Unio dombeyana Humboldt & Bonpland, 1827
Valenciennes in Humboldt & Bonpland, 1827, Receuil Observ. Zool. 2: 227, pl. 53, figs. 1a-b.

Unio dombeyana — Humboldt & Bonpland (1827)
Unio plicatus — Lea (1829), Ferussac (1835), Hanley (1843), Reeve (1864), Sowerby (1866)
Margarita (Unio) plicatus — Lea (1836)
Unio (Theliderma) dombeyana — Swainson (1840)
Margaron (Unio) plicatus — Lea (1852), Lea (1870)
Plectomerus plicatus — Conrad (1853)
Quadrula (sec. Crenodonta) trapezoides — Simpson (1900), Simpson (1914)
Plectomerus trapezoides — Ortmann & Walker (1922)
Amblema (Plectomerus) dombeyana — Frierson (1927), Haas (1969)
Amblema dombeyana — Thiele (1934)
Plectomerus dombeyanus — Haas (1969), Burch (1975), Gordon et al. (1979), R.I. Johnson (1980), Turgeon et al. (1988), Williams et al. (1993), Rosenberg et al. (1994), Howells et al. (1996), Lydeard et al. (1996), Rosenberg et al. (1997), Parmalee & Bogan (1998), Johnson et al. (1998), Turgeon et al. (1998), Lydeard et al. (1999), Huang et al. (2002), Krebs et al. (2003), Cicerello & Schuster (2003), Serb et al. (2003), Jones et al. (2005), Campbell et al. (2005), Curole & Kocher (2005), Graf & Cummings (2007), Chapman et al. (2008), Williams et al. (2008), Chapman et al. (2008), Campbell et al. (2008), Cummings & Graf (2010), Bogan (2010), Williams et al. (2011), Haag (2012), McMurray et al. (2012), IUCN (2012), Burlakova et al. (2012), ITIS (2012), Campbell & Lydeard (2012), Campbell & Lydeard (2012), Williams et al. (2014), Williams et al. (2017), Perkins et al. (2017), Inoue et al. (2018), Marshall et al. (2018), Huang et al. (2019), Pfeiffer et al. (2019), Burlakova et al. (2019), Pfeiffer et al. (2019), Smith et al. (2019), Smith et al. (2020), Graf & Cummings (2021)
Amblema dombeyanus — Davis & Fuller (1981)
Plectomerus dombeyana — Oesch (1984), Vidrine (1993)

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]
(misidentified reference to Unio crassidens Lamarck, 1819)

Unio crassidens — Lamarck (1819)
Unio plicatus — Lea (1829)
Unio plicata — Ravenel (1834)
Unio trapezoides — Lea (1834), Hanley (1843), Küster (1862)
Unio trapezoïdes — Ferussac (1835)
Margarita (Unio) trapezoides — Lea (1836)
Mysca crassidens — Schlüter (1838)
Unio (Theliderma) crassidens — Swainson (1840)
Margaron (Unio) trapezoides — Lea (1852), Lea (1870)
Plectomerus crassidens — Conrad (1853)
Quadrula (sec. Crenodonta) trapezoides — Simpson (1900), Simpson (1914)
Unio (s.s.) trapezoides — Call (1900)
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)

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

Bariosta ponderosus — Rafinesque (1831), Simpson (1900), Simpson (1914)
Unio niger — Ferussac (1835)
Unio (Limnium sec. Bariosta) ponderosus — Fischer (1887)
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.

Lasmigona ponderosa — Rafinesque (1831)
Alasmodonta ponderosa — Ferussac (1835)

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

Unio interruptus — Say (1831)
Unio trapezoïdes — Ferussac (1835)
Margarita (Unio) trapezoides — Lea (1836)
Unio trapezoides — Hanley (1843), Küster (1862), Reeve (1864), Call (1895)
Margaron (Unio) trapezoides — Lea (1852), Lea (1870)
Plectomerus crassidens — Conrad (1853)
Quadrula (sec. Crenodonta) trapezoides — Simpson (1900), 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)

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

Unio trapezoides — Lea (1831), Lea (1834), Jay (1835), Hanley (1843), Küster (1862), Reeve (1864), Singley (1893), Call (1895), Pilsbry & Rhoads (1896)
Unio trapezoïdes — Ferussac (1835)
Margarita (Unio) trapezoides — Lea (1836)
Complanaria trapezius — Agassiz (1852)
Margaron (Unio) trapezoides — Lea (1852), Lea (1870)
Plectomerus crassidens — Conrad (1853)
Unio (Diplodon) trapezoides — Adams & Adams (1857)
Quadrula (sec. Crenodonta) trapezoides — Simpson (1900), Simpson (1914)
Unio (s.s.) trapezoides — Call (1900)
Quadrula trapezoides — Ortmann (1909)
Crenodonta trapezoides — Ortmann (1912)
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 dombeiana Ferussac, 1835
‘Valenciennes’ of Authors.
Ferussac, 1835, Mag. Zool. 5: 27, 33.
Hanley, 1843, Illustr. Descr. Cat. Rec. Bivalve Shells: 175.
(error for Unio dombeyana Humboldt & Bonpland, 1827)

Unio dombeiana — Ferussac (1835)

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

Complanaria trapezius — Agassiz (1852)

Quadrula trapezoides var. pentagonoides Frierson, 1902
Frierson, 1902, Nautilus 16: 39.
Frierson, 1927, Check List N. Amer. Naiades: 62 [as ‘A. (Plectomerus) dombeyana’].
(intro'd as intra-sp. of Unio trapezoides Lea, 1831)
Type(s): LECTOTYPE ANSP_128928, Lake Charles, La.

Quadrula trapezoides var. pentagonoides — Frierson (1902)
Quadrula (sec. Crenodonta) trapezoides var. pentagonoides — Simpson (1914)
Amblema (Plectomerus) dombeyana — Frierson (1927)
Plectomerus dombeyanus — Haas (1969), Parmalee & Bogan (1998)