Unio rhuacoica d’Orbigny, 1835
d’Orbigny, 1835. Mag. Zool. 5(61-62): 36.
d’Orbigny, 1846. Voyage dans l’Amérique Méridionale 5: 606, pl. 69, figs. 4-5.
Type(s): LECTOTYPE BMNH_54-12-4-838, Maldonado, Banda orientali, Uruguay.

Diplodon (s.s.) rhuacoicus — Simpson (1900), Simpson (1914), Haas (1930), Bonetto (1964), Bonetto (1965), Figueiras (1965), Haas (1969), Rumi et al. (2008), Pereira et al. (2014), Torres et al. (2018)
Unio rhuacoica — Corsi (1900)
Diplodon (s.s.) charruanus — Ortmann (1921)
Diplodon rhuacoicus — Haas (1930), Schade (1965), Parodiz (1968), Mansur (1970), Simone (2006), Graf & Cummings (2007), Bogan (2010), Mansur et al. (2020), Graf & Cummings (2021), Torres et al. (2024)

Unio binneyi Lea, 1845
Lea, 1845. Proc. Amer. Phil. Soc. 4: 165.
Lea, 1848. Trans. Amer. Phil. Soc. 10 [O. 4]: 77 [51], pl. 6, figs. 18.
Type(s): HOLOTYPE (MONOTYPY) USNM_85170, South America, Alabama?

Diplodon (s.s.) binneyi — Simpson (1900), Simpson (1914)
Diplodon rhuacoicus — Haas (1930), Simone (2006)
Diplodon (s.s.) rhuacoicus — Haas (1930), Haas (1969)
Diplodon martensi — Parodiz (1968), Mansur (1970)

Unio rhyacoicus Martens, 1868
Martens, 1868. Malak. Blatt. 15: 195.

Diplodon (s.s.) rhuacoicus — Simpson (1900), Simpson (1914), Bonetto (1964), Bonetto (1965), Figueiras (1965), Haas (1969)
Diplodon rhuacoicus — Haas (1930), Mansur (1970), Simone (2006)

Diplodon subcylindricus Marshall, 1922
Marshall, 1922. Proc. U.S. Nat. Mus. 61(2437): 3, pl. 2, figs. 1-2; pl. 3, figs. 1, 2, 11.
Type(s): HOLOTYPE (ORIG. DESIG.) USNM_341375, Arroyo Manga, Dept. Montevideo, Uruguay.

Diplodon subcylindricus — Marshall (1922)
Diplodon rhuacoicus — Haas (1930), Parodiz (1968), Mansur (1970), Simone (2006)
Diplodon (s.s.) rhuacoicus — Bonetto (1964), Bonetto (1965), Figueiras (1965), Haas (1969)

Diplodon yaguaronis Marshall, 1930
Marshall, 1930. Proc. U.S. Nat. Mus. 77(2825): 5, pl. 2, figs. 2-3, 5-6.
Type(s): HOLOTYPE (ORIG. DESIG.) USNM_380554, Rio Yaguaron, Cerro Largo, Uruguay.

Diplodon rhuacoicus — Haas (1930), Parodiz (1968), Mansur (1970)
Diplodon yaguaronis — Marshall (1930), Bonetto (1959)
Diplodon delodontus pilsbryi — Bonetto (1962)
Diplodon (s.s.) delodontus pilsbryi — Bonetto (1964), Figueiras (1965)
Diplodon (s.s.) rhuacoicus — Haas (1969)
Diplodon (s.s.) delodontus wimanii [sic] — Bonetto & Mansur (1970)

Diplodon bakeri of Authors, unknown year
Marshall, in USNM coll. of Authors.
Type(s): MANUSCRIPT NAME USNM_380556, Rio Yaguaron, Cerro Largo, Uruguay.

Unio charruanus Sowerby, 1868
‘d’Orbigny’ Sowerby, 1868. Conch. Icon. 16: pl. 93, sp. 505.

Diplodon rhuacoicus — Mansur (1970)

Monocondylaea rhyacoeca Paetel, 1890
‘Orb.’ Paetel, 1890. Cat. Conch.-Samml. 3: 147.

Diplodon (s.s.) rhuacoicus — Simpson (1900), Simpson (1914)
Diplodon rhuacoicus — Simone (2006)