Obovaria cordata Rafinesque, 1820
Rafinesque, 1820, Ann. Gén. Sci. Phys. 5 (13): 312, pl. 82, figs. 6-7.
Rafinesque, 1864, [in] Binney & Tryon, reprint: 55.
Type(s): LECTOTYPE ANSP_20221, Ohio River.

Obovaria cordata — Rafinesque (1820), Simpson (1900), Simpson (1914)
Unio cordatus — Ferussac (1835), Conrad (1836), Küster (1852), Conrad (1853)
Margarita (Unio) obliqua — Lea (1836)
Margaron (Unio) obliquus — Lea (1852), Lea (1870)
Quadrula cordata — Vanatta (1915)
Pleurobema obliqua cordatum — Ortmann (1918)
Pleurobema cordata — Ortmann & Walker (1922), Davis & Fuller (1981)
Pleurobema cordatum — Ortmann (1924), Ortmann (1925), Burch (1975), Mathiak (1979), R.I. Johnson (1980), Turgeon et al. (1988), Cummings & Mayer (1992), Williams et al. (1993), Rosenberg et al. (1994), IUCN (1996), Rosenberg et al. (1997), Strayer & Jirka (1997), Parmalee & Bogan (1998), Turgeon et al. (1998), Lydeard et al. (1999), Cicerello & Schuster (2003), Campbell et al. (2005), Graf & Cummings (2007), Burdick & White (2007), Williams et al. (2008), Campbell et al. (2008), Watters et al. (2009), Cummings & Graf (2010), Bogan (2010), Haag (2012), Jones (2015), Pfeiffer et al. (2016), Williams et al. (2017), Inoue et al. (2018), Klymus et al. (2020), Graf & Cummings (2021)
Quadrula (Obliquata) cordata — Frierson (1927), Haas (1930)
Quadrula (Obliquata) cordata cordata — Haas (1969)
Pleurobema obliquum — Morrison (1969)
Pleurobema (Sintoxia) cordatum — Campbell & Lydeard (2012), Campbell & Lydeard (2012), Burlakova et al. (2012)
Pleurobema cordatum cordatum — ITIS (2012)

Unio obliqua Lamarck, 1819
Lamarck, 1819, Hist. Natur. Anim. sans Vert. 6: 72, sp. 8.
Type(s): HOLOTYPE MNHN_MPL_0041, Wabash.

Unio obliqua — Lamarck (1819), Ferussac (1835)
Unio obliquus — Menke (1828), Menke (1830), Conrad (1837), Hanley (1843), Küster (1852), Conrad (1853), Küster (1861), Call (1895), Pilsbry & Rhoads (1896)
Unio undatus — Lea (1834)
Margarita (Unio) obliqua — Lea (1836)
Unio (s.s.) obliqua — Swainson (1840)
Margaron (Unio) obliquus — Lea (1852), Lea (1870)
Unio (Lampsilis) obliquus — Adams & Adams (1857)
Quadrula (sec. Fusconaia) obliqua — Simpson (1900), Simpson (1914)
Unio (s.s.) obliquus — Call (1900)
Quadrula obliqua — Ortmann (1909), Ortmann (1909), Vanatta (1915)
Pleurobema obliqua — Ortmann (1910), Ortmann (1918)
Pleurobema obliquum — Ortmann (1912), Utterback (1915), Morrison (1969)
Pleurobema cordata — Ortmann & Walker (1922)
Quadrula (Obliquata) cordata cordata — Haas (1969)
Pleurobema cordatus — R.I. Johnson (1969)
Pleurobema cordatum — R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Obovaria cordata var. rosea Rafinesque, 1820
Rafinesque, 1820, Ann. Gén. Sci. Phys. 5 (13): 312.
Rafinesque, 1864, [in] Binney & Tryon, reprint: 56.
(intro'd as intra-sp. of Obovaria cordata Rafinesque, 1820; homonym of Obovaria striata var. rosea Rafinesque, 1820)

Obovaria cordata var. rosea — Rafinesque (1820)
Pleurobema cordatum — Williams et al. (2008), Watters et al. (2009)

Unio mytiloides Short & Eaton, 1831
‘Rafinesque’ Short & Eaton, 1831, Transylvania J. Med. Assoc. Sci. 1831: 74.
(misidentified reference to Pleurobema mytiloides Rafinesque, 1820)

Unio mytiloides — Short & Eaton (1831)
Margarita (Unio) obliqua — Lea (1836)
Margaron (Unio) obliquus — Lea (1852), Lea (1870)
Quadrula (sec. Fusconaia) obliqua — Simpson (1900), Simpson (1914)
Quadrula (Obliquata) cordata — Frierson (1927)
Pleurobema cordatum — Parmalee & Bogan (1998), Watters et al. (2009)

Unio obliquus Call, 1900
‘Lamarck’ of Authors.
Call, 1900, Ind. Dept. Geol. Nat. Res. (1899): 501, pl. 57.
Ortmann, 1912, Ann. Carnegie Mus. 8: 264.
(reference to Unio obliqua Lamarck, 1819)

Unio obliquus — Call (1900)
Pleurobema obliquum — Utterback (1915)
Quadrula (Obliquata) cordata — Frierson (1927)
Pleurobema cordatum — Watters et al. (2009)