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Obliquaria (Quadrula) quadrula Rafinesque, 1820

Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 307 [also as ‘Unio quadrula’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 51.
Type(s): NEOTYPE ANSP_20224 (by Johnson & Baker, 1973: 167), Salt River.

Quadrula quadrula — Utterback (1915), Vanatta (1915), Ortmann & Walker (1922), Ortmann (1924), Ortmann (1925), ... Freeman et al. (2025), Chen et al. (2025), FMCS (2025), Cummings et al. (2025), Hou et al. (2025)
Quadrula (s.s.) quadrula — Frierson (1927), F.C. Baker (1928), Haas (1969)
Quadrula (s.s.) gigantea [sic] — Haas (1930)
Quadrula (s.s.) quadrula quadrula — Haas (1969)
Obliquaria quadrula — Burch (1975)
Quadrula quedrula [sic] — Contreras-Arquieta (2000)
Quadrula quadrula quadrula — ITIS (2012)
Q. quadrula — Sheng et al. (2014)

Unio rugosus Barnes, 1823

Barnes, 1823. Amer. J. Sci. 6 (1-2): 126, pl. 8, fig. 9a-b.
(homonym of Unio rugosa Poiret, 1801)

Quadrula quadrula — Ortmann & Walker (1922), Burch (1975), R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), Lopes-Lima et al. (2019)
Quadrula (s.s.) quadrula — Frierson (1927), F.C. Baker (1928)
Quadrula (s.s.) gigantea [sic] — Haas (1930)
Quadrula (s.s.) quadrula quadrula — Haas (1969)
Quadrula fragosa — Watters et al. (2009)

Unio lacrymosus Lea, 1828

Lea, 1828. Trans. Amer. Phil. Soc. 3 [O. 1]: 272 [14], pl. 6, fig. 8.
Type(s): HOLOTYPE USNM_84165, Cincinnati, Ohio.

Quadrula (sec. Theliderma) lachrymosa [sic] — Simpson (1900), Simpson (1914)
Unio (s.s.) lachrymosus [sic] — Call (1900)
Quadrula lachrymosus [sic] — Ortmann (1909)
Quadrula lachrymosa [sic] — Ortmann (1909), Ortmann (1910), Ortmann (1910), Ortmann (1912)
Quadrula quadrula — Utterback (1915), Vanatta (1915), Ortmann & Walker (1922), Burch (1975), R.I. Johnson (1980), ... Strayer & Jirka (1997), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009), Lopes-Lima et al. (2019)
Quadrula (s.s.) quadrula — Frierson (1927), F.C. Baker (1928)
Quadrula (s.s.) quadrula quadrula — Haas (1969)

Unio apiculatus Say, 1829

Say, 1829. New Harm. Dissem. 2(20): 309, sp. 8.
Say, 1834. Amer. Conch. 6: pl. 52.
Say, 1858. [in] Binney, Compl. Writings T. Say: 131, 207, 225.
Type(s): TYPE LOCALITY TYPE_LOCALITY_MP_016, Lake Ponchartrain, near N. Orleans.

Quadrula (sec. Theliderma) apiculata — Simpson (1900), Simpson (1914)
Quadrula apiculata — Ortmann (1910), R.I. Johnson (1980), Davis & Fuller (1981), Turgeon et al. (1988), Williams et al. (1993), ... Marshall et al. (2018), Pfeiffer et al. (2019), Pfeiffer et al. (2019), Inoue et al. (2020), Hauck et al. (2023)
Quadrula (s.s.) quadrula-apiculata — Frierson (1927)
Quadrula (s.s.) quadrula apiculata — Haas (1969)
Quadrula quadrula — Burch (1975), Lopes-Lima et al. (2019), Graf & Cummings (2021), FMCS (2021), Keogh et al. (2024), FMCS (2025), Cummings et al. (2025)

Unio asper Lea, 1831

Lea, 1831. Trans. Amer. Phil. Soc. 4 [O. 1]: 85 [95], pl. 9, fig. 15.
Type(s): UNKNOWN USNM_84212, Claiborne, Ala. R., Alabama.

Quadrula (sec. Theliderma) asper — Simpson (1900)
Quadrula aspera — Ortmann (1912), Utterback (1915)
Quadrula (sec. Theliderma) aspera — Simpson (1914)
Quadrula (s.s.) quadrula-aspera — Frierson (1927)
Quadrula (s.s.) quadrula aspera — Haas (1969)
Quadrula quadrula — Burch (1975), R.I. Johnson (1980), Vidrine (1993), Lopes-Lima et al. (2019)
Quadrula apiculata — Williams et al. (2008)

Unio asperrimus Lea, 1831

Lea, 1831. Trans. Amer. Phil. Soc. 4 [O. 1]: 71 [81], pl. 5, fig. 3.
Type(s): HOLOTYPE USNM_84174, Cincinnati, Ohio.

Quadrula (sec. Theliderma) lachrymosa [sic] — Simpson (1900), Simpson (1914)
Unio (s.s.) lachrymosus [sic] — Call (1900)
Unio asperrimus — de Gregorio (1914)
Quadrula quadrula — Utterback (1915), Ortmann & Walker (1922), Burch (1975), R.I. Johnson (1980), Oesch (1984), Vidrine (1993), Howells et al. (1996), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009), Lopes-Lima et al. (2019)
Quadrula (s.s.) quadrula — Frierson (1927), F.C. Baker (1928)
Quadrula (s.s.) quadrula quadrula — Haas (1969)

Unio quadrulus Say, 1834

‘Rafinesque’ of Authors.
Say, 1834. Amer. Conch. 6: pl. 53.
Conrad, 1840. Monogr. Fam. Unionidae 2(13): 112, pl. 62.
(reference to Obliquaria (Quadrula) quadrula Rafinesque, 1820)

Quadrula (sec. Theliderma) lachrymosa [sic] — Simpson (1900), Simpson (1914)
Quadrula quadrula — Utterback (1915), Watters et al. (2009)

Quadrula lachrymosa Swainson, 1840

‘Lea’ of Authors.
Swainson, 1840. Treat. Malacol.: 378.
Hanley, 1843. Illustr. Descr. Cat. Rec. Bivalve Shells: 177.
Conrad, 1853. Proc. Acad. Nat. Sci. 6: 256.
Adams & Adams, 1857. Gen. Rec. Moll. 2(31-32): 497.
Reeve, 1864. Conch. Icon. 16: pl. 9, sp. 33.
Call, 1895. Trans. Acad. Sci. St. Louis 7: 21.
F.C. Baker, 1898. Bull. Chicago Acad. Sci. 3(1): 83, pl. 25, fig. 1; pl. 12, fig. 2.
Simpson, 1900. Proc. U.S. Nat. Mus. 22: 776.
Call, 1900. Ind. Dept. Geol. Nat. Res. (1899): 489.
Ortmann, 1909. Nautilus 22(10): 100.
Ortmann, 1909. Ann. Carnegie Mus. 5: 199.
Ortmann, 1910. Nautilus 23(11): 140.
Ortmann, 1910. Nautilus 23: 116.
Ortmann, 1912. Ann. Carnegie Mus. 8: 253.
Simpson, 1914. Descr. Cat. Naiades: 839, 841.
Vanatta, 1915. Proc. Acad. Nat. Sci. 67: 556.
Ortmann & Walker, 1922. Occ. Pap. Mus. Zool. Univ. Mich. (112): 14, 16.
Frierson, 1927. Check List N. Amer. Naiades: 47.
F.C. Baker, 1928. Bull. Wisconsin Geol. Nat. Hist. Survey 70(2): 84.
R.I. Johnson, 1980. Bull. MCZ 149(2): 90.
Vidrine, 1993. Histr. Distr. Freshw. Mussels LA: 53.
Strayer & Jirka, 1997. Pearly Mussels NY (26): 98.
(error for Unio lacrymosus Lea, 1828)

Quadrula quadrula — Utterback (1915), Murray & Leonard (1962), Oesch (1984), Vidrine (1993), Parmalee & Bogan (1998), Watters et al. (2009)

Unio rumphianus Lea, 1852

Lea, 1852. Trans. Amer. Phil. Soc. 10 [O. 5]: 276 [32], pl. 22, fig. 34.
Lea, 1852. Proc. Amer. Phil. Soc. 5: 252. [nomen nudum]
Type(s): HOLOTYPE USNM_84189, West Georgia.

Quadrula (sec. Theliderma) rumphiana — Simpson (1900), Simpson (1914)
Quadrula (s.s.) quadrula-rumphiana — Frierson (1927)
Quadrula (s.s.) quadrula rumphiana — Haas (1969)
Quadrula quadrula — Burch (1975), Lopes-Lima et al. (2019), Graf & Cummings (2021), FMCS (2021), FMCS (2025)
Quadrula rumphiana — Turgeon et al. (1988), Williams et al. (1993), Turgeon et al. (1998), Lydeard et al. (1999), Serb et al. (2003), ... Haag (2012), Williams et al. (2017), Inoue et al. (2018), Burlakova et al. (2019), Hauck et al. (2023)
Quadrula quadrula rumphiana — Keogh et al. (2024)

Unio blandianus Lea, 1857

Lea, 1857. Proc. Acad. Nat. Sci. 8: 263.
Lea, 1857. Proc. Acad. Nat. Sci. 9: 31.
Lea, 1858. Jour. Acad. Nat. Sci. 4 [O. 6]: 65, pl. 11, fig. 47.
Type(s): HOLOTYPE USNM_84190, Othcaloosa Cr., Ga.

Quadrula (sec. Theliderma) rumphiana — Simpson (1900), Simpson (1914)
Quadrula (s.s.) quadrula-rumphiana — Frierson (1927)
Quadrula (s.s.) quadrula rumphiana — Haas (1969)
Quadrula quadrula — Burch (1975), Lopes-Lima et al. (2019)
Quadrula rumphiana — Williams et al. (2008)

Unio forsheyi Lea, 1859

Lea, 1859. Proc. Acad. Nat. Sci. 11: 155.
Lea, 1860. Jour. Acad. Nat. Sci. 4 [O. 8]: 357 [39], pl. 60, fig. 182.
Type(s): LECTOTYPE [AS HOLOTYPE] USNM_84169 (by R.I. Johnson, 1974: 59), Texas.

Quadrula (sec. Theliderma) forsheyi — Simpson (1900), Simpson (1914)
Quadrula forsheyi — Ortmann (1910)
Quadrula (s.s.) quadrula-forsheyi — Frierson (1927)
Quadrula (s.s.) quadrula forsheyi — Haas (1969)
Quadrula quadrula — Burch (1975), Howells et al. (1996), Lopes-Lima et al. (2019), Cummings et al. (2025)
Quadrula apiculata — Williams et al. (2008)

Unio speciosus Lea, 1862

Lea, 1862. Proc. Acad. Nat. Sci. 14: 168.
Lea, 1862. Jour. Acad. Nat. Sci. 5 [O. 9]: 207 [29], pl. 31, fig. 276.
Type(s): LECTOTYPE [AS HOLOTYPE] USNM_84172 (by R.I. Johnson, 1974: 134), Leon Co., Texas.

Quadrula (sec. Theliderma) speciosa — Simpson (1900), Simpson (1914)
Quadrula speciosa — Ortmann (1910)
Quadrula (s.s.) quadrula-speciosa — Frierson (1927)
Quadrula (s.s.) quadrula speciosa — Haas (1969)
Quadrula quadrula — Burch (1975), Cummings et al. (2025)
Quadrula apiculata — R.I. Johnson (1999)

Unio quadratus Reeve, 1864

‘Rafinesque’ Reeve, 1864. Conch. Icon. 16: pl. 6, sp. 24.
(error for Obliquaria (Quadrula) quadrula Rafinesque, 1820)

Quadrula (sec. Theliderma) lachrymosa [sic] — Simpson (1900), Simpson (1914)
Quadrula (s.s.) quadrula — Frierson (1927)
Quadrula (s.s.) quadrula quadrula — Haas (1969)
Quadrula quadrula — Parmalee & Bogan (1998), Watters et al. (2009)

Unio turgidus Reeve, 1864

‘Lea’ Reeve, 1864. Conch. Icon. 16: pl. 3, sp. 10.
(misidentified reference to Unio turgidus Lea, 1838)

Quadrula (sec. Theliderma) asper — Simpson (1900)
Quadrula (sec. Theliderma) aspera — Simpson (1914)

Unio lunulatus Pratt, 1876

Pratt, 1876. Proc. Davenport Acad. Nat. Sci. 1: 168, pl. 31, fig. 1a-b [as ‘unul atus’; corrected in Errata].
(correct name for Unio unul atus Pratt, 1876)

Quadrula (sec. Theliderma) lachrymosa [sic] var. lunulata — Simpson (1900)
Tritogonia nobilis — Simpson (1914)
Quadrula (s.s.) quadrula — Frierson (1927)
Quadrula (s.s.) quadrula quadrula — Haas (1969)
Quadrula quadrula — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009), Lopes-Lima et al. (2019)

Quadrula quadrula contraryensis Utterback, 1915

Utterback, 1915. Amer. Midl. Nat. 4(4): 138, pl. 18, figs. 47a-b.
(intro'd as intra-sp. of Obliquaria (Quadrula) quadrula Rafinesque, 1820)
Type(s): NEOTYPE CM_61.6892 (by Parodiz & Tripp, 1988: 118), Lake Contrary, St. Joseph, Buchanan Co., Missouri.

Quadrula quadrula contraryensis — Utterback (1915)
Quadrula quadrula — Burch (1975), R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009), Lopes-Lima et al. (2019)

Quadrula (Quadrula) quadrula bullocki F.C. Baker, 1928

F.C. Baker, 1928. Bull. Wisconsin Geol. Nat. Hist. Survey 70(2): 87, pl. 46, figs. 1-3.
(intro'd as intra-sp. of Obliquaria (Quadrula) quadrula Rafinesque, 1820)
Type(s): HOLOTYPE (ORIG. DESIG.) UMMZ_209203, Fox River, nr. De Pere, Wisc.

Quadrula (s.s.) quadrula bullocki — F.C. Baker (1928)
Quadrula quadrula — Clarke (1973), Burch (1975), R.I. Johnson (1980), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009), Lopes-Lima et al. (2019)

Unio dombeyanus Barnes, 1828

Barnes, 1828. Amer. J. Sci. 13(2): 360.
(misidentified reference to Unio dombeyana Valenciennes, 1827)

Quadrula (s.s.) quadrula — Frierson (1927)

Unio asperimus Ravenel, 1834

‘Lea’ Ravenel, 1834. Cat. Rec. Shells: 5.
(error for Unio asperrimus Lea, 1831)

Unio asper Jay, 1839

‘Lea’ Jay, 1839. Cat. Rec. Shells: 55.
(reference to Unio asper Lea, 1831)

Unio nobilis Conrad, 1854

Conrad, 1854. Jour. Acad. Nat. Sci. 2(4): 297, pl. 27, figs. 2. [in part]
(misidentified reference to Unio nobilis Conrad, 1854)

Quadrula (sec. Theliderma) apiculata — Simpson (1900), Simpson (1914)
Quadrula nobilis — Utterback (1915)
Quadrula quadrula — Burch (1975), R.I. Johnson (1980), Howells et al. (1996)
Quadrula apiculata — Vidrine (1993), Parmalee & Bogan (1998)

Unio unul atus Pratt, 1876

Pratt, 1876. Proc. Davenport Acad. Nat. Sci. 1: 168.
(incorrect original spelling of Unio lunulatus Pratt, 1876)

Quadrula quadrula — Lopes-Lima et al. (2019)

Quadrula (s.s.) gigantea Haas, 1930

‘Raf.’ Haas, 1930. Senckenbergiana 12(6): 327.
(error for Obliquaria (Quadrula) quadrula Rafinesque, 1820)

Quadrula contrayensis R.I. Johnson, 1969

‘Utterback’ R.I. Johnson, 1969. Nautilus 82(4): 132.
(error for Quadrula quadrula contraryensis Utterback, 1915)

Quadrula quadrula — Parmalee & Bogan (1998)

Quadrula quedrula Contreras-Arquieta, 2000

‘Rafinesque’ Contreras-Arquieta, 2000. Mexicoa 2(1): 44.
(error for Obliquaria (Quadrula) quadrula Rafinesque, 1820)