Obliquaria (Scalenaria) obliquata Rafinesque, 1820
Rafinesque, 1818. Amer. Mon. Mag. 3: 355 [as ‘Potamilus obliquatus’]. [nomen nudum]
Rafinesque, 1819. Jour. Phys. Chim. Hist. Nat. 88: 426 [as ‘U. (Plagiola) obliquatus’]. [nomen nudum]
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 309 [also as ‘U. obliquata’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 22, 29, 53.
Type(s): LECTOTYPE ANSP_20226, Kentucky River.

— Simpson (1900), Simpson (1914)
Truncilla obliquata — Vanatta (1915)
Dysnomia (Scalenilla) sulcata — Ortmann & Walker (1922)
Quadrula (Obliquata) obliquata — Frierson (1927), Haas (1930), Haas (1969), Haas (1969)
Pleurobema obliquata — Morrison (1969)
Obliquaria obliquata — Burch (1975)
Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Plagiola obliquata — R.I. Johnson (1980)
Epioblasma obliquata obliquata — Turgeon et al. (1988), Williams et al. (1993), Turgeon et al. (1998), Lydeard et al. (1999), Cicerello & Schuster (2003), Watters et al. (2009), ITIS (2012)
Epioblasma obliquata — Cummings & Mayer (1992), Strayer & Jirka (1997), Cummings & Mayer (1997), Parmalee & Bogan (1998), Graf (2002), ... Graf & Cummings (2021), FMCS (2021), Hopper et al. (2023), FMCS (2025), Campbell & Lydeard (2026)
Pleurobema pyramidatum — Vidrine (1993)
Pleurobema (Sintoxia) rubrum — Campbell & Lydeard (2012)

Unio perplexus Say, 1829
Say, 1829. New Harm. Dissem. 2(19): 309.
Say, 1830. Amer. Conch. 1: pl. 5.
Say, 1858. [in] Binney, Compl. Writings T. Say: 155, 225.

Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Epioblasma obliquata — Parmalee & Bogan (1998), Williams et al. (2008)

Unio ridibundus Say, 1829
Say, 1829. New Harm. Dissem. 2(20): 308, sp. 6.
Say, 1830. Amer. Conch. 1: pl. 5, upper fig.
Say, 1858. [in] Binney, Compl. Writings T. Say: 131, 154.

Truncilla (Scalenaria) sulcata — Simpson (1900)
Truncilla (Scalenaria) (Group of Truncilla sulcata) sulcata — Simpson (1914)
Dysnomia (Scalenilla) sulcata — Ortmann & Walker (1922)
Dysnomia (Pilea) sulcata — Frierson (1927), Haas (1969)
Plagiola ridibundus — Morrison (1969)
Dysnomia sulcata — Burch (1975)
Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Epioblasma obliquata — Parmalee & Bogan (1998), Williams et al. (2008)
Epioblasma obliquata obliquata — Watters et al. (2009)

Unio sulcatus Lea, 1829
Lea, 1828. Trans. Amer. Phil. Soc. 3 [O. 1]: 269 [as ‘Unio ellipsis var. a’].
Lea, 1829. Trans. Amer. Phil. Soc. 3 [O. 1]: 430, pl. 8, fig. 12.
Say, 1830. Amer. Conch. 1: pl. 5, lower figs.
Type(s): SYNTYPES USNM_84803, Ohio.

Truncilla (Scalenaria) sulcata — Simpson (1900)
Unio (s.s.) sulcatus — Call (1900)
Truncilla (Scalenaria) (Group of Truncilla sulcata) sulcata — Simpson (1914)
— de Gregorio (1914)
Truncilla obliquata — Vanatta (1915)
Dysnomia (Scalenilla) sulcata — Ortmann & Walker (1922), Ortmann (1925), Haas (1969)
Dysnomia (s.s.) sulcata — Ortmann (1924)
Dysnomia (Pilea) sulcata — Frierson (1927), Haas (1930), Haas (1969)
Epioblasma (sec. Scalenilla) sulcatus — Thiele (1934)
Plagiola ridibundus — Morrison (1969)
Dysnomia sulcata — Stansbery (1970), Burch (1975), Mackie et al. (1980)
Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Plagiola obliquata — R.I. Johnson (1980)
Epioblasma obliquata — Parmalee & Bogan (1998), Williams et al. (2008)
Dysnomia sulcata sulcata — ITIS (2012)

Unio flagellatus Say, 1830
Say, 1830. Amer. Conch. 1: [no pagination].
Say, 1858. [in] Binney, Compl. Writings T. Say: 154.
(intro'd as syn of Unio sulcatus Lea, 1829)

Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Epioblasma obliquata — Parmalee & Bogan (1998), Williams et al. (2008)

Unio obliquatus Say, 1834
‘Rafinesque’ of Authors.
Say, 1834. Amer. Conch. 6: ??.
Conrad, 1834. New Fresh-Water Shells: 70.
(reference to Obliquaria (Scalenaria) obliquata Rafinesque, 1820)

Truncilla (Scalenaria) sulcata — Simpson (1900)
Truncilla (Scalenaria) (Group of Truncilla sulcata) sulcata — Simpson (1914)
Dysnomia (Pilea) sulcata — Frierson (1927)

Unio pectitus Conrad, 1854
Conrad, 1853. Proc. Acad. Nat. Sci. 6: 255. [nomen nudum]
Conrad, 1854. Jour. Acad. Nat. Sci. 2(4): 297, pl. 27, 4.

Truncilla (Scalenaria) sulcata — Simpson (1900)
Truncilla (Scalenaria) (Group of Truncilla sulcata) sulcata — Simpson (1914)
Dysnomia (Pilea) sulcata-pectita — Frierson (1927)
Dysnomia (Pilea) sulcata — Haas (1969)
Dysnomia sulcata — Burch (1975)
Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Epioblasma obliquata — Parmalee & Bogan (1998), Williams et al. (2008)
Epioblasma obliquata obliquata — Watters et al. (2009)

Unio propesulcatus de Gregorio, 1914
de Gregorio, 1914. Il Nat. Siciliano 2: 60, pl. 10. figs. 2a-d.

Unio propesulcatus — de Gregorio (1914)
Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Epioblasma obliquata — Parmalee & Bogan (1998), Williams et al. (2008)
Epioblasma obliquata obliquata — Watters et al. (2009)

Unio stewardsonii var. stewensoni de Gregorio, 1914
de Gregorio, 1914. Il Nat. Siciliano 2: 45, pl. 6, fig. 3.
(intro'd as intra-sp. of Unio stewardsonii Lea, 1852)

Unio stewardsonii var. stewensoni — de Gregorio (1914)
Plagiola (Pilea) obliquata — R.I. Johnson (1978)
Epioblasma obliquata — Parmalee & Bogan (1998)
Epioblasma obliquata obliquata — Watters et al. (2009)

Unio stewardsonii var. stewardsonii Parmalee & Bogan, 1998
‘De Gregorio’ of Authors.
Parmalee & Bogan, 1998. The Freshwater Mussels of Tennessee: 97.
Watters et al., 2009. Freshw. Mussels OH: 95.
(error for Unio stewardsonii var. stewensoni de Gregorio, 1914)

Unio rudibundus Hanley, 1843
‘Say’ Hanley, 1843. Illustr. Descr. Cat. Rec. Bivalve Shells: 188.
(error for Unio ridibundus Say, 1829)

Unio propeculcatus Parmalee & Bogan, 1998
‘de Gregorio’ Parmalee & Bogan, 1998. The Freshwater Mussels of Tennessee: 97.
(error for Unio propesulcatus de Gregorio, 1914)

Epioblasma obliquata obliquata — Watters et al. (2009)

Unio pectitis Williams et al., 2008
‘Conrad’ Williams et al., 2008. Freshw. Mussels AL and Mobile Basin: 258.
(error for Unio pectitus Conrad, 1854)