species Simpsonaias ambigua (Say, 1825): synonymy

Alasmodonta ambigua Say, 1825

Say, 1825. Jour. Acad. Nat. Sci. 5(3-4): 131.
Say, 1858. [in] Binney, Compl. Writings T. Say: 118.

Hemilastena ambigua — Simpson (1900), Simpson (1914)
Simpsoniconcha ambigua — Walker (1918), Frierson (1927), F.C. Baker (1928), Thiele (1934), Stansbery (1970), Burch (1975), Heard (1975), Gordon et al. (1979), Mathiak (1979), R.I. Johnson (1980), Mackie et al. (1980)
Simpsonaias ambigua — Haas (1969), Haas (1969), Oesch (1984), Clarke (1985), Turgeon et al. (1988), ... Graf & Cummings (2021), FMCS (2021), Jeratthitikul et al. (2022), Hopper et al. (2023), FMCS (2025)
Simpsonais [sic] ambigua — Whelan et al. (2023)

Unio hildrethianus Lea, 1834

Lea, 1834. Trans. Amer. Phil. Soc. 5 [O. 1]: 36 [148], pl. 3, fig. 8.
Type(s): FIGURED SYNTYPE USNM_122252, Ohio R., Louisville, Ky.

Hemilastena ambigua — Simpson (1900), Simpson (1914)
Unio (Margaritana) hildrethiana — Call (1900)
Simpsoniconcha ambigua — Frierson (1927), F.C. Baker (1928)
Simpsonaias ambigua — Haas (1969), Clarke (1985), Strayer & Jirka (1997), Parmalee & Bogan (1998), Watters et al. (2009)

Alasmidonta dubia Ferussac, 1835

‘Say’ Ferussac, 1835. Mag. Zool. 5(59-60): 26.
(error for Alasmodonta ambigua Say, 1825)

Hemilastena ambigua — Simpson (1900), Simpson (1914)
Simpsoniconcha ambigua — Frierson (1927)
Simpsonaias ambigua — Haas (1969), Clarke (1985), Parmalee & Bogan (1998), Watters et al. (2009)

Unio hildreihianus Frierson, 1914

‘Lea’ Frierson, 1914. Nautilus 28: 7.
(error for Unio hildrethianus Lea, 1834)