species Elliptio crassidens (Lamarck, 1819): synonymy

Unio crassidens Lamarck, 1819

Lamarck, 1819. Hist. Natur. Anim. sans Vert. 6: 71, sp. 3, var. b. [in part]
Type(s): LECTOTYPE MNHN_MPL_0030, “du lac Erie” .

Unio (sec. Elliptio) crassidens — Simpson (1900)
Unio (s.s.) crassidens — Call (1900)
Unio crassidens — Ortmann (1909), Ortmann (1909), Ortmann (1909), Ortmann (1910), Vanatta (1915)
Elliptio crassidens — Ortmann (1911), Ortmann (1912), Ortmann & Walker (1922), Ortmann (1924), Ortmann (1925), ... Hopper et al. (2023), Hauck et al. (2023), MolluscaBase (2024), FMCS (2025), Campbell & Lydeard (2026)
Unio (sec. Elliptio) (Group of U. crassidens) crassidens — Simpson (1914)
Elliptio niger — Ortmann (1918), Modell (1942)
Elliptio (s.s.) niger — Frierson (1927)
Elliptio (s.s.) crassidens — Thiele (1934), Haas (1969), Burch (1975)
Elliptio (s.s.) crassidens crassidens — Haas (1969), R.I. Johnson (1970)
Elliptio crassidens crassidens — R.I. Johnson (1980), Oesch (1984)

Unio (Elliptio) nigra Rafinesque, 1820

Rafinesque, 1818. Amer. Mon. Mag. 3: 355 [as ‘Potamilus niger’]. [nomen nudum]
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 291, pl. 80, figs. 1-4.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 22, 37.
Type(s): LECTOTYPE ANSP_20243, River Ohio.

Unio (sec. Elliptio) crassidens — Simpson (1900)
Unio (sec. Elliptio) (Group of U. crassidens) crassidens — Simpson (1914)
Elliptio nigra — Utterback (1915)
Unio crassidens — Vanatta (1915)
Elliptio niger — Ortmann (1918), Modell (1942)
Elliptio crassidens — Ortmann & Walker (1922), F.C. Baker (1928), Vidrine (1993), Parmalee & Bogan (1998), Brim Box & Williams (2000), Graf & Cummings (2007), Williams et al. (2008), Watters et al. (2009), Campbell & Lydeard (2012), Williams et al. (2014), Graf & Cummings (2021), MolluscaBase (2024)
Elliptio (s.s.) niger — Frierson (1927), Haas (1930)
Elliptio (s.s.) crassidens crassidens — Haas (1969), R.I. Johnson (1970)
Elliptio (s.s.) crassidens — Burch (1975)
Elliptio crassidens crassidens — R.I. Johnson (1980), Oesch (1984)

Unio (Elliptio) nigra var. fusca Rafinesque, 1820

(intro'd as intra-sp. of Unio (Elliptio) nigra Rafinesque, 1820)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 293.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 39.

Elliptio crassidens — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio (Elliptio) nigra var. maculata Rafinesque, 1820

(intro'd as intra-sp. of Unio (Elliptio) nigra Rafinesque, 1820)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 293.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 39.

Elliptio (s.s.) niger — Frierson (1927)
Fusconaia subrotunda — R.I. Johnson (1980)
Elliptio crassidens — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio cuneatus Barnes, 1823

Barnes, 1823. Amer. J. Sci. 6 (1-2): 263.

Unio (sec. Elliptio) crassidens — Simpson (1900)
Unio (sec. Elliptio) (Group of U. crassidens) crassidens — Simpson (1914)
Elliptio nigra — Utterback (1915)
Elliptio crassidens — Ortmann & Walker (1922), F.C. Baker (1928), Parmalee & Bogan (1998), Brim Box & Williams (2000), Williams et al. (2008), Watters et al. (2009)
Elliptio (s.s.) niger — Frierson (1927), Haas (1930)
Elliptio (s.s.) crassidens crassidens — Haas (1969), R.I. Johnson (1970)
Elliptio (s.s.) crassidens — Burch (1975)
Elliptio crassidens crassidens — Oesch (1984)

Obliquaria (Aximedia) venus Rafinesque, 1831

Rafinesque, 1831. Continuation: 3.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 75.

Quadrula (Fusconia [sic]) subrotunda — Frierson (1927)
Fusconaia subrotunda — Haas (1969)
Elliptio crassidens — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio incrassatus Lea, 1840

Lea, 1840. Proc. Amer. Phil. Soc. 1: 286.
Lea, 1842. Trans. Amer. Phil. Soc. 8 [O. 3]: 217 [55], pl. 16, fig. 34.
Type(s): HOLOTYPE USNM_84537, Columbus, Ga.

Unio (sec. Elliptio) incrassatus — Simpson (1900)
Unio (sec. Elliptio) (Group of U. crassidens) crassidens var. incrassatus — Simpson (1914)
Elliptio (s.s.) niger-incrassatus — Frierson (1927)
Elliptio crassidens incrassatus — Clench & Turner (1956)
Elliptio (s.s.) crassidens crassidens — Haas (1969), R.I. Johnson (1970)
Elliptio (s.s.) crassidens — Burch (1975)
Elliptio crassidens — Parmalee & Bogan (1998), Brim Box & Williams (2000), Williams et al. (2008), IUCN (2011), Williams et al. (2011), Williams et al. (2014)

Unio discus Sowerby, 1868

(misidentified reference to Unio discus Lea, 1838)
‘Lea’ Sowerby, 1868. Conch. Icon. 16: pl. 62, sp. 310; errata.

Unio (sec. Elliptio) crassidens — Simpson (1900)
Unio (Lampsilis) discus — Martens (1900)
Unio (sec. Elliptio) (Group of U. crassidens) crassidens — Simpson (1914)
Elliptio (s.s.) niger — Frierson (1927)
Elliptio (s.s.) crassidens crassidens — Haas (1969), R.I. Johnson (1970)
Elliptio (s.s.) crassidens — Burch (1975)
Elliptio crassidens — Parmalee & Bogan (1998), Watters et al. (2009)

Unio danielsii B.H. Wright, 1899

B.H. Wright, 1899. Nautilus 13(3): 31.
B.H. Wright, 1899. Nautilus 13(4): 43.
Type(s): HOLOTYPE USNM_168967, Spring Creek, Decatur Co., Georgia.

Unio (sec. Elliptio) danielsii — Simpson (1900)
Unio (sec. Elliptio) (Group of U. crassidens) danielsii — Simpson (1914)
Elliptio (s.s.) niger-danielsi — Frierson (1927)
Elliptio crassidens incrassatus — Clench & Turner (1956)
Elliptio (s.s.) crassidens danielsii — Haas (1969)
Elliptio (s.s.) crassidens crassidens — R.I. Johnson (1970)
Elliptio (s.s.) crassidens — Burch (1975)
Elliptio crassidens — Parmalee & Bogan (1998), Brim Box & Williams (2000), Watters et al. (2009), Williams et al. (2011), Williams et al. (2014)

Elliptio pachyodon Pilsbry in Olson & Harbison, 1953

Pilsbry in Olson & Harbison, 1953. ANSP Monogr. 8: 447, pl. 65, fig. 8.

Elliptio (s.s.) crassidens crassidens — R.I. Johnson (1970)
Elliptio (s.s.) crassidens — Burch (1975)
Elliptio crassidens — Watters et al. (2009)
Elliptio pachyodon — MolluscaBase (2024)

Unio okefenokensis B.H. Wright, in USNM Coll. of Authors

B.H. Wright, in USNM Coll. of Authors.
Type(s): MANUSCRIPT NAME USNM_168966, Spanish Creek, Okefenokee Swamp, Georgia.

Unio niger Conrad, 1836

(reference to Unio (Elliptio) nigra Rafinesque, 1820)
‘Rafinesque’ Conrad, 1836. Monogr. Fam. Unionidae 1(6): 49, pl. 46.
‘Rafinesque’ Conrad, 1853. Proc. Acad. Nat. Sci. 6: 253.

Unio (sec. Elliptio) crassidens — Simpson (1900)

Unio crassus Sowerby, 1868

(misidentified reference to Unio crassus Say, 1817)
‘Say’ Sowerby, 1868. Conch. Icon. 16: pl. 95, sp. 520.

Lampsilis (sec. Eurynia) ligamentinus var. gibbus — Simpson (1900)
Lampsilis (Eurynia) (Group of L. ligamentina) ligamentina var. gibba — Simpson (1914)
Lampsilis (Ortmanniana) carinata-calendis — Frierson (1927)
Elliptio (s.s.) crassidens crassidens — Haas (1969)
Elliptio crassidens — Parmalee & Bogan (1998), Watters et al. (2009)