species Plectomerus dombeyanus (Valenciennes in Humboldt & Bonpland, 1827): synonymy

Unio crassidens Lamarck, 1819

(misidentified reference to Unio crassidens Lamarck, 1819)
Lister, 1685. Conch.: pl. 150, fig. 5.
Lamarck, 1819. Hist. Natur. Anim. sans Vert. 6: 71, sp. 3, var. a. [in part]

Quadrula (sec. Crenodonta) trapezoides — Simpson (1900)
Unio (s.s.) trapezoides — Call (1900)
Quadrula (sec. Crenodonta) (Group of Q. trapezoides) trapezoides — Simpson (1914)
Plectomerus trapezoides — Ortmann & Walker (1922)
Amblema (Plectomerus) dombeyana — Frierson (1927)
Plectomerus dombeyana — R.I. Johnson (1969), Oesch (1984)
Plectomerus dombeyanus — Howells et al. (1996), Parmalee & Bogan (1998), Williams et al. (2008)

Unio dombeyana Valenciennes, 1827

Valenciennes, 1827. Receuil Observ. Zool. 2(11-12): 227, pl. 53, figs. 1a-b.

Quadrula (sec. Crenodonta) trapezoides — Simpson (1900)
Quadrula (sec. Crenodonta) (Group of Q. trapezoides) trapezoides — Simpson (1914)
Plectomerus trapezoides — Ortmann & Walker (1922)
Amblema (Plectomerus) dombeyana — Frierson (1927), Haas (1969)
Amblema dombeyana — Thiele (1934)
Plectomerus dombeyanus — Morrison (1966), Haas (1969), Burch (1975), Gordon et al. (1979), R.I. Johnson (1980), ... de Moulpied et al. (2022), Hopper et al. (2023), Freeman et al. (2025), FMCS (2025), Campbell & Lydeard (2026)
Amblema dombeyanus — Davis & Fuller (1981)
Plectomerus dombeyana — Oesch (1984), Vidrine (1993)

Unio trapezoides Lea, 1831

Lea, 1831. Trans. Amer. Phil. Soc. 4 [O. 1]: 69 [79], pl. 3, fig. 1.
FIGURED SYNTYPE USNM_84103, Lake St. Joseph, Mis.

Quadrula (sec. Crenodonta) trapezoides — Simpson (1900)
Unio (s.s.) trapezoides — Call (1900)
Quadrula trapezoides — Ortmann (1909)
Crenodonta trapezoides — Ortmann (1912)
Quadrula (sec. Crenodonta) (Group of Q. trapezoides) trapezoides — Simpson (1914)
Plectomerus trapezoides — Ortmann & Walker (1922)
Amblema (Plectomerus) dombeyana — Frierson (1927)
Plectomerus dombeyanus — Haas (1969), Burch (1975), R.I. Johnson (1980), Howells et al. (1996), Parmalee & Bogan (1998), Williams et al. (2008), Williams et al. (2014), Graf & Cummings (2021)
Plectomerus dombeyana — Oesch (1984), Vidrine (1993)

Unio interruptus Say, 1831

(homonym of Unio (Eurynia) solenoides var. interrupta Rafinesque, 1820)
Say, 1831. Transylvania J. Med. Assoc. Sci. 4: 525.
Say, 1832. Amer. Conch. 4: pl. 33.

Quadrula (sec. Crenodonta) trapezoides — Simpson (1900)
Quadrula (sec. Crenodonta) (Group of Q. trapezoides) trapezoides — Simpson (1914)
Plectomerus trapezoides — Ortmann & Walker (1922)
Amblema (Plectomerus) dombeyana — Frierson (1927)
Plectomerus dombeyanus — Haas (1969), Burch (1975), Howells et al. (1996), Parmalee & Bogan (1998), Williams et al. (2008)
Plectomerus dombeyana — Oesch (1984)

Bariosta ponderosus Rafinesque, 1831

Rafinesque, 1831. Continuation: 2.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 73.

Plectomerus trapezoides — Ortmann & Walker (1922)
Amblema (Plectomerus) dombeyana — Frierson (1927)
Plectomerus dombeyanus — Burch (1975), Howells et al. (1996)
Plectomerus dombeyana — Oesch (1984)

Lasmigona ponderosa Rafinesque, 1831

Rafinesque, 1831. Continuation: 5.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 79.

Unio dombeiana ‘Valenciennes’ of Authors

(error for Unio dombeyana Valenciennes, 1827)
‘Valenciennes’ of Authors.
Ferussac, 1835. Mag. Zool. 5(59-60): 27, 33.
Hanley, 1843. Illustr. Descr. Cat. Rec. Bivalve Shells: 175.

Quadrula trapezoides var. pentagonoides Frierson, 1902

(intro'd as intra-sp. of Unio trapezoides Lea, 1831)
Frierson, 1902. Nautilus 16(4): 39.
Frierson, 1927. Check List N. Amer. Naiades: 62 [as ‘A. (Plectomerus) dombeyana’].
LECTOTYPE ANSP_128928 (by R.I. Johnson, 1972: 147), Lake Charles, La.

Quadrula (sec. Crenodonta) (Group of Q. trapezoides) trapezoides var. pentagonoides — Simpson (1914)
Amblema (Plectomerus) dombeyana — Frierson (1927)
Plectomerus dombeyanus — Haas (1969), Parmalee & Bogan (1998)

Complanaria trapezius Agassiz, 1852

(error for Unio trapezoides Lea, 1831)
Agassiz, 1852. Arch. Naturg. 18(1): 49.