Unio intermedius Conrad, 1836
Conrad, 1836. Monogr. Fam. Unionidae 1(7): 63, pl. 35, fig. 2.
Conrad, 1853. Proc. Acad. Nat. Sci. 6: 250.
Type(s): LECTOTYPE ANSP_41606, Nolachucky R., Tenn.

Quadrula (s.s.) intermedia — Simpson (1900), Simpson (1914)
— de Gregorio (1914)
Quadrula intermedia — Ortmann (1918), Ortmann (1924), Ortmann (1925), Stansbery (1970), Burch (1975), ... Szumowski et al. (2012), IUCN (2012), Haag (2012), Jones (2015), Klymus et al. (2020)
Quadrula (Orthonymus) intermedia — Frierson (1927)
Orthonymus intermedius — Haas (1969)
Theliderma intermedia — IUCN (2000), Graf & Cummings (2007), Cummings & Graf (2010), Williams et al. (2017), Lopes-Lima et al. (2019), Graf & Cummings (2021), FMCS (2021), Neemuchwala et al. (2023), Hopper et al. (2023), FMCS (2025)

Unio tuberosus var. perlobatus de Gregorio, 1914
de Gregorio, 1914. Il Nat. Siciliano 2: 39, pl. 3, fig. 3a-c.
(intro'd as intra-sp. of Unio tuberosus Lea, 1840)

Unio tuberosus var. perlobatus — de Gregorio (1914)
Quadrula intermedia — Parmalee & Bogan (1998), Williams et al. (2008)
Theliderma intermedia — Lopes-Lima et al. (2019)

Quadrula biangulata Morrison, 1942
Morrison, 1942. Bulletin Bur. Amer. Ethnol. 129: 356.
Type(s): HOLOTYPE USNM_84221, Tuscumbia, Alabama.

Quadrula tuberosa — R.I. Johnson (1980)
Quadrula quadrula — Parmalee & Bogan (1998)
Quadrula intermedia — Williams et al. (2008)
Theliderma intermedia — Lopes-Lima et al. (2019)

Unio kleinianus Küster, 1861
‘Lea’ Küster, 1861. Conchyl. Cab. 9(2): 191, pl. 60, fig. 4.
(misidentified reference to Unio kleinianus Lea, 1852)

Quadrula (s.s.) intermedia — Simpson (1900), Simpson (1914)
Quadrula (Orthonymus) metanevra-tuberosa — Frierson (1927)
Quadrula intermedia — Parmalee & Bogan (1998)