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

— Simpson (1900), Simpson (1914), Burch (1975)
Medionidus plateolus — Ortmann (1918), Ortmann (1918)
Medionidus conradicus — Ortmann & Walker (1922), Frierson (1927), Haas (1969), R.I. Johnson (1977), R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008)

Unio conradicus Lea, 1834
Lea, 1834. Trans. Amer. Phil. Soc. 5 [O. 1]: 63 [175], pl. 9, fig. 23.
Type(s): HOLOTYPE USNM_84134, [no locality available - North America].

Medionidus conradicus — Simpson (1900), Ortmann (1912), Simpson (1914), Ortmann (1915), Ortmann & Walker (1922), ... Graf & Cummings (2021), FMCS (2021), Hopper et al. (2023), FMCS (2025), Campbell & Lydeard (2026)
Unio conradicus — de Gregorio (1914)
Medionidus plateolus — Ortmann (1918), Ortmann (1918)
Medionidus conradianus [sic] — Haas (1969)

Unio conradius Conrad, 1838
‘Lea’ Conrad, 1838. Monogr. Fam. Unionidae 1(10): 87, pl. 47, fig. 3.
(error for Unio conradicus Lea, 1834)

Medionidus conradicus — Simpson (1900), Simpson (1914), Frierson (1927), Haas (1969), Parmalee & Bogan (1998)

Margaron (Unio) conradianus Lea, 1870
‘Lea’ Lea, 1870. Synopsis Fam. Naiades: 32.
‘Lea’ Pilsbry & Rhoads, 1896. Proc. Acad. Nat. Sci. 48: 501 [as ‘Unio conradianus’].
‘Lea’ Haas, 1969. Treatise on Invert. Paleo 1: N455 [as ‘Medionidus’].
(error for Unio conradicus Lea, 1834)

Medionidus conradicus — Simpson (1900), Simpson (1914), Frierson (1927), Haas (1969), Parmalee & Bogan (1998)
Medionidus plateolus — Ortmann (1918)

Unio platiolus Simpson, 1900
‘Rafinesque’ Simpson, 1900. Proc. U.S. Nat. Mus. 22: 744.
‘Rafinesque’ Simpson, 1914. Descr. Cat. Naiades: 731.
(error for Obliquaria plateolus Rafinesque, 1831)

Unio conradi Ortmann, 1918
Ortmann, 1918. Nautilus 32(1): 14.
(error for Unio conradicus Lea, 1834)