species Pleurobema sintoxia (Rafinesque, 1820): synonymy

Obliquaria rubra Rafinesque, 1820

Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 314 [also as ‘U. rubra’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 57.
LECTOTYPE ANSP_20237, [no locality available - North America].

Quadrula rubra — Vanatta (1915)
Pleurobema obliqua rubrum — Ortmann (1918)
Pleurobema pyramidatum — Ortmann & Walker (1922), Vidrine (1993)
Quadrula (Obliquata) coccinea — Frierson (1927)
Obliquaria rubra — Burch (1975)
Pleurobema rubrum — Cummings & Mayer (1992), IUCN (1996), Cummings & Mayer (1997), Parmalee & Bogan (1998), Turgeon et al. (1998), ... Inoue et al. (2018), Klymus et al. (2020), Graf & Cummings (2021), FMCS (2021), Hopper et al. (2023)
Pleurobema cordatum — Strayer & Jirka (1997)
Pleurobema (Sintoxia) rubrum — Campbell & Lydeard (2012), Burlakova et al. (2012)
Pleurobema sintoxia — Johnson et al. (2024), FMCS (2025)

Obliquaria rubra var. lineata Rafinesque, 1820

(intro'd as intra-sp. of Obliquaria rubra Rafinesque, 1820)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 314.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 57.

Obliquaria rubra var. pallida Rafinesque, 1820

(intro'd as intra-sp. of Obliquaria rubra Rafinesque, 1820)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 314.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 57.

Obliquaria (Scalenaria) triangularis Rafinesque, 1820

Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 309 [also as ‘U. triangularis’]. [nomen dubium]
Rafinesque, 1864. [in] Binney & Tryon, reprint: 53.

Fusconaia subrotunda — Ortmann & Walker (1922)
Quadrula (Obliquata) catilla — Frierson (1927)
Obliquaria triangularis — Burch (1975)

Obliquaria (Scalenaria) triangularis var. nigrescens Rafinesque, 1820

(intro'd as intra-sp. of Obliquaria (Scalenaria) triangularis Rafinesque, 1820)
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 309.
Rafinesque, 1864. [in] Binney & Tryon, reprint: 53.

Obliquaria (Sintoxia) sintoxia Rafinesque, 1820

(correct name for Unio (Obovaria) syntoxis Rafinesque, 1819)
Rafinesque, 1819. Jour. Phys. Chim. Hist. Nat. 88: 427 [as ‘U. (Obovaria) syntoxis’]. [nomen nudum]
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 310 [also as ‘U. sintoxia’].
Rafinesque, 1864. [in] Binney & Tryon, reprint: 29, 54.
LECTOTYPE ANSP_20208, Ohio River.

Quadrula sintoxia — Vanatta (1915)
Fusconaia subrotunda — Ortmann & Walker (1922)
Quadrula (Fusconia [sic]) subrotunda — Frierson (1927)
Sintoxia sintoxia — Morrison (1966)
Pleurobema sintoxia — Morrison (1969), Oesch (1984), Cummings & Mayer (1997), Parmalee & Bogan (1998), Turgeon et al. (1998), ... Hopper et al. (2023), Johnson et al. (2024), Freeman et al. (2025), FMCS (2025), Campbell & Lydeard (2026)
Obliquaria sintoxia — Burch (1975)
Pleurobema cordatum — R.I. Johnson (1980), Strayer & Jirka (1997)
Pleurobema (Sintoxia) sintoxia — Campbell & Lydeard (2012), Campbell & Lydeard (2012), Burlakova et al. (2012)
“Pleurobema sintoxia” ** — Huang et al. (2019)

Unio cardiacea Guérin-Méneville, 1823

Guérin-Méneville, 1823. Icon. Règne Animal Cuvier 2: pl. 28, fig. 7.

Quadrula (sec. Fusconaia) pyramidata — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) pyramidata — Simpson (1914)
Quadrula (Obliquata) obliquata — Frierson (1927), Haas (1930), Haas (1969)
Pleurobema cordatum — R.I. Johnson (1980)
Pleurobema rubrum — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio mytiloides Bory de St. Vincent, 1827

(homonym of Pleurobema mytiloides Rafinesque, 1820)
Bruguière, 1797. Encycl. Méth. 2: pl. 249, fig. 4a-b [as Unio sp.].
‘Val.’ Bory de St. Vincent, 1827. Encycl. Méth. 2: 151.
Deshayes, 1832. Enc. Méth. 2 (Deuxième partie): 585.

Quadrula (sec. Fusconaia) pyramidata — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) pyramidata — Simpson (1914)
Quadrula (Obliquata) obliquata — Haas (1969)
Pleurobema rubrum — Parmalee & Bogan (1998), Watters et al. (2009)

Unio obliquus Wood, 1828

(misidentified reference to Unio obliqua Lamarck, 1819)
Wood, 1828. Suppl. Index Testac.: 3 [as ‘Mya obliqua’].
Wood, 1828. Suppl. Index Testac.: 57, pl. 1, sp. 8.
Wood & Hanley, 1856. Index Testac.: 200, pl. 1, fig. 8.

Quadrula (sec. Fusconaia) pyramidata — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) pyramidata — Simpson (1914)
Pleurobema rubrum — Parmalee & Bogan (1998), Watters et al. (2009)

Unio pyramidatus Lea, 1831

Lea, 1831. Trans. Amer. Phil. Soc. 4 [O. 1]: 109 [119], pl. 16, fig. 39.
SYNTYPES ANSP_41726, Ohio River.

Quadrula (sec. Fusconaia) pyramidata — Simpson (1900)
Quadrula pyramidata — Ortmann (1909)
Quadrula obliqua — Ortmann (1909)
Pleurobema obliqua form pyramidata — Ortmann (1910)
Pleurobema obliquum — Ortmann (1912)
Quadrula (sec. Fusconaia) (Group of Q. undata) pyramidata — Simpson (1914)
Unio pyramidatus — de Gregorio (1914)
Pleurobema obliquum pyramidatum — Utterback (1915)
Quadrula rubra — Vanatta (1915)
Pleurobema obliqua rubrum — Ortmann (1918)
Pleurobema pyramidatum — Ortmann & Walker (1922), Stansbery (1970), Turgeon et al. (1988), Williams et al. (1993), Vidrine (1993), ITIS (2012)
Pleurobema cordatum pyramidatum — Ortmann (1924), Ortmann (1925), Murray & Leonard (1962), Gordon et al. (1979)
Quadrula (Obliquata) obliquata — Frierson (1927), Haas (1969)
Pleurobema obliquata — Morrison (1969)
Pleurobema cordatum — R.I. Johnson (1980), Strayer & Jirka (1997)
Pleurobema rubrum — Parmalee & Bogan (1998), Turgeon et al. (1998), Williams et al. (2008), Watters et al. (2009)

Unio catillus Conrad, 1836

Conrad, 1836. Monogr. Fam. Unionidae 1(3): 30, pl. 13, fig. 2.
Conrad, 1853. Proc. Acad. Nat. Sci. 6: 246.

Quadrula (sec. Fusconaia) coccinea — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea — Simpson (1914)
Pleurobema obliquum catillus — Utterback (1915)
Pleurobema catillus — Utterback (1915), Ortmann & Walker (1922)
Pleurobema obliqua catillus — Ortmann (1918)
Pleurobema cordatum catillus — Ortmann (1924), Ortmann (1925), Murray & Leonard (1962), Gordon et al. (1979)
Quadrula (Obliquata) catilla — Frierson (1927)
Pleurobema coccineum catillus — F.C. Baker (1928)
Quadrula (Obliquata) catillus — Haas (1969)
Pleurobema cordatum — Burch (1975), R.I. Johnson (1980)
Pleurobema sintoxia — Oesch (1984), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio coccineus Conrad, 1836

‘Hildreth’ Conrad, 1836. Monogr. Fam. Unionidae 1(3): 29, pl. 13, fig. 1.
‘Hildreth’ Conrad, 1853. Proc. Acad. Nat. Sci. 6: 247.
FIGURED SYNTYPE USNM_85848, Columbus, Ohio.

Quadrula (sec. Fusconaia) coccinea — Simpson (1900)
Quadrula coccinea — Ortmann (1909), Ortmann (1909)
Pleurobema obliqua var. coccinea — Ortmann (1910)
Pleurobema coccineum — Ortmann (1912), Utterback (1915), F.C. Baker (1928), Turgeon et al. (1988), Cummings & Mayer (1992), Williams et al. (1993), Graf & Ó Foighil (2000), Graf (2002), ITIS (2012)
Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea — Simpson (1914)
Pleurobema obliquum coccineum — Utterback (1915)
Pleurobema obliqua coccineum — Ortmann (1918)
Quadrula (Obliquata) coccinea — Frierson (1927)
Pleurobema cordatum coccineum — Murray & Leonard (1962), Gordon et al. (1979)
Quadrula (Obliquata) coccinea coccinea — Haas (1969)
Pleurobema cordatum — Mathiak (1979), R.I. Johnson (1980), Strayer & Jirka (1997)
Pleurobema cordatum f. coccineum — Mackie et al. (1980)
Pleurobema sintoxia — Oesch (1984), Parmalee & Bogan (1998), Turgeon et al. (1998), Williams et al. (2008), Watters et al. (2009), IUCN (2012), Zieritz et al. (2015)

Unio coccineus Lea, 1838

(homonym of Unio coccineus Conrad, 1836)
“Dr. Hildreth’s Letter” Lea, 1836. Synopsis Fam. Naiades: 34. [nomen nudum]
Lea, 1838. Trans. Amer. Phil. Soc. 6 [O. 2]: 12, pl. 5, fig. 12.
FIGURED SYNTYPE USNM_85848, Columbus, Ohio.

Quadrula (sec. Fusconaia) coccinea — Simpson (1900)
Unio (s.s.) coccineus — Call (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea — Simpson (1914)
Unio coccineus — de Gregorio (1914)
Quadrula (Obliquata) catilla — Frierson (1927)
Pleurobema coccineum — F.C. Baker (1928), Graf & Cummings (2006), Hoeh et al. (2009)
Pleurobema cordatum — R.I. Johnson (1980)

Unio cuneus Conrad, 1838

Conrad, 1838. Monogr. Fam. Unionidae 2(11): back cover.
Conrad, 1840. Monogr. Fam. Unionidae 2(12): 105, pl. 58, fig. 1.
HOLOTYPE (MONOTYPY) ANSP_41645, Arkansas River.

Quadrula (sec. Fusconaia) cuneus — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. subrotunda) cuneus — Simpson (1914)
Quadrula (Obliquata) coccinea-cunea — Frierson (1927)
Quadrula (Obliquata) coccinea cunea — Haas (1969)
Pleurobema cordatum — R.I. Johnson (1980)
Pleurobema pyramidatum — Vidrine (1993)
Pleurobema sintoxia — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio solidus Lea, 1838

Lea, 1836. Synopsis Fam. Naiades: 20. [nomen nudum]
Lea, 1838. Trans. Amer. Phil. Soc. 6 [O. 2]: 13, pl. 5, fig. 13.

Quadrula (sec. Fusconaia) solida — Simpson (1900)
Unio (s.s.) solidus — Call (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) solida — Simpson (1914)
Pleurobema obliquum catillus — Utterback (1915)
Pleurobema catillus — Utterback (1915), Ortmann & Walker (1922)
Pleurobema obliqua catillus — Ortmann (1918)
Pleurobema cordatum catillus — Ortmann (1925), Murray & Leonard (1962)
Quadrula (Obliquata) catilla — Frierson (1927)
Pleurobema coccineum solida — F.C. Baker (1928)
Quadrula (Obliquata) catillus — Haas (1969)
Pleurobema sintoxia — Morrison (1969), Oesch (1984), Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)
Pleurobema cordatum — Burch (1975), R.I. Johnson (1980), Strayer & Jirka (1997)

Unio cardiacea Deshayes, 1839

(reference to Unio cardiacea Guérin-Méneville, 1823)
‘Guérin’ Deshayes, 1839. Traité Élém. Conchyl.: 19, pl. 31, figs. 1-2.

Quadrula (sec. Fusconaia) solida — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) solida — Simpson (1914)
Quadrula (Obliquata) catillus — Haas (1969)
Pleurobema sintoxia — Parmalee & Bogan (1998), Watters et al. (2009)

Unio fulgidus Lea, 1845

Lea, 1845. Proc. Amer. Phil. Soc. 4: 164.
Lea, 1848. Trans. Amer. Phil. Soc. 10 [O. 4]: 73 [47], pl. 4, fig. 10.
FIGURED SYNTYPE USNM_84649, Alexandria, La.

Quadrula (sec. Fusconaia) solida — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) solida — Simpson (1914)
Pleurobema catillus — Utterback (1915)
Quadrula (Obliquata) catilla — Frierson (1927)
Quadrula (Obliquata) catillus — Haas (1969)
Pleurobema cordatum — R.I. Johnson (1980)
Pleurobema sintoxia — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio obliquus ‘Lamarck’ of Authors

(misidentified reference to Unio obliqua Lamarck, 1819)
‘Lamarck’ of Authors.
Lapham, 1860. Proc. Acad. Nat. Sci. 12: 156.
Baker, 1905. Trans. Acad. Sci. St. Louis 15: 256.
Ortmann, 1919. Mem. Carnegie Mus. 8(1): 73. [in part]

Pleurobema coccineum solida — F.C. Baker (1928)

Unio catilus ‘Conrad’ of Authors

(error for Unio catillus Conrad, 1836)
‘Conrad’ of Authors.
B.H. Wright, 1888. Check List N. Amer. Unionidae etc.: [2].
Ortmann, 1924. Amer. Midl. Nat. 9(1): 38.

Quadrula (sec. Fusconaia) coccinea — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea — Simpson (1914)
Pleurobema sintoxia — Parmalee & Bogan (1998), Watters et al. (2009)

Unio cuneus Call, 1895

(reference to Unio cuneus Conrad, 1838)
Call, 1895. Trans. Acad. Sci. St. Louis 7: 14.

Quadrula (sec. Fusconaia) coccinea — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea — Simpson (1914)

Quadrula (sec. Fusconaia) coccinea var. paupercula Simpson, 1900

(intro'd as intra-sp. of Unio coccineus Conrad, 1836; homonym of Unio pauperculus Lea, 1861; renamed Quadrula (sec. Fusconaia) coccinea var. magnalacustris Simpson, 1914)
Simpson, 1900. Proc. U.S. Nat. Mus. 22: 789.

Quadrula (sec. Fusconaia) coccinea var. paupercula — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea var. magnalacustris — Simpson (1914)
Pleurobema coccineum paupercula — Ortmann & Walker (1922)
Quadrula (Obliquata) coccinea-magnalacustris — Frierson (1927)
Quadrula (Obliquata) coccinea magnalacustris — Haas (1969)
Pleurobema cordatum — R.I. Johnson (1980), Strayer & Jirka (1997)
Pleurobema sintoxia — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009), IUCN (2012)

Pleurobema missouriensis Marsh, 1901

Marsh, 1901. Nautilus 15(7): 74.
Walker, 1915. Nautilus 28(12): 140, pl. 5, figs. 1-2.
FIGURED SYNTYPE UMMZ_113527, Black River, Poplar Bluff, Butler Co., Missouri.

Pleurobema (Group of P. argenteum) missouriense — Simpson (1914)
Pleurobema missourense [sic] — Utterback (1915)
Quadrula (Obliquata) missouriensis — Frierson (1927), Haas (1969)
Fusconaia subrotunda — R.I. Johnson (1980)
Pleurobema sintoxia — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Quadrula (sec. Fusconaia) coccinea var. magnalacustris Simpson, 1914

(intro'd as intra-sp. of Unio coccineus Conrad, 1836; new name for Quadrula (sec. Fusconaia) coccinea var. paupercula Simpson, 1900)
Simpson, 1914. Descr. Cat. Naiades: 884.
LECTOTYPE USNM_133834, Niagara Riv., 3 mi above Falls.

Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea var. magnalacustris — Simpson (1914)
Pleurobema coccineum paupercula — Ortmann & Walker (1922)
Quadrula (Obliquata) coccinea-magnalacustris — Frierson (1927)
Quadrula (Obliquata) coccinea magnalacustris — Haas (1969)
Pleurobema cordatum — R.I. Johnson (1980)
Pleurobema sintoxia — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Pleurobema coccineum var. mississippiensis F.C. Baker, 1928

(intro'd as intra-sp. of Unio coccineus Conrad, 1836)
F.C. Baker, 1928. Bull. Wisconsin Geol. Nat. Hist. Survey 70(2): 121, pl. 53, figs. 1-5.
HOLOTYPE (ORIG. DESIG.) INHS_82273, Lake Pepin, Wisconsin.

Pleurobema coccineum mississippiensis — F.C. Baker (1928)
Pleurobema cordatum — R.I. Johnson (1980)
Pleurobema sintoxia — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio (Obovaria) syntoxis Rafinesque, 1819

(incorrect original spelling of Obliquaria (Sintoxia) sintoxia Rafinesque, 1820)
Rafinesque, 1819. Jour. Phys. Chim. Hist. Nat. 88: 427. [nomen nudum]
Rafinesque, 1864. [in] Binney & Tryon, reprint: 29.

Fusconaia subrotunda — Haas (1969)

Unio caridacea Conrad, 1836

(error for Unio cardiacea Guérin-Méneville, 1823)
‘Guérin’ Conrad, 1836. Monogr. Fam. Unionidae 1(5): 41.

Unio mytiloides Conrad, 1836

(misidentified reference to Pleurobema mytiloides Rafinesque, 1820)
‘Rafinesque’ Conrad, 1836. Monogr. Fam. Unionidae 1(4): 41, pl. 20.

Quadrula (sec. Fusconaia) pyramidata — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) pyramidata — Simpson (1914)
Quadrula (Obliquata) obliquata — Frierson (1927)

Unio gouldianus Ward in Jay, 1839

Ward in Jay, 1839. Cat. Rec. Shells: 24. [nomen nudum]

Quadrula (sec. Fusconaia) coccinea — Simpson (1900)
Unio (s.s.) coccineus — Call (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) coccinea — Simpson (1914)
Quadrula (Fusconia [sic]) antrosa — Frierson (1927)
Fusconaia antrosa — Haas (1969)
Pleurobema cordatum — R.I. Johnson (1980)
Pleurobema sintoxia — Parmalee & Bogan (1998), Williams et al. (2008), Watters et al. (2009)

Unio coccineus Jay, 1850

(reference to Unio coccineus Conrad, 1836)
Jay, 1850. Cat. Rec. Shells: 66.

Unio obovalis Conrad, 1853

(misidentified reference to Obovaria obovalis Rafinesque, 1820)
‘Rafinesque’ Conrad, 1853. Proc. Acad. Nat. Sci. 6: 253.

Quadrula (sec. Fusconaia) solida — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) solida — Simpson (1914)
Pleurobema sintoxia — Parmalee & Bogan (1998), Watters et al. (2009)

Unio ruber Conrad, 1853

(reference to Obliquaria rubra Rafinesque, 1820)
‘Rafinesque’ Conrad, 1853. Proc. Acad. Nat. Sci. 6: 257.

Quadrula (sec. Fusconaia) pyramidata — Simpson (1900)
Quadrula (sec. Fusconaia) (Group of Q. undata) pyramidata — Simpson (1914)
Quadrula (Obliquata) obliquata — Frierson (1927), Haas (1969)
Pleurobema rubrum — Parmalee & Bogan (1998), Watters et al. (2009)

Unio mytiloides Lapham, 1860

(misidentified reference to Pleurobema mytiloides Rafinesque, 1820)
‘Raf.’ Lapham, 1860. Proc. Acad. Nat. Sci. 12: 156.

Pleurobema coccineum catillus — F.C. Baker (1928)

Unio cardidiacea Lea, 1870

(error for Unio caridacea Conrad, 1836)
‘Conrad’ Lea, 1870. Synopsis Fam. Naiades: 39.

Unio pyramidatus Call, 1885

(reference to Unio pyramidatus Lea, 1831)
Call, 1885. unknown publication: 46.

Pleurobema coccineum catillus — F.C. Baker (1928)

Quadrula kirtlandiana Simpson, 1900

(misidentified reference to Unio kirtlandianus Lea, 1834)
‘Conrad’ Simpson, 1900. Proc. U.S. Nat. Mus. 22: 791. [in part]
‘Conrad’ Simpson, 1914. Descr. Cat. Naiades: 891. [in part]

Pleurobema coccineum — F.C. Baker (1928)

Quadrula pyramidata Simpson, 1900

(reference to Unio pyramidatus Lea, 1831)
‘Lea’ Simpson, 1900. Proc. U.S. Nat. Mus. 22: 789. [in part]
Chadwick, 1906. unknown publication: 97.
‘Lea’ Simpson, 1914. Descr. Cat. Naiades: 889. [in part]

Pleurobema coccineum solida — F.C. Baker (1928)

Pleurobema missourense Utterback, 1915

(error for Pleurobema missouriensis Marsh, 1901)
‘Marsh’ Utterback, 1915. Amer. Midl. Nat. 4(5): 195.

Unio mytilloides Frierson, 1927

(misidentified reference to Pleurobema mytiloides Rafinesque, 1820; error for Pleurobema mytiloides Rafinesque, 1820)
‘Lea, 1829’ Frierson, 1927. Check List N. Amer. Naiades: 52.

Pleurobema rubrum — Parmalee & Bogan (1998), Watters et al. (2009)