Diplodon Wagner, 1827
Spix in Wagner, 1827, Test. Fluv. Brasil.: pl. 26.
Type species: Diplodon ellipticum Wagner, 1827 (sub. desig. by of Authors, 0) = Diplodon ellipticus

Diptodon Lea, 1836
Lea, 1836, Synopsis Fam. Naiades: 11 [corrected in the errata].
(error for Diplodon Wagner, 1827)

Iridea Swainson, 1840
Swainson, 1840, Treat. Malacol.: 283-285, 379.
Type species: Unio granosa Bruguière, 1792 (monotypy) = Diplodon granosus

Rhipidodonta Mörch, 1853
Mörch, 1853, Cat. Conch. Yoldi 2: 47.
(intro'd as sub-gen. of Unio Retzius, 1788)
Type species: Unio paranensis Lea, 1834 (monotypy) = Diplodon paranensis

Bulloideus Simpson, 1900
Simpson, 1900, Proc. U.S. Nat. Mus. 22: 887.
Simpson, 1914, Descr. Cat. Naiades: 1286.
(intro'd as sub-gen. of Diplodon Wagner, 1827)
Type species: Unio bulloides Lea, 1859 (original designation) = Diplodon variabilis

Cyclomya Simpson, 1900
Simpson, 1900, Proc. U.S. Nat. Mus. 22: 885.
Simpson, 1914, Descr. Cat. Naiades: 1278.
(intro'd as sub-gen. of Diplodon Wagner, 1827)
Type species: Unio funebralis Lea, 1860 (orig. desig.) = Diplodon funebralis

Ecuadorea Marshall & Bowles, 1932
Marshall & Bowles, 1932, Proc. U.S. Nat. Mus. 82(5): 5.
Type species: Ecuadorea bibliana Marshall & Bowles, 1932 (orig. desig.) = Diplodon hylaeus

Ecuadoria Modell, 1942
‘Marsh. & Bowles’ Modell, 1942, Arch. Moll. 74(5/6): 186.
(error for Ecuadorea Marshall & Bowles, 1932)

Schleschiella Modell, 1950
Modell, 1950, Arch. Moll. 79(4/6): 140.
Type species: Unio burroughianus Lea, 1834 (orig. desig.) = Diplodon burroughianus

Iridella Haas, 1969
‘Swainson’ Haas, 1969, Treatise on Invert. Paleo: N460.
(error for Iridea Swainson, 1840)

Australis Bonetto et al., 1986
Bonetto et al., 1986, Bol. Soc. Biol. Concepción, Chile 57: 60.
(intro'd as sub-gen. of Diplodon Wagner, 1827)
Type species: Unio solidulus Philippi, 1869 (orig. desig.) = Diplodon solidulus

Rhipidiodonta Rumi et al., 2008
Rumi et al., 2008, Rev. Biol. Trop. 56(1): 84.
(error for Rhipidodonta Mörch, 1853)

Taxonomic History (since 1900)

Diplodon (s.s.) — Simpson (1900), Simpson (1914), Ortmann (1921), Haas (1930), ..., Mansur & Pereira (2006), Rumi et al. (2008), Pereira et al. (2014), Torres et al. (2018)
Glabaris (s.s.) — Simpson (1900)
Diplodon (Cyclomya s.s.) — Simpson (1900), Simpson (1914)
Diplodon (Cyclomya sec. Bulloideus) — Simpson (1900), Simpson (1914)
Diplodon — Simpson (1900), Bartsch (1906), Ihering (1910), F. Baker (1913), ..., Bieler (2021), Breure et al. (2022), Bolotov et al. (2022), Torres et al. (2024)
Nodularia (s.s.) — Simpson (1900), Simpson (1914), Preston (1915)
Unio (Sphenonaias) — Martens (1900)
Unio — Corsi (1900)
Anodonta — Corsi (1900)
Anodontites (s.s.) — Simpson (1914)
— de Gregorio (1914), Simpson (1914), Pilsbry & Bequaert (1927), Parodiz (1968), Haas (1969), Millard (2001), Petit & Coan (2008), Miyahira et al. (2019)
Diplodon (Cyclomya) — Ortmann (1921), Haas (1930), Haas (1931), Pilsbry (1933)
Oxynaia — Haas (1924)
Lampsilis (Cyrtonaias) — Frierson (1927)
Hyridella — Haas (1930)
Diplodon (Bulloideus) — Haas (1931), Thiele (1934), Haas (1969), Haas (1969)
Ecuadorea — Marshall & Bowles (1932), Modell (1950)
Diplodon (Rhipidodonta) — Thiele (1934), Morretes (1949), Parodiz & Bonetto (1963), Bonetto (1964), ..., Bonetto & Mansur (1970), Mansur & Pereira (2006), Pereira et al. (2014), Torres et al. (2018)
Schleschiella — Modell (1950)
Diplodon (Schleschiella) — Haas (1969), Haas (1969)
Lanceolaria — Haas (1969)
Diplodon (Australis) — Parada & Peredo (2002), Pereira et al. (2014), Mansur et al. (2020)
Rhipidodonta — Simone (2006), Graf & Cummings (2007), Bogan (2010), IUCN (2011), Miyahira et al. (2019), Mansur et al. (2020), Bieler (2021), Torres et al. (2024)
Diplodon (Rhipidiodonta) [sic] — Rumi et al. (2008)