Bivalvia | Unionida | Hyrioidea | Hyriidae | Hyriinae | Castaliini | Castalia
Schumacher, 1817. Essai. Nouv. Syst.: 139.
Tetraplodon ambiguus — Simpson (1900), Simpson (1914), Haas (1916)
Castalia (s.s.) ambigua ambigua — Modell (1950)
Castalia ambigua — Simone (2006)
Castalia cordata — Prié et al. (2026)

d’Orbigny, 1835. Mag. Zool. 5(61-62): 42.
d’Orbigny, 1846. Voyage dans l’Amérique Méridionale 5(3): 599, pl. 73.
Type(s): SYNTYPE SMF_4344, Rio San Miguel, Guarayos, Bolivia.
Tetraplodon quadrilaterum — Simpson (1900)
Tetraplodon quadrilaterus — Ihering (1910), Simpson (1914)
Castalia quadrilatera — F. Baker (1913), Haas (1931), Haas (1969), Quintana (1982)
Castalia (s.s.) quadrilatera quadrilatera — Modell (1950)
Castalia ambigua ambigua — Bonetto (1965), Ramírez et al. (2003)
Castalia ambigua — Simone (2006)
Castalia cordata — Prié et al. (2026)

Humphrey, 1797. Mus. Col.: ??. [non-binomial]
‘Humphrey’ Swainson, 1840. Treat. Malacol.: 284, 379, footnote.
‘Humphrey’ Adams & Adams, 1857. Gen. Rec. Moll. 2(31-32): 509.
Adams & Adams, 1858. Gen. Rec. Moll. 3: pl. 120, figs. 2-2a.
Type(s): HOLOTYPE BMNH_1965197, British Guayana.
Tetraplodon quadrilaterum — Simpson (1900)
Tetraplodon cordatus — Ihering (1910)
Tetraplodon cordata — Simpson (1914)
Castalia (s.s.) quadrilatera retusa — Modell (1950)
Castalia cordata — Haas (1969), Pereira et al. (2014), Mansur et al. (2020), Graf & Cummings (2021), Prié et al. (2026)
Castalia multisulcata — Ramírez et al. (2003)
Hupé, 1857. [in] Castelnau, Anim. Nouv. Rares d’Amer. Sud: 75, pl. 14, fig. 2.
Type(s): POSSIBLE SYNTYPE MNHN_MP_0294, Guyane.
Tetraplodon retusus — Simpson (1900), Ihering (1910), Simpson (1914)
Castalia retusa — Haas (1931), Haas (1969), Mansur (1991)
Castalia (s.s.) quadrilatera retusa — Modell (1950)
Castalia ambigua ambigua — Bonetto (1965), Ramírez et al. (2003)
Castalia ambigua — Simone (2006)
Castalia cordata — Prié et al. (2026)
Tetraplodon ambiguus — Simpson (1900), Simpson (1914), Haas (1916)
Tetraplodon quadrilaterum — Simpson (1900)
Tetraplodon retusus — Simpson (1900), Ihering (1910), Simpson (1914)
Tetraplodon quadrilaterus — Ihering (1910), Simpson (1914)
Tetraplodon cordatus — Ihering (1910)
Castalia quadrilatera — F. Baker (1913), Haas (1931), Haas (1969), Quintana (1982)
Tetraplodon cordata — Simpson (1914)
Castalia retusa — Haas (1931), Haas (1969), Mansur (1991)
Castalia (s.s.) ambigua ambigua — Modell (1950)
Castalia (s.s.) quadrilatera quadrilatera — Modell (1950)
Castalia (s.s.) quadrilatera retusa — Modell (1950)
Castalia ambigua ambigua — Bonetto (1965), Ramírez et al. (2003)
Castalia cordata — Haas (1969), Pereira et al. (2014), Mansur et al. (2020), Graf & Cummings (2021), Prié et al. (2026)
Castalia multisulcata — Ramírez et al. (2003)
Castalia ambigua — Simone (2006)