Obliquaria (Quadrula) flava Rafinesque, 1820
Rafinesque, 1819. Jour. Phys. Chim. Hist. Nat. 88: 426 [as ‘U. (Plagiola) flava’]. [nomen nudum]
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 305, pl. 81, figs. 13-14 [also as ‘U. flava’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 29, 49.
Type(s): LECTOTYPE ANSP_20230, small creeks in Kentucky.

— Simpson (1900), Simpson (1914)
Fusconaia flava — Utterback (1915), Ortmann (1919), Ortmann & Walker (1922), Ortmann (1924), F.C. Baker (1928), ... Hnytka et al. (2022), Hopper et al. (2023), Hauck et al. (2023), Freeman et al. (2025), FMCS (2025)
Quadrula flava — Vanatta (1915)
Quadrula (Fusconia [sic]) flava — Frierson (1927)
Fusconaia flava flava — Haas (1969)

Obliquaria (Sintoxia) lateralis Rafinesque, 1820
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 310 [also as ‘U. lateralis’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 53.
Type(s): LECTOTYPE ANSP_20247, Riv. Kentucky.

— Simpson (1900), Simpson (1914)
Quadrula obliqua — Vanatta (1915)
Pleurobema cordata — Ortmann & Walker (1922)
Quadrula (Fusconia [sic]) undata — Frierson (1927)
Fusconaia undata undata — Haas (1969)
Fusconaia lateralis — Morrison (1969)
Pleurobema cordatum — Burch (1975)
Fusconaia undata — R.I. Johnson (1980)
Fusconaia flava — Parmalee & Bogan (1998), Watters et al. (2009)

Unio undatus Barnes, 1823
Barnes, 1823. Amer. J. Sci. 6 (1-2): 121, pl. 4, figs. 4a-b.

Quadrula (sec. Fusconaia) obliqua — Simpson (1900)
Fusconaia undata — Ortmann (1912), Utterback (1915), F.C. Baker (1928), Burch (1975), R.I. Johnson (1980), ITIS (2012)
Quadrula (sec. Fusconaia) undata — Simpson (1914)
— de Gregorio (1914)
Fusconaia undatus — Ortmann & Walker (1922)
Quadrula (Fusconia [sic]) undata — Frierson (1927)
Fusconaia undata undata — Haas (1969)
Fusconaia lateralis — Morrison (1969)
Fusconaia flava — Clarke (1973), Mathiak (1979), Vidrine (1993), Parmalee & Bogan (1998), Watters et al. (2009), IUCN (2011)
Fusconaia f. undata — Gordon et al. (1979)

Unio rubiginosus Lea, 1829
Lea, 1829. Trans. Amer. Phil. Soc. 3 [O. 1]: 427 [41], pl. 8, fig. 10.
Type(s): HOLOTYPE USNM_84556, Cincinnati, Ohio.

Quadrula (sec. Fusconaia) rubiginosa — Simpson (1900), Simpson (1914)
Unio (s.s.) rubiginosus — Call (1900)
Quadrula rubiginosa — Ortmann (1909), Ortmann (1909), Ortmann (1909), Ortmann (1910)
Fusconaia rubiginosa — Ortmann (1912)
Unio rubiginosus — de Gregorio (1914)
Fusconaia flava — Utterback (1915), Ortmann & Walker (1922), F.C. Baker (1928), Murray & Leonard (1962), Clarke (1973), ... Howells et al. (1996), Strayer & Jirka (1997), Parmalee & Bogan (1998), Watters et al. (2009), IUCN (2011)
Quadrula flava — Vanatta (1915)
Quadrula (Fusconia [sic]) flava — Frierson (1927)
Fusconaia flava flava — Haas (1969)

Unio trigonus Lea, 1831
Lea, 1831. Trans. Amer. Phil. Soc. 4 [O. 1]: 110 [120], pl. 16, fig. 40.
Type(s): HOLOTYPE USNM_84629, Louisville, KY.

Quadrula (sec. Fusconaia) trigona — Simpson (1900)
Unio (s.s.) trigonus — Call (1900)
Quadrula rubiginosa var. trigona — Ortmann (1910)
Quadrula (sec. Fusconaia) undata — Simpson (1914)
Unio trigonus — de Gregorio (1914)
Fusconaia undata trigona — Utterback (1915), F.C. Baker (1928), Haas (1969), Haas (1969)
Fusconaia flava trigona — Ortmann (1919)
Fusconaia undatus — Ortmann & Walker (1922)
Quadrula (Fusconia [sic]) undata-trigona — Frierson (1927)
Fusconaia trigonus — Thiele (1934)
Fusconaia flava — Clarke (1973), Vidrine (1993), Howells et al. (1996), Strayer & Jirka (1997), Parmalee & Bogan (1998), Graf & Cummings (2007), Watters et al. (2009), IUCN (2011), Campbell & Lydeard (2012), Williams et al. (2014), Graf & Cummings (2021)
Fusconaia undata — Burch (1975), R.I. Johnson (1980)

Unio undatus Conrad, 1834
‘Barnes’ Conrad, 1834. New Fresh-Water Shells: 72.

Quadrula (sec. Fusconaia) trigona — Simpson (1900)
Fusconaia flava — Watters et al. (2009)

Unio hebetatus Conrad, 1854
Conrad, 1854. Jour. Acad. Nat. Sci. 2(4): 296, pl. 26, fig. 5.

Quadrula (sec. Fusconaia) hebetata — Simpson (1900), Simpson (1914)
Fusconaia hebetata — Utterback (1915), Haas (1969), Graf & Cummings (2007), Cummings & Graf (2010), Campbell & Lydeard (2012), Burlakova et al. (2012)
Quadrula (Fusconia [sic]) hebetata — Frierson (1927)
Fusconaia flava — Burch (1975), R.I. Johnson (1980), Graf & Cummings (2021)

Fusconaia selecta Wheeler, 1914
Wheeler, 1914. Nautilus 28(7): 76, pl. 4.
Type(s): PARATYPE FMNH_22816, Cache River, at Nemo, Craighead Co., Arkansas.

Quadrula (Fusconia [sic]) undata-selecta — Frierson (1927)
Fusconaia undata selecta — Haas (1969)
Fusconaia undata — Burch (1975), R.I. Johnson (1980)
Fusconaia flava — Parmalee & Bogan (1998), Watters et al. (2009)

Quadrula (sec. Fusconaia) chunii var. nasuta Simpson, 1914
Simpson, 1914. Descr. Cat. Naiades: 877.

Quadrula (sec. Fusconaia) chunii var. nasuta — Simpson (1914)
Quadrula (Fusconia [sic]) flava-nasuta — Frierson (1927)
Fusconaia flava nasuta — Haas (1969)

Unio validus var. continuus de Gregorio, 1914
de Gregorio, 1914. Il Nat. Siciliano 2: 51.

Unio validus var. continuus — de Gregorio (1914)
Fusconaia flava — Watters et al. (2009)

Fusconaia undata trigonoides Utterback, 1915
‘Frierson, MS’ Utterback, 1915. Amer. Midl. Nat. 4(4): 107, pl. 15, figs. 30A-D; pl. 4, figs. 9a-b.
Frierson, 1927. Check List N. Amer. Naiades: 55, sp. 232d.

Fusconaia undata trigonoides — Utterback (1915), Haas (1969)
Quadrula (Fusconia [sic]) undata-trigonoides — Frierson (1927)
Fusconaia undata — R.I. Johnson (1980)
Fusconaia flava — Parmalee & Bogan (1998), Watters et al. (2009)

Fusconaia flava var. parvula Grier, 1918
Grier, 1918. Nautilus 32(1): 11.
Type(s): HOLOTYPE (ORIG. DESIG.) CM_61.4513, “Big Bend” Presque Isle Bay, Erie, Erie County, Pennsylvania.

Fusconaia flava parvula — Ortmann (1919), F.C. Baker (1928), Haas (1969)
Quadrula (Fusconia [sic]) flava-parvula — Frierson (1927)
Fusconaia flava — Clarke (1973), Burch (1975), R.I. Johnson (1980), Strayer & Jirka (1997), Parmalee & Bogan (1998), Watters et al. (2009)

Fusconaia undata wagneri F.C. Baker, 1928
F.C. Baker, 1928. Bull. Wisconsin Geol. Nat. Hist. Survey 70(2): 64, pl. 40, figs. 1-3.
Type(s): HOLOTYPE (ORIG. DESIG.) UMMZ_209194, Lake Pepin, Lake City, Minnesota.

Fusconaia undata wagneri — F.C. Baker (1928)
Fusconaia flava — Clarke (1973), Parmalee & Bogan (1998), Watters et al. (2009)
Fusconaia undata — Burch (1975), R.I. Johnson (1980)

Fusconaia askewi Campbell & Lydeard, 2012
‘Marsh’ of Authors.
Campbell & Lydeard, 2012. Amer. Malac. Bull. 30(1): 13 [as ‘”askewi”’].

Fusconaia “askewi” — Burlakova et al. (2012)

Unio cordatus Conrad, 1836
‘Raf.’ Conrad, 1836. Monogr. Fam. Unionidae 1(5): 48, pl. 25.

Quadrula (sec. Fusconaia) obliqua — Simpson (1900), Simpson (1914)

Unio flavus Conrad, 1837
‘Rafinesque’ Conrad, 1837. Monogr. Fam. Unionidae 1(9): 74, pl. 41, fig. 2.

Quadrula (sec. Fusconaia) rubiginosa — Simpson (1900), Simpson (1914)
Fusconaia flava — Ortmann & Walker (1922), Watters et al. (2009)

Unio triangularis Küster, 1852
Küster, 1852. Conchyl. Cab. 9(2): 56, pl. 12, fig. 3.

Quadrula (sec. Fusconaia) trigona — Simpson (1900)
Quadrula (sec. Fusconaia) undata — Simpson (1914)
Quadrula (Fusconia [sic]) undata — Frierson (1927)
Fusconaia undata undata — Haas (1969)
Fusconaia flava — Parmalee & Bogan (1998), Watters et al. (2009)

Unio coccineus Reeve, 1865
‘Lea’ Reeve, 1865. Conch. Icon. 16: pl. 22, sp. 104.

Quadrula (Fusconia [sic]) flava — Frierson (1927)

Unio pilaris Reeve, 1865
‘Lea’ Reeve, 1865. Conch. Icon. 16: pl. 27, sp. 138.

Quadrula (sec. Fusconaia) trigona — Simpson (1900)
Quadrula (sec. Fusconaia) undata — Simpson (1914)
Fusconaia flava — Parmalee & Bogan (1998), Watters et al. (2009)

Unio trigonus Sowerby, 1868
‘Lea’ Sowerby, 1868. Conch. Icon. 16: pl. 64, sp. 322; errata.

Quadrula (sec. Fusconaia) rubiginosa — Simpson (1900), Simpson (1914)

Margaron (Unio) habetatus Lea, 1870
‘Con.’ Lea, 1870. Synopsis Fam. Naiades: 38.