Unio hydianus Lea, 1838
Lea, 1836. Synopsis Fam. Naiades: 25. [nomen nudum]
Lea, 1838. Trans. Amer. Phil. Soc. 6 [O. 2]: 14, pl. 6, fig. 14.
Type(s): HOLOTYPE USNM_85010, Bayou Teche, Louisiana.

Lampsilis (sec. Eurynia) hydianus — Simpson (1900)
Lampsilis hydiana — Ortmann (1912), Burch (1975), Gordon et al. (1979), R.I. Johnson (1980), Davis & Fuller (1981), ... FMCS (2021), Stodola et al. (2021), Walters et al. (2021), Hopper et al. (2023), Hauck et al. (2023)
Lampsilis (Eurynia) hydiana — Simpson (1914)
Lampsilis (Ligumia) fasciata-hydiana — Frierson (1927)
Ligumia siliquoidea straminea — Haas (1969)
Lampsilis siliquoidea — Haag (2012)

Unio approximus Lea, 1845
Lea, 1845. Proc. Amer. Phil. Soc. 4: 164.
Lea, 1848. Trans. Amer. Phil. Soc. 10 [O. 4]: 74 [48], pl. 5, fig. 13.
Type(s): FIGURED SYNTYPE USNM_85017, Red R., Alexandria, Louisiana.

Lampsilis (sec. Eurynia) approximus — Simpson (1900)
Lampsilis (Eurynia) approxima — Simpson (1914)
Lampsilis (Ligumia) fasciata-hydiana — Frierson (1927)
Ligumia siliquoidea straminea — Haas (1969)
Lampsilis hydiana — Vidrine (1993), Howells et al. (1996), IUCN (2012)

Unio hydianus Küster, 1861
‘Lea’ Küster, 1861. Conchyl. Cab. 9(2): 201, pl. 67, fig. 1. [in part]
(reference to Unio hydianus Lea, 1838)

Lampsilis (sec. Eurynia) hydianus — Simpson (1900)
Lampsilis (Eurynia) hydiana — Simpson (1914)

Unio hydeanus Sowerby, 1866
‘Lea’ Sowerby, 1866. Conch. Icon. 16: pl. 37, sp. 203.
(error for Unio hydianus Lea, 1838)

Unio hydeianus Lea, 1874
Lea, 1874. Jour. Acad. Nat. Sci. 8 [O. 13]: 68 [anatomy].
(error for Unio hydianus Lea, 1838)