Truncilla triqueter Rafinesque, 1820
Rafinesque, 1818. Amer. Mon. Mag. 3: 355 [as ‘Potamilus triqueter’]. [nomen nudum]
Rafinesque, 1819. Jour. Phys. Chim. Hist. Nat. 88: 427 [as ‘U. (Truncilla) triquetra’]. [nomen nudum]
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 300, pl. 81, figs. 1-4 [also as ‘Unio triqueter’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 22, 29, 45.
Type(s): LECTOTYPE ANSP_20231, [no locality available - North America].

Truncilla (s.s.) triquetra — Simpson (1900), Wright & Walker (1902), Simpson (1914)
Truncilla triquetra — Ortmann (1909), Ortmann (1909), Ortmann (1910), Ortmann (1912), Vanatta (1915), Ortmann (1918)
Dysnomia (Truncillopsis) triquetra — Ortmann & Walker (1922), Ortmann (1924), Ortmann (1925), Frierson (1927), Haas (1969), Haas (1969)
Dysnomia (Truncillopsis) triqueter — F.C. Baker (1928)
Epioblasma (sec. Truncillopsis) triquetrum — Thiele (1934)
Dysnomia triquetra — Murray & Leonard (1962), Burch (1975), Gordon et al. (1979), Mackie et al. (1980)
Plagiola (Truncillopsis) triquetra — R.I. Johnson (1978)
Plagiola triquetra — R.I. Johnson (1980), Oesch (1984)
Epioblasma triquetra — Turgeon et al. (1988), Cummings & Mayer (1992), Williams et al. (1993), Strayer & Jirka (1997), Cummings & Mayer (1997), ... Klymus et al. (2020), Gasparini et al. (2020), Graf & Cummings (2021), FMCS (2021), Hopper et al. (2023)

Unio cuneatus Swainson, 1823
Swainson, 1823. Philos. Mag. & J. 61: 112.

Truncilla (s.s.) triquetra — Simpson (1900), Simpson (1914)
Dysnomia (Truncillopsis) triquetra — Ortmann & Walker (1922), Frierson (1927), Haas (1969)
Dysnomia triquetra — Burch (1975)
Plagiola (Truncillopsis) triquetra — R.I. Johnson (1978)
Epioblasma triquetra — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio triangularis Barnes, 1823
Barnes, 1823. Amer. J. Sci. 6 (1-2): 272, pl. 13, figs. 17a-b.
Say, 1830. Amer. Conch. 1: pl. 4.

Truncilla (s.s.) triquetra — Simpson (1900), Simpson (1914)
Unio (s.s.) triangularis — Call (1900)
Unio triangularis — de Gregorio (1914)
Truncilla triquetra — Ortmann (1918)
Dysnomia (Truncillopsis) triquetra — Ortmann & Walker (1922), Ortmann (1924), Frierson (1927), Haas (1969)
Dysnomia triquetra — Burch (1975)
Plagiola (Truncillopsis) triquetra — R.I. Johnson (1978)
Epioblasma triquetra — Strayer & Jirka (1997), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio formosus Lea, 1831
Lea, 1831. Trans. Amer. Phil. Soc. 4 [O. 1]: 111, pl. 16, fig. 41.

Truncilla (s.s.) triquetra — Simpson (1900), Simpson (1914)
Unio (s.s.) triangularis — Call (1900)
Unio triangularis — de Gregorio (1914)
Dysnomia (Truncillopsis) triquetra — Ortmann & Walker (1922), Frierson (1927), Haas (1969)
Dysnomia triquetra — Burch (1975)
Plagiola (Truncillopsis) triquetra — R.I. Johnson (1978)
Epioblasma triquetra — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio triangularis var. longiusculus de Gregorio, 1914
de Gregorio, 1914. Il Nat. Siciliano 2: 40, pl. 4, figs. 5a-c.
(intro'd as intra-sp. of Unio triangularis Barnes, 1823)

Unio triangularis var. longiusculus — de Gregorio (1914)
Plagiola (Truncillopsis) triquetra — R.I. Johnson (1978)
Epioblasma triquetra — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio triangularis var. pergibosus de Gregorio, 1914
de Gregorio, 1914. Il Nat. Siciliano 2: 40, pl. 4, figs. 4a-c.
(intro'd as intra-sp. of Unio triangularis Barnes, 1823)

Unio triangularis var. pergibosus — de Gregorio (1914)
Plagiola (Truncillopsis) triquetra — R.I. Johnson (1978)
Epioblasma triquetra — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio triangularis var. longisculus Parmalee & Bogan, 1998
‘de Gregorio’ Parmalee & Bogan, 1998. The Freshwater Mussels of Tennessee: 108.
‘de Gregorio’ Williams et al., 2008. Freshw. Mussels AL and Mobile Basin: 283.
(error for Unio triangularis var. longiusculus de Gregorio, 1914)