee and Ohio River drainage populations. We recognize all three of these species. Molecular studies showed that Lasmigona is polyphyletic: L. alabamensis, L. complanata, and L. costata formed a monophyletic clade, and L. compressa and L. subviridis represented another monophyletic clade more closely related to Alasmidonta (King et al. 1999). However, this study did not include all species of Lasmigona, and a broader study within the context of the tribe Anodontini is needed to clarify these relationships. Populations of Lasmigona costata in the Ozark Highlands represented a monophyletic clade strongly differentiated from populations east of the Mississippi River, suggesting the presence of at least one cryptic species within this taxon; additional investigation across the range of L. costata is needed to better understand these patterns (Hewitt et al. 2016). An endemic form of Lasmigona in the Barrens region of the upper Caney Fork drainage in Tennessee was recognized by Layzer et al. (1993), but the status of this putative taxon has not been evaluated further. Lemiox Rafinesque, 1831.—Turgeon et al. (1998) recognized one species, Lemiox rimosus, and recent evidence supports no changes to this classification. Leptodea Rafinesque, 1820.—Turgeon et al. (1998) recognized three species, and recent evidence supports no changes to this classification. Smith (2000) proposed moving Leptodea ochracea into the genus Ligumia based on mantle margin pigment and size of glochidia. We do not accept this proposal due to the limited number of taxa (four species in two genera) in that analysis, and we retain ochracea in Leptodea. Lexingtonia Ortmann, 1914.—Turgeon et al. (1998) recognized two species. However, the type species, Lexingtonia subplana, was subsequently relegated to the synonymy of Fusconaia masoni based on Johnson (1970) and Bogan et al. (2003). As such, Lexingtonia is a junior synonym of Fusconaia. The other species recognized by Turgeon et al. (1998), Lexingtonia dolabelloides, did not group with Fusconaia in molecular analyses but formed a monophyletic clade with two other species (Campbell et al. 2005; Campbell and Lydeard 2012a, 2012b). Pleuronaia was resurrected by Williams et al. (2008) to accommodate this clade (see Pleuronaia). Ligumia Swainson, 1840.—Turgeon et al. (1998) recognized three species. Subsequent molecular studies indicated the genus is not monophyletic, but further research is needed to fully elucidate these patterns (Campbell et al. 2005; Kuehnl 2009). We retain the classification of Turgeon et al. (1998), but as additional information becomes available taxa assigned to this genus will likely change (see Raley et al. 2007). Gangloff et al. (2013) identified a genetically divergent clade of Ligumia recta from the Mobile Basin that may warrant recognition as a distinct taxon. Medionidus Simpson, 1900.—Turgeon et al. (1998) recognized seven species. We no longer recognize Medionidus mcglameriae, which was placed in the synonymy of Leptodea fragilis based on examination of the type specimen (Williams et al. 2008). Campbell et al. (2005) found some evidence for polyphyly of Medionidus, but this evidence was not conclusive and we make no other changes to this genus. Megalonaias Utterback, 1915.—Turgeon et al. (1998) recognized one species, Megalonaias nervosa, and recent evidence supports no changes to this classification. Obliquaria Rafinesque, 1820.—Turgeon et al. (1998) recognized one species, Obliquaria reflexa, and recent evidence supports no changes to this classification. Obovaria Rafinesque, 1819.—Turgeon et al. (1998) recognized six species. Molecular data showed that Obovaria as depicted by Turgeon et al. (1998) is polyphyletic (Campbell et al. 2005). Notably, Obovaria rotulata was not a member of this group, and it was later reassigned to Reginaia (Campbell and Lydeard 2012b); we recognize this reassignment. In an analysis by Campbell et al. (2005), O. olivaria fell outside the clade containing other Obovaria and Epioblasma, but this conclusion was not consistently supported. We retain olivaria within Obovaria, but further work on this species is needed to resolve its generic assignment. Evidence also supports reassignment to Obovaria of species recognized by Turgeon et al. (1998) under other genera. We reassign Villosa arkansasensis and V. choctawensis to Obovaria based on molecular data (Kuehnl 2009; Inoue et al. 2013) and marsupial morphology (Williams et al. 2011, for choctawensis). We also recognize reassignment of Lampsilis haddletoni to Obovaria based on shell morphology of the type lot (Williams et al. 2008, 2011), but this species is considered extinct and there are no available soft parts for anatomical or molecular study. Obovaria jacksoniana was recognized in Turgeon et al. (1998) but is synonymous with Villosa arkansasensis (Inoue et al. 2013). Unio jacksoniana Frierson, 1912, is a junior synonym of Unio arkansasensis Lea, 1862, and we place O. jacksoniana in the synonymy of Obovaria arkansasensis. There is also potential for unrecognized taxa within O. arkansasensis in central Gulf Slope drainages (Inoue et al. 2013). REVISED LIST OF FRESHWATER MUSSELS In summary, we recognize seven species of Obovaria, including four species recognized by Turgeon et al. (1998) and three species reassigned from other genera, one from Lampsilis and two from Villosa. Parvaspina Perkins, Gangloff, and Johnson, 2017.— Parvaspina was described subsequent to Turgeon et al. (1998) to accommodate a monophyletic clade of two species previously recognized as Elliptio steinstansana and Pleurobema collina (Perkins et al. 2017). We recognize these species as Parvaspina steinstansana and Parvaspina collina. Pegias Simpson, 1900.—Turgeon et al. (1998) recognized one species, Pegias fabula, and recent evidence supports no changes to this classification. Plectomerus Conrad, 1853.—Turgeon et al. (1998) recognized one species, Plectomerus dombeyanus, and recent evidence supports no changes to this classification. Plethobasus Simpson, 1900.—Turgeon et al. (1998) recognized three species, and recent evidence supports no changes to this classification. Pleurobema Rafinesque, 1819.—Turgeon et al. (1998) recognized 32 species, making it one of the largest unionid genera. Molecular data largely support the monophyly of Pleurobema as depicted by Turgeon et al. (1998) with two exceptions (Campbell et al. 2005, 2008; Campbell and Lydeard 2012b). These studies support reassignment of P. collina to Parvaspina and P. gibberum to Pleuronaia (Campbell et al. 2005, 2008; Campbell and Lydeard 2012b; see Parvaspina and Pleuronaia). However, Campbell et al. (2008) and Campbell and Lydeard (2012b) provided evidence that Pleurobema includes two distinct lineages, one including P. sintoxia, P. cordatum, P. plenum, P. riddellii, and P. rubrum and the other including all other species. Further research is needed to elucidate these relationships; we retain traditional use of Pleurobema. Pleurobema rivals Elliptio in its large number of described species and the intractability of many species concepts, particularly in the Mobile Basin, but these problems are compounded for Pleurobema because many putative taxa are considered extinct. Based on a comprehensive comparison of shell type specimens and other available material, Williams et al. (2008) placed into synonymy nine species of Mobile Basin Pleurobema recognized by Turgeon et al. (1998): P. chattanoogaense (into P. decisum); P. murrayense (into P. stabile); P. nucleopsis and P. troschelianum (into P. georgianum); P. flavidulum and P. johannis (into P. perovatum); and P. avellanum, P. furvum, and P. hagleri (into P. rubellum). Some of these synonyms are further supported by molecular data (e.g., P. chattanoogaense, P. furvum; Campbell et al. 2008), and we recognize all of these changes. We do not recognize Pleurobema altum since it was deemed a nomen dubium because it is not identifiable due to incomplete description, vague type locality, and lack of type material (Williams et al. 2008). One Ohio River drainage species, Pleurobema bournianum, was placed into the synonymy of Pleurobema clava based on shell morphology (Watters et al. 2009), and we recognize this change. 51 We recognize four additional Mobile Basin species of Pleurobema not recognized by Turgeon et al. (1998). Williams et al. (2008) recognized three species based on examination of shell type specimens: P. fibuloides, P. hartmanianum, and P. stabile. We correct the spelling of P. stabilis as used by Williams et al. (2008) to stabile based on Lee (2008). Pleurobema athearni Gangloff, Williams, and Feminella, 2006, was described subsequent to Turgeon et al. (1998) based on morphological data (Gangloff et al. 2006). In addition, preliminary findings identified an undescribed species in the upper Tennessee River drainage (Schilling 2015). In summary, we recognize 23 species of Pleurobema, including 19 species recognized by Turgeon et al. (1998), three species elevated from synonymy, and one newly described species. Pleuronaia Frierson, 1927.—Pleuronaia was not included in Turgeon et al. (1998). This was the senior available name for a monophyletic clade of three species—Fusconaia barnesiana, Lexingtonia dolabelloides, and Pleurobema gibberum—identified in a molecular study by Campbell et al. (2005). We recognize resurrection of Pleuronaia to accommodate this group and reassignment of these three species to Pleuronaia as proposed previously (Williams et al. 2008; Campbell and Lydeard 2012a, 2012b). There are likely cryptic taxa of Pleuronaia in the upper Tennessee River drainage (Schilling 2015). We correct the gender agreement of the specific name of Pleuronaia gibberum to gibber (H. Lee, Jacksonville, Florida, personal communication). Popenais Frierson, 1927.—Turgeon et al. (1998) recognized one species, Popenais popeii, and recent evidence supports no changes to this classification. Potamilus Rafinesque, 1818.—Turgeon et al. (1998) recognized six species. One additional species, Potamilus metnecktayi Johnson, 1998, was described subsequently, and we recognize this species. Potamilus inflatus was referred to as the Inflated Heelsplitter by Turgeon et al. (1988) but was changed to Alabama Heelsplitter by Turgeon et al. (1998) without comment. Alabama Heelsplitter is the established common name for Lasmigona alabamensis, and we adopt the original common name Inflated Heelsplitter for P. inflatus. Roe and Lydeard (1998) found the Amite River population of P. inflatus to be genetically divergent, and it may warrant recognition as a distinct taxon. Ptychobranchus Simpson, 1900.—Turgeon et al. (1998) recognized five species. Ptychobranchus foremanianus was elevated from the synonymy of Ptychobranchus greenii (in part) by Williams et al. (2008) based on shell morphology and periostracum color. A molecular analysis of this genus included insufficient material to resolve the relationship between these two taxa (Roe 2013), but we recognize both species. We correct the gender agreement of Ptychobranchus subtentum to P. subtentus following Lee (2008). Pyganodon Crosse and Fischer, 1894.—Turgeon et al. (1998) recognized five species. Graf and Cummings (2007) without comment moved Anodonta implicata to Pyganodon 52 WILLIAMS ET AL. and omitted P. fragilis and P. lacustris. However, molecular data demonstrated the validity of P. fragilis and P. lacustris (Doucet-Beaupré et al. 2012). Based on these results and the lack of justification for movement of A. implicata to Pyganodon, we retain the classification of Turgeon et al. (1998) for Pyganodon. Quadrula Rafinesque, 1820.—Turgeon et al. (1998) recognized 18 species and two subspecies. Molecular studies generally supported the monophyly of Quadrula as depicted by Turgeon et al. (1998), but they also showed that it is composed of three deeply divergent monophyletic clades plus Tritogonia verrucosa, each of which warranted generic recognition (Serb et al. 2003; Campbell et al. 2005; Campbell and Lydeard 2012b). The type species for Quadrula is Q. quadrula, and the clade containing this species also includes Q. apiculata, Q. fragosa, Q. nobilis, and Q. rumphiana. Quadrula nobilis was elevated from synonymy based on shell morphology and unspecified genetic data (Howells et al. 1996) but not recognized by Turgeon et al. (1998). Relationships among species in the Q. quadrula group were not clearly resolved by Serb et al. (2003), but we recognize all five species. We also recognize within this group Q. couchiana on the basis of its shell morphology, which is similar to that of Q. quadrula (see Cyclonaias). Based on molecular data, we reassign to Cyclonaias 10 taxa recognized by Turgeon et al. (1998) under Quadrula, and we reassign 5 species to Theliderma (Serb et al. 2003; Campbell et al. 2005; Campbell and Lydeard 2012b; see also Graf and Cummings 2007). We also synonymize two taxa recognized by Turgeon et al. (1998) under Quadrula (see Theliderma). In summary, we recognize six species of Quadrula, including five recognized under this genus by Turgeon et al. (1998) and one elevated from synonymy (Q. nobilis). Quincuncina Ortmann, 1922.—Turgeon et al. (1998) recognized three species. Molecular data showed that the type species, Quincuncina burkei, belongs in Fusconaia (Lydeard et al. 2000; Serb et al. 2003; Campbell et al. 2005). As such, Quincuncina is a junior synonym of Fusconaia, and we reassign to this genus Q. burkei and Q. mitchelli (see also Pfeiffer et al. 2016). Based on these findings, we also reassign Q. infucata to Cyclonaias (see Cyclonaias). Reginaia Campbell and Lydeard, 2012.—Reginaia was described subsequent to Turgeon et al. (1998) to accommodate a monophyletic clade of two species identified in a phylogenetic analysis of Ambleminae (Campbell and Lydeard 2012b). The two Reginaia species were included in Turgeon et al. (1998) as Fusconaia ebena and Obovaria rotulata (Campbell and Lydeard 2012b); we recognize assignment of these species to Reginaia. We follow Watters et al. (2009) in correcting the spelling of the species name ebena to ebenus. A third species, Fusconaia apalachicola Williams and Fradkin, 1999, was described subsequent to Turgeon et al. (1998) from archaeological material; we reassign this species to Reginaia based on its shell characters, which are similar to those of R. ebenus and R. rotulata. Simpsonaias Frierson, 1914.—Turgeon et al. (1998) recognized one species, Simpsonaias ambigua, and recent evidence supports no changes to this classification. Sinanodonta Modell, 1945.—Sinanodonta was not included in Turgeon et al. (1998). This genus was previously considered to be confined to Asia and not part of the North America fauna. Molecular data showed that A. beringiana is more closely related to the Asian species Sinanodonta woodiana than to other western North American Anodonta (Chong et al. 2008; see Anodonta). Based on this evidence, we reassign beringiana to Sinanodonta. In 2010 S. woodiana, Chinese Pondmussel, was found in Wickecheoke Creek, a tributary of the Delaware River, New Jersey (Bogan et al. 2011a). Several known glochidial host fishes, native and introduced species, occur in the watershed (Bogan et al. 2011b). The species appears to have become established in that stream despite eradication efforts (J. Bowers-Altman, New Jersey Division of Fish and Wildlife, personal communication). We recognize S. woodiana as established in New Jersey (Table 2). This is the only nonindigenous unionid mussel known to have become established in the United States or Canada. Strophitus Rafinesque, 1820.—Turgeon et al. (1998) recognized three species, and recent evidence supports no changes to this classification. Strophitus undulatus, one of the most wide-ranging species in the United States and Canada, likely contains unrecognized cryptic taxa (Watters et al. 2009). Theliderma Swainson, 1840.—Theliderma was not recognized by Turgeon et al. (1998). This genus was resurrected from synonymy by Graf and Cummings (2007) to accommodate a monophyletic clade of five species recognized by Turgeon et al. (1998) under Quadrula (Q. cylindrica, Q. intermedia, Q. metanevra, Q. sparsa, and Q. stapes; see Serb et al. 2003). Theliderma is the oldest available name for this clade and has T. metanevra as its type species. We recognize placement of all five of these species in Theliderma. No molecular data are available for Theliderma stapes, but its shell morphology is very similar to that of other Theliderma, and we include it in this genus following Graf and Cummings (2007). Turgeon et al. (1998) recognized Quadrula tuberosa, but we place this taxon in the synonymy of Theliderma metanevra following Parmalee and Bogan (1998, as Q. metanevra). However, the relationship of tuberosa to other species is uncertain, and if it represents a valid species, it is considered extinct (see Haag and Cicerello 2016). Quadrula cylindrica was recognized in Turgeon et al. (1998) as containing two subspecies, Theliderma cylindrica cylindrica and T. cylindrica strigillata. These subspecies traditionally were distinguished from each other based on shell morphology and distribution, with strigillata being confined mainly to the upper Tennessee River system in Tennessee and Virginia (Parmalee and Bogan 1998). However, the distributional limits of strigillata have never been clearly defined as it grades into typical T. c. cylindrica in larger streams, suggesting that the shell forms represent ecophenotypic variation (Ortmann 1920), and REVISED LIST OF FRESHWATER MUSSELS molecular data provide no support for recognition of T. c. strigillata (Serb et al. 2003; Sproules et al. 2006). Based on this evidence, we do not recognize subspecies within T. cylindrica. Both T. c. cylindrica (threatened) and T. c. strigillata (endangered) are federally protected taxa. Synonymizing strigillata under T. cylindrica will not remove the protection provided by the Endangered Species Act but may impact the status of populations formerly recognized as strigillata. Toxolasma Rafinesque, 1831.—Turgeon et al. (1998) recognized eight species. Recent evidence supports no changes at the genus level, but species boundaries within Toxolasma remain uncertain. Howells et al. (1996) placed Toxolasma mearnsi in the synonymy of Toxolasma texasiense based on electrophoretic analysis, a change overlooked by Turgeon et al. (1998); we recognize placement of T. mearnsi in the synonymy of T. texasiense. Undescribed species of Toxolasma have been recognized (e.g., Gulf Lilliput) but have yet to be formerly described (Williams et al. 2008, 2014). Lee (2006) concluded that Toxolasma has a neuter gender, which necessitates correction of spellings from lividus to lividum, parvus to parvum, and paulus to paulum, without change to corvunculus, cylindrellus, or pullus; we recognize these spelling changes. Lee (2006) provided an incorrect spelling of Toxolasma texasiense (as texasense), but we correct it based on the spelling presented in the original description. Tritogonia Agassiz, 1852.—Turgeon et al. (1998) recognized one species, Tritogonia verrucosa. Molecular data clearly supported inclusion of T. verrucosa within the tribe Quadrulini, but its placement within that group was unresolved, and Serb et al. (2003) recommended its placement within Quadrula (sensu lato) until relationships were better understood (e.g., see Williams et al. 2008; Haag and Cicerello 2016). Regardless of its relationship to other clades within the Quadrulini, Tritogonia represents a deeply divergent lineage (Serb et al. 2003; Campbell et al. 2012b), and our recognition of three other genera within this tribe (Cyclonaias, Theliderma, and Quadrula sensu stricto) warrants retention of Tritogonia as a monotypic genus (e.g., see Watters et al. 2009; Sietman et al. 2012). Truncilla Rafinesque, 1819.—Turgeon et al. (1998) recognized four species, and recent evidence supports no changes to this classification. Uniomerus Conrad, 1853.—Turgeon et al. (1998) recognized three species. Recent evidence supports no changes at the genus level, but species concepts within Uniomerus are uncertain (see Williams et al. 2008). Uniomerus columbensis was not recognized by Turgeon et al. (1998) but was elevated from synonymy by Williams et al. (2008) based on unpublished molecular data and shell morphology; we recognize this change. Species boundaries for other taxa (e.g., Uniomerus declivis) remain unresolved. The inappropriate and misleading common name for Uniomerus carolinianus, Florida Pondhorn, was changed to Eastern Pondhorn by Williams et al. (2014) because the 53 species occurs not only in Florida but northward along the Atlantic Coast; we recognize this change. Utterbackia Baker, 1927.—Turgeon et al. (1998) recognized three species and recent evidence supports no changes to this classification. Utterbackiana Frierson, 1927.—Utterbackiana was not recognized by Turgeon et al. (1998). We resurrect this genus as the senior available name for a monophyletic clade of four eastern North American species included in Turgeon et al. (1998) under Anodonta (A. couperiana, A. heardi, A. implicata, and A. suborbiculata; Mock et al. 2004; Zanatta et al. 2007; see Anodonta). The type species for the genus is Anodonta suborbiculata Say, 1831. In addition to the four taxa mentioned above, a new species was described subsequent to Turgeon et al. (1998), Anodonta hartfieldorum (Williams et al. 2009). We also place this species in Utterbackiana because it appears closely related to U. suborbiculata and was formerly associated with that species. Venustaconcha Frierson, 1927.—Turgeon et al. (1998) recognized two species. Molecular data showed that Villosa perpurpurea and Villosa trabalis also are members of Venustaconcha (Kuehnl 2009; Lane et al. 2016). Molecular data further showed that Venustaconcha perpurpurea is a junior synonym of Venustaconcha trabalis, and populations of this species in the Tennessee River drainage are genetically and morphologically distinct from those in the Cumberland River drainage (Lane et al. 2016). Based on the type locality of trabalis, Flint River, Alabama, this name is applicable to the Tennessee River drainage species. Unio troostensis Lea, 1834, is the oldest available name for the Cumberland drainage species (type locality is Stones River, Tennessee), and we recognize this species as Venustaconcha troostensis (see Haag and Cicerello 2016; Lane et al. 2016). Cumberland Bean was the common name used for V. trabalis by Turgeon et al. (1998), but Lane et al. (2016) proposed Tennessee Bean for Venustaconcha trabalis and Cumberland Bean for Venustaconcha troostensis; we follow this use. Venustaconcha sima was not included in Turgeon et al. (1998) but was elevated from synonymy by Gordon (1995) based on shell coloration and conchological characters, and its distinctiveness is supported by molecular data (Kuehnl 2009). This species was synonymized under Villosa iris by Parmalee and Bogan (1998), and molecular data support its relationship to Villosa (Kuehnl 2009). We recognize sima as a species of Villosa. Villosa Frierson, 1927.—Turgeon et al. (1998) recognized 17 species and one subspecies. Molecular data show that Villosa, as depicted by Turgeon et al. (1998), is wildly polyphyletic, with species occurring in as many as seven different clades within the Lampsilini (Kuehnl 2009). These and other data support reassignment of Villosa trabalis to Venustaconcha, synonymization of Villosa perpurpurea under Venustachoncha trabalis (see Venustaconcha), and reassignment of Villosa choctawensis and V. arkansasensis to Obovaria (see Obovaria). Most other species will require reassignment to existing genera (e.g., V. vaughniana to Ligumia; Raley et al. 2007; Kuehnl 2009) or resurrected or newly described genera, potentially with only Villosa amygdala 54 WILLIAMS ET AL. and V. villosa remaining in Villosa (Kuehnl 2009). However, these relationships are not fully understood, and currently synonymized or newly described generic names have not been proposed. With the exception of Villosa trabalis, V. perpurpurea, V. choctawensis, and V. arkansasensis, we retain all other species recognized by Turgeon et al. (1998) in Villosa. Villosa vanuxemensis umbrans was elevated to species status by Williams et al. (2008) based on shell characters and preliminary molecular data, and subsequent molecular data support this change (Kuehnl 2009); based on this evidence, we recognize V. umbrans. There are several undescribed taxa within Villosa (Kuehnl 2009; Harris et al. 2009). We recognize correction of gender agreement for Villosa amygdala, as given by Turgeon et al. (1998), to Villosa amygdalum following Williams et al. (2011, 2014). We recognize fifteen species of Villosa. mussels: John Alderman, Gerry Dinkins, Mike Gangloff, Dan Graf, Jordan Holcomb, Bob Howells, Sarina Jepsen, Paul Johnson, Stephen McMurray, Terry Myers, Charles Randklev, Kevin Roe, Tim Savidge, Daniel Schilling, Brian Watson, and Jason Wisniewski. We acknowledge Harry G. Lee (Jacksonville, Florida) for providing expert advice on the proper terminations for numerous species names. We also thank Sherry L. Bostick for assistance in preparation and review of several drafts of the manuscript. Although the individuals mentioned here provided assistance and input, we bear full responsibility for any errors. The findings and conclusions in this article are those of the authors and do not necessarily represent the views of their agencies and institutions. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. DISCUSSION LITERATURE CITED Changes in mussel taxonomy compared to Turgeon et al. (1998) reflect our better understanding of mussel phylogenetic relationships obtained mainly from molecular genetic data (e.g., Serb et al. 2003; Campbell and Lydeard 2012a, 2012b; Inoue et al. 2013, 2014; Pfeiffer et al. 2016). Molecular genetics continues to be one of the most important tools for understanding unionoid relationships and taxonomy, but other data sets (e.g., life history, host use, soft anatomy, shell morphology, zoogeography) are informative and should not be overlooked when constructing phylogenies and conducting taxonomic studies (e.g., Roe et al. 2001; Jones and Neves 2010; Lane et al. 2016). We recognize a larger number of genera than Turgeon et al. (1998; 56 vs. 49), but the number of currently recognized species is similar. However, recent studies show that considerable cryptic biodiversity exists in the Unionidae (e.g., Cyprogenia, Lampsilis, Villosa). Most of this biodiversity remains to be discovered, and its future recognition may result in increased numbers of species in the United States and Canada (see Haag 2012). Currently unrecognized species may be narrowly distributed (e.g., one river system) and in need of conservation measures. Development of additional molecular markers, more inclusive taxon sampling, advancements in phylogenetic analyses, and other techniques for species delineation are facilitating taxonomic recognition of species. More thorough understanding of life histories with improved husbandry techniques should also help facilitate species recognition. Future research will most likely reveal unrecognized taxa. Conversely, additional synonymy may be warranted for some currently recognized species. Much more research is needed to delineate true diversity of the mussels of the United States and Canada. Ahlstedt, S. A., M. T. Fagg, R. S. Butler, J. F. Connell, and J. W. Jones. 2016. Quantitative monitoring of freshwater mussel populations from 1979– 2004 in the Clinch and Powell Rivers of Tennessee and Virginia, with miscellaneous notes on the fauna. Freshwater Mollusk Biology and Conservation 19:1–18. Araujo, R., S. Schneider, K. J. Roe, D. Erpenbeck, and A. Machrodom. 2017. The origin and phylogeny of Margaritiferidae (Bivalvia, Unionoida): A synthesis of molecular and fossil data. Zoologica Stripta 46:289–307. doi: 10.1111/zsc.12217 Arizona Game and Fish Department. 2017. Heritage data management system. Anodonta californiensis, California Floater. Available at http://www. azgfd.gov/pdfs/w_c/hdms/Invertibrates/Anodcali.fo.pdf (accessed June 15, 2017). Bequaert, J. C., and W. B. Miller. 1973. The Mollusks of the Arid Southwest, with an Arizona Check List. The University of Arizona Press, Tucson. 271 pp. Bieler, R., J. G. Carter, and E. V. Coan. 2010. Classification of bivalve families. Pages 113–133 in P. Bouchet, J.-P. Rocroi, Rüdiger Bieler, J. G. Carter, and E. V. Coan, editors. Nomenclator of Bivalve Families with a Classification of Bivalve Families. Malacologia 52:1–184. Bogan, A. E., J. Bowers-Altman, and M. E. Raley. 2011a. A new threat to conservation of North American freshwater mussels: Chinese Pond Mussel Sinanodonta woodiana in the United States. Tentacle 19:39–40. Bogan, A. E., J. Bowers-Altman, and M. E. Raley. 2011b. The first confirmed record of the Chinese Pond Mussel (Sinanodonta woodiana) (Bivalvia: Unionidae) in the United States. The Nautilus 125:41–43. Bogan, A. E., and M. E. Raley. 2013. Taxonomic status of the Cumberland Papershell, Anodontoides argenteus (Lea, 1840) [formerly Anodontoides denigrata (Lea, 1852)] (Mollusca: Bivalvia: Unionidae). Unpublished report submitted to U.S. Fish and Wildlife Service, Frankfort, Kentucky. 32 pp. Bogan, A. E., M. Raley, and J. Levine. 2003. Determination of the systematic position and relationships of the Atlantic Pigtoe, Fusconaia masoni (Conrad, 1834) (Mollusca: Bivalvia: Unionidae) with distributions in Virginia, North and South Carolina, and Georgia. Unpublished report submitted to U.S. Fish and Wildlife Service, Asheville, North Carolina. 14 pp. Bolotov, I. N., Y. V. Bespalaya, I. V. Vikhrev, O. V. Aksenova, P. E. Aspholm, M. Y. Gofarov, O. K. Klishko, Y. S. Kolosova, A. V. Kondakov, A. A. Lyubas, I. S. Paltser, E. S. Konopleva, S. Tumpeesuwan, N. N. Bolotov, and I. S. Voroshilova. 2015. Taxonomy ACKNOWLEDGMENTS We thank the following individuals who were always very responsive to our questions regarding names of freshwater REVISED LIST OF FRESHWATER MUSSELS and distribution of the freshwater pearl mussels (Unionoida: Margaritiferidae) in the Far East of Russia. PLoS ONE 10:e0122408. doi: 10. 1371/journal.pone.0122408 Bolotov, I. N., I. V. Vikhrev, Y. V. Bespalaya, M. Y. Gofarov, A. V. Kondakov, E. S. Konopleva, N. N. Bolotov, and A. A. Lyubas. 2016. Multi-locus fossil-calibrated phylogeny, biogeography and a subgeneric revision of the Margaritiferidae (Mollusca: Bivalvia: Unionoida). Molecular Phylogenetics and Evolution 103:104–121. Brim Box, J., and J. D. Williams. 2000. Unionid mollusks of the Apalachicola Basin in Alabama, Florida, and Georgia. Alabama Museum of Natural History Bulletin 21:1–143. Burch, J. B. 1973. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Biota of Freshwater Ecosystems. Identification Manual 11, U.S. Environmental Protection Agency, Washington, D.C. 176 pp. Burch, J. B. 1975. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Revised edition. Malacological Publications, Hamburg, Michigan. 204 pp. Burlakova, L. E., D. Campbell, A. Y. Karatayev, and D. Barclay. 2012. Distribution, genetic analysis and conservation priorities for rare Texas freshwater molluscs in the genera Fusconaia and Pleurobema (Bivalvia: Unionidae). Aquatic Biosystems 8:1–15. Campbell, D. C., P. D. Johnson, J. D. Williams, A. K. Rindsberg, J. M. Serb, K. K. Small, and C. Lydeard. 2008. Identification of ‘extinct’ freshwater mussel species using DNA barcoding. Molecular Ecology Resources 8:711–724. doi: 10.1111/j.1755-0998.2008.02108.x Campbell, D. C., and C. Lydeard. 2012a. Molecular systematics of Fusconaia (Bivalvia: Unionidae: Ambleminae). American Malacological Bulletin 30:1–17. Campbell, D. C., and C. Lydeard. 2012b. The genera of Pleurobemini (Bivalvia: Unionidae: Ambleminae). American Malacological Bulletin 30:19–38. Campbell, D. C., J. M. Serb, J. E. Buhay, K. J. Roe, R. L. Minton, and C. Lydeard. 2005. Phylogeny of North American amblemines (Bivalvia, Unionoida): Prodigious polyphyly proves pervasive across genera. Invertebrate Biology 124:131–164. Carter, J. G., C. R. Altaba, L. C. Anderson, R. Araujo, A. S. Biakov, A. E. Bogan, D. C. Campbell, M. Campbell, C. Jin-hua, J. C. W. Cope, G. Delvene, H. H. Dijkstra, F. Zong-jie, R. N. Gardner, V. A. Gavrilova, I. A. Goncharova, P. J. Harries, J. H. Hartman, M. Hautmann, W. R. Hoeh, J. Hylleberg, J. Bao-yu, P. Johnston, L. Kirkendale, K. Kleemann, J. Koppka, J. Křı́ž, D. Machado, N. Malchus, A. Márquez-Aliaga, J.-P. Masse, C. A. McRoberts, P. U. Middelfart, S. Mitchell, L. A. Nevesskaja, S. Özer, J. Pojeta, Jr., I. V. Polubotko, J. M. Pons, S. Popov, T. Sánchez, A. F. Sartori, R. W. Scott, I. I. Sey, J. H. Signorelli, V. V. Silantiev, P. W. Skelton, T. Steuber, J. B. Waterhouse, G. L. Wingard, and T. Yancey. 2011. A synoptical classification of the Bivalvia (Mollusca). Paleontological Contributions No. 4. Kansas University Paleontological Institute. The University of Kansas, Lawrence. 47 pp. Chong, J. P., J. C. Brim Box, J. K. Howard, D. Wolf, T. L. Myers, and K. E. Mock. 2008. Three deeply divided lineages of the freshwater mussel genus Anodonta in western North America. Conservation Genetics 9:1303–1309. Chong, J. P., J. L. Harris, and K. J. Roe. 2016. Incongruence between mtDNA and nuclear data in the freshwater mussel genus Cyprogenia (Bivalvia: Unionidae) and its impact on species delineation. Ecology and Evolution 6:2439–2452. doi: 10.1002/ece3.2071 Cicerello, R. R., and G. A. Schuster. 2003. A guide to the freshwater mussels of Kentucky. Kentucky State Nature Preserves Commission, Scientific and Technical Series, No. 7. 62 pp. Clarke, A. H. 1981. The tribe Alasmidontini (Unionidae: Anodontinae). Part I: Pegias, Alasmidonta, and Arcidens. Smithsonian Contributions to Zoology, No. 326. 101 pp. 55 Clarke, A. H. 1992. Brief communications. Malacology Data Net 3:98. Clench, W. J., and R. 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 1:97–239, plates 1–9. Combosch, D. J., T. M. Collins, E. A. Glover, D. L. Graf, E. M. Harper, J. M. Healy, G. Y. Kawauchi, S. Lemer, E. McIntyre, E. E. Strong, J. D. Taylor, J. D. Zardus, P. M. Mikkelsen, G. Giribet, and R. Bieler. 2017. A familylevel Tree of Life for bivalves based on a Sanger-sequencing approach. Molecular Phylogenetics and Evolution 107:191–208. Cummings, K. S., and J. M. K. Berlocher. 1990. The naiades or freshwater mussels (Bivalvia: Unionidae) of the Tippecanoe River, Indiana. Malacological Review 23:83–98. Cummings, K. S., and D. L. Graf. 2010. Mollusca: Bivalvia. Pages 309–384 in J. H. Thorp and A. P. Covich, editors. Ecology and Classification of North American Freshwater Invertebrates. 3rd ed. Elsevier, Amsterdam, The Netherlands. Davis, G. M., and S. L. H. Fuller. 1981. Genetic relationships among Recent Unionacea (Bivalvia) of North America. Malacologia 20:217–253. Davis, G. M., and P. Mulvey. 1993. Species status of Mill Creek Elliptio. Savannah River Plant National Environment Research Park, SRO–NERP 22:4–58. Doucet-Beaupré, H., P. U. Blier, E. G. Chapman, H. Piontkivska, F. Dufresne, B. E. Sietman, R. S. Mulcrone, and W. R. Hoeh. 2012. Pyganodon (Bivalvia: Unionoida: Unionidae) phylogenetics: A male- and femaletransmitted mitochondrial DNA perspective. Molecular Phylogenetics and Evolution 63:430–444. Elderkin, C. L., A. D. Christian, J. L. Metcalfe-Smith, and D. J. Berg. 2008. Population genetics and phylogeography of freshwater mussels in North America, Elliptio dilatata and Actinonaias ligamentina (Bivalvia: Unionidae). Molecular Ecology 17:2149–2163. Frierson, L. S. 1927. A Classification and Annotated Check List of the North American Naiades. Baylor University Press, Waco, Texas. 111 pp. Errata et Corrigenda. Gangloff, M. M., B. A. Hamstead, E. F. Abernethy, and P. D. Hartfield. 2013. Genetic distinctiveness of Ligumia recta, the Black Sandshell, in the Mobile River Basin and implications for its conservation. Conservation Genetics 14:913–916. doi: 10.1007/s10592-013-0480-0 Gangloff, M. M., J. D. Williams, and J. W. Feminella. 2006. A new species of freshwater mussel (Bivalvia: Unionidae), Pleurobema athearni, from the Coosa River drainage of Alabama, USA. Zootaxa 1118:43–56. Gilbert, C. R. 1961. Hybridization versus intergradation: An inquiry into the relationship of two cyprinid fishes. Copeia 1961:181–192. Gordon, M. E. 1995. Venustaconcha sima (Lea), an overlooked freshwater mussel (Bivalvia: Unionoidea) from the Cumberland River basin of central Tennessee. The Nautilus 108:55–60. Graf, D. L. 2002. Molecular phylogenetic analysis of two problematic freshwater mussel genera (Unio and Gonidea) and a re-evaluation of the classification of Nearctic Unionidae (Bivalvia: Palaeoheterodonta: Unionoida). Journal of Molluscan Studies 68:65–71. Graf, D. L., and K. S. Cummings. 2007. Review of the systematics and global diversity of freshwater mussel species (Bivalvia: Unionoida). Journal of Molluscan Studies 73:291–314. Graf, D. L., and K. S. Cummings. 2017. The freshwater mussels (Unionoida) of the world (and other less consequential bivalves). MUSSELp database. Available at http://mussel-project.uwsp.edu/db/ (accessed March 25, 2017). Graf, D. L., and D. Ó Foighill. 2000. The evolution of brooding characters among the freshwater pearly mussels (Bivalvia: Unionoidea) of North America. Journal of Molluscan Studies 66:157–170. Grobler, J. P., J. W. Jones, N. A. Johnson, R. J. Neves, and E. M. Hallerman. 2011. Homogeneity at nuclear microsatellite loci masks mitochondrial 56 WILLIAMS ET AL. haplotype diversity in the endangered Fanshell Pearlymussel (Cyprogenia stegaria). Journal of Heredity 102:196–206. Haag, W. R. 2012. North American Freshwater Mussels: Natural History, Ecology, and Conservation. Cambridge University Press, New York. 505 pp. Haag, W. R., and R. R. Cicerello. 2016. A distributional atlas of the freshwater mussels of Kentucky. Scientific and Technical Series 8. Kentucky State Nature Preserves Commission, Frankfort. 299 pp. Harris, J. L., W. R. Hoeh, A. D. Christian, J. Walker, J. L. Farris, R. L. Johnson, and M. E. Gordon. 2004. Species limits and phylogeography of Lampsilinae (Bivalvia; Unionoida) in Arkansas with emphasis on species of Lampsilis. Unpublished final report to Arkansas Game and Fish Commission and U.S. Fish and Wildlife Service. 70 pp, 10 plates. Harris, J. L., W. R. Posey, 2nd, C. L. Davidson, J. L. Farris, S. R. Oetker, J. N. Stoeckel, M. G. Crump, S. Barnett, H. C. Martin, J. H. Seagraves, N. J. Wentz, R. Winterringer, C. Osborne, and A. D. Christian. 2009. Unionoida (Mollusca: Margaritiferidae, Unionidae) in Arkansas, third status review. Journal of the Arkansas Academy of Science 63:50–86. Heard, W. H., and R. H. Guckert. 1971. A re-evaluation of the Recent Unionacea (Pelecypoda) of North America. Malacologia 10:333–355. Herrmannsen, A. N. 1848. Indicis generum Malacozoorum primordia. Nomina subgenerum, familiarum, tribuum, ordinum, classium; adjectis auctoribus, temporibus, locis systematicis atque literariis, etymis, synonymis. Praetermittuntur Cirripedia, Tunicata et Rhizopoda. 2:353–492. Hewitt, T. L., J. L. Bergner, D. A. Woolnough, and D. T. Zanatta. 2016. Phylogeography of the freshwater mussel species Lasmigona costata: Testing post-glacial colonization hypotheses. Hydrobiologia. doi: 10. 1007/s10750-016-2834-3 Hoeh, W. R., A. E. Bogan, K. S. Cummings, and S. I. Guttman. 2002. Evolutionary relationships among the higher taxa of freshwater mussels (Bivalvia: Unionoida): Inferences on phylogeny and character evolution from analyses of DNA sequence data. Malacological Review 31–32:123– 141. Hoeh, W. R., A. E. Bogan, and W. H. Heard. 2001. A phylogenetic perspective on the evolution of morphological and reproductive characteristics in the Unionoida. Pages 257–280 in G. Bauer and K. Wächtler, editors. Ecology and Evolution of the Freshwater Mussels Unionoida. Ecological Studies, Vol. 145. Springer-Verlag, Berlin. Hoeh, W. R., A. E. Bogan, W. H. Heard, and E. G. Chapman. 2009. Palaeoheterodont phylogeny, character evolution, diversity and phylogenetic classification: A reflection on methods of analysis. Malacologia 51:307–317. Howells, R. G., R. W. Neck, and H. D. Murray. 1996. Freshwater Mussels of Texas. Texas Parks and Wildlife Department, Inland Fisheries Division, Austin. 218 pp. Huang, J., and L. L. Knowles. 2016. The species versus subspecies conundrum: Quantitative delimitation from integrating multiple data types within a single Bayesian approach in Hercules Beetles. Systematic Biology 65:685–699. Huff, S. W., D. Campbell, D. L. Gustafson, C. Lydeard, C. R. Altaba, and G. Giribet 2004. Investigations into the phylogenetic relationships of freshwater pearl mussels (Bivalvia: Margaritiferidae) based on molecular data: Implications for their taxonomy and biogeography. Journal of Molluscan Studies 70:379–388. Inoue, K., D. M. Hayes, J. L. Harris, and A. D. Christian. 2013. Phylogenetic and morphometric analyses reveal ecophenotypic plasticity in freshwater mussels Obovaria jacksoniana and Villosa arkansasensis (Bivalvia: Unionidae). Ecology and Evolution 3:2670–2683. Inoue, K., A. L. McQueen, J. L. Harris, and D. J. Berg. 2014. Molecular phylogenetics and morphological variation reveal recent speciation in freshwater mussels of the genera Arcidens and Arkansia (Bivalvia: Unionidae). Biological Journal of the Linnean Society 112:535–545. Johnson, R. I. 1970. The systematics and zoogeography of the Unionidae (Mollusca: Bivalvia) of the southern Atlantic Slope Region. Bulletin of the Museum of Comparative Zoology 140:263–449. Johnson, R. I. 1998. A new mussel, Potamilis metnecktayi (Bivalvia: Unionidae), from the Rio Grande system, Mexico and Texas with notes on Mexican Disconaias. Occasional Papers on Mollusks 5:427–455, plates 22–27. Jones, J. W., and R. J. Neves. 2010. Descriptions of a new species and a new subspecies of freshwater mussels, Epioblasma ahlstedti and Epioblasma florentina aureola (Bivalvia: Unionidae), in the Tennessee River drainage, USA. The Nautilus 124:77–92. Jones, J. W., R. J. Neves, S. A. Ahlstedt, and E. M. Hallerman. 2006. A holistic approach to taxonomic evaluation of two closely related endangered freshwater mussel species, the Oyster Mussel Epioblasma capsaeformis and Tan Riffleshell Epioblasma florentina walkeri (Bivalvia: Unionidae). Journal of Molluscan Studies 72:267–283. doi: 10.1093/ mollus/eyl004 King, T. L., M. S. Eackles, B. Gjetvaj, and W. R. Hoeh. 1999. Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): Conservation implications of range discontinuity. Molecular Ecology 8:S65–S78. Kuehnl, K. F. 2009. Exploring levels of genetic variation in the freshwater mussel genus Villosa (Bivalvia: Unionidae) at different spatial and systematic scales: Implications for biogeography, taxonomy, and conservation. Doctoral dissertation, The Ohio State University, Columbus. Lane, T. W., E. M. Hallerman, and J. W. Jones. 2016. Phylogenetic and taxonomic assessment of the endangered Cumberland Bean, Villosa trabalis and Purple Bean, Villosa perpurpurea (Bivalvia: Unionidae). Conservation Genetics 17:1109–1124. doi: 10.1007/s10592-016-0847-0 Layzer, J. B., M. E. Gordon, and R. M. Anderson. 1993. Mussels: The forgotten fauna of regulated rivers. A case study of the Caney Fork River. Regulated Rivers: Research and Management 8:63–71. Lee, H. G. 2006. Musings on a local specimen of Toxolasma paulum (I. Lea, 1840), the Iridescent Lilliput. Shell-O-Gram 47:3–6. Lee, H. G. 2008. Book review: Freshwater Mussels of Alabama and the Mobile Basin in Georgia, Mississippi and Tennessee. The Nautilus 122:261–263. Lopes-Lima, M., E. Froufe, V. T. Do, M. Ghamizi, K. E. Mock, U. Kebapci, O. Klishko, S. Kovitvadhi, U. Kovitvadhi, O. S. Paul, J. M. Pfeiffer, 3rd, M. Raley, N. Riccardi, H. Sereflisan, R. Sousa, A. Teirxeira, S. Varandas, X. P. Wu, D. T. Zanatta, A. Zieritz, and A. E. Bogan. 2017. Phylogeny of the most species rich freshwater bivalve family (Bivalvia: Unionida: Unionidae): Defining modern subfamilies and tribes. Molecular Phylogeny and Evolution 106:174–191. Available at http://dx.doi.org/10.1016/j. ympev.2016.08.021 Lydeard, C., R. L. Minton, and J. D. Williams. 2000. Prodigious polyphyly in imperiled freshwater pearly-mussels (Bivalvia: Unionidae): A phylogenetic test of species and generic designations. Pages 145–158 in E. M. Harper, J. D. Taylor, and J. A. Crane, editors. The Evolutionary Biology of the Bivalvia. Geological Society Special Publication, No. 177. Mayr, E., E. G. Linsley, and R. L. Usinger. 1953. Methods and Principles of Systematic Zoology. McGraw-Hill, New York. 336 pp. McCartney, M. A., A. E. Bogan, K. M. Sommer, and A. E. Wilbur. 2016. Phylogenetic analysis of Lake Waccamaw freshwater mussel species. American Malacological Bulletin 34:109–120. McMurray, S. E., J. S. Faiman, A. Roberts, B. Simmons, and M. C. Barnhart. 2012. A guide to Missouri’s freshwater mussels. Missouri Department of Conservation, Jefferson City. 94 pp. Miller, R. R., W. L. Minckley, and S. M. Norris. 2005. Freshwater Fishes of México. University of Chicago Press, Chicago, Illinois. 490 pp. Mock, K. E., J. C. Brim Box, M. P. Miller, M. E. Downing, and W. R. Hoeh. 2004. Genetic diversity and divergence among freshwater mussel REVISED LIST OF FRESHWATER MUSSELS (Anodonta) populations in the Bonneville Basin of Utah. Molecular Ecology 13:1085–1098. Modell, H. 1964. Das natürliche system der Najaden. 3. Archiv für Molluskenkunde 93:71–126. Morrison, J. P. E. 1942. Preliminary report on mollusks found in the shell mounds of the Pickwick Landing Basin in the Tennessee River Valley. Pages 337–392 in W. S. Webb and D. L. DeJarnette, editors. An archaeological survey of Pickwick Basin in the adjacent portions of the states of Alabama, Mississippi and Tennessee. Bureau of American Ethnology, Bulletin 129. Neves, R. J., A. E. Bogan, J. D. Williams, S. A. Ahlstedt, and P. W. Hartfield. 1997. Status of aquatic mollusks in the southeastern United States: A downward spiral of diversity. Pages 43–85 in G. A. Benz and D. E. Collins, editors. Aquatic Fauna in Peril: The Southeastern Perspective. Special Publication No. 1, Southeast Aquatic Research Institute. Lenz Design & Communications, Decatur, Georgia. Ortmann, A. E. 1918. The nayades (freshwater mussels) of the upper Tennessee drainage. With notes on synonymy and distribution. Proceedings of the American Philosophical Society 57:521–626. Ortmann, A. E. 1920. Correlation of shape and station in freshwater mussels (Naiades). Proceedings of the American Philosophical Society 59:269– 312. Parmalee, P. W., and A. E. Bogan. 1998. The Freshwater Mussels of Tennessee. The University of Tennessee Press, Knoxville. 328 pp. Perkins, M. A., N. A. Johnson, and M. M. Gangloff. 2017. Molecular systematics of the critically-endangered North American spinymussels (Unionidae: Elliptio and Pleurobema) and description of Parvaspina gen. nov. Conservation Genetics 18:745–757. doi: 10.1007/ s10592-017-0924-z Pfeiffer, J. M., 3rd, N. A. Johnson, C. R. Randklev, R. G. Howells, and J. D. Williams. 2016. Generic reclassification and species boundaries in the rediscovered freshwater mussel ‘‘Quadrula’’ mitchelli (Simpson in Dall, 1896). Conservation Genetics 17:279–292. doi: 0.1007/s10592-015-07807 Raley, M. E., A. E. Bogan, C. B. Eads, and J. F. Levine. 2007. Molecular evidence for a novel placement of the Carolina Creekshell, Villosa vaughaniana (Lea, 1836). Page 41 in Freshwater Mollusk Conservation Society Symposium, Little Rock, Arkansas. Roe, K. J. 2013. Molecular phylogenetics and zoogeography of the freshwater mussel genus Ptychobranchus (Bivalvia: Unionidae). Bulletin of the American Malacological Society 31:257–265. Roe, K. J., and P. D. Hartfield. 2005. Hamiota, a new genus of freshwater mussel (Bivalvia: Unionidae) from the Gulf of Mexico drainages of the southeastern United States. The Nautilus 119:1–10. Roe, K. J., P. D. Hartfield, and C. Lydeard. 2001. Phylogenetic analysis of the threatened and endangered superconglutinate-producing mussels of the genus Lampsilis (Bivalvia: Unionidae). Molecular Ecology 10:2225– 2234. Roe, K. J., and W. R. Hoeh. 2003. Systematics of freshwater mussels (Bivalvia: Unionoida). Pages 91–122 in C. Lydeard and D. R. Lindberg, editors. Molecular Systematics and Phylogeography of Mollusks. Smithsonian Books, Washington, D.C. Roe, K. J., and C. Lydeard. 1998. Species delineation and the identification of evolutionarily significant units: Lessons from the freshwater mussel genus Potamilus (Bivalvia: Unionidae). Journal of Shellfish Research 17:1359– 1363. Schilling, D. E. 2015. Assessment of morphological and molecular genetic variation of freshwater mussel species belonging to the genera Fusconaia, Pleurobema, and Pleuronaia in the upper Tennessee River basin. Master’s thesis, Virginia Polytechnic Institute and State University, Blacksburg. Serb, J. M., and M. C. Barnhart. 2008. Congruence and conflict between molecular and reproductive characters when assessing biological diversity 57 in the Western Fanshell Cyprogenia aberti (Bivalvia, Unionidae). Annals of the Missouri Botanical Garden 95:248–261. Serb, J. M., J. E. Buhay, and C. Lydeard. 2003. Molecular systematics of the North American freshwater bivalve genus Quadrula (Unionidae: Ambleminae) based on mitochondrial ND1 sequences. Molecular Phylogenetics and Evolution 28:1–11. Sietman, B. E., J. M. Davis, and M. C. Hove. 2012. Mantle display and glochidia release behaviors of five quadruline freshwater mussel species (Bivalvia: Unionidae). American Malacological Bulletin 30:39–46. Smith, D. G. 2000. On the taxonomic placement of Unio ochraceus Say, 1817 in the genus Ligumia (Bivalvia: Unionidae). The Nautilus 114:115–160. Smith, D. G. 2001. Systematics and distribution of the recent Margaritiferidae. Pages 33–49 in G. Bauer and K. Wächtler, editors. Ecology and Evolution of Freshwater Mussels Unionoida. Ecological Studies, Vol. 145. SpringerVerlag, Berlin. Sproules, J., P. Grobler, N. Johnson, J. W. Jones, R. J. Neves, and E. M. Hallerman. 2006. Genetic analysis of selected populations of the Rabbitsfoot Pearlymussel (Quadrula cylindrica cylindrica) (Bivalvia: Unionidae). Unpublished final report submitted to U.S. Fish and Wildlife Service, Frankfort, Kentucky. 16 pp. Stiven, A. E., and J. Alderman. 1992. Genetic similarities among certain freshwater mussel populations of the Lampsilis genus in North Carolina. Malacologia 34:355–369. Turgeon, D. D., A. E. Bogan, E. V. Coan, W. K. Emerson, W. G. Lyons, W. L. Pratt, C. F. E. Roper, A. Scheltema, F. G. Thompson, and J. D. Williams. 1988. Common and Scientific Names of Aquatic Invertebrates from the United States and Canada: Mollusks. American Fisheries Society, Special Publication 16. 277 pp., 12 plates. Turgeon, D. D., J. F. Quinn, A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and Scientific Names of Aquatic Invertebrates from the United States and Canada: Mollusks, 2nd ed. American Fisheries Society, Special Publication 26. 526 pp. Valenciennes, A. 1827. Coquilles fluviatiles bivalves du Nouveau-Continent, recueillies pendant le voyage de MM. De Humboldt et Bonpland. In A. von Humboldt and A. J. A. Bonpland, editors. Recueil d’observations de zoologie et d’anatomie compare, faites dans l’ocean Atlantique, dans l’intérieur du nouveau continent et dans la mer du sud pendant les années 1799, 1800, 1801, 1802 et 1803; par Al. de Humbodt et A. Bonpland. J. Smith and Gide, Paris, 2:225–237, colored plates 48, 50, 53, 54. Walker, J. M., J. P. Curole, D. E. Wade, E. G. Chapman, A. E. Bogan, G. T. Watters, and W. R. Hoeh. 2006. Taxonomic distribution and phylogenetic utility of gender-associated mitochondrial genomes in the Unionoida (Bivalvia). Malacologia 48:265–282. Watters, G. T., M. A. Hoggarth, and D. H. Stansbery. 2009. The Freshwater Mussels of Ohio. The Ohio State University Press, Columbus. 421 pp. Williams, J. D., A. E. Bogan, and J. T. Garner. 2008. The Freshwater Mussels of Alabama and the Mobile Basin of Georgia, Mississippi, and Tennessee. University of Alabama Press, Tuscaloosa. 908 pp. Williams, J. D., A. E. Bogan, and J. T. Garner. 2009. A new species of freshwater mussel, Anodonta hartfieldorum (Bivalvia: Unionidae), from the Gulf Coastal Plain drainages of Alabama, Florida, Louisiana and Mississippi, USA. The Nautilus 123:25–33. Williams, J. D., R. S. Butler, G. L. Warren, and N. A. Johnson. 2014. Freshwater Mussels of Florida. University of Alabama Press, Tuscaloosa. 498 pp. Williams, J. D., R. S. Butler, and J. M. Wisniewski. 2011. Annotated synonymy of the recent freshwater mussel taxa of the families Margaritiferidae and Unionidae described from Florida and drainages contiguous with Alabama and Georgia. Bulletin of the Florida Museum of Natural History 51:1–84. 58 WILLIAMS ET AL. Williams, J. D., and A. Fradkin. 1999. Fusconaia apalachicola, a new species of freshwater mussel (Bivalvia: Unionidae) from pre-Columbian archaeological sites in the Apalachicola basin of Alabama, Florida, and Georgia. Tulane Studies in Zoology 31:51–62. Williams, J. D., M. L. Warren, Jr., K. S. Cummings, J. L. Harris, and R. J. Neves. 1993. Conservation status of the freshwater mussels of the United States and Canada. Fisheries 18:6–22. Zanatta, D. T., and R. W. Murphy. 2006. Evolution of active host-attraction strategies in the freshwater mussel tribe Lampsilini (Bivalvia: Unionidae). Molecular Phylogenetics and Evolution 41:195–208. doi: 10.1016/j. ympev.2006.05.030 Zanatta, D. T., A. Ngo, and J. Lindell. 2007. Reassessment of the phylogenetic relationships among Anodonta, Pyganodon, and Utterbackia (Bivalvia: Unionoida) using mutation coding of allozyme data. Proceedings of the Academy of Natural Sciences of Philadelphia 156:211–216.