Bivalvia | Unionida | Unionoidea | Unionidae | Ambleminae | Pleurobemini | Eurynia
9 specimens + 7 GenBank vouchers

(homonym of Unio nasutus Say, 1817)
Lamarck, 1819. Hist. Natur. Anim. sans Vert. 6: 75, sp. 22.
Type(s): SYNTYPE MNHN_MPL_0022, rapporte Lac Erie.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Elliptio dilatata — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 321.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 63.
Obliquaria atroviolacea — Burch (1975)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 304, pl. 81, figs. 8-9 [also as ‘U. cuprea’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 48.
Elliptio dilatatus — Ortmann & Walker (1922)
Elliptio (s.s.) dilatata — R.I. Johnson (1970), Burch (1975)

(renamed Unio cultratus Rafinesque, 1831)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 321 [also as ‘Unio sinuata’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 63.
Type(s): LECTOTYPE ANSP_20252, Kentucky River.
Unio dilatata — Vanatta (1915)
Ptychobranchus (s.s.) fasciolare — Frierson (1927)
Obliquaria sinuata — Burch (1975)
Elliptio dilatata — Watters et al. (2009)

(renamed Obliquaria violacea Rafinesque, 1831)
Rafinesque, 1819. Jour. Phys. Chim. Hist. Nat. 88: 426. [nomen nudum]
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 297 [also as ‘Elliptio dilatata’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 29, 42.
Type(s): LECTOTYPE ANSP_20248, Kentucky River.
Elliptio dilatata — Utterback (1915), R.I. Johnson (1980), Mackie et al. (1980), Oesch (1984), Davis (1984), ... Wu et al. (2018), Huang et al. (2019), Klymus et al. (2020), Gasparini et al. (2020), Jeratthitikul et al. (2022)
Unio dilatata — Vanatta (1915)
Elliptio dilatatus — Ortmann (1918), Ortmann & Walker (1922), Ortmann (1924), Ortmann (1925), F.C. Baker (1928), Murray & Leonard (1962), Gordon et al. (1979), Mathiak (1979)
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) dilatatus — Haas (1930)
Elliptio (s.s.) dilatata — Thiele (1934), Burch (1975)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Elliptio sp. — Caveney et al. (2006)
Eurynia dilatata — Campbell & Lydeard (2012), Williams et al. (2017), Inoue et al. (2018), Pieri et al. (2018), Inoue et al. (2020), Smith et al. (2020), Graf & Cummings (2021), FMCS (2021), Hopper et al. (2023), FMCS (2025), Campbell & Lydeard (2026)
Elliptio (Eurynia) dilatata — Campbell & Lydeard (2012), Burlakova et al. (2012), Perkins et al. (2017)
Eurynia (Elliptio) dilatata — Porto-Hannes et al. (2021)
Barnes, 1823. Amer. J. Sci. 6 (1-2): 262, pl. 11, figs. 12a-b.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
Unio (s.s.) gibbosus — Call (1900)
Unio gibbosus — Ortmann (1909), Ortmann (1909), Ortmann (1909), Ortmann (1910)
Elliptio gibbosus — Ortmann (1911), Ortmann (1912)
Elliptio dilatata — Utterback (1915), R.I. Johnson (1980), Oesch (1984), Vidrine (1993), Howells et al. (1996), Strayer & Jirka (1997), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
Unio dilatata — Vanatta (1915)
Elliptio dilatatus — Ortmann (1918), Ortmann & Walker (1922), F.C. Baker (1928), Murray & Leonard (1962)
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) dilatatus — Haas (1930)
Elliptio (s.s.) dilatata — Thiele (1934), Burch (1975)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Barnes, 1823. Amer. J. Sci. 6 (1-2): 266, pl. 13, fig. 13.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
Lampsilis (Venusta) ellipsiformis — Frierson (1927)
Elliptio dilatatus — F.C. Baker (1928)
Lampsilis (Venustaconcha) ellipsiformis — Haas (1969)
Elliptio dilatata — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
Rafinesque, 1831. Continuation: 3.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 74.
Elliptio (Eurynaia [sic]) dilatatus-fulvus — Frierson (1927)
Elliptio (Eurynia) nasutus fulvus — Haas (1969)
Elliptio dilatata — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
(intro'd as intra-sp. of Bariosta fulvus Rafinesque, 1831)
Rafinesque, 1831. Continuation: 3.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 74.
(intro'd as intra-sp. of Bariosta fulvus Rafinesque, 1831)
Rafinesque, 1831. Continuation: 3.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 74.
Rafinesque, 1831. Continuation: 3.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 75.
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Elliptio dilatata — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
(new name for Unio (Eurynia) dilatata Rafinesque, 1820)
Rafinesque, 1831. Continuation: 3.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 75.
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Elliptio dilatata — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
(new name for Obliquaria (Ellipsaria) sinuata Rafinesque, 1820)
Rafinesque, 1831. Continuation: 4.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 77.
Ptychobranchus (s.s.) fasciolare — Frierson (1927)
Rafinesque, 1831. Continuation: 4.
Elliptio dilatata — Watters et al. (2009)
(reference to Unio (Eurynia) dilatata Rafinesque, 1820)
‘Rafinesque’ of Authors.
Say, 1834. Amer. Conch. 6: ??.
Conrad, 1836. Monogr. Fam. Unionidae 1(5): 42, pl. 21.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
Elliptio dilatata — Watters et al. (2009)

Lea, 1836. Synopsis Fam. Naiades: 39. [nomen nudum]
Lea, 1838. Trans. Amer. Phil. Soc. 6 [O. 2]: 10, pl. 4, fig. 10.
Type(s): HOLOTYPE USNM_86103, Ohio R., Cincinnati, Ohio.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
Unio (s.s.) gibbosus — Call (1900)
Unio arctior — de Gregorio (1914)
Elliptio dilatata — Utterback (1915), Oesch (1984), Howells et al. (1996), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)

Lea, 1840. Proc. Amer. Phil. Soc. 1: 286.
Lea, 1842. Trans. Amer. Phil. Soc. 8 [O. 3]: 195 [33], pl. 8, fig. 5.
Type(s): HOLOTYPE USNM_84969, Stone R., Tenn.
Unio (sec. Elliptio) stonensis — Simpson (1900), Simpson (1914)
Unio (s.s.) gibbosus — Call (1900)
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Elliptio dilatata — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

(intro'd as intra-sp. of Unio gibbosus Barnes, 1823)
B.H. Wright, 1898. Nautilus 11(11): 123.
Type(s): LECTOTYPE USNM_150523, Armathwaite, Fentress Co., Tenn.
Unio (sec. Elliptio) gibbosus var. armathwaitensis — Simpson (1900), Simpson (1914)
Elliptio (Eurynaia [sic]) dilatatus-armathwaitensis — Frierson (1927)
Elliptio (Eurynia) nasutus armathwaitensis — Haas (1969)
Elliptio dilatata — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

(homonym of Unio delicatus Lea, 1863; intro'd as intra-sp. of Unio gibbosus Barnes, 1823)
Simpson, 1900. Proc. U.S. Nat. Mus. 22: 704.
Simpson, 1914. Descr. Cat. Naiades: 600.
Type(s): LECTOTYPE USNM_128797, St. Francis R., Greenway, Clay Co., Arkansas.
Unio (sec. Elliptio) gibbosus var. delicatus — Simpson (1900), Simpson (1914)
Elliptio dilatata delicata — Utterback (1915)
Elliptio (Eurynaia [sic]) dilatatus-delicatus — Frierson (1927)
Elliptio dilatatus delicatus — F.C. Baker (1928)
Elliptio (Eurynia) nasutus delicatus — Haas (1969)
Elliptio dilatata — R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
de Gregorio, 1914. Il Nat. Siciliano 2: 38, pl. 3, figs. 1a-d.
Unio propeverutus — de Gregorio (1914)
Elliptio dilatata — Williams et al. (2008), Watters et al. (2009)

(intro'd as intra-sp. of Unio (Eurynia) dilatata Rafinesque, 1820)
Grier, 1918. Nautilus 32(1): 9.
Type(s): HOLOTYPE (ORIG. DESIG.) CM_61.4628, Presque Isle Bay, Erie, Erie County, Pennsylvania.
Elliptio dilatatus sterkii — F.C. Baker (1928)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Elliptio (s.s.) dilatata — Burch (1975)
Elliptio dilatata — R.I. Johnson (1980), Strayer & Jirka (1997), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
(misidentified reference to Unio arctatus Conrad, 1834)
‘Conrad’ Ferussac, 1835. Mag. Zool. 5(59-60): 29.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
(misidentified reference to Amblema torulosa Rafinesque, 1820)
‘Rafinesque’ Ferussac, 1835. Mag. Zool. 5(59-60): 28.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
(error for Obliquaria bicolor Rafinesque, 1831)
‘Rafinesque’ Lea, 1852. Synopsis Fam. Naiades: 57.
(misidentified reference to Unio subgibbosus Lea, 1857)
‘Lea’ Utterback, 1915. Amer. Midl. Nat. 4(5): 202-203, pl. 21, figs. 68a-d.
Elliptio dilatata — Parmalee & Bogan (1998), Watters et al. (2009)
(error for Unio arctior Lea, 1838)
‘Lea’ Howells et al., 1996. Freshw. Mussels Tex.: 51.
Unio (sec. Elliptio) gibbosus — Simpson (1900), Simpson (1914)
Unio (sec. Elliptio) gibbosus var. armathwaitensis — Simpson (1900), Simpson (1914)
Unio (sec. Elliptio) gibbosus var. delicatus — Simpson (1900), Simpson (1914)
Unio (sec. Elliptio) stonensis — Simpson (1900), Simpson (1914)
Unio (s.s.) gibbosus — Call (1900)
Unio gibbosus — Ortmann (1909), Ortmann (1909), Ortmann (1909), Ortmann (1910)
Elliptio gibbosus — Ortmann (1911), Ortmann (1912)
Unio propeverutus — de Gregorio (1914)
Unio arctior — de Gregorio (1914)
Elliptio dilatata — Utterback (1915), R.I. Johnson (1980), Mackie et al. (1980), Oesch (1984), Davis (1984), ... Wu et al. (2018), Huang et al. (2019), Klymus et al. (2020), Gasparini et al. (2020), Jeratthitikul et al. (2022)
“Elliptio dilatata subgibbosa” ** — Utterback (1915)
Elliptio dilatata delicata — Utterback (1915)
Unio dilatata — Vanatta (1915)
Elliptio dilatatus — Ortmann (1918), Ortmann & Walker (1922), Ortmann (1924), Ortmann (1925), F.C. Baker (1928), Murray & Leonard (1962), Gordon et al. (1979), Mathiak (1979)
Elliptio (Eurynaia [sic]) dilatatus — Frierson (1927)
Elliptio (Eurynaia [sic]) dilatatus-fulvus — Frierson (1927)
Elliptio (Eurynaia [sic]) dilatatus-armathwaitensis — Frierson (1927)
Elliptio (Eurynaia [sic]) dilatatus-delicatus — Frierson (1927)
Ptychobranchus (s.s.) fasciolare — Frierson (1927)
Lampsilis (Venusta) ellipsiformis — Frierson (1927)
Elliptio dilatatus delicatus — F.C. Baker (1928)
Elliptio dilatatus sterkii — F.C. Baker (1928)
Elliptio (Eurynia) dilatatus — Haas (1930)
Elliptio (s.s.) dilatata — Thiele (1934), R.I. Johnson (1970), Burch (1975)
Lampsilis (Venustaconcha) ellipsiformis — Haas (1969)
Elliptio (Eurynia) nasutus nasutus — Haas (1969)
Elliptio (Eurynia) nasutus fulvus — Haas (1969)
Elliptio (Eurynia) nasutus armathwaitensis — Haas (1969)
Elliptio (Eurynia) nasutus delicatus — Haas (1969)
Obliquaria atroviolacea — Burch (1975)
Obliquaria sinuata — Burch (1975)
Elliptio sp. — Caveney et al. (2006)
Eurynia dilatata — Campbell & Lydeard (2012), Williams et al. (2017), Inoue et al. (2018), Pieri et al. (2018), Inoue et al. (2020), Smith et al. (2020), Graf & Cummings (2021), FMCS (2021), Hopper et al. (2023), FMCS (2025), Campbell & Lydeard (2026)
Elliptio (Eurynia) dilatata — Campbell & Lydeard (2012), Burlakova et al. (2012), Perkins et al. (2017)
Eurynia (Elliptio) dilatata — Porto-Hannes et al. (2021)