MolluscaBase taxon details

Unionini Rafinesque, 1820

1351486  (urn:lsid:marinespecies.org:taxname:1351486)

accepted
Tribe
Genus Aculamprotula X.-P. Wu, Y.-L. Liang, H.-Z. Wang & O.-Y. Shan, 1999
Genus Acuticosta Simpson, 1900
Genus Betekeia Starobogatov, 1970 †
Genus Cuneopsis Simpson, 1900
Genus Diaurora Cockerell, 1903
Genus Heterunio Lindholm, 1932 †
Genus Inversiunio Habe, 1991
Genus Middendorffinaia Moskvicheva & Starobogatov, 1973
  » Species Middendorffinaia mongolica (Middendorff, 1851)
  » Subgenus Middendorffinaia (Middendorffinaia) Moskvicheva & Starobogatov, 1973 accepted as Middendorffinaia Moskvicheva & Starobogatov, 1973
  » Species Middendorffinaia alimovi Bogatov, 2012 accepted as Middendorffinaia mongolica (Middendorff, 1851) (a junior synonym)
  » Species Middendorffinaia arsenievi Moskvicheva & Starobogatov, 1973 accepted as Middendorffinaia mongolica (Middendorff, 1851)
  » Species Middendorffinaia ochotica Bogatov, 2000 accepted as Middendorffinaia mongolica (Middendorff, 1851) (a junior synonym)
  » Species Middendorffinaia ussuriensis Moskvicheva & Starobogatov, 1973 accepted as Middendorffinaia mongolica (Middendorff, 1851) (a junior synonym)
Genus Nodularia Conrad, 1853
  » Species Nodularia cunhatia S. Schneider, 2013 †
  » Species Nodularia diespiter (Mabille, 1887)
  » Species Nodularia distinguenda (LIndholm, 1932) †
  » Species Nodularia dorri (Wattebled, 1886)
  » Species Nodularia douglasiae (Gray, 1833)
  » Species Nodularia gladiator (Ancey, 1881)
  » Species Nodularia jourdyi (Morlet, 1886)
  » Species Nodularia kizylaigirensis (Lindholm, 1932)
  » Species Nodularia micheloti (Morlet, 1886)
  » Species Nodularia nuxpersica (Dunker, 1848)
  » Species Nodularia cariei Germain, 1919 (taxon inquirendum)
  » Species Nodularia continentalis F. Haas, 1910 (taxon inquirendum)
  » Species Nodularia denserugata F. Haas, 1910 (taxon inquirendum)
  » Species Nodularia undulata F. Haas, 1910 (taxon inquirendum)
  » Subgenus Nodularia (Amurunio) Zatravkin & Starobogatov, 1987 accepted as Nodularia Conrad, 1853
  » Subgenus Nodularia (Inversidens) F. Haas, 1911 accepted as Inversidens F. Haas, 1911 (original rank)
  » Subgenus Nodularia (Lanceolaria) Conrad, 1853 accepted as Lanceolaria Conrad, 1853 (new combination)
  » Subgenus Nodularia (Magadaninaia) Martynov & Chernychev, 1992 accepted as Nodularia Conrad, 1853
  » Subgenus Nodularia (Nodularia) Conrad, 1853 accepted as Nodularia Conrad, 1853
  » Subgenus Nodularia (Radiatula) Simpson, 1900 accepted as Radiatula Simpson, 1900 (original rank)
  » Subgenus Nodularia (Scabies) F. Haas, 1911 accepted as Scabies F. Haas, 1911 (original rank)
  » Species Nodularia chaudhurii Preston, 1912 accepted as Radiatula chaudhurii (Preston, 1912) (original combination)
  » Species Nodularia cylindrica Simpson, 1900 accepted as Lanceolaria cylindrica (Simpson, 1900) (basionym)
  » Species Nodularia extremalis Martynov & Chernychev, 1992 accepted as Nodularia douglasiae (Gray, 1833)
  » Species Nodularia fischeriania Simpson, 1900 accepted as Contradens contradens (I. Lea, 1838) (in error for Unio fischerianus Morlet, 1883)
  » Species Nodularia lebedevi Zatravkin & Starobogatov, 1984 accepted as Nodularia douglasiae (Gray, 1833)
  » Species Nodularia moskvichevae Bogatov & Starobogatov, 1992 accepted as Nodularia douglasiae (Gray, 1833)
  » Species Nodularia sakhalinensis Bogatov, 2001 accepted as Nodularia douglasiae (Gray, 1833)
  » Species Nodularia sobolus Simpson, 1900 accepted as Contradens contradens (I. Lea, 1838) (in error for Unio soboles Fischer, 1891)
  » Species Nodularia suifunica Moskvicheva, 1973 accepted as Nodularia douglasiae (Gray, 1833)
  » Species Nodularia vladivostokensis Moskvicheva, 1973 accepted as Nodularia douglasiae (Gray, 1833)
Genus Palindonaia Modell, 1950 †
Genus Protunio Haas, 1912
Genus Pseudobaphia Simpson, 1900
Genus Rhombuniopsis F. Haas, 1920
Genus Schistodesmus Simpson, 1900
Genus Sculptunio Lindholm, 1932 †
Genus Sibirunio Starobogatov, 1970 †
Genus Tuberunio Lindholm, 1932 †
Genus Unio Philipsson, 1788
  » Species Unio abyssinicus von Martens, 1866
  » Species Unio bruguierianus Bourguignat, 1853
  » Species Unio caffer F. Krauss, 1848
    » Subspecies Unio caffer connollyi Pilsbry, 1923
    » Subspecies Unio caffer verreauxi Küster, 1856
  » Species Unio crassus Philipsson, 1788
  » Species Unio delphinus Spengler, 1793
  » Species Unio dembeae Reeve, 1865
  » Species Unio elongatulus C. Pfeiffer, 1825
  » Species Unio foucauldianus Pallary, 1936
  » Species Unio gibbus Spengler, 1793
  » Species Unio indifferens Lindholm, 1932 †
  » Species Unio ionicus Drouët, 1879
  » Species Unio kirchbergensis Krauss, 1852 †
  » Species Unio mancus Lamarck, 1819
    » Subspecies Unio mancus mancus Lamarck, 1819
    » Subspecies Unio mancus requienii Michaud, 1831
    » Subspecies Unio mancus turtonii Payraudeau, 1826
  » Species Unio migliorinii Magrograssi, 1928 †
  » Species Unio pictorum (Linnaeus, 1758)
    » Variety Unio pictorum var. amurensis Mousson, 1887 accepted as Nodularia douglasiae (Gray, 1833)
    » Variety Unio pictorum var. parva Stabile, 1845 accepted as Unio elongatulus C. Pfeiffer, 1825 (invalid: junior homonym of Unio parvus Barnes, 1823; U. eucallistellus is a replacement name)
  » Species Unio pseudatavus Bukowski, 1896 †
    » Variety Unio pseudatavus var. calavardensis Bukowski, 1896 † (taxon inquirendum)
    » Variety Unio pseudatavus var. dorica Bukowski, 1896 † (taxon inquirendum)
  » Species Unio ravoisieri Deshayes, 1848
  » Species Unio subplanatus Lindholm, 1932 †
  » Species Unio tigridis Bourguignat, 1852
  » Species Unio tumidiformis Castro, 1885
  » Species Unio tumidus Philipsson, 1788
  » Species Unio delphinus I. Lea, 1840 (taxon inquirendum, invalid, a junior homonym of Unio delphinus Spengler, 1793)
  » Species Unio shuttleworthi Küster, 1856 (taxon inquirendum)
  » Species Unio tenuis Gray in Griffith & Pidgeon, 1833 (taxon inquirendum)
  » Species Unio malgachensis Germain, 1911 (nomen dubium)
  » Species Unio radula Say, 1829 (nomen dubium)
  » Species Unio pequottinus Linsley, 1845 (nomen nudum)
  » Subgenus Unio (Actinonaias) Fischer & Crosse, 1894 accepted as Actinonaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Alasmodon) Sowerby I., 1824 accepted as Alasmidonta Say, 1818 (invalid: unjustified emendation)
  » Subgenus Unio (Amphinaias) Crosse & P. Fischer, 1894 accepted as Quadrula Rafinesque, 1820
  » Subgenus Unio (Anodontes) Cuvier, 1817 accepted as Anodontites Bruguière, 1792 (a junior synonym)
  » Subgenus Unio (Arconaia) accepted as Arconaia Conrad, 1865
  » Subgenus Unio (Arotonaias) von Martens, 1900 accepted as Arotonaias von Martens, 1900 (original rank)
  » Subgenus Unio (Aximedia) accepted as Pleurobema Rafinesque, 1819
  » Subgenus Unio (Barynaias) Fischer & Crosse, 1894 accepted as Barynaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Canthyria) Swainson, 1840 accepted as Elliptio Rafinesque, 1819
    » Species Unio (Canthyria) spinosus (I. Lea, 1836) accepted as Elliptio spinosa (I. Lea, 1836) (recombination)
  » Subgenus Unio (Coelatura) Conrad, 1853 accepted as Coelatura Conrad, 1853 (original rank)
  » Subgenus Unio (Cuneopsis) Simpson, 1900 accepted as Cuneopsis Simpson, 1900
  » Subgenus Unio (Cyrtonaias) Crosse & P. Fischer, 1894 accepted as Cyrtonaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Delphinonaias) Crosse & P. Fischer, 1894 accepted as Delphinonaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Diplodon) Spix, 1827 accepted as Diplodon Spix, 1827 (original rank)
  » Subgenus Unio (Disconaias) Crosse & P. Fischer, 1894 accepted as Disconaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Elliptio) Rafinesque, 1819 accepted as Elliptio Rafinesque, 1819 (original rank)
    » Species Unio (Elliptio) aheneus (I. Lea, 1843) accepted as Elliptio ahenea (I. Lea, 1843) (recombination)
    » Species Unio (Elliptio) amabilis (I. Lea, 1865) accepted as Pleurobema pyriforme (I. Lea, 1857)
    » Species Unio (Elliptio) angustatus (I. Lea, 1831) accepted as Elliptio angustata (I. Lea, 1831) (recombination)
    » Species Unio (Elliptio) aquilus (I. Lea, 1857) accepted as Elliptio pullata (I. Lea, 1857)
    » Species Unio (Elliptio) arctatus (Conrad, 1834) accepted as Elliptio arctata (Conrad, 1834)
    » Species Unio (Elliptio) attenuatus (I. Lea, 1872) accepted as Elliptio folliculata (I. Lea, 1838)
    » Species Unio (Elliptio) aurata Rafinesque, 1820 accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) brimleyi (Wright, S.H., 1897) accepted as Fusconaia masoni (Conrad, 1834)
    » Species Unio (Elliptio) buckleyi (I. Lea, 1843) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) burkensis (I. Lea, 1859) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) burtchianus (Wright, S.H., 1897) accepted as Elliptio occulta (I. Lea, 1843)
    » Species Unio (Elliptio) buxtoni (Wright, B.H., 1897) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) catawbensis (I. Lea, 1862) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) chipolaensis (Walker, 1905) accepted as Elliptio chipolaensis (Walker, 1905)
    » Species Unio (Elliptio) complanatus (Lightfoot, 1786) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) confertus (I. Lea, 1834) accepted as Elliptio raveneli (Conrad, 1834) (recombination)
    » Species Unio (Elliptio) congaraeus (I. Lea, 1831) accepted as Elliptio congaraea (I. Lea, 1831) (recombination)
    » Species Unio (Elliptio) coruscus (Gould, 1856) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) crassidens (Lamarck, 1819) accepted as Elliptio crassidens (Lamarck, 1819)
    » Species Unio (Elliptio) cunninghami (Wright, B.H., 1883) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) cuvierianus (I. Lea, 1853) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) danielsii (Wright, B.H., 1899) accepted as Elliptio crassidens (Lamarck, 1819)
    » Species Unio (Elliptio) dariensis (I. Lea, 1842) accepted as Elliptio dariensis (I. Lea, 1842) (recombination)
    » Species Unio (Elliptio) differtus (I. Lea, 1872) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) dispalans (Wright, B.H., 1899) accepted as Elliptio occulta (I. Lea, 1843)
    » Species Unio (Elliptio) dorei (Wright, B.H., 1888) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) dorsatus (I. Lea, 1868) accepted as Elliptio congaraea (I. Lea, 1831)
    » Species Unio (Elliptio) downiei (I. Lea, 1858) accepted as Elliptio downiei (I. Lea, 1858)
    » Species Unio (Elliptio) duttonianus (I. Lea, 1841) accepted as Elliptio lanceolata (I. Lea, 1827)
    » Species Unio (Elliptio) emmonsii (I. Lea, 1857) accepted as Elliptio lanceolata (I. Lea, 1827)
    » Species Unio (Elliptio) errans (I. Lea, 1857) accepted as Elliptio errans (I. Lea, 1857)
    » Species Unio (Elliptio) fasciata Rafinesque, 1820 accepted as Ortmanniana ligamentina (Lamarck, 1819)
    » Species Unio (Elliptio) ferrissii (Marsh, 1891) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) fisherianus (I. Lea, 1838) accepted as Elliptio fisheriana (I. Lea, 1838)
    » Species Unio (Elliptio) folliculatus (I. Lea, 1838) accepted as Elliptio folliculata (I. Lea, 1838) (recombination)
    » Species Unio (Elliptio) forbesianus (I. Lea, 1852) accepted as Elliptio congaraea (I. Lea, 1831)
    » Species Unio (Elliptio) fraternus (I. Lea, 1852) accepted as Elliptio fraterna (I. Lea, 1852)
    » Species Unio (Elliptio) fuscatus (I. Lea, 1843) accepted as Elliptio occulta (I. Lea, 1843) (recombination)
    » Species Unio (Elliptio) geminus (I. Lea, 1856) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) gibbosus (Barnes, 1823) accepted as Eurynia dilatata (Rafinesque, 1820)
    » Species Unio (Elliptio) hartwrighti (Wright, B.H., 1896) accepted as Elliptio monroensis (I. Lea, 1843)
    » Species Unio (Elliptio) hazelhurstianus (I. Lea, 1858) accepted as Elliptio lanceolata (I. Lea, 1827)
    » Species Unio (Elliptio) hinkleyi (Wright, B.H., 1888) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) hopetonensis (I. Lea, 1838) accepted as Elliptio hopetonensis (I. Lea, 1838)
    » Species Unio (Elliptio) icterinus (Conrad, 1834) accepted as Elliptio icterina (Conrad, 1834)
    » Species Unio (Elliptio) iheringi (Wright, B.H., 1898) accepted as Sphenonaias taumilapana (Conrad, 1855)
    » Species Unio (Elliptio) incrassatus (I. Lea, 1840) accepted as Elliptio crassidens (Lamarck, 1819)
    » Species Unio (Elliptio) insulsus (I. Lea, 1857) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) inusitatis (I. Lea, 1859) accepted as Elliptio hopetonensis (I. Lea, 1838)
    » Species Unio (Elliptio) jayensis (I. Lea, 1838) accepted as Elliptio jayensis (I. Lea, 1838) (recombination)
    » Species Unio (Elliptio) lanceolatus (I. Lea, 1827) accepted as Elliptio lanceolata (I. Lea, 1827)
    » Species Unio (Elliptio) lazarus (I. Lea, 1852) accepted as Elliptio arctata (Conrad, 1834)
    » Species Unio (Elliptio) lecontianus I. Lea, 1838 accepted as Elliptio congaraea (I. Lea, 1831) (recombination)
    » Species Unio (Elliptio) lehmanii (Wright, S.H., 1897) accepted as Elliptio occulta (I. Lea, 1843)
    » Species Unio (Elliptio) livingstonensis (I. Lea, 1863) accepted as Elliptio icterina (Conrad, 1834)
    » Species Unio (Elliptio) luridus (I. Lea, 1852) accepted as Elliptio arca (Conrad, 1834)
    » Species Unio (Elliptio) masoni (Conrad, 1834) accepted as Fusconaia masoni (Conrad, 1834)
    » Species Unio (Elliptio) merus (I. Lea, 1852) accepted as Fusconaia masoni (Conrad, 1834)
    » Species Unio (Elliptio) micans (I. Lea, 1857) accepted as Elliptio icterina (Conrad, 1834)
    » Species Unio (Elliptio) mitchelli (Simpson in Dall, 1895) accepted as Fusconaia mitchelli (Simpson in Dall, 1895)
    » Species Unio (Elliptio) monroensis (I. Lea, 1843) accepted as Elliptio monroensis (I. Lea, 1843)
    » Species Unio (Elliptio) nasutulus (I. Lea, 1863) accepted as Elliptio producta (Conrad, 1836)
    » Species Unio (Elliptio) naviculoides (I. Lea, 1857) accepted as Elliptio lanceolata (I. Lea, 1827)
    » Species Unio (Elliptio) nigellus (I. Lea, 1852) accepted as Elliptio nigella (I. Lea, 1852)
    » Species Unio (Elliptio) nigra Rafinesque, 1820 accepted as Elliptio crassidens (Lamarck, 1819)
    » Species Unio (Elliptio) oblatus (I. Lea, 1863) accepted as Elliptio icterina (Conrad, 1834)
    » Species Unio (Elliptio) obnubilus (I. Lea, 1857) accepted as Elliptio icterina (Conrad, 1834)
    » Species Unio (Elliptio) occultus (I. Lea, 1843) accepted as Elliptio occulta (I. Lea, 1843) (recombination)
    » Species Unio (Elliptio) ocmulgeensis (I. Lea, 1861) accepted as Elliptio icterina (Conrad, 1834)
    » Species Unio (Elliptio) oscari (Wright, B.H., 1892) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) perstriatus (I. Lea, 1852) accepted as Elliptio arctata (Conrad, 1834)
    » Species Unio (Elliptio) pinei (Wright, B.H., 1897) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) plantii (I. Lea, 1857) accepted as Elliptio fumata (I. Lea, 1857)
    » Species Unio (Elliptio) polymorphus (Wright, B.H., 1899) accepted as Elliptio monroensis (I. Lea, 1843)
    » Species Unio (Elliptio) popeii (I. Lea, 1857) accepted as Popenaias popeii (I. Lea, 1857)
    » Species Unio (Elliptio) productus (Conrad, 1836) accepted as Elliptio producta (Conrad, 1836)
    » Species Unio (Elliptio) purus (I. Lea, 1858) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) pusillus (Barnes, 1840) accepted as Elliptio congaraea (I. Lea, 1831)
    » Species Unio (Elliptio) pygmaeus (I. Lea, 1852) accepted as Lasmigona subviridis (Conrad, 1835)
    » Species Unio (Elliptio) roanokensis I. Lea, 1838 accepted as Elliptio roanokensis (I. Lea, 1838) (recombination)
    » Species Unio (Elliptio) rostraeformis (I. Lea, 1857) accepted as Elliptio lanceolata (I. Lea, 1827)
    » Species Unio (Elliptio) rostrum (I. Lea, 1862) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) sagittiformis (I. Lea, 1852) accepted as Elliptio lanceolata (I. Lea, 1827)
    » Species Unio (Elliptio) sanctorumjohanium Wright, B.H., 1933 accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) shepardianus (I. Lea, 1834) accepted as Elliptio shepardiana (I. Lea, 1834) (recombination)
    » Species Unio (Elliptio) singularis (Wright, B.H., 1899) accepted as Elliptio pullata (I. Lea, 1857)
    » Species Unio (Elliptio) sloatianus (I. Lea, 1840) accepted as Elliptoideus sloatianus (I. Lea, 1840)
    » Species Unio (Elliptio) sordidus (I. Lea, 1852) accepted as Elliptio congaraea (I. Lea, 1831)
    » Species Unio (Elliptio) spadiceus (I. Lea, 1857) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) spissus (I. Lea, 1859) accepted as Elliptio downiei (I. Lea, 1858)
    » Species Unio (Elliptio) stonensis (I. Lea, 1840) accepted as Eurynia dilatata (Rafinesque, 1820)
    » Species Unio (Elliptio) striatulus (I. Lea, 1857) accepted as Fusconaia masoni (Conrad, 1834)
    » Species Unio (Elliptio) strigosus (I. Lea, 1840) accepted as Elliptio arctata (Conrad, 1834)
    » Species Unio (Elliptio) strumosus (I. Lea, 1872) accepted as Elliptio congaraea (I. Lea, 1831)
    » Species Unio (Elliptio) subinflatus (Conrad, 1835) accepted as Elliptio complanata (Lightfoot, 1786)
    » Species Unio (Elliptio) subluridus (Simpson, 1892) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) subniger (I. Lea, 1857) accepted as Elliptio fumata (I. Lea, 1857)
    » Species Unio (Elliptio) subplanus (Conrad, 1837) accepted as Fusconaia masoni (Conrad, 1834)
    » Species Unio (Elliptio) tenuisculus (Frierson, 1911) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Elliptio) tuomeyi (I. Lea, 1852) accepted as Elliptio cylindracea Frierson, 1927 (unaccepted)
    » Species Unio (Elliptio) viridis Rafinesque, 1820 accepted as Alasmidonta viridis (Rafinesque, 1820) (unaccepted)
    » Species Unio (Elliptio) viridulus (I. Lea, 1863) accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
    » Species Unio (Elliptio) waccamawensis (I. Lea, 1863) accepted as Elliptio waccamawensis (I. Lea, 1863) (unaccepted)
    » Species Unio (Elliptio) waltoni Wright, B.H., 1888 accepted as Elliptio ahenea (I. Lea, 1843) (unaccepted)
    » Species Unio (Elliptio) webbianus Wright, B.H., 1934 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
    » Species Unio (Elliptio) websteri (Wright, B.H., 1888) accepted as Elliptio monroensis (I. Lea, 1843) (unaccepted)
  » Subgenus Unio (Eurynia) Rafinesque, 1819 accepted as Eurynia Rafinesque, 1819 (original rank)
  » Subgenus Unio (Glebula) Conrad, 1853 accepted as Glebula Conrad, 1853 (original rank)
  » Subgenus Unio (Grandidieria) Bourguignat, 1885 accepted as Grandidieria Bourguignat, 1885
  » Subgenus Unio (Heterunio) Lindholm, 1932 † accepted as Heterunio Lindholm, 1932 † (original rank)
  » Subgenus Unio (Lampsilis) accepted as Lampsilis Rafinesque, 1820
  » Subgenus Unio (Lanceolaria) Conrad, 1853 accepted as Lanceolaria Conrad, 1853
  » Subgenus Unio (Lemiox) Rafinesque, 1831 accepted as Lemiox Rafinesque, 1831 (original rank)
  » Subgenus Unio (Leptodea) Rafinesque, 1820 accepted as Leptodea Rafinesque, 1820 (original rank)
  » Subgenus Unio (Ligumia) Swainson, 1840 accepted as Ligumia Swainson, 1840 (original rank)
  » Subgenus Unio (Metaptera) Rafinesque, 1820 accepted as Potamilus Rafinesque, 1818 (a junior synonym)
    » Species Unio (Metaptera) johnstoni E.A. Smith, 1893 accepted as Prisodontopsis aviculaeformis F.R. Woodward, 1991 (unavailable; a junior homonym of Unio johnstoni Etheridge, 1881)
  » Subgenus Unio (Microdontia) Tapparone Canefri, 1883 accepted as Microdontia Tapparone Canefri, 1883 (original rank)
  » Subgenus Unio (Micronaias) Simpson, 1900 accepted as Micronaias Simpson, 1900 (original rank)
  » Subgenus Unio (Monocondylaea) d'Orbigny, 1835 accepted as Monocondylaea d'Orbigny, 1835 (original rank)
    » Species Unio (Monocondylaea) corrientesensis d'Orbigny, 1835 accepted as Monocondylaea corrientesensis (d'Orbigny, 1835)
    » Species Unio (Monocondylaea) costulata Moricand, 1858 accepted as Monocondylaea costulata (Moricand, 1858) (basionym)
    » Species Unio (Monocondylaea) fossiculifera d'Orbigny, 1835 accepted as Fossula fossiculifera (d'Orbigny, 1835) (basionym)
    » Species Unio (Monocondylaea) franciscana Moricand, 1836 accepted as Monocondylaea franciscana (Moricand, 1836) (basionym)
    » Species Unio (Monocondylaea) guarayana d'Orbigny, 1835 accepted as Monocondylaea guarayana (d'Orbigny, 1835) (basionym)
    » Species Unio (Monocondylaea) minuana d'Orbigny, 1835 accepted as Monocondylaea minuana (d'Orbigny, 1835) (basionym)
    » Species Unio (Monocondylaea) paraguayana d'Orbigny, 1835 accepted as Monocondylaea paraguayana (d'Orbigny, 1835) (basionym)
    » Species Unio (Monocondylaea) parchappii d'Orbigny, 1835 accepted as Monocondylaea parchappii (d'Orbigny, 1835) (basionym)
  » Subgenus Unio (Nephronaias) Crosse & P. Fischer, 1894 accepted as Nephronaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Nodularia) Conrad, 1853 accepted as Nodularia Conrad, 1853 (original rank)
    » Species Unio (Nodularia) caesariana Preston, 1913 accepted as Coelatura hypsiprymna (von Martens, 1897) (a junior synonym)
    » Species Unio (Nodularia) geayi Germain, 1911 accepted as Germainaia geayi (Germain, 1911) (basionym)
    » Species Unio (Nodularia) luapulaensis Preston, 1913 accepted as Coelatura luapulaensis (Preston, 1913) (original combination)
    » Species Unio (Nodularia) nyassanus accepted as Nyassunio nyassaensis (I. Lea, 1864) (misspelling)
  » Subgenus Unio (Obovaria) Rafinesque, 1819 accepted as Obovaria Rafinesque, 1819
  » Subgenus Unio (Pachynaias) Crosse & P. Fischer, 1894 accepted as Pachynaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Parreysia) Conrad, 1853 accepted as Parreysia Conrad, 1853 (original combination)
    » Species Unio (Parreysia) alluaudi Dautzenberg, 1908 accepted as Coelatura alluaudi (Dautzenberg, 1908) (original combination)
  » Subgenus Unio (Pleurobema) Rafinesque, 1819 accepted as Pleurobema Rafinesque, 1819 (original rank)
  » Subgenus Unio (Psoronaias) Crosse & P. Fischer, 1894 accepted as Psoronaias Crosse & P. Fischer, 1894 (original rank)
  » Subgenus Unio (Quadrula) Rafinesque, 1820 accepted as Quadrula Rafinesque, 1820
  » Subgenus Unio (Rhipidodonta) Mörch, 1853 accepted as Rhipidodonta Mörch, 1853 (original rank)
  » Subgenus Unio (Sayunio) accepted as Hemistena Rafinesque, 1820
  » Subgenus Unio (Sculptunio) Lindholm, 1932 † accepted as Sculptunio Lindholm, 1932 † (original rank)
  » Subgenus Unio (Simonaias) Crosse & P. Fischer, 1894 accepted as Nephronaias Crosse & P. Fischer, 1894 (a junior synonym)
  » Subgenus Unio (Sphenonaias) Crosse & P. Fischer, 1894 accepted as Sphenonaias Crosse & P. Fischer, 1894 (Original rank)
  » Subgenus Unio (Symphynota) accepted as Potamilus Rafinesque, 1818
  » Subgenus Unio (Theliderma) Swainson, 1840 accepted as Theliderma Swainson, 1840 (original rank)
  » Subgenus Unio (Toxolasma) Rafinesque, 1831 accepted as Toxolasma Rafinesque, 1831 (original rank)
  » Subgenus Unio (Truncilla) Rafinesque, 1819 accepted as Truncilla Rafinesque, 1819 (original rank)
  » Subgenus Unio (Tuberunio) Lindholm, 1932 † accepted as Tuberunio Lindholm, 1932 † (original rank)
  » Subgenus Unio (Uniomerus) Conrad, 1853 accepted as Uniomerus Conrad, 1853 (original rank)
    » Species Unio (Uniomerus) bisselianus (I. Lea, 1867) accepted as Uniomerus carolinianus (Bosc, 1801)
    » Species Unio (Uniomerus) bissellianus (I. Lea, 1867) accepted as Uniomerus carolinianus (Bosc, 1801) (incorrect subsequent spelling)
    » Species Unio (Uniomerus) columbensis (I. Lea, 1857) accepted as Uniomerus columbensis (I. Lea, 1857)
    » Species Unio (Uniomerus) obesus (I. Lea, 1831) accepted as Uniomerus carolinianus (Bosc, 1801)
    » Species Unio (Uniomerus) subluridus (Simpson, 1892) accepted as Elliptio jayensis (I. Lea, 1838)
    » Species Unio (Uniomerus) tetralasmus (Say, 1831) accepted as Uniomerus tetralasmus (Say, 1831)
  » Species Unio abacoides Haldeman, 1846 accepted as Dromus dromas (I. Lea, 1834)
  » Species Unio abacus Haldeman, 1842 accepted as Ptychobranchus fasciolaris (Rafinesque, 1820)
  » Species Unio abbevillensis I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786)
  » Species Unio abbreviatus Westerlund, 1897 accepted as Nodularia douglasiae (Gray, 1833) (invalid: junior homonym of Unio abbreviatus de Joannis, 1859)
  » Species Unio aberrans I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786)
  » Species Unio aberti Conrad, 1850 accepted as Cyprogenia aberti (Conrad, 1850)
  » Species Unio ablatus (I. Lea, 1863) accepted as Elliptio icterina (Conrad, 1834) (incorrect original spelling)
  » Species Unio abruptus Say, 1831 accepted as Lampsilis abrupta (Say, 1831)
  » Species Unio acrorrhynchus von Martens, 1894 accepted as Lanceolaria acrorrhyncha (von Martens, 1894) (basionym)
  » Species Unio acuens I. Lea, 1871 accepted as Pleurobema oviforme (Conrad, 1834)
  » Species Unio acuminatus H. Adams, 1866 accepted as Nitia acuminata (H. Adams, 1866) (basionym)
  » Species Unio acutissimus I. Lea, 1831 accepted as Medionidus acutissimus (I. Lea, 1831) (original combination)
  » Species Unio aegyptiacus Cailliaud, 1827 accepted as Coelatura aegyptiaca (Cailliaud, 1827) (original combination)
  » Species Unio aequatorius Morelet, 1885 accepted as Coelatura gabonensis (Küster, 1862) (junior synonym)
  » Species Unio aequatus I. Lea, 1857 accepted as Elliptio icterina (Conrad, 1834)
  » Species Unio aeruginosus Morelet, 1849 accepted as Nephronaias aeruginosa (Morelet, 1849)
  » Species Unio aesopus Green, 1827 accepted as Plethobasus cyphyus (Rafinesque, 1820)
  » Species Unio aethiops I. Lea, 1860 accepted as Diplodon aethiops (I. Lea, 1860) (basionym)
  » Species Unio affinis I. Lea, 1852 accepted as Lampsilis straminea (Conrad, 1834)
  » Species Unio africanus I. Lea, 1856 accepted as Unio caffer F. Krauss, 1848 (junior synonym)
  » Species Unio aheneus I. Lea, 1843 accepted as Elliptio ahenea (I. Lea, 1843) (original combination)
  » Species Unio alabamensis Conrad, 1834 accepted as Potamilus inflatus (I. Lea, 1831)
  » Species Unio alatus Say, 1817 accepted as Potamilus alatus (Say, 1817)
  » Species Unio alienigenus Crosse & P. Fischer, 1893 accepted as Cyrtonaias umbrosa (I. Lea, 1856)
  » Species Unio altilis Conrad, 1834 accepted as Hamiota altilis (Conrad, 1834)
  » Species Unio altus Conrad, 1854 accepted as Pleurobema altum (Conrad, 1854)
  » Species Unio amabilis I. Lea, 1865 accepted as Pleurobema pyriforme (I. Lea, 1857)
  » Species Unio ambiguus Philippi, 1847 accepted as Velesunio ambiguus (Philippi, 1847) (original combination)
  » Species Unio amoenus I. Lea, 1840 accepted as Villosa iris (I. Lea, 1829) (synonym)
  » Species Unio amplus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786)
  » Species Unio ampullaceus I. Lea, 1866 accepted as Diplodon uruguayensis (I. Lea, 1860) (a junior synonym)
  » Species Unio amygdalum I. Lea, 1843 accepted as Villosa amygdalum (I. Lea, 1843) (original combination)
  » Species Unio anaticulus I. Lea, 1861 accepted as Pleurobema decisum (I. Lea, 1831)
  » Species Unio andersonensis I. Lea, 1872 accepted as Fusconaia cor (Conrad, 1834)
  » Species Unio andersoniana G. Nevill, 1877 accepted as Indonaia andersoniana (G. Nevill, 1877) (original combination)
  » Species Unio angasi G. B. Sowerby II, 1867 accepted as Velesunio angasi (G. B. Sowerby II, 1867) (original combination)
  » Species Unio angoniensis Preston, 1910 accepted as Coelatura hypsiprymna (von Martens, 1897) (junior synonym)
  » Species Unio angustatus I. Lea, 1831 accepted as Elliptio angustata (I. Lea, 1831) (original combination)
  » Species Unio anodontoides I. Lea, 1831 accepted as Lampsilis teres (Rafinesque, 1820)
  » Species Unio anthonyi I. Lea, 1861 accepted as Elliptio monroensis (I. Lea, 1843)
  » Species Unio apicinus I. Lea, 1857 accepted as Villosa lienosa (Conrad, 1834) (synonym)
  » Species Unio apiculatus Say, 1829 accepted as Quadrula apiculata (Say, 1829)
  » Species Unio appressus I. Lea, 1871 accepted as Fusconaia cuneolus (I. Lea, 1840)
  » Species Unio approximus I. Lea, 1845 accepted as Lampsilis hydiana (I. Lea, 1838)
  » Species Unio aquilus I. Lea, 1857 accepted as Elliptio pullata (I. Lea, 1857)
  » Species Unio aratus Conrad, 1849 accepted as Elliptoideus sloatianus (I. Lea, 1840)
  » Species Unio aratus I. Lea, 1843 accepted as Micronaias arata (I. Lea, 1843) (original combination)
  » Species Unio arcaeformis I. Lea, 1831 accepted as Epioblasma arcaeformis (I. Lea, 1831) (original combination)
  » Species Unio arctatus Conrad, 1834 accepted as Elliptio arctata (Conrad, 1834)
  » Species Unio arctior I. Lea, 1838 accepted as Eurynia dilatata (Rafinesque, 1820)
  » Species Unio arcus Conrad, 1834 accepted as Elliptio arca (Conrad, 1834)
  » Species Unio argenteus I. Lea, 1841 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio arkansasensis I. Lea, 1862 accepted as Obovaria arkansasensis (I. Lea, 1862) (unaccepted)
  » Species Unio arquatus Conrad, 1854 accepted as Ligumia recta (Lamarck, 1819) (unaccepted)
  » Species Unio ascia Hanley, 1856 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio askewi Marsh, 1896 accepted as Fusconaia askewi (Marsh, 1896) (unaccepted)
  » Species Unio asper I. Lea, 1831 accepted as Quadrula apiculata (Say, 1829) (unaccepted)
  » Species Unio asperatus I. Lea, 1861 accepted as Rotundaria asperata (I. Lea, 1861) (unaccepted)
  » Species Unio asperrimus I. Lea, 1831 accepted as Quadrula quadrula (Rafinesque, 1820) (unaccepted)
  » Species Unio asperulus I. Lea, 1866 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio ater Nilsson, 1822 accepted as Unio crassus Philipsson, 1788 (unaccepted)
  » Species Unio ater I. Lea, 1829 accepted as Potamilus purpuratus (Lamarck, 1819) (unaccepted)
  » Species Unio athesinus Adami, 1886 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio athleta Lindholm, 1932 † accepted as Betekeia athleta (Lindholm, 1932) † (unaccepted, original combination)
    » Subspecies Unio athleta praeruptus Lindholm, 1932 † accepted as Betekeia athleta (Lindholm, 1932) † (a junior synonym)
  » Species Unio atrata Swainson, 1823 accepted as Leptodea fragilis (Rafinesque, 1820) (unaccepted)
  » Species Unio atrocostatus I. Lea, 1845 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio atromarginatus I. Lea, 1840 accepted as Elliptoideus sloatianus (I. Lea, 1840) (unaccepted)
  » Species Unio attenuatus I. Lea, 1872 accepted as Elliptio folliculata (I. Lea, 1838) (unaccepted)
  » Species Unio aucklandicus Gray, 1843 accepted as Echyridella aucklandica (Gray, 1843) (unaccepted)
  » Species Unio aureus I. Lea, 1859 accepted as Rotundaria aurea (I. Lea, 1859) (unaccepted)
  » Species Unio auricularius Spengler, 1793 accepted as Pseudunio auricularius (Spengler, 1793) (unaccepted, original combination)
  » Species Unio auroreus Heude, 1883 accepted as Diaurora aurorea (Heude, 1883) (unaccepted, original combination)
  » Species Unio australis Lamarck, 1819 accepted as Hyridella australis (Lamarck, 1819) (unaccepted, original combination)
  » Species Unio averellii Wright, B.H., 1888 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio aztecorum Philippi, 1847 accepted as Nephronaias aztecorum (Philippi, 1847) (unaccepted, original combination)
  » Species Unio bairdianus I. Lea, 1857 accepted as Toxolasma texasiense (I. Lea, 1857) (unaccepted)
  » Species Unio bakeri H. Adams, 1866 accepted as Coelatura bakeri (H. Adams, 1866) (unaccepted, original combination)
  » Species Unio baldwinensis I. Lea, 1859 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio balonnensis Conrad, 1850 accepted as Velesunio ambiguus (Philippi, 1847) (unaccepted, junior synonym)
  » Species Unio barnesianus I. Lea, 1838 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio barrattii I. Lea, 1852 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio barrotti Küster, 1861 accepted as Elliptio producta (Conrad, 1836) (unaccepted)
  » Species Unio basalis I. Lea, 1872 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio bazini Heude, 1877 accepted as Lamprotula bazini (Heude, 1877) (unaccepted, basionym)
  » Species Unio beadleianus I. Lea, 1861 accepted as Pleurobema beadleianum (I. Lea, 1861) (unaccepted)
  » Species Unio bealei I. Lea, 1862 accepted as Toxolasma texasiense (I. Lea, 1857) (unaccepted)
  » Species Unio beaverensis I. Lea, 1868 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio bednalli Tate, 1882 accepted as Velesunio angasi (G. B. Sowerby II, 1867) (unaccepted, junior synonym)
  » Species Unio bellulus I. Lea, 1872 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio benacinus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio bengalensis I. Lea, 1838 accepted as Simpsonella purpurea (Valenciennes, 1827) (unaccepted)
  » Species Unio berlandieri I. Lea, 1857 accepted as Unio berlandierii I. Lea, 1857 (unaccepted, incorrect spelling)
  » Species Unio berlandierii I. Lea, 1857 accepted as Cyrtonaias tampicoensis (I. Lea, 1838) (unaccepted)
  » Species Unio besckeanus Dunker, 1848 accepted as Diplodon ellipticus Spix, 1827 (unaccepted)
  » Species Unio betekeiensis Lindholm, 1932 † accepted as Sibirunio betekeiensis (Lindholm, 1932) † (unaccepted, original combination)
  » Species Unio bhamoensis Theobald, 1873 accepted as Leoparreysia bhamoensis (Theobald, 1873) (unaccepted, original combination)
  » Species Unio biangularis I. Lea, 1840 accepted as Ortmanniana pectorosa (Conrad, 1834) (unaccepted)
  » Species Unio biangulatus I. Lea, 1842 accepted as Ortmanniana pectorosa (Conrad, 1834) (unaccepted, synonym; an emendation of Unio biangularis I. Lea, 1840))
  » Species Unio bicaelatus Reeve, 1865 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio biemarginatus I. Lea, 1857 accepted as Epioblasma biemarginata (I. Lea, 1857) (unaccepted)
  » Species Unio biesianus Heude, 1877 accepted as Pseudobaphia biesiana (Heude, 1877) (unaccepted, original combination)
  » Species Unio bigbyensis I. Lea, 1841 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio binneyi I. Lea, 1845 accepted as Diplodon rhuacoicus (d'Orbigny, 1835) (unaccepted, junior synonym)
  » Species Unio bisselianus I. Lea, 1867 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio bituberculosus von Martens, 1874 † accepted as Sculptunio bituberculosus (von Martens, 1874) † (unaccepted)
  » Species Unio blandianus I. Lea, 1857 accepted as Quadrula rumphiana (I. Lea, 1852) (unaccepted)
  » Species Unio blandingianus I. Lea, 1834 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio bollii Call, 1881 accepted as Rotundaria petrina (Gould, 1855) (unaccepted)
  » Species Unio bonellii Férussac, 1827 accepted as Microcondylaea bonellii (Férussac, 1827) (unaccepted, original combination)
  » Species Unio bonneaudii Eydoux, 1838 accepted as Radiatula bonneaudii (Eydoux, 1838) (unaccepted, basionym)
  » Species Unio borealis Gray, 1882 accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio borneeensis Issel, 1874 accepted as Ctenodesma borneensis (Issel, 1874) (unaccepted, basionym)
  » Species Unio bourguignatianus Adami, 1886 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted, invalid: junior homonym of Unio bourguignatianus I. Lea, 1863; U. magistri is a replacement name)
  » Species Unio bournianus I. Lea, 1840 accepted as Pleurobema clava (Lamarck, 1819) (unaccepted)
  » Species Unio boydianus I. Lea, 1840 accepted as Leptodea ochracea (Say, 1817) (unaccepted)
  » Species Unio boykinianus I. Lea, 1840 accepted as Megalonaias nervosa (Rafinesque, 1820) (unaccepted)
  » Species Unio brachyrhynchus Drouët, 1881 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio bracteatus Gould, 1855 accepted as Lampsilis bracteata (Gould, 1855) (unaccepted)
  » Species Unio brandtii Kobelt, 1879 accepted as Inversidens brandtii (Kobelt, 1879) (unaccepted, basionym)
  » Species Unio brazoensis I. Lea, 1868 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio brazosensis I. Lea, 1868 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio breviculus Call, 1887 accepted as Lampsilis reeveiana (I. Lea, 1852) (unaccepted)
  » Species Unio brevidens I. Lea, 1831 accepted as Epioblasma brevidens (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio breviplicatus Noulet, 1864 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio brevis I. Lea, 1872 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio brianteus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio briarti Dautzenberg, 1901 accepted as Coelatura briarti (Dautzenberg, 1901) (unaccepted, original combination)
  » Species Unio brimleyi Wright, S.H., 1897 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio broti Deshayes, 1876 accepted as Unionetta fabagina (Deshayes, 1876) (unaccepted)
  » Species Unio brownianus I. Lea, 1838 accepted as Paxyodon syrmatophorus (Gmelin, 1791) (unaccepted)
  » Species Unio brownii I. Lea, 1856 accepted as Diplodon delodontus (Lamarck, 1819) (unaccepted, junior synonym)
  » Species Unio brumbyanus I. Lea, 1841 accepted as Ptychobranchus greenii (Conrad, 1834) (unaccepted)
  » Species Unio brumleyanus I. Lea, 1841 accepted as Unio brumbyanus I. Lea, 1841 (unaccepted, incorrect original spelling)
  » Species Unio buckleyi I. Lea, 1843 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio buddianus I. Lea, 1843 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio bulbosus I. Lea, 1857 accepted as Pleurobema pyriforme (I. Lea, 1857) (unaccepted)
  » Species Unio burkensis I. Lea, 1859 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio burmanus Blanford, 1869 accepted as Leoparreysia burmana (Blanford, 1869) (unaccepted, original combination)
  » Species Unio burroughianus I. Lea, 1834 accepted as Rhipidodonta burroughiana (I. Lea, 1834) (unaccepted, basionym)
  » Species Unio bursapastoris Wright, B.H., 1896 accepted as Fusconaia subrotunda (I. Lea, 1831) (unaccepted)
  » Species Unio burtchianus Wright, S.H., 1897 accepted as Elliptio occulta (I. Lea, 1843) (unaccepted)
  » Species Unio burtoni Woodward, 1859 accepted as Grandidieria burtoni (Woodward, 1859) (unaccepted, original combination)
  » Species Unio buxeus I. Lea, 1852 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio buxtoni Wright, B.H., 1897 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio cacao I. Lea, 1859 accepted as Rotundaria succissa (I. Lea, 1852) (unaccepted)
  » Species Unio caelatus Conrad, 1834 accepted as Lemiox rimosus (Rafinesque, 1831) (unaccepted)
  » Species Unio caeruleus I. Lea, 1831 accepted as Indonaia caerulea (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio cahabensis I. Lea, 1871 accepted as Rotundaria asperata (I. Lea, 1861) (unaccepted)
  » Species Unio caipira Ihering, 1893 accepted as Diplodon caipira (Ihering, 1893) (unaccepted, basionym)
  » Species Unio calamitarum Morelet, 1849 accepted as Nephronaias calamitarum (Morelet, 1849) (unaccepted, basionym)
  » Species Unio calceolus I. Lea, 1827 accepted as Alasmidonta viridis (Rafinesque, 1820) (unaccepted)
  » Species Unio caldwellii I. Lea, 1858 accepted as Barynaias caldwellii (I. Lea, 1858) (unaccepted, basionym)
  » Species Unio caliginosus I. Lea, 1845 accepted as Leaunio lienosus caliginosus (Lea, 1845) (unaccepted, original combination)
  » Species Unio callosus I. Lea, 1841 accepted as Sphenonaias callosa (I. Lea, 1841) (unaccepted, basionym)
  » Species Unio cambodiensis I. Lea, 1856 accepted as Physunio cambodiensis (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio cambojensis Sowerby, 1866 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio camelopardilis I. Lea, 1860 accepted as Villosa taeniata (Conrad, 1834) (unaccepted, synonym)
  » Species Unio camelus I. Lea, 1834 accepted as Ptychobranchus fasciolaris (Rafinesque, 1820) (unaccepted)
  » Species Unio camptodon Say, 1832 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio canadensis I. Lea, 1857 accepted as Lampsilis cardium Rafinesque, 1820 (unaccepted)
  » Species Unio capax Green, 1832 accepted as Potamilus capax (Green, 1832) (unaccepted)
  » Species Unio caperatus I. Lea, 1845 accepted as Dromus dromas (I. Lea, 1834) (unaccepted)
  » Species Unio capillaris I. Lea, 1834 accepted as Epioblasma personata (Say, 1829) (unaccepted)
  » Species Unio capillus Say, 1831 accepted as Paetulunio fabalis (I. Lea, 1831) (unaccepted, synonym)
  » Species Unio capitatus Heude, 1874 accepted as Cuneopsis capitatus (Heude, 1874) (unaccepted, basionym)
  » Species Unio capsaeformis I. Lea, 1834 accepted as Epioblasma capsaeformis (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio carbonarius I. Lea, 1838 accepted as Barynaias plexus (Conrad, 1838) (unaccepted)
  » Species Unio cardiacea Guerin, 1823 accepted as Pleurobema rubrum (Rafinesque, 1820) (unaccepted)
  » Species Unio carinatus Barnes, 1823 accepted as Ortmanniana ligamentina (Lamarck, 1819) (unaccepted)
  » Species Unio carinifera Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio cariosus Say, 1817 accepted as Lampsilis cariosa (Say, 1817) (unaccepted, original combination)
  » Species Unio caroliniana Bosc, 1801 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio castaneus I. Lea, 1831 accepted as Obovaria arkansasensis (I. Lea, 1862) (unaccepted)
  » Species Unio castus I. Lea, 1860 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio catawbensis I. Lea, 1862 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio catillus Conrad, 1836 accepted as Pleurobema sintoxia (Rafinesque, 1820) (unaccepted)
  » Species Unio caudiculatus von Martens, 1867 accepted as Caudiculatus caudiculatus (von Martens, 1867) (unaccepted, original combination)
  » Species Unio caveatus Heude, 1877 accepted as Lamprotula caveata (Heude, 1877) (unaccepted, basionym)
  » Species Unio celtiformis Heude, 1874 accepted as Cuneopsis celtiformis (Heude, 1874) (unaccepted, basionym)
  » Species Unio ceratinus Drouët, 1879 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio cerinus Conrad, 1838 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio charlottensis I. Lea, 1863 accepted as Lasmigona decorata (I. Lea, 1852) (unaccepted)
  » Species Unio charon Preston, 1910 accepted as Unio caffer F. Krauss, 1848 (unaccepted, junior synonym)
  » Species Unio charruana d'Orbigny, 1835 accepted as Rhipidodonta charruana (d'Orbigny, 1835) (unaccepted, basionym)
  » Species Unio chathamensis I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio chattanoogaensis I. Lea, 1858 accepted as Pleurobema decisum (I. Lea, 1831) (unaccepted)
  » Species Unio chickasawhensis I. Lea, 1861 accepted as Pleurobema beadleianum (I. Lea, 1861) (unaccepted)
  » Species Unio childreni Gray in Griffith & Pidgeon, 1833 accepted as Diplodon chilensis (Gray, 1828) (unaccepted, junior synonym)
  » Species Unio chilensis Gray, 1828 accepted as Diplodon chilensis (Gray, 1828) (unaccepted, original combination)
  » Species Unio chinensis Lea, 1868 accepted as Acuticosta chinensis (I. Lea, 1868) (unaccepted, original combination)
  » Species Unio chipolaensis Walker, 1905 accepted as Elliptio chipolaensis (Walker, 1905) (unaccepted)
  » Species Unio choziensis Preston, 1910 accepted as Coelatura choziensis (Preston, 1910) (unaccepted, original combination)
  » Species Unio chunii I. Lea, 1862 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio cicatricoides Frierson, 1911 accepted as Plethobasus cicatricosus (Say, 1829) (unaccepted)
  » Species Unio cicatricosus Say, 1829 accepted as Plethobasus cicatricosus (Say, 1829) (unaccepted)
  » Species Unio cicur I. Lea, 1861 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio cilindricus Say, 1817 accepted as Unio cylindricus Say, 1817 (unaccepted, incorrect subsequent spelling)
  » Species Unio cincinnatiensis I. Lea, 1840 accepted as Epioblasma cincinnatiensis (I. Lea, 1840) (unaccepted)
  » Species Unio cinnamomicus I. Lea, 1861 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio circulus I. Lea, 1829 accepted as Obovaria subrotunda (Rafinesque, 1820) (unaccepted)
  » Species Unio circumactus I. Lea, 1871 accepted as Pleuronaia dolabelloides (I. Lea, 1840) (unaccepted)
  » Species Unio cirratus I. Lea, 1874 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio cistellaeformis I. Lea, 1863 accepted as Elliptio cistellaeformis (I. Lea, 1863) (unaccepted)
  » Species Unio claibornensis I. Lea, 1838 accepted as Lampsilis straminea (Conrad, 1834) (unaccepted)
  » Species Unio clarkianus I. Lea, 1852 accepted as Hamiota altilis (Conrad, 1834) (unaccepted)
  » Species Unio clava Lamarck, 1819 accepted as Pleurobema clava (Lamarck, 1819) (unaccepted)
  » Species Unio clinchensis I. Lea, 1867 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio coarctata Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio coccineus Conrad, 1836 accepted as Pleurobema sintoxia (Rafinesque, 1820) (unaccepted)
  » Species Unio coccineus I. Lea, 1838 accepted as Pleurobema sintoxia (Rafinesque, 1820) (unaccepted)
  » Species Unio cocoduensis Reeve, 1865 accepted as Ligumia subrostrata (Say, 1831) (unaccepted, synonym)
  » Species Unio coelatus Conrad, 1834 accepted as Lemiox rimosus (Rafinesque, 1831) (unaccepted)
  » Species Unio cognatus I. Lea, 1860 accepted as Truncilla cognata (I. Lea, 1860) (unaccepted)
  » Species Unio collinus Conrad, 1837 accepted as Parvaspina collina (Conrad, 1837) (unaccepted, original combination)
  » Species Unio coloradoensis I. Lea, 1856 accepted as Potamilus purpuratus (Lamarck, 1819) (unaccepted)
  » Species Unio coloratus Küster, 1856 accepted as Sphenonaias colorata (Küster, 1856) (unaccepted, basionym)
  » Species Unio columbensis I. Lea, 1857 accepted as Uniomerus columbensis (I. Lea, 1857) (unaccepted)
  » Species Unio compactus I. Lea, 1859 accepted as Epioblasma metastriata (Conrad, 1838) (unaccepted)
  » Species Unio compertus Frierson, 1911 accepted as Plethobasus cyphyus (Rafinesque, 1820) (unaccepted)
  » Species Unio complanatus (Lightfoot, 1786) accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio compressa (I. Lea, 1830) accepted as Lasmigona compressa (I. Lea, 1829) (unaccepted)
  » Species Unio compressissimus I. Lea, 1845 accepted as Ptychobranchus fasciolaris (Rafinesque, 1820) (unaccepted)
  » Species Unio compressus Rafinesque, 1831 accepted as Ellipsaria lineolata (Rafinesque, 1820) (unaccepted)
  » Species Unio comptus Deshayes & Jullien, 1876 accepted as Contradens comptus (Deshayes & Jullien, 1874) (unaccepted, basionym)
  » Species Unio computatus Crosse & P. Fischer, 1893 accepted as Actinonaias computata (Crosse & P. Fischer, 1893) (unaccepted, basionym)
  » Species Unio conasaugaensis I. Lea, 1872 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio concavus I. Lea, 1852 accepted as Villosa delumbis (Conrad, 1834) (unaccepted, synonym)
  » Species Unio concestator I. Lea, 1857 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio concolor I. Lea, 1861 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio confertus I. Lea, 1834 accepted as Elliptio raveneli (Conrad, 1834) (unaccepted)
  » Species Unio congaraeus I. Lea, 1831 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio congareus I. Lea, 1831 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted, incorrect spelling)
  » Species Unio conjugans Wright, B.H., 1899 accepted as Tritogonia verrucosa (Rafinesque, 1820) (unaccepted)
  » Species Unio conradicus I. Lea, 1834 accepted as Medionidus conradicus (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio consanguineus I. Lea, 1861 accepted as Pleurobema decisum (I. Lea, 1831) (unaccepted)
  » Species Unio conspicuus I. Lea, 1872 accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio contiguus I. Lea, 1862 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio contortus (I. Lea, 1857) accepted as Lanceolaria lanceolata (I. Lea, 1856) (unaccepted, junior synonym)
  » Species Unio contractus I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio contradens I. Lea, 1838 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, original name)
  » Species Unio contrarius Conrad, 1849 accepted as Lampsilis straminea (Conrad, 1834) (unaccepted)
  » Species Unio conus Spengler, 1793 accepted as Unio tumidus Philipsson, 1788 (unaccepted)
  » Species Unio cooperianus I. Lea, 1834 accepted as Plethobasus cooperianus (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio copei I. Lea, 1868 accepted as Villosa vanuxemensis (I. Lea, 1838) (unaccepted)
  » Species Unio cor Conrad, 1834 accepted as Fusconaia cor (Conrad, 1834) (unaccepted)
  » Species Unio corbis Hanley, 1856 accepted as Parreysia corbis (Hanley, 1856) (unaccepted)
  » Species Unio coreanus von Martens, 1886 accepted as Aculamprotula coreana (Martens, 1886) (unaccepted, basionym)
  » Species Unio coriaceus Dunker, 1848 accepted as Diplodon multistriatus (I. Lea, 1831) (unaccepted)
  » Species Unio corneus I. Lea, 1874 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio cornutus Barnes, 1823 accepted as Obliquaria reflexa Rafinesque, 1820 (unaccepted)
  » Species Unio cornuumlunae Heude, 1883 accepted as Lamprotula cornuumlunae (Heude, 1883) (unaccepted, basionym)
  » Species Unio corrianus I. Lea, 1834 accepted as Lamellidens corrianus (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio corrosus A. Villa & J. B. Villa, 1841 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio coruscus Gould, 1856 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio corvinus I. Lea, 1868 accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted)
  » Species Unio corvunculus I. Lea, 1868 accepted as Toxolasma corvunculus (I. Lea, 1868) (unaccepted)
  » Species Unio corvus I. Lea, 1859 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio costatus Goldfuss, 1837 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio couchianus I. Lea, 1860 accepted as Quadrula couchiana (I. Lea, 1860) (unaccepted, original combination)
  » Species Unio crapulus I. Lea, 1861 accepted as Pleurobema fibuloides (I. Lea, 1859) (unaccepted)
  » Species Unio crassidens Lamarck, 1819 accepted as Elliptio crassidens (Lamarck, 1819) (unaccepted)
  » Species Unio crassus Say, 1817 accepted as Ortmanniana ligamentina (Lamarck, 1819) (unaccepted, invalid: junior homonym of Unio crassus Philipsson, 1788)
  » Species Unio crebrivittatus I. Lea, 1861 accepted as Pleurobema decisum (I. Lea, 1831) (unaccepted)
  » Species Unio creperus I. Lea, 1838 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio crispisulcatus Benson, 1862 accepted as Radiatula crispisulcata (Benson, 1862) (unaccepted, original combination)
  » Species Unio cristophori Adami, 1886 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio crocatus I. Lea, 1841 accepted as Leptodea ochracea (Say, 1817) (unaccepted)
  » Species Unio crocodilorum Morelet, 1849 accepted as Psoronaias semigranosa (Philippi, 1843) (unaccepted, a junior synonym)
  » Species Unio cromwellii I. Lea, 1865 accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted)
  » Species Unio crossei Deshayes, 1876 accepted as Contradens crossei (Deshayes, 1876) (unaccepted, original combination)
  » Species Unio crudus I. Lea, 1871 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio cucumoides I. Lea, 1840 accepted as Cucumerunio novaehollandiae (Gray, 1834) (unaccepted, junior synonym)
  » Species Unio cultelliformis Conrad, 1850 accepted as Hyridella depressa (Lamarck, 1819) (unaccepted, junior synonym)
  » Species Unio cultratus Rafinesque, 1831 accepted as Eurynia dilatata (Rafinesque, 1820) (unaccepted)
  » Species Unio cumberlandicus I. Lea, 1838 accepted as Cambarunio simus (Lea, I., 1838) (unaccepted, synonym)
  » Species Unio cumingianus Dunker, 1852 accepted as Cucumerunio novaehollandiae (Gray, 1834) (unaccepted, junior synonym)
  » Species Unio cumingii I. Lea, 1852 accepted as Sinohyriopsis cumingii (I. Lea, 1852) (unaccepted, original combination)
  » Species Unio cuneatus Swainson, 1823 accepted as Epioblasma triquetra (Rafinesque, 1820) (unaccepted)
  » Species Unio cuneatus Barnes, 1823 accepted as Elliptio crassidens (Lamarck, 1819) (unaccepted)
  » Species Unio cuneolus I. Lea, 1840 accepted as Fusconaia cuneolus (I. Lea, 1840) (unaccepted, original combination)
  » Species Unio cuneus Conrad, 1838 accepted as Pleurobema sintoxia (Rafinesque, 1820) (unaccepted)
  » Species Unio cunninghami Wright, B.H., 1883 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio cuprinus I. Lea, 1831 accepted as Popenaias metallica (Say, 1831) (unaccepted)
  » Species Unio curatus I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio curtus I. Lea, 1859 accepted as Pleurobema curtum (I. Lea, 1859) (unaccepted)
  » Species Unio curvatus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio cusianus Pini, 1885 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio cuspidatus I. Lea, 1872 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio cuvierianus I. Lea, 1852 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio cylindrellus I. Lea, 1868 accepted as Toxolasma cylindrellus (I. Lea, 1868) (unaccepted)
  » Species Unio cylindricus Say, 1817 accepted as Theliderma cylindrica (Say, 1817) (unaccepted, original combination)
  » Species Unio cyphia (Rafinesque, 1820) accepted as Plethobasus cyphyus (Rafinesque, 1820) (unaccepted)
  » Species Unio cyrenoides Philippi, 1847 accepted as Arotonaias cyrenoides (Philippi, 1847) (unaccepted, basionym)
  » Species Unio dactylus I. Lea, 1840 accepted as Cambarunio dactylus dactylus (Lea, I., 1840) (unaccepted)
  » Species Unio dahuricus Middendorff, 1850 accepted as Margaritifera dahurica (Middendorff, 1850) (unaccepted, original combination)
  » Species Unio dalli Wright, B.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio dalmaticus Drouët, 1879 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio danelli Villa, 1871 accepted as Velesunio ambiguus (Philippi, 1847) (unaccepted, junior synonym)
  » Species Unio danielsii Wright, B.H., 1899 accepted as Elliptio crassidens (Lamarck, 1819) (unaccepted)
  » Species Unio dariensis I. Lea, 1842 accepted as Elliptio dariensis (I. Lea, 1842) (unaccepted, original combination)
  » Species Unio datus I. Lea, 1868 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio dautzenbergi Morlet, 1889 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio decipiens Drouët, 1881 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio decisus I. Lea, 1831 accepted as Pleurobema decisum (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio declivis Say, 1831 accepted as Uniomerus declivis (Say, 1831) (unaccepted)
  » Species Unio decoratus I. Lea, 1852 accepted as Lasmigona decorata (I. Lea, 1852) (unaccepted)
  » Species Unio decumbens I. Lea, 1861 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio dehiscens Say, 1829 accepted as Hemistena lata (Rafinesque, 1820) (unaccepted)
  » Species Unio delesserti Bourguignat, 1852 accepted as Potomida semirugata (Lamarck, 1819) (unaccepted)
  » Species Unio delodonta Lamarck, 1819 accepted as Diplodon delodontus (Lamarck, 1819) (unaccepted, basionym)
  » Species Unio delphinulus Morelet, 1849 accepted as Delphinonaias delphinula (Morelet, 1849) (unaccepted, original combination)
  » Species Unio delpretei Bourguignat, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio delumbis Conrad, 1834 accepted as Villosa delumbis (Conrad, 1834) (unaccepted, original combination)
  » Species Unio depressa Lamarck, 1819 accepted as Hyridella depressa (Lamarck, 1819) (unaccepted, original combination)
  » Species Unio depressus Reeve, 1864 accepted as Velesunio moretonicus (Reeve, 1865) (unaccepted, Invalid: junior homonym of Unio depressus Lamarck, 1819)
  » Species Unio depygis Conrad, 1866 accepted as Obovaria subrotunda (Rafinesque, 1820) (unaccepted)
  » Species Unio detectus Frierson, 1911 accepted as Plethobasus cicatricosus (Say, 1829) (unaccepted)
  » Species Unio deviatus Reeve, 1864 accepted as Epioblasma turgidula (I. Lea, 1858) (unaccepted)
  » Species Unio diazensis Wright, S.H., 1897 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio diespiter Mabille, 1887 accepted as Nodularia diespiter (Mabille, 1887) (unaccepted, original combination)
  » Species Unio differtus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio difficilis I. Lea, 1868 accepted as Villosa nebulosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio dimotus I. Lea, 1870 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio directus Drouët, 1896 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio discrepans I. Lea, 1860 accepted as Cambarunio nebulosus (Conrad, 1834) (unaccepted, synonym)
  » Species Unio discus I. Lea, 1838 accepted as Disconaias discus (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio dispalans Wright, B.H., 1899 accepted as Elliptio occulta (I. Lea, 1843) (unaccepted)
  » Species Unio dispansus I. Lea, 1871 accepted as Leaunio vanuxemensis (I. Lea, 1838) (unaccepted, synonym)
  » Species Unio dispar I. Lea, 1860 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio dissimilis I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio distans J. G. Anthony, 1865 accepted as Lampsilis siliquoidea (Barnes, 1823) (unaccepted)
  » Species Unio distinctus Crosse & P. Fischer, 1893 accepted as Psoronaias distincta (Crosse & P. Fischer, 1893) (unaccepted, basionym)
  » Species Unio distinguendus Lindholm, 1932 † accepted as Nodularia distinguenda (LIndholm, 1932) † (unaccepted, basionym)
  » Species Unio divaricatus I. Lea, 1834 accepted as Diplodon delodontus (Lamarck, 1819) (unaccepted)
  » Species Unio diversus Conrad, 1856 accepted as Alasmidonta viridis (Rafinesque, 1820) (unaccepted)
  » Species Unio dolabelloides I. Lea, 1840 accepted as Pleuronaia dolabelloides (I. Lea, 1840) (unaccepted, original combination)
  » Species Unio dolabraeformis I. Lea, 1838 accepted as Lampsilis dolabraeformis (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio doliaris I. Lea, 1865 accepted as Hamiota altilis (Conrad, 1834) (unaccepted)
  » Species Unio dolichorhynchus Tapparone Canefri, 1889 accepted as Trapezidens obesa (Hanley & Theobald, 1876) (unaccepted)
  » Species Unio dolosus I. Lea, 1860 accepted as Potamilus purpuratus (Lamarck, 1819) (unaccepted)
  » Species Unio dombeyana Valenciennes, 1827 accepted as Plectomerus dombeyanus (Valenciennes, 1827) (unaccepted)
  » Species Unio donaciformis I. Lea, 1827 accepted as Truncilla donaciformis (I. Lea, 1827) (unaccepted, original combination)
  » Species Unio donacopsis de Gregorio, 1914 accepted as Villosa fabalis (I. Lea, 1831) (unaccepted, synonym)
  » Species Unio dooleyensis I. Lea, 1874 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio dorei Wright, B.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio dorfeuillianus I. Lea, 1838 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio dorri Wattebled, 1886 accepted as Nodularia dorri (Wattebled, 1886) (unaccepted, original combination)
  » Species Unio dorsatus I. Lea, 1868 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio dorsuosus Gould, 1850 accepted as Hyridella australis (Lamarck, 1819) (unaccepted, junior synonym)
  » Species Unio douglasiae Gray, 1833 accepted as Nodularia douglasiae (Gray, 1833) (unaccepted, original combination)
  » Species Unio downiei I. Lea, 1858 accepted as Elliptio downiei (I. Lea, 1858) (unaccepted)
  » Species Unio dromas I. Lea, 1834 accepted as Dromus dromas (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio duclerci Rochebrune, 1882 accepted as Chamberlainia hainesiana (I. Lea, 1856) (unaccepted, junior synonym)
  » Species Unio dunkerianus I. Lea, 1856 accepted as Diplodon ellipticus Spix, 1827 (unaccepted)
  » Species Unio duttonianus I. Lea, 1841 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio dysonii I. Lea, 1859 accepted as Nephronaias dysonii (I. Lea, 1859) (unaccepted, basionym)
  » Species Unio ebenus I. Lea, 1831 accepted as Reginaia ebenus (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio edentulus (Say, 1829) accepted as Strophitus undulatus (Say, 1817) (unaccepted)
  » Species Unio edgarianus I. Lea, 1840 accepted as Fusconaia cor (Conrad, 1834) (unaccepted)
  » Species Unio effulgens I. Lea, 1856 accepted as Diplodon multistriatus (I. Lea, 1831) (unaccepted, junior synonym)
  » Species Unio eightsii I. Lea, 1860 accepted as Megalonaias nervosa (Rafinesque, 1820) (unaccepted)
  » Species Unio electrinus Reeve, 1865 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio elegans I. Lea, 1831 accepted as Truncilla truncata Rafinesque, 1820 (unaccepted)
  » Species Unio elliottii I. Lea, 1857 accepted as Amblema elliottii (I. Lea, 1857) (unaccepted, original combination)
  » Species Unio ellipsiformis Conrad, 1836 accepted as Venustaconcha ellipsiformis (Conrad, 1836) (unaccepted, original combination)
  » Species Unio ellipsis I. Lea, 1827 accepted as Obovaria olivaria (Rafinesque, 1820) (unaccepted)
  » Species Unio ellipticus Barnes, 1823 accepted as Ortmanniana ligamentina (Lamarck, 1819) (unaccepted)
  » Species Unio elongata Lamarck, 1819 accepted as Unio elongatus Lamarck, 1819 (unaccepted, incorrect gender agreement of specific epithet)
  » Species Unio elongatus Lamarck, 1819 accepted as Margaritifera margaritifera (Linnaeus, 1758) (unaccepted)
  » Species Unio emarginatus I. Lea, 1834 accepted as Unio mancus Lamarck, 1819 (unaccepted)
  » Species Unio emmonsii I. Lea, 1857 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio errans I. Lea, 1857 accepted as Elliptio errans (I. Lea, 1857) (unaccepted, original combination)
  » Species Unio essoensis Chaper, 1885 accepted as Coelatura essoensis (Chaper, 1885) (unaccepted, original combination)
  » Species Unio estabrookianus I. Lea, 1845 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio eucallistellus Bourguignat, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio euliratus Rafinesque, 1831 accepted as Eurynia dilatata (Rafinesque, 1820) (unaccepted)
  » Species Unio euphraticus Bourguignat, 1852 accepted as Pseudodontopsis euphratica (Bourguignat, 1852) (unaccepted, original combination)
  » Species Unio exactus I. Lea, 1858 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio exacutus I. Lea, 1872 accepted as Elliptio folliculata (I. Lea, 1838) (unaccepted)
  » Species Unio exanthematicus Küster, 1861 accepted as Pressidens exanthematicus (Küster, 1861) (unaccepted, basionym)
  » Species Unio excavatus I. Lea, 1857 accepted as Lampsilis ornata (Conrad, 1835) (unaccepted)
  » Species Unio excultus Conrad, 1838 accepted as Uniomerus declivis (Say, 1831) (unaccepted)
  » Species Unio exiguus I. Lea, 1840 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio exilis Dunker, 1846 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio eximius I. Lea, 1856 accepted as Contradens eximius (I. Lea, 1856) (unaccepted)
  » Species Unio exolescens Gould, 1843 accepted as Trapezidens exolescens (Gould, 1843) (unaccepted, original combination)
  » Species Unio expansus Küster, 1856 accepted as Diplodon multistriatus (I. Lea, 1831) (unaccepted)
  » Species Unio explicatus Morelet, 1849 accepted as Cyrtonaias explicata (Morelet, 1849) (unaccepted, original combination)
  » Species Unio extensus I. Lea, 1857 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio fabaceus I. Lea, 1861 accepted as Villosa umbrans (I. Lea, 1857) (unaccepted, synonym)
  » Species Unio fabagina Deshayes, 1876 accepted as Unionetta fabagina (Deshayes, 1876) (unaccepted, original combination)
  » Species Unio fabalis I. Lea, 1831 accepted as Paetulunio fabalis (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio fallax I. Lea, 1857 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio fassinans I. Lea, 1868 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio fatuus I. Lea, 1840 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio favidens Benson, 1862 accepted as Parreysia favidens (Benson, 1862) (unaccepted, basionym)
  » Species Unio favosus I. Lea, 1857 accepted as Pleurobema georgianum (I. Lea, 1841) (unaccepted)
  » Species Unio feae Tapparone Canefri, 1889 accepted as Leoparreysia feae (Tapparone Canefri, 1889) (unaccepted, original combination)
  » Species Unio feddeni Theobald, 1873 accepted as Leoparreysia feddeni (Theobald, 1873) (unaccepted, original combination)
  » Species Unio fellmanni Deshayes, 1848 accepted as Potomida littoralis (Cuvier, 1798) (unaccepted)
  » Species Unio ferrissii Marsh, 1891 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio fibrosus Heude, 1877 accepted as Aculamprotula fibrosa (Heude, 1877) (unaccepted, basionym)
  » Species Unio fibuloides I. Lea, 1859 accepted as Pleurobema fibuloides (I. Lea, 1859) (unaccepted)
  » Species Unio fiscallianus Kobelt, 1873 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio fischerianus Morlet, 1883 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio fisherianus I. Lea, 1838 accepted as Elliptio fisheriana (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio fissidentatus Lindholm, 1932 † accepted as Cuneopsis fissidentatus (Lindholm, 1932) † (unaccepted, basionym)
  » Species Unio flabellatus Goldfuss, 1837 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio flabelliferus Noulet, 1864 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio flagellatus Say, 1830 accepted as Epioblasma obliquata (Rafinesque, 1820) (unaccepted)
  » Species Unio flavescens I. Lea, 1845 accepted as Ptychobranchus greenii (Conrad, 1834) (unaccepted)
  » Species Unio flavidulus I. Lea, 1861 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio flavidus I. Lea, 1872 accepted as Fusconaia cuneolus (I. Lea, 1840) (unaccepted)
  » Species Unio florentinus I. Lea, 1857 accepted as Epioblasma florentina (I. Lea, 1857) (unaccepted, original combination)
  » Species Unio floridensis I. Lea, 1852 accepted as Lampsilis floridensis (I. Lea, 1852) (unaccepted)
  » Species Unio fluminalis Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio fluviatilis Green, 1827 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio flyensis Tapparone Canefri, 1883 accepted as Westralunio flyensis (Tapparone Canefri, 1883) (unaccepted, original combination)
  » Species Unio foliaceus Gould, 1843 accepted as Trapezoideus foliaceus (Gould, 1843) (unaccepted, original combination)
  » Species Unio foliatus Hildreth, 1828 accepted as Epioblasma flexuosa (Rafinesque, 1820) (unaccepted)
  » Species Unio folliculatus I. Lea, 1838 accepted as Elliptio folliculata (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio fontainiana Unio accepted as Diplodon fontainianus (d'Orbigny, 1835) (unaccepted, basionym)
  » Species Unio fontanus Conrad, 1866 accepted as Leaunio lienosus caliginosus (Lea, 1845) (unaccepted, synonym)
  » Species Unio footei Theobald, 1876 accepted as Arcidopsis footei (Theobald, 1876) (unaccepted, basionym)
  » Species Unio forbesianus I. Lea, 1852 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio foremanianus I. Lea, 1842 accepted as Ptychobranchus foremanianus (I. Lea, 1842) (unaccepted, original combination)
  » Species Unio formosus I. Lea, 1831 accepted as Epioblasma triquetra (Rafinesque, 1820) (unaccepted)
  » Species Unio forsheyi I. Lea, 1859 accepted as Quadrula apiculata (Say, 1829) (unaccepted)
  » Species Unio fragosus Conrad, 1835 accepted as Quadrula fragosa (Conrad, 1835) (unaccepted, original combination)
  » Species Unio fragrosus accepted as Quadrula fragosa (Conrad, 1835) (unaccepted, incorrect subsequent spelling)
  » Species Unio framesi (Connolly, 1925) accepted as Coelatura mossambicensis framesi (Connolly, 1925) (unaccepted, superseded combination)
  » Species Unio fraternus I. Lea, 1852 accepted as Elliptio fraterna (I. Lea, 1852) (unaccepted)
  » Species Unio friersoni Wright, B.H., 1896 accepted as Pleurobema riddellii (I. Lea, 1862) (unaccepted)
  » Species Unio fruhstorferi Dautzenberg, 1900 accepted as Lanceolaria fruhstorferi (Dautzenberg, 1900) (unaccepted, basionym)
  » Species Unio fryanus Wright, B.H., 1888 accepted as Elliptio occulta (I. Lea, 1843) (unaccepted)
  » Species Unio fucatus I. Lea, 1860 accepted as Villosa taeniata (Conrad, 1834) (unaccepted, synonym)
  » Species Unio fulgidus I. Lea, 1845 accepted as Pleurobema sintoxia (Rafinesque, 1820) (unaccepted)
  » Species Unio fuliginosus I. Lea, 1845 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio fuligo Reeve, 1856 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio fulvaster Drouët & Chaper, 1892 accepted as Contradens fulvaster (Drouët & Chaper, 1892) (unaccepted)
  » Species Unio fulvus I. Lea, 1834 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio fumatus I. Lea, 1857 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio funebralis I. Lea, 1860 accepted as Rhipidodonta funebralis (I. Lea, 1860) (unaccepted, basionym)
  » Species Unio furvus Conrad, 1834 accepted as Pleurobema rubellum (Conrad, 1834) (unaccepted)
  » Species Unio fuscatus I. Lea, 1843 accepted as Elliptio occulta (I. Lea, 1843) (unaccepted)
  » Species Unio fusculus Ziegler in Rossmässler, 1835 accepted as Unio crassus Philipsson, 1788 (unaccepted)
  » Species Unio gabbianus I. Lea, 1868 accepted as Arotonaias gabbianus (I. Lea, 1868) (unaccepted, basionym)
  » Species Unio gabonensis Küster, 1862 accepted as Coelatura gabonensis (Küster, 1862) (unaccepted, original combination)
  » Species Unio gastonensis I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio gaudichaudii Eydoux, 1838 accepted as Indonaia caerulea (I. Lea, 1831) (unaccepted, a junior synonym)
  » Species Unio geddingsianus I. Lea, 1840 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio geminus I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio generosus Gould, 1847 accepted as Lamellidens generosus (Gould, 1847) (unaccepted, original combination)
  » Species Unio genthii I. Lea, 1857 accepted as Villosa constricta (Conrad, 1838) (unaccepted)
  » Species Unio genuinus I. Lea, 1868 accepted as Villosa delumbis (Conrad, 1834) (unaccepted, synonym)
  » Species Unio geometricus I. Lea, 1834 accepted as Uniomerus declivis (Say, 1831) (unaccepted)
  » Species Unio georgianus I. Lea, 1841 accepted as Pleurobema georgianum (I. Lea, 1841) (unaccepted, original combination)
  » Species Unio georgina Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio gerbidoni Eydoux, 1838 accepted as Indonaia caerulea (I. Lea, 1831) (unaccepted, a junior synonym)
  » Species Unio gereti Preston, 1910 accepted as Coelatura horei (E.A. Smith, 1880) (unaccepted, junior synonym)
  » Species Unio gerhardtii I. Lea, 1862 accepted as Hamiota altilis (Conrad, 1834) (unaccepted)
  » Species Unio germanus I. Lea, 1861 accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted)
  » Species Unio gesnerii I. Lea, 1874 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio gianellii Tapparone Canefri, 1889 accepted as Lamellidens savadiensis (G. Nevill, 1877) (unaccepted)
  » Species Unio gibber I. Lea, 1838 accepted as Pleuronaia gibber (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio gibbesianus I. Lea, 1852 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio gibbosus Barnes, 1823 accepted as Eurynia dilatata (Rafinesque, 1820) (unaccepted)
  » Species Unio giganteus Barnes, 1823 accepted as Megalonaias nervosa (Rafinesque, 1820) (unaccepted)
  » Species Unio gigas Swainson, 1824 accepted as Lasmigona complanata (Barnes, 1823) (unaccepted)
  » Species Unio glaber I. Lea, 1838 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio glabrata Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio gladiator Ancey, 1881 accepted as Nodularia gladiator (Ancey, 1881) (unaccepted, original combination)
  » Species Unio gladiolus Heude, 1877 accepted as Lanceolaria gladiola (Heude, 1877) (unaccepted, basionym)
  » Species Unio glandaceus I. Lea, 1861 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio glans I. Lea, 1831 accepted as Toxolasma lividum (Rafinesque, 1831) (unaccepted)
  » Species Unio glaucinus Porro, 1838 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio glebulus Say, 1831 accepted as Glebula rotundata (Lamarck, 1819) (unaccepted)
  » Species Unio glenelgensis Dennant, 1898 accepted as Hyridella glenelgensis (Dennant, 1898) (unaccepted, original combination)
  » Species Unio globatus I. Lea, 1871 accepted as Fusconaia subrotunda (I. Lea, 1831) (unaccepted)
  » Species Unio goascoranensis I. lea, 1858 accepted as Nephronaias goascoranensis (I. Lea, 1858) (unaccepted, basionym)
  » Species Unio gottschei von Martens, 1894 accepted as Lamprotula gottschei (von Martens, 1894) (unaccepted, basionym)
  » Species Unio gouldii I. Lea, 1845 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio gowhattensis Theobald, 1873 accepted as Parreysia gowhattensis (Theobald, 1873) (unaccepted)
  » Species Unio gracilentus I. Lea, 1857 accepted as Elliptio arctata (Conrad, 1834) (unaccepted)
  » Species Unio gracilior I. Lea, 1857 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio gracilis Barnes, 1823 accepted as Leptodea fragilis (Rafinesque, 1820) (unaccepted)
  » Species Unio granadensis I. Lea, 1868 accepted as Micronaias granadensis (I. Lea, 1868) (unaccepted, basionym)
  » Species Unio grandensis Conrad, 1855 accepted as Glebula rotundata (Lamarck, 1819) (unaccepted)
  » Species Unio grandidens I. Lea, 1862 accepted as Aculamprotula grandidens (I. Lea, 1862) (unaccepted, basionym)
  » Species Unio graniferus (I. Lea, 1838) accepted as Rotundaria tuberculata (Rafinesque, 1820) (unaccepted, recombination)
  » Species Unio granosa Bruguière, 1792 accepted as Diplodon granosus (Bruguière, 1792) (unaccepted, basionym)
  » Species Unio granulatis (I. Lea, 1861) accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted, incorrect original spelling)
  » Species Unio granulatus I. Lea, 1861 accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted)
  » Species Unio granuliferus Dunker, 1848 accepted as Diplodon multistriatus (I. Lea, 1831) (unaccepted)
  » Species Unio gratiosus Philippi, 1843 accepted as Contradens gratiosus (Philippi, 1843) (unaccepted, basionym)
  » Species Unio gratus I. Lea, 1860 accepted as Diplodon gratus (I. Lea, 1860) (unaccepted, basionym)
  » Species Unio gravidus I. Lea, 1856 accepted as Physunio superbus (I. Lea, 1843) (unaccepted, junior synonym)
  » Species Unio grayanus I. Lea, 1834 accepted as Lanceolaria grayana (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio grayii Griffith & Pidgeon, 1833 accepted as Lanceolaria grayi (Gray in Griffith & Pidgeon, 1833) (unaccepted, basionym)
  » Species Unio gredleri Adami, 1886 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted, invalid: junior homonym of Unio gredleri Drouët, 1883; U. humerosus is a replacement name)
  » Species Unio gredleri Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio greeffeanus Ihering, 1893 accepted as Diplodon greeffeanus (Ihering, 1893) (unaccepted, basionym)
  » Species Unio greenii Conrad, 1834 accepted as Ptychobranchus greenii (Conrad, 1834) (unaccepted)
  » Species Unio griffithianus I. Lea, 1834 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio guaraniana d'Orbigny, 1835 accepted as Diplodon guaranianus (d'Orbigny, 1835) (unaccepted, basionym)
  » Species Unio gubernaculum Reeve, 1865 accepted as Epioblasma gubernaculum (Reeve, 1865) (unaccepted, original combination)
  » Species Unio gundlachi Dunker, 1858 accepted as Nephronaias gundlachi (Dunker, 1858) (unaccepted, basionym)
  » Species Unio guppyi E. A. Smith, 1885 accepted as Hyridella guppyi (E. A. Smith, 1885) (unaccepted, original combination)
  » Species Unio gurkensis Bourguignat, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio hageni Strubell, 1897 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio hagnei Simpson, 1900 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, in error for Unio hageni Strubell, 1897)
  » Species Unio hainesianus I. Lea, 1856 accepted as Chamberlainia hainesiana (I. Lea, 1856) (unaccepted, original name)
  » Species Unio haleianus I. Lea, 1842 accepted as Villosa lienosa (Conrad, 1834) (unaccepted)
  » Species Unio hallenbeckii I. Lea, 1859 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio hanleyianus I. Lea, 1852 accepted as Pleurobema hanleyianum (I. Lea, 1852) (unaccepted, original combination)
  » Species Unio harperi Wright, B.H., 1899 accepted as Pleurobema pyriforme (I. Lea, 1857) (unaccepted)
  » Species Unio hartmanianus I. Lea, 1860 accepted as Pleurobema hartmanianum (I. Lea, 1860) (unaccepted)
  » Species Unio hartwrightii Wright, B.H., 1896 accepted as Elliptio monroensis (I. Lea, 1843) (unaccepted)
  » Species Unio hastatus I. Lea, 1874 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio hauttecoeuri Bourguignat, 1883 accepted as Coelatura hauttecoeuri (Bourguignat, 1883) (unaccepted, original combination)
  » Species Unio haysianus I. Lea, 1834 accepted as Epioblasma haysiana (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio hazelhurstianus I. Lea, 1858 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio hazlehurstianus I. Lea, 1858 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio hebes I. Lea, 1852 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio hebetatus Conrad, 1854 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio heermannii I. Lea, 1862 accepted as Cyrtonaias tampicoensis (I. Lea, 1838) (unaccepted)
  » Species Unio hembeli Conrad, 1838 accepted as Margaritifera hembeli (Conrad, 1838) (unaccepted, original combination)
  » Species Unio hepaticus I. Lea, 1859 accepted as Elliptio hepatica (Lea, 1859) (unaccepted)
  » Species Unio heres Neumayr, 1899 accepted as Rhombuniopsis superstes (Neumayr, 1899) (unaccepted, a junior synonym)
  » Species Unio heros Say, 1829 accepted as Megalonaias nervosa (Rafinesque, 1820) (unaccepted)
  » Species Unio heterodon I. Lea, 1829 accepted as Alasmidonta heterodon (I. Lea, 1829) (unaccepted, original combination)
  » Species Unio heudei Heude, 1874 accepted as Cuneopsis heudei (Heude, 1874) (unaccepted, basionym)
  » Species Unio hians Valenciennes, 1821 accepted as Alasmidonta undulata (Say, 1817) (unaccepted)
  » Species Unio higginsii I. Lea, 1857 accepted as Lampsilis higginsii (I. Lea, 1857) (unaccepted, original combination)
  » Species Unio hildrethi Delessert, 1841 accepted as Hemistena lata (Rafinesque, 1820) (unaccepted)
  » Species Unio hildrethianus I. Lea, 1834 accepted as Simpsonaias ambigua (Say, 1825) (unaccepted)
  » Species Unio hinkleyi Wright, B.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio hippopoeus I. Lea, 1845 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio hjalmarsoni Dunker, 1858 accepted as Nephronaias hjalmarsoni (Dunker, 1858) (unaccepted, basionym)
  » Species Unio holstonensis I. Lea, 1840 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio homsensis I. Lea, 1865 accepted as Pseudunio homsensis (I. Lea, 1865) (unaccepted, original combination)
  » Species Unio hopetonensis I. Lea, 1838 accepted as Elliptio hopetonensis (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio horei E.A. Smith, 1880 accepted as Coelatura horei (E.A. Smith, 1880) (unaccepted, original combination)
  » Species Unio houngdarauicus Tapparone Canefri, 1889 accepted as Leoparreysia houngdarauica (Tapparone Canefri, 1889) (unaccepted, original combination)
  » Species Unio housei I. Lea, 1856 accepted as Hyriopsis myersiana (I. Lea, 1856) (unaccepted)
  » Species Unio houstonensis I. Lea, 1859 accepted as Rotundaria houstonensis (I. Lea, 1859) (unaccepted)
  » Species Unio humerosus I. Lea, 1868 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio humerosus Westerlund, 1890 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted, invalid: junior homonym of Unio humerosus I. Lea, 1868)
    » Variety Unio humerosus var. elongata Kobelt, 1914 accepted as Unio elongatulus C. Pfeiffer, 1825 (invalid: junior homonym of Unio elongata Lamarck, 1819)
    » Variety Unio humerosus var. roboretana Kobelt, 1914 accepted as Unio elongatulus C. Pfeiffer, 1825
  » Species Unio humilior Lindholm, 1932 † accepted as Cuneopsis humilior (LIndholm, 1932) † (unaccepted, basionym)
  » Species Unio humilis I. Lea, 1856 accepted as Radiatula humilis (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio hyalinus I. Lea, 1845 accepted as Lasmigona subviridis (Conrad, 1835) (unaccepted)
  » Species Unio hydianus I. Lea, 1838 accepted as Lampsilis hydiana (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio hylaea d'Orbigny, 1835 accepted as Rhipidodonta hylaea (d'Orbigny, 1835) (unaccepted, basionym)
  » Species Unio hypsiprymnus von Martens, 1897 accepted as Coelatura hypsiprymna (von Martens, 1897) (unaccepted, original combination)
  » Species Unio icterinus Conrad, 1834 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio idrinus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio iheringi Wright, B.H., 1898 accepted as Sphenonaias taumilapana (Conrad, 1855) (unaccepted)
  » Species Unio imbricatus Mörch, 1861 accepted as Arotonaias imbricata (Mörch, 1861) (unaccepted, basionym)
  » Species Unio imperialis Morelet, 1862 accepted as Chamberlainia hainesiana (I. Lea, 1856) (unaccepted, junior synonym)
  » Species Unio imperitus de Gregorio, 1914 accepted as Ptychobranchus fasciolaris (Rafinesque, 1820) (unaccepted)
  » Species Unio inaequalis Rochebrune, 1881 accepted as Contradens inaequalis (Rochebrune, 1881) (unaccepted, basionym)
  » Species Unio incrassatus I. Lea, 1840 accepted as Elliptio crassidens (Lamarck, 1819) (unaccepted)
  » Species Unio incurvus I. Lea, 1831 accepted as Potomida littoralis (Cuvier, 1798) (unaccepted)
  » Species Unio indefinilus (I. Lea, 1863) accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted, incorrect subsequent spelling)
  » Species Unio indefinitus I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio ineptus I. Lea, 1852 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio inflata Hutton, 1873 † accepted as Echyridella huttoni (McMichael, 1956) † (unaccepted, Invalid: not Studer, 1820)
  » Species Unio inflatus Barnes, 1823 accepted as Lampsilis siliquoidea (Barnes, 1823) (unaccepted)
  » Species Unio infucatus Conrad, 1834 accepted as Rotundaria infucata (Conrad, 1834) (unaccepted)
  » Species Unio infulgens I. Lea, 1874 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio infuscus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio ingallsianus I. Lea, 1852 accepted as Ensidens ingallsianus (I. Lea, 1852) (unaccepted, basionym)
  » Species Unio inornatus I. Lea, 1856 accepted as Physunio inornatus (I. Lea, 1856) (unaccepted)
  » Species Unio inornatus Reeve, 1865 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio insolidus I. Lea, 1872 accepted as Lasmigona decorata (I. Lea, 1852) (unaccepted)
  » Species Unio instructus I. Lea, 1861 accepted as Pleurobema verum (I. Lea, 1861) (unaccepted)
  » Species Unio insulsus I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio intercedens I. Lea, 1857 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio intermedius Conrad, 1836 accepted as Theliderma intermedia (Conrad, 1836) (unaccepted)
  » Species Unio interruptus I. Lea, 1838 accepted as Cambarunio taeniatus pictus (I. Lea, 1834) (unaccepted, synonym)
  » Species Unio interruptus Say, 1831 accepted as Plectomerus dombeyanus (Valenciennes, 1827) (unaccepted)
  » Species Unio interventus I. Lea, 1861 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio introrugatus Connolly, 1931 accepted as Coelatura hauttecoeuri (Bourguignat, 1883) (unaccepted, junior synonym)
  » Species Unio inusitatis I. Lea, 1859 accepted as Elliptio hopetonensis (I. Lea, 1838) (unaccepted)
  » Species Unio invenustus I. Lea, 1874 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio involutus Hanley, 1856 accepted as Indonaia involuta (Hanley, 1856) (unaccepted, basionym)
  » Species Unio irgizlaica Lindholm, 1904 accepted as Unio crassus Philipsson, 1788 (unaccepted)
  » Species Unio iridescens Conrad, 1838 accepted as Venustaconcha ellipsiformis (Conrad, 1836) (unaccepted, synonym)
  » Species Unio iris I. Lea, 1829 accepted as Cambarunio iris (I. Lea, 1829) (unaccepted, original combination)
  » Species Unio irrasus I. Lea, 1861 accepted as Pleurobema georgianum (I. Lea, 1841) (unaccepted)
  » Species Unio irroratus I. Lea, 1827 accepted as Cyprogenia stegaria (Rafinesque, 1820) (unaccepted, original combination)
  » Species Unio irtyshensis Lindholm, 1932 † accepted as Betekeia irtyshensis (Lindholm, 1932) † (unaccepted, basionym)
  » Species Unio irwinensis I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio istrianus Stossich, 1899 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio jamesianus I. Lea, 1857 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio japanensis I. Lea, 1859 accepted as Pronodularia japanensis (I. Lea, 1859) (unaccepted, original combination)
  » Species Unio jaspidea Hupé, 1857 accepted as Monocondylaea jaspidea (Hupé, 1857) (unaccepted, basionym)
  » Species Unio javanus I. Lea, 1840 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio jayensis I. Lea, 1838 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio jeffreysianus I. Lea, 1871 accepted as Velesunio ambiguus (Philippi, 1847) (unaccepted, junior synonym)
  » Species Unio jejunus I. Lea, 1838 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio jensenii Baker accepted as Lasmigona complanata (Barnes, 1823) (unaccepted)
  » Species Unio jewettii I. Lea, 1867 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio johannis I. Lea, 1859 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio jokohamensis Ihering, 1893 accepted as Inversiunio jokohamensis (Ihering, 1893) (unaccepted, basionym)
  » Species Unio jonesii I. Lea, 1859 accepted as Cambarunio jonesii (Lea, I., 1859) (unaccepted)
  » Species Unio jourdyi Morlet, 1886 accepted as Nodularia jourdyi (Morlet, 1886) (unaccepted, original combination)
  » Species Unio katherinae I. Lea, 1838 accepted as Lasmigona complanata (Barnes, 1823) (unaccepted)
  » Species Unio keinerianus I. Lea, 1852 accepted as Unio kienerianus I. Lea, 1852 (unaccepted, incorrect original spelling)
  » Species Unio keraudreni Eydoux, 1838 accepted as Indonaia caerulea (I. Lea, 1831) (unaccepted, a junior synonym)
  » Species Unio kienerianus I. Lea, 1852 accepted as Rotundaria kieneriana (I. Lea, 1852) (unaccepted)
  » Species Unio kingii Wright, B.H., 1900 accepted as Medionidus penicillatus (I. Lea, 1857) (unaccepted)
  » Species Unio kirklandianus Wright, S.H., 1897 accepted as Hamiota subangulata (I. Lea, 1840) (unaccepted)
  » Species Unio kirtlandianus I. Lea, 1834 accepted as Fusconaia subrotunda (I. Lea, 1831) (unaccepted)
  » Species Unio kizylaigirensis Lindholm, 1932 † accepted as Nodularia kizylaigirensis (Lindholm, 1932) (unaccepted, original combination)
  » Species Unio kleciaki Drouët, 1879 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio kleinianus I. Lea, 1852 accepted as Rotundaria kleiniana (I. Lea, 1852) (unaccepted, original combination)
  » Species Unio kobelti Neumayr, 1899 accepted as Nodularia douglasiae (Gray, 1833) (unaccepted, unavailable; a junior homonym of Unio kobelti Kobelt & Rolle, 1895)
  » Species Unio koseritzi Clessin, 1888 accepted as Rhipidodonta koseritzi (Clessin, 1888) (unaccepted, basionym)
  » Species Unio kraussii Lea, 1853 accepted as Castaliella sulcata (Krauss, 1848) (unaccepted, a replacement name for Castalia sulcata Krauss, 1848 to avoid secondary homonymy with Unio sulcatus I. Lea, 1829)
  » Species Unio kunenensis Mousson, 1888 accepted as Coelatura kunenensis (Mousson, 1888) (unaccepted, original combination)
  » Species Unio lacrymosus I. Lea, 1827 accepted as Quadrula quadrula (Rafinesque, 1820) (unaccepted)
  » Species Unio lacteolus I. Lea, 1834 accepted as Diplodon delodontus (Lamarck, 1819) (unaccepted)
  » Species Unio laevissimus (I. Lea, 1829) accepted as Potamilus ohiensis (Rafinesque, 1820) (unaccepted, recombination)
  » Species Unio lamarckianus I. Lea, 1852 accepted as Cyprogenia aberti (Conrad, 1850) (unaccepted)
  » Species Unio lamellatus I. Lea, 1838 accepted as Lamellidens lamellatus (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio lanceolatus I. Lea, 1827 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted, original combination)
  » Species Unio laosensis Lea, 1863 accepted as Margaritifera laosensis (I. Lea, 1863) (unaccepted, original combination)
  » Species Unio lapillus Say, 1831 accepted as Unio capillus Say, 1831 (unaccepted, incorrect subsequent spelling of Unio capillus)
  » Species Unio largillierti Philippi, 1847 accepted as Delphinonaias largillierti (Philippi, 1847) (unaccepted, basionym)
  » Species Unio larius Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio latecostatus I. Lea, 1845 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio latiplicatus Noulet, 1864 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio latiradiatus Conrad, 1838 accepted as Cambarunio taeniatus pictus (I. Lea, 1834) (unaccepted, synonym)
  » Species Unio latissimus Sowerby, 1868 accepted as Lampsilis cardium Rafinesque, 1820 (unaccepted)
  » Species Unio latus I. Lea, 1859 accepted as Elliptio roanokensis (I. Lea, 1838) (unaccepted)
  » Species Unio lawii I. Lea, 1871 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio lazarus I. Lea, 1852 accepted as Elliptio arctata (Conrad, 1834) (unaccepted)
  » Species Unio leaii Gray in Griffith & Pidgeon, 1833 accepted as Lamprotula leaii (Gray in Griffith & Pidgeon, 1833) (unaccepted, original combination)
  » Species Unio lecontianus I. Lea, 1838 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio legrandi Petterd, 1889 accepted as Velesunio moretonicus (Reeve, 1865) (unaccepted, junior synonym)
  » Species Unio lehmanii Wright, S.H., 1897 accepted as Elliptio occulta (I. Lea, 1843) (unaccepted)
  » Species Unio leibii I. Lea, 1862 accepted as Obovaria subrotunda (Rafinesque, 1820) (unaccepted)
  » Species Unio lenior I. Lea, 1842 accepted as Epioblasma lenior (I. Lea, 1842) (unaccepted, original combination)
  » Species Unio lenis I. Lea, 1840 accepted as Unio lenior I. Lea, 1842 (unaccepted, invalid, a junior homonym of Unio lenis Conrad, 1838)
  » Species Unio lenis Conrad, 1838 accepted as Lampsilis cardium Rafinesque, 1820 (unaccepted)
  » Species Unio lens I. Lea, 1831 accepted as Obovaria subrotunda (Rafinesque, 1820) (unaccepted)
  » Species Unio lenticularis I. Lea, 1872 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio leonensis Simpson, 1892 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio leopoldvillensis Putzeys, 1898 accepted as Coelatura leopoldvillensis (Putzeys, 1898) (unaccepted, original combination)
  » Species Unio lepidus Gould, 1856 accepted as Villosa amygdalum (I. Lea, 1843) (unaccepted, synonym)
  » Species Unio leprosus Miles, 1861 accepted as Ligumia recta (Lamarck, 1819) (unaccepted)
  » Species Unio lesleyi I. Lea, 1860 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio lessoni Küster, 1855 accepted as Hyridella australis (Lamarck, 1819) (unaccepted, junior synonym)
  » Species Unio lesueurianus I. Lea, 1840 accepted as Fusconaia subrotunda (I. Lea, 1831) (unaccepted)
  » Species Unio lewisii I. Lea, 1861 accepted as Pleurobema fibuloides (I. Lea, 1859) (unaccepted)
  » Species Unio liebmanni Philippi, 1847 accepted as Sphenonaias liebmanni (Philippi, 1847) (unaccepted, original combination)
  » Species Unio liedtkei Rolle, 1904 accepted as Aculamprotula nodulosa (Wood, 1815) (unaccepted, junior synonym)
  » Species Unio lienosus Conrad, 1834 accepted as Leaunio lienosus (Conrad, 1834) (unaccepted, original combination)
  » Species Unio ligamentina Lamarck, 1819 accepted as Ortmanniana ligamentina (Lamarck, 1819) (unaccepted, original combination)
  » Species Unio ligatus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio lijacensis Kobelt, 1890 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio limatulus Conrad, 1849 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio limosus Nilsson, 1822 accepted as Unio pictorum (Linnaeus, 1758) (unaccepted)
  » Species Unio lincecumii I. Lea, 1868 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio lindholmi Zhadin, 1938 accepted as Unio pictorum (Linnaeus, 1758) (unaccepted, a junior synonym)
  » Species Unio lindsleyi I. Lea, 1860 accepted as Villosa taeniata (Conrad, 1834) (unaccepted, synonym)
  » Species Unio lineata Bory de St. Vincent, 1827 accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio lineatus I. Lea, 1840 accepted as Lampsilis binominata Simpson, 1900 (unaccepted, invalid, a homonym of Unio lineata Bory de St. Vincent, 1827)
  » Species Unio lineolatus (Rafinesque, 1820) accepted as Ellipsaria lineolata (Rafinesque, 1820) (unaccepted)
  » Species Unio linguaeformis I. Lea, 1860 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, tentative synonym)
  » Species Unio lingulatus Drouet & Chaper, 1892 accepted as Rectidens lingulatus (Drouet & Chaper, 1892) (unaccepted, basionym)
  » Species Unio littoralis Cuvier, 1798 accepted as Potomida littoralis (Cuvier, 1798) (unaccepted, original combination)
  » Species Unio litus I. Lea, 1871 accepted as Pleurobema pyriforme (I. Lea, 1857) (unaccepted)
  » Species Unio livingstonensis I. Lea, 1863 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio longirostris Rossmässler, 1836 accepted as Unio pictorum (Linnaeus, 1758) (unaccepted)
  » Species Unio longobardus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio lucidus I. Lea, 1863 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio lugens Drouet & Chaper, 1892 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio lugubris Say, 1832 accepted as Potamilus purpuratus (Lamarck, 1819) (unaccepted)
  » Species Unio lugubris I. Lea, 1838 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio lunulatus Pratt, 1876 accepted as Quadrula quadrula (Rafinesque, 1820) (unaccepted)
  » Species Unio luridus I. Lea, 1852 accepted as Elliptio arca (Conrad, 1834) (unaccepted)
  » Species Unio lutens I. Lea, 1856 accepted as Unio luteus I. Lea, 1856 (unaccepted, incorrect original spelling)
  » Species Unio luteola Lamarck, 1819 accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio luteus I. Lea, 1856 accepted as Parreysia corrugata (O. F. Müller, 1774) (unaccepted, junior synonym)
  » Species Unio lyonii I. Lea, 1865 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio macer I. Lea, 1857 accepted as Elliptio roanokensis (I. Lea, 1838) (unaccepted)
  » Species Unio macnielii (I. Lea, 1869) accepted as Nephronaias macnielii (I. Lea, 1869) (unaccepted, basionym)
  » Species Unio maconensis I. Lea, 1857 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio macrodon I. Lea, 1859 accepted as Truncilla macrodon (I. Lea, 1859) (unaccepted)
  » Species Unio maculatus Conrad, 1834 accepted as Pleuronaia dolabelloides (I. Lea, 1840) (unaccepted)
  » Species Unio madagascariensis Sganzin, 1841 accepted as Coelatura madagascariensis (Sganzin, 1841) (unaccepted, original combination)
  » Species Unio magistri Westerlund, 1890 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio manca Lamarck, 1819 accepted as Unio mancus Lamarck, 1819 (unaccepted)
  » Species Unio mandelayensis Theobald, 1873 accepted as Leoparreysia bhamoensis (Theobald, 1873) (unaccepted)
  » Species Unio manubius Gould, 1855 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio margaritifera (Linnaeus, 1758) accepted as Margaritifera margaritifera (Linnaeus, 1758) (unaccepted)
  » Species Unio marginalis Lamarck, 1819 accepted as Lamellidens marginalis (Lamarck, 1819) (unaccepted, original combination)
  » Species Unio marginis I. Lea, 1865 accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted)
  » Species Unio marshii Wright, B.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio martensi Ihering, 1893 accepted as Diplodon martensi (Ihering, 1893) (unaccepted, basionym)
  » Species Unio mashonae Preston, 1910 accepted as Cafferia caffra (Krauss, 1848) (unaccepted, junior synonym)
  » Species Unio masoni Conrad, 1834 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio mauritianus Lea, 1859 accepted as Simpsonella purpurea (Valenciennes, 1827) (unaccepted, junior synonym)
  » Species Unio mecklenbergensis I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio medellinus I. Lea, 1838 accepted as Actinonaias medellina (I. Lea, 1838) (unaccepted, basionym)
  » Species Unio mederianus Küster, 1861 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio mediocris I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio medius I. Lea, 1861 accepted as Pleurobema georgianum (I. Lea, 1841) (unaccepted)
  » Species Unio melinus Conrad, 1838 accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio melleus I. Lea, 1859 accepted as Nephronaias mellea (I. Lea, 1859) (unaccepted, basionym)
  » Species Unio menkianus I. Lea, 1838 accepted as Cambarunio taeniatus pictus (I. Lea, 1834) (unaccepted, synonym)
  » Species Unio menziesii Gray, 1843 accepted as Echyridella menziesii (Gray, 1843) (unaccepted)
  » Species Unio mercerii I. Lea, 1862 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio meredithii I. Lea, 1858 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio merus I. Lea, 1852 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio metallicus Say, 1831 accepted as Popenaias metallica (Say, 1831) (unaccepted, basionym)
  » Species Unio metanevra (Rafinesque, 1820) accepted as Theliderma metanevra (Rafinesque, 1820) (unaccepted)
  » Species Unio metastriatus Conrad, 1838 accepted as Epioblasma metastriata (Conrad, 1838) (unaccepted)
  » Species Unio mexicanus Philippi, 1847 accepted as Sphenonaias mexicana (Philippi, 1847) (unaccepted, basionym)
  » Species Unio micans I. Lea, 1857 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio micheloti Morlet, 1886 accepted as Nodularia micheloti (Morlet, 1886) (unaccepted, original combination)
  » Species Unio microdon von Martens, 1887 accepted as Sphenonaias microdon (von Martens, 1887) (unaccepted, basionym)
  » Species Unio micropterus Morelet, 1866 accepted as Physunio micropterus (Morelet, 1866) (unaccepted, basionym)
  » Species Unio middendorffi Westerlund, 1890 accepted as Nodularia douglasiae (Gray, 1833) (unaccepted)
  » Species Unio minor I. Lea, 1843 accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted)
  » Species Unio minusculus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio misellus Morelet, 1865 accepted as Contradens misellus (Morelet, 1865) (unaccepted, basionym)
  » Species Unio misoolensis Schepman, 1897 accepted as Hyridella misoolensis (Schepman, 1897) (unaccepted, original combination)
  » Species Unio mississippiensis Conrad, 1850 accepted as Ligumia subrostrata (Say, 1831) (unaccepted, synonym)
  » Species Unio mitchelli Simpson in Dall, 1895 accepted as Fusconaia mitchelli (Simpson in Dall, 1895) (unaccepted)
  » Species Unio modicellus I. Lea, 1859 accepted as Epioblasma othcaloogensis (I. Lea, 1857) (unaccepted)
  » Species Unio modicus I. Lea, 1857 accepted as Pleurobema pyriforme (I. Lea, 1857) (unaccepted)
  » Species Unio modioliformis I. Lea, 1834 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio moestus I. Lea, 1841 accepted as Toxolasma lividum (Rafinesque, 1831) (unaccepted)
  » Species Unio molleuri Morlet, 1891 accepted as Unionetta fabagina (Deshayes, 1876) (unaccepted)
  » Species Unio monceti Bourguignat, 1883 accepted as Nitia monceti (Bourguignat, 1883) (unaccepted, basionym)
  » Species Unio mongolicus Middendorff, 1851 accepted as Middendorffinaia mongolica (Middendorff, 1851) (unaccepted, original combination)
  » Species Unio monodonta Say, 1829 accepted as Margaritifera monodonta (Say, 1829) (unaccepted, original combination)
  » Species Unio monroensis I. Lea, 1843 accepted as Elliptio monroensis (I. Lea, 1843) (unaccepted, original combination)
  » Species Unio mooresianus I. Lea, 1857 accepted as Pleuronaia dolabelloides (I. Lea, 1840) (unaccepted)
  » Species Unio moraiensis Suzuki, 1941 † accepted as Calyptogena pacifica Dall, 1891 (unaccepted)
  » Species Unio moretonicus Reeve, 1865 accepted as Velesunio moretonicus (Reeve, 1865) (unaccepted, original combination)
  » Species Unio morlachicus Kobelt, 1914 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio mortoni Conrad, 1835 accepted as Cyclonaias mortoni (Conrad, 1835) (unaccepted, original combination)
  » Species Unio mossambicensis E. von Martens, 1860 accepted as Coelatura mossambicensis (E. von Martens, 1860) (unaccepted, original combination)
  » Species Unio moussonianus I. Lea, 1852 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio mucronatus Barnes, 1823 accepted as Eurynia dilatata (Rafinesque, 1820) (unaccepted)
  » Species Unio muelleri Rossmässler, 1838 accepted as Unio tumidus Philipsson, 1788 (unaccepted)
  » Species Unio muhlfeldianus I. Lea, 1838 accepted as Cambarunio dactylus dactylus (Lea, I., 1840) (unaccepted, tentative synonymy)
  » Species Unio multidentatus Philippi, 1847 accepted as Parreysia corrugata (O. F. Müller, 1774) (unaccepted)
  » Species Unio multiplicatus I. Lea, 1831 accepted as Megalonaias nervosa (Rafinesque, 1820) (unaccepted)
  » Species Unio multiradiatus I. Lea, 1829 accepted as Lampsilis fasciola Rafinesque, 1820 (unaccepted)
  » Species Unio multistriatus I. Lea, 1831 accepted as Diplodon multistriatus (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio mundus I. Lea, 1857 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio murchinsonianus I. Lea, 1834 accepted as Nodularia douglasiae (Gray, 1833) (unaccepted)
  » Species Unio murrayensis I. Lea, 1868 accepted as Pleurobema stabilis (I. Lea, 1861) (unaccepted)
  » Species Unio musivus Spengler, 1793 accepted as Unio crassus Philipsson, 1788 (unaccepted)
  » Species Unio mutabilis I. Lea, 1859 accepted as Hyridella depressa (Lamarck, 1819) (unaccepted, junior synonym)
  » Species Unio mutatus Mousson, 1849 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio mutelaeformis Germain, 1906 accepted as Nitia mutelaeformis (Germain, 1906) (unaccepted)
  » Species Unio mweruensis E.A. Smith, 1908 accepted as Prisodontopsis mweruensis (E.A. Smith, 1908) (unaccepted, basionym)
  » Species Unio myersianus I. Lea, 1856 accepted as Hyriopsis myersiana (I. Lea, 1856) (unaccepted, basionym)
  » Species Unio mytiloides (Rafinesque, 1820) accepted as Pleurobema clava (Lamarck, 1819) (unaccepted)
  » Species Unio nana Lamarck, 1819 accepted as Unio crassus Philipsson, 1788 (unaccepted)
  » Species Unio nashvillianus I. Lea, 1834 accepted as Ligumia subrostrata (Say, 1831) (unaccepted, synonym)
  » Species Unio nasuta Lamarck, 1819 accepted as Eurynia dilatata (Rafinesque, 1820) (unaccepted)
  » Species Unio nasutidus (I. Lea, 1863) accepted as Elliptio producta (Conrad, 1836) (unaccepted, incorrect original spelling)
  » Species Unio nasutulus I. Lea, 1863 accepted as Elliptio producta (Conrad, 1836) (unaccepted)
  » Species Unio nasutus Say, 1817 accepted as Sagittunio nasutus (Say, 1817) (unaccepted, original combination)
  » Species Unio naviculoides I. Lea, 1857 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio naviformis Lamarck, 1819 accepted as Theliderma cylindrica (Say, 1817) (unaccepted)
  » Species Unio naviglioformis I. Lea, 1859 accepted as Cucumerunio novaehollandiae (Gray, 1834) (unaccepted, junior synonym)
  » Species Unio nebulosus Conrad, 1834 accepted as Villosa nebulosa (Conrad, 1834) (unaccepted, original combination)
  » Species Unio negatus I. Lea, 1861 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio neglectus I. Lea, 1843 accepted as Lasmigona subviridis (Conrad, 1835) (unaccepted)
  » Species Unio neislerii I. Lea, 1858 accepted as Amblema neislerii (I. Lea, 1858) (unaccepted)
  » Species Unio nepeanensis Conrad, 1850 accepted as Hyridella australis (Lamarck, 1819) (unaccepted, junior synonym)
  » Species Unio neusensis I. Lea, 1858 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio newcombianus I. Lea, 1856 accepted as Arotonaias cyrenoides (Philippi, 1847) (unaccepted, junior synonym)
  » Species Unio nexus Say, 1831 accepted as Epioblasma arcaeformis (I. Lea, 1831) (unaccepted)
  » Species Unio nicklinianus I. Lea, 1834 accepted as Megalonaias nickliniana (I. Lea, 1834) (unaccepted, basionym)
  » Species Unio nieuwenhuisi Schepman, 1898 accepted as Schepmania nieuwenhuisi (Schepman, 1898) (unaccepted, basionym)
  » Species Unio nigellus I. Lea, 1852 accepted as Elliptio nigella (I. Lea, 1852) (unaccepted, original combination)
  » Species Unio nigerrimus I. Lea, 1852 accepted as Leaunio lienosus caliginosus (Lea, 1845) (unaccepted, synonym)
  » Species Unio nigrinus I. Lea, 1852 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio nitens I. Lea, 1840 accepted as Villosa vanuxemensis (I. Lea, 1838) (unaccepted)
  » Species Unio nitidus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio nobilis Conrad, 1854 accepted as Quadrula nobilis (Conrad, 1854) (unaccepted)
  » Species Unio nodiferus Conrad, 1849 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted)
  » Species Unio nodosa Swainson, 1840 accepted as Aculamprotula nodulosa (Wood, 1815) (unaccepted, in error for Mya nodulosa Wood, 1815)
  » Species Unio nodosus Barnes, 1823 accepted as Theliderma metanevra (Rafinesque, 1820) (unaccepted)
  » Species Unio nolani Wright, B.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio northamptonensis I. Lea, 1862 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio notatus I. Lea, 1838 accepted as Cambarunio simus (Lea, I., 1838) (unaccepted, synonym)
  » Species Unio novaehollandiae Gray, 1834 accepted as Cucumerunio novaehollandiae (Gray, 1834) (unaccepted, original combination)
  » Species Unio novieboraci I. Lea, 1838 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio nubilus I. Lea, 1868 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio nucleopsis Conrad, 1849 accepted as Pleurobema georgianum (I. Lea, 1841) (unaccepted)
  » Species Unio nucleus I. Lea, 1856 accepted as Scabies nucleus (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio nuttalianus I. Lea, 1856 accepted as Indonaia nuttaliana (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio nux I. Lea, 1852 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio nyassaensis I. Lea, 1864 accepted as Nyassunio nyassaensis (I. Lea, 1864) (unaccepted, basionym)
  » Species Unio obesus I. Lea, 1831 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio obfuscus I. Lea, 1857 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio oblatus I. Lea, 1863 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio obliqua Lamarck, 1819 accepted as Pleurobema cordatum (Rafinesque, 1820) (unaccepted)
  » Species Unio obliquiradiatus Reeve, 1865 accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio oblongus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio obnubilus I. Lea, 1857 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio obscurus I. Lea, 1838 accepted as Leaunio vanuxemensis (I. Lea, 1838) (unaccepted, synonym)
  » Species Unio obtusus I. Lea, 1840 accepted as Lampsilis straminea (Conrad, 1834) (unaccepted)
  » Species Unio obuncus I. Lea, 1871 accepted as Fusconaia cor (Conrad, 1834) (unaccepted)
  » Species Unio occatus I. Lea, 1860 accepted as Indonaia occata (I. Lea, 1860) (unaccepted, basionym)
  » Species Unio occidens I. Lea, 1829 accepted as Lampsilis cardium Rafinesque, 1820 (unaccepted)
  » Species Unio occidentalis Conrad, 1836 accepted as Ptychobranchus occidentalis (Conrad, 1836) (unaccepted)
  » Species Unio occultus I. Lea, 1843 accepted as Elliptio occulta (I. Lea, 1843) (unaccepted, original combination)
  » Species Unio ochmulgensis (I. Lea, 1861) accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio ochraceus Say, 1817 accepted as Leptodea ochracea (Say, 1817) (unaccepted, original combination)
  » Species Unio ocmulgeensis I. Lea, 1861 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio ogeecheensis Conrad, 1849 accepted as Villosa delumbis (Conrad, 1834) (unaccepted, synonym)
  » Species Unio olivarius I. Lea, 1831 accepted as Indonaia olivaria (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio omiensis Heimburg, 1884 accepted as Pseudodon omiensis (Heimburg, 1884) (unaccepted, original combination)
  » Species Unio opacatus Crosse & P. Fischer, 1893 accepted as Barynaias opacata (Crosse & P. Fischer, 1893) (unaccepted, basionym)
  » Species Unio opacus I. Lea, 1857 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio opalinus J. G. Anthony, 1866 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio opisodartos Adami, 1882 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio oratus Conrad, 1849 accepted as Lampsilis cariosa (Say, 1817) (unaccepted)
  » Species Unio orbiculatus Hildreth, 1828 accepted as Obovaria subrotunda (Rafinesque, 1820) (unaccepted)
  » Species Unio orbignyi Deville & Hupé, 1850 accepted as Castalia orbignyi (Deville & Hupé, 1850) (unaccepted, basionym)
  » Species Unio orcuttii Wright, S.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio oregonensis I. Lea, 1852 accepted as Nephronaias oregonensis (I. Lea, 1852) (unaccepted)
  » Species Unio oriens I. Lea, 1831 accepted as Hemistena lata (Rafinesque, 1820) (unaccepted)
  » Species Unio orientalis I. Lea, 1840 accepted as Elongaria orientalis (I. Lea, 1840) (unaccepted, original combination)
  » Species Unio orientalis Bourguignat, 1852 accepted as Unio bruguierianus Bourguignat, 1853 (unaccepted, unavailable, junior homonym of Unio orientalis Lea, 1840)
  » Species Unio orlovi Lindholm, 1932 † accepted as Acuticosta orlovi (Lindholm, 1932) † (unaccepted, original combination)
  » Species Unio ornatus I. Lea, 1861 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio oscari Wright, B.H., 1892 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio ostreata Morelet, 1849 accepted as Psoronaias ostreata (Morelet, 1849) (unaccepted, basionym)
  » Species Unio otcaloogensis "I. Lea, 1857" accepted as Epioblasma othcaloogensis (I. Lea, 1857) (unaccepted, incorrect subsequent spelling)
  » Species Unio othcaloogensis I. Lea, 1857 accepted as Epioblasma othcaloogensis (I. Lea, 1857) (unaccepted)
  » Species Unio ovalis (Montagu, 1803) accepted as Unio tumidus Philipsson, 1788 (unaccepted)
    » Variety Unio ovalis var. intercedens Gredler, 1860 accepted as Unio elongatulus C. Pfeiffer, 1825 (invalid: junior homonym of Unio intercedens I. Lea, 1857)
  » Species Unio ovatus Say, 1817 accepted as Lampsilis ovata (Say, 1817) (unaccepted, original combination)
    » Subspecies Unio ovatus ornatus Conrad, 1835 accepted as Lampsilis ornata (Conrad, 1835) (original combination)
  » Species Unio ovatus Y.-Y. Liu, Y.-H. Duan & Y.-X. Wang, 1994 accepted as Lamellidens liuovatus He & Zhuang, 2013 (unaccepted, invalid: junior homonym of Unio ovatus Say, 1817; Lamellidens liuovatus is a replacement name)
  » Species Unio oviformis Conrad, 1834 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio oxyrhynchus von Martens, 1861 accepted as Lanceolaria oxyrhyncha (von Martens, 1861) (unaccepted, basionym)
  » Species Unio ozarkensis Call, 1887 accepted as Fusconaia ozarkensis (Call, 1887) (unaccepted)
  » Species Unio pachysoma Benson, 1862 accepted as Indonaia pachysoma (Benson, 1862) (unaccepted, original combination)
  » Species Unio padanus Bourguignat, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio paivaeanus Morelet, 1875 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio paivanus Morelet, 1865 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio pajakomboensis Bullen, 1906 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio pallens Rossmässler, 1842 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted, invalid: junior homonym of Unio pallens Rafinesque, 1831)
  » Species Unio pallescens I. Lea, 1845 accepted as Lampsilis straminea (Conrad, 1834) (unaccepted)
  » Species Unio pallidofulvus I. Lea, 1861 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio paludicolus Gould, 1845 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio palustris Drouët, 1896 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio panacoensis Philippi, 1843 accepted as Disconaias panacoensis (Philippi, 1843) (unaccepted, original combination)
  » Species Unio pantoensis Neumayr, 1899 accepted as Inversidens pantoensis (Neumayr, 1899) (unaccepted)
  » Species Unio papyraceus Gould, 1845 accepted as Villosa amygdalum (I. Lea, 1843) (unaccepted, synonym)
  » Species Unio paralellus (Conrad, 1841) accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted, incorrect original spelling)
  » Species Unio parallelopipedon I. Lea, 1834 accepted as Diplodon parallelopipedon (I. Lea, 1834) (unaccepted, basionym)
  » Species Unio parallelus Conrad, 1841 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio paramattensis I. Lea, 1862 accepted as Hyridella depressa (Lamarck, 1819) (unaccepted, junior synonym)
  » Species Unio paranensis I. Lea, 1834 accepted as Rhipidodonta paranensis (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio parvulus I. Lea, 1860 accepted as Medionidus parvulus (I. Lea, 1860) (unaccepted)
  » Species Unio parvus Barnes, 1823 accepted as Toxolasma parvum (Barnes, 1823) (unaccepted)
  » Species Unio pattinoides I. Lea, 1871 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio patulus I. Lea, 1829 accepted as Pleurobema clava (Lamarck, 1819) (unaccepted)
  » Species Unio pauciplicatus I. Lea, 1872 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio paulista Ihering, 1893 accepted as Diplodon paulista (Ihering, 1893) (unaccepted, basionym)
  » Species Unio paulus I. Lea, 1840 accepted as Toxolasma paulum (I. Lea, 1840) (unaccepted, original combination)
  » Species Unio pauperculus I. Lea, 1861 accepted as Rotundaria asperata (I. Lea, 1861) (unaccepted)
  » Species Unio paviei Morlet, 1891 accepted as Chamberlainia hainesiana (I. Lea, 1856) (unaccepted, junior synonym)
  » Species Unio pawensis I. Lea, 1868 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio pealei I. Lea, 1871 accepted as Obovaria olivaria (Rafinesque, 1820) (unaccepted)
  » Species Unio pearlensis Conrad, 1855 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio pectitus Conrad, 1854 accepted as Epioblasma obliquata (Rafinesque, 1820) (unaccepted)
  » Species Unio pectorosus Conrad, 1834 accepted as Ortmanniana pectorosa (Conrad, 1834) (unaccepted)
  » Species Unio peguensis J. G. Anthony, 1865 accepted as Yaukthwa peguensis (Antony, 1865) (unaccepted, original combination)
  » Species Unio pellucidus I. Lea, 1845 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio penicillatus I. Lea, 1857 accepted as Medionidus penicillatus (I. Lea, 1857) (unaccepted)
  » Species Unio penitus Conrad, 1834 accepted as Epioblasma penita (Conrad, 1834) (unaccepted)
  » Species Unio peraeformis I. Lea, 1860 accepted as Rhipidodonta peraeformis (I. Lea, 1860) (unaccepted, basionym)
  » Species Unio percoarctatus I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio percompressus von Martens, 1887 accepted as Psoronaias percompressa (von Martens, 1887) (unaccepted)
  » Species Unio perdeclivis Lindholm, 1932 † accepted as Betekeia perdeclivis (LIndholm, 1932) † (unaccepted, original combination)
  » Species Unio perdix I. Lea, 1834 accepted as Ortmanniana pectorosa (Conrad, 1834) (unaccepted)
  » Species Unio perlatus I. Lea, 1863 accepted as Elliptio arctata (Conrad, 1834) (unaccepted)
  » Species Unio perlucens I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio permiscens I. Lea, 1859 accepted as Potamilus purpuratus (Lamarck, 1819) (unaccepted)
  » Species Unio pernodosus I. Lea, 1845 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted)
  » Species Unio perovalis Conrad, 1834 accepted as Hamiota perovalis (Conrad, 1834) (unaccepted)
  » Species Unio perovatus Conrad, 1834 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio perpastus I. Lea, 1861 accepted as Lampsilis straminea (Conrad, 1834) (unaccepted)
  » Species Unio perpictus I. Lea, 1860 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio perplexus Say, 1829 accepted as Epioblasma obliquata (Rafinesque, 1820) (unaccepted)
  » Species Unio perplexus I. Lea, 1831 accepted as Epioblasma torulosa (Rafinesque, 1820) (unaccepted)
  » Species Unio perplicatus Conrad, 1841 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio perpurpureus I. Lea, 1861 accepted as Villosa perpurpurea (I. Lea, 1861) (unaccepted, original combination)
  » Species Unio perradiatus I. Lea, 1858 accepted as Lampsilis fasciola Rafinesque, 1820 (unaccepted)
  » Species Unio personatus Say, 1829 accepted as Epioblasma personata (Say, 1829) (unaccepted)
  » Species Unio perstriatus I. Lea, 1852 accepted as Elliptio arctata (Conrad, 1834) (unaccepted)
  » Species Unio pertennis de Gregorio, 1914 accepted as Toxolasma parvum (Barnes, 1823) (unaccepted)
  » Species Unio pertenuis I. Lea, 1863 accepted as Lasmigona subviridis (Conrad, 1835) (unaccepted)
  » Species Unio peruviana Lamarck, 1819 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio petrinus Gould, 1855 accepted as Rotundaria petrina (Gould, 1855) (unaccepted)
  » Species Unio petrovichii Küster, 1854 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio petterianus Küster, 1854 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio pfeifferi Dunker, 1848 accepted as Diplodon multistriatus (I. Lea, 1831) (unaccepted)
  » Species Unio phaselus I. Lea, 1856 accepted as Scabies phaselus (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio phaseolus Hildreth, 1828 accepted as Ptychobranchus fasciolaris (Rafinesque, 1820) (unaccepted)
  » Species Unio philippianus Küster, 1861 accepted as Velesunio ambiguus (Philippi, 1847) (unaccepted, junior synonym)
  » Species Unio phillipsii Conrad, 1835 accepted as Obliquaria reflexa Rafinesque, 1820 (unaccepted)
  » Species Unio piccinellii Adami, 1886 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio piceus I. Lea, 1860 accepted as Diplodon piceus (I. Lea, 1860) (unaccepted, basionym)
  » Species Unio pictus I. Lea, 1834 accepted as Cambarunio taeniatus pictus (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio piger I. Lea, 1860 accepted as Diplodon uruguayensis (I. Lea, 1860) (unaccepted, a junior synonym)
  » Species Unio pigerrimus Crosse & P. Fischer, 1893 accepted as Barynaias pigerrima (Crosse & P. Fischer, 1893) (unaccepted, original combination)
  » Species Unio pilaris I. Lea, 1840 accepted as Fusconaia subrotunda (I. Lea, 1831) (unaccepted)
  » Species Unio pilatus I. Lea, 1866 accepted as Radiatula pilata (I. Lea, 1866) (unaccepted, basionym)
  » Species Unio pileus I. Lea, 1831 accepted as Epioblasma personata (Say, 1829) (unaccepted)
  » Species Unio pilsbryi Marsh, 1891 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio pinax Benson, 1862 accepted as Parreysia favidens (Benson, 1862) (unaccepted, a junior synonym)
  » Species Unio pinchonianus Heude, 1883 accepted as Pseudodon pinchonianus (Heude, 1883) (unaccepted)
  » Species Unio pinei Wright, B.H., 1897 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio pinguis I. Lea, 1857 accepted as Ortmanniana ligamentina (Lamarck, 1819) (unaccepted)
  » Species Unio pinkstonii Wright, S.H., 1897 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio pisciculus Heude, 1874 accepted as Cuneopsis pisciculus (Heude, 1874) (unaccepted, basionym)
  » Species Unio placidus Küster, 1862 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio placitus I. Lea, 1852 accepted as Hamiota perovalis (Conrad, 1834) (unaccepted)
  » Species Unio plancus I. Lea, 1860 accepted as Villosa nebulosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio planicostatus I. Lea, 1860 accepted as Cambarunio nebulosus (Conrad, 1834) (unaccepted, synonym)
  » Species Unio planilateris Conrad, 1838 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio planior I. Lea, 1868 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio plantii I. Lea, 1857 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio planulatus I. Lea, 1829 accepted as Ptychobranchus fasciolaris (Rafinesque, 1820) (unaccepted)
  » Species Unio planus Barnes, 1823 accepted as Leptodea fragilis (Rafinesque, 1820) (unaccepted)
  » Species Unio pleasii Marsh, 1891 accepted as Venustaconcha pleasii (Marsh, 1891) (unaccepted, original combination)
  » Species Unio plectophorus Conrad, 1849 accepted as Elliptoideus sloatianus (I. Lea, 1840) (unaccepted)
  » Species Unio plectrophorus Conrad, 1849 accepted as Elliptoideus sloatianus (I. Lea, 1840) (unaccepted)
  » Species Unio plenus I. Lea, 1840 accepted as Pleurobema plenum (I. Lea, 1840) (unaccepted, original combination)
  » Species Unio plexus Conrad, 1838 accepted as Barynaias plexus (Conrad, 1838) (unaccepted, basionym)
  » Species Unio plicata Say, 1817 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio plicatulus Küster, 1856 accepted as Nephronaias plicatula (Küster, 1856) (unaccepted, basionym)
  » Species Unio plicatulus I. Lea, 1859 accepted as Unio borneeensis Issel, 1874 (unaccepted, invalid: junior homonym of Unio plicatulus Küster, 1856; U. borneensis is a replacement name)
  » Species Unio pliciferus I. Lea, 1838 accepted as Barynaias plexus (Conrad, 1838) (unaccepted)
  » Species Unio poeyanus I. Lea, 1857 accepted as Nephritica poeyana (I. Lea, 1857) (unaccepted, basionym)
  » Species Unio politus Conrad, 1837 accepted as Fusconaia subrotunda (I. Lea, 1831) (unaccepted)
  » Species Unio polymorphus Wright, B.H., 1899 accepted as Elliptio monroensis (I. Lea, 1843) (unaccepted)
  » Species Unio polysticta Heude, 1877 accepted as Gibbosula polysticta (Heude, 1877) (unaccepted, basionym)
  » Species Unio popeii I. Lea, 1857 accepted as Popenaias popeii (I. Lea, 1857) (unaccepted, original combination)
  » Species Unio popenoi Call, 1885 accepted as Cyprogenia aberti (Conrad, 1850) (unaccepted)
  » Species Unio porphyreus I. Lea, 1861 accepted as Villosa umbrans (I. Lea, 1857) (unaccepted, synonym)
  » Species Unio porrectus Conrad, 1854 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio postellii I. Lea, 1858 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio poulsoni Conrad, 1834 accepted as Potamilus purpuratus (Lamarck, 1819) (unaccepted)
  » Species Unio powellii I. Lea, 1852 accepted as Lampsilis powellii (I. Lea, 1852) (unaccepted)
  » Species Unio praelongus Barnes, 1823 accepted as Ligumia recta (Lamarck, 1819) (unaccepted)
  » Species Unio prasinatus Conrad, 1866 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio prasinus Conrad, 1834 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted)
  » Species Unio prattii I. Lea, 1858 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio premorsus Rafinesque, 1831 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted)
  » Species Unio preobrazhenskii Lindholm, 1932 † accepted as Heterunio preobrazhenskii (Lindholm, 1932) † (unaccepted, original combination)
  » Species Unio pressus I. Lea, 1843 accepted as Lasmigona compressa (I. Lea, 1829) (unaccepted)
  » Species Unio prevostianus I. Lea, 1852 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio productus Conrad, 1836 accepted as Elliptio producta (Conrad, 1836) (unaccepted)
  » Species Unio profugus Gould, 1850 accepted as Alathyria profuga (Gould, 1850) (unaccepted)
  » Species Unio propecoelatus de Gregorio, 1914 accepted as Pegias fabula (I. Lea, 1838) (unaccepted)
  » Species Unio propesulcatus de Gregorio, 1914 accepted as Epioblasma obliquata (Rafinesque, 1820) (unaccepted)
  » Species Unio propeverutus de Gregorio, 1914 accepted as Eurynia dilatata (Rafinesque, 1820) (unaccepted)
  » Species Unio propinquus I. Lea, 1857 accepted as Epioblasma propinqua (I. Lea, 1857) (unaccepted)
  » Species Unio proprius I. Lea, 1865 accepted as Villosa umbrans (I. Lea, 1857) (unaccepted, synonym)
  » Species Unio protensus I. Lea, 1865 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio protovittatus Hale & Tindale, 1930 accepted as Velesunio ambiguus (Philippi, 1847) (unaccepted, junior synonym)
  » Species Unio protractus Lindholm, 1932 accepted as Unio pictorum (Linnaeus, 1758) (unaccepted)
    » Subspecies Unio protractus subpictorum Lindholm, 1932 † accepted as Unio protractus Lindholm, 1932 (a junior synonym)
  » Species Unio proximus I. Lea, 1852 accepted as Villosa delumbis (Conrad, 1834) (unaccepted, synonym)
  » Species Unio psammactinus Philippi, 1849 accepted as Diplodon multistriatus (I. Lea, 1831) (unaccepted)
  » Species Unio psammoica d'Orbigny, 1835 accepted as Castalia psammoica (d'Orbigny, 1835) (unaccepted, basionym)
  » Species Unio psoricus Morelet, 1851 accepted as Psoronaias semigranosa (Philippi, 1843) (unaccepted, a junior synonym)
  » Species Unio pudicus I. Lea, 1860 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio pugio Benson, 1862 accepted as Indochinella pugio (Benson, 1862) (unaccepted, original combination)
  » Species Unio pulcher I. Lea, 1838 accepted as Cambarunio taeniatus pictus (I. Lea, 1834) (unaccepted, synonym)
  » Species Unio pullatis I. Lea, 1857 accepted as Unio pullatus I. Lea, 1857 (unaccepted, incorrect original spelling)
  » Species Unio pullatus I. Lea, 1857 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio pullescens I. Lea, 1845 accepted as Lampsilis straminea (Conrad, 1834) (unaccepted, incorrect original spelling)
  » Species Unio pullus Conrad, 1838 accepted as Toxolasma pullus (Conrad, 1838) (unaccepted)
  » Species Unio pulvinulus I. Lea, 1845 accepted as Pleurobema rubellum (Conrad, 1834) (unaccepted)
  » Species Unio pumilus I. Lea, 1838 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio punctatus I. Lea, 1865 accepted as Cambarunio taeniatus punctatus (Lea, 1865) (unaccepted, original combination)
  » Species Unio puniceus Haldeman, 1842 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio purpurascens Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio purpurata Lamarck, 1819 accepted as Potamilus purpuratus (Lamarck, 1819) (unaccepted)
  » Species Unio purpurellus I. Lea, 1857 accepted as Elliptio purpurella (I. Lea, 1857) (unaccepted)
  » Species Unio purpureus Say, 1817 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted, original combination)
  » Species Unio purpuriatus Say, 1831 accepted as Disconaias purpuriata (Say, 1831) (unaccepted, original combination)
  » Species Unio purus I. Lea, 1858 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio pusillus I. Lea, 1840 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio pustulata Swainson, 1840 accepted as Tritogonia verrucosa (Rafinesque, 1820) (unaccepted)
  » Species Unio pustulatus I. Lea, 1831 accepted as Rotundaria nodulata (Rafinesque, 1820) (unaccepted)
  » Species Unio pustulosus I. Lea, 1831 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio pybasii I. Lea, 1858 accepted as Villosa vanuxemensis (I. Lea, 1838) (unaccepted)
  » Species Unio pygmaeus I. Lea, 1852 accepted as Lasmigona subviridis (Conrad, 1835) (unaccepted)
  » Species Unio pyramidatus I. Lea, 1831 accepted as Pleurobema rubrum (Rafinesque, 1820) (unaccepted)
  » Species Unio pyriformis I. Lea, 1857 accepted as Pleurobema pyriforme (I. Lea, 1857) (unaccepted)
  » Species Unio quadrans I. Lea, 1860 accepted as Glebula rotundata (Lamarck, 1819) (unaccepted)
  » Species Unio quadratus I. Lea, 1859 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio quadrilaterus I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio quadrulus (Rafinesque, 1820) accepted as Quadrula quadrula (Rafinesque, 1820) (unaccepted)
  » Species Unio quintardii Cragin, 1887 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio radians I. Lea, 1857 accepted as Villosa nebulosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio radiatus (Gmelin, 1791) accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio radiolus I. Lea, 1871 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio radiosus I. Lea, 1871 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio radulosus Drouët & Chaper, 1892 accepted as Discomya radulosa (Drouët & Chaper, 1892) (unaccepted, original combination)
  » Species Unio raeensis I. Lea, 1859 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio rafinesquei Vanatta, 1915 accepted as Elliptio occulta (I. Lea, 1843) (unaccepted)
  » Species Unio rajahensis I. Lea, 1841 accepted as Parreysia rajahensis (I. Lea, 1841) (unaccepted, basionym)
  » Species Unio raleighensis I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio rangianus I. Lea, 1838 accepted as Epioblasma rangiana (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio rariplicata Lamarck, 1819 accepted as Amblema plicata (Say, 1817) (unaccepted)
  » Species Unio rarisulcata Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio ratidotus Charmes, 1885 accepted as Coelatura ratidota (Charmes, 1885) (unaccepted, original combination)
  » Species Unio ratus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio raveneli Conrad, 1834 accepted as Elliptio raveneli (Conrad, 1834) (unaccepted, original combination)
  » Species Unio ravenelianus I. Lea, 1834 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio ravistellus Morelet, 1849 accepted as Nephronaias ravistella (Morelet, 1849) (unaccepted, basionym)
  » Species Unio reclusus Wright, B.H., 1898 accepted as Pleurobema pyriforme (I. Lea, 1857) (unaccepted)
  » Species Unio recta Lamarck, 1819 accepted as Ligumia recta (Lamarck, 1819) (unaccepted)
  » Species Unio rectangularis Tapparone Canefri, 1889 accepted as Indonaia rectangularis (Tapparone Canefri, 1889) (unaccepted, original combination)
  » Species Unio rectus (Lamarck, 1819) accepted as Ligumia recta (Lamarck, 1819) (unaccepted)
  » Species Unio recurvatus I. Lea, 1871 accepted as Pleuronaia dolabelloides (I. Lea, 1840) (unaccepted)
  » Species Unio reeveianus I. Lea, 1852 accepted as Lampsilis reeveiana (I. Lea, 1852) (unaccepted)
  » Species Unio refulgens I. Lea, 1868 accepted as Cyclonaias refulgens (Lea, 1868) (unaccepted, original combination)
  » Species Unio regularis I. Lea, 1841 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio reinianus Kobelt, 1879 accepted as Inversiunio reinianus (Kobelt, 1879) (unaccepted, basionym)
  » Species Unio requienii Michaud, 1831 accepted as Unio mancus requienii Michaud, 1831 (unaccepted, original rank)
  » Species Unio retiarius Heude, 1883 accepted as Acuticosta retiaria (Heude, 1883) (unaccepted, basionym)
  » Species Unio retusa Lamarck, 1819 accepted as Obovaria retusa (Lamarck, 1819) (unaccepted)
  » Species Unio rhombeus Spix, 1827 accepted as Diplodon rhombeus (Spix, 1827) (unaccepted, basionym)
  » Species Unio rhombula Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio rhuacoica d'Orbigny, 1835 accepted as Diplodon rhuacoicus (d'Orbigny, 1835) (unaccepted, basionym)
  » Species Unio rhuaconicus Küster, 1856 accepted as Diplodon ellipticus Spix, 1827 (unaccepted)
  » Species Unio ribeiroi Fontannes, 1883 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio riddellii I. Lea, 1862 accepted as Pleurobema riddellii (I. Lea, 1862) (unaccepted)
  » Species Unio ridibundus Say, 1829 accepted as Epioblasma obliquata (Rafinesque, 1820) (unaccepted)
  » Species Unio rivicolus Conrad, 1868 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio rivularis Conrad, 1853 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio roanokensis I. Lea, 1838 accepted as Elliptio roanokensis (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio robustus Lindholm, 1932 † accepted as Betekeia athleta (Lindholm, 1932) † (unaccepted, a junior synonym)
    » Subspecies Unio robustus robustus Lindholm, 1932 † (taxon inquirendum)
    » Subspecies Unio robustus fortis Lindholm, 1932 † accepted as Betekeia athleta (Lindholm, 1932) † (a junior synonym)
  » Species Unio robustus Drouët, 1879 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted, invalid: junior homonym of Unio robustus J. de C. Sowerby, 1840; U. larius is a replacement name)
  » Species Unio rochechouartii Heude, 1875 accepted as Gibbosula rochechouartii (Heude, 1875) (unaccepted, original combination)
  » Species Unio rosaceus Conrad, 1849 accepted as Leptodea ochracea (Say, 1817) (unaccepted)
  » Species Unio rosaceus DeKay, 1843 accepted as Lampsilis siliquoidea (Barnes, 1823) (unaccepted)
  » Species Unio rostellum I. Lea, 1872 accepted as Elliptio folliculata (I. Lea, 1838) (unaccepted)
  » Species Unio rostraeformis I. Lea, 1857 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio rostratus Lamarck, 1819 accepted as Unio pictorum (Linnaeus, 1758) (unaccepted)
  » Species Unio rostrum I. Lea, 1862 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio roswellensis I. Lea, 1858 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio rotulatus Wright, B.H., 1899 accepted as Reginaia rotulata (Wright, B.H., 1899) (unaccepted)
  » Species Unio rotundata Lamarck, 1819 accepted as Glebula rotundata (Lamarck, 1819) (unaccepted, original combination)
  » Species Unio rotundatus (Lamarck, 1819) accepted as Glebula rotundata (Lamarck, 1819) (unaccepted)
  » Species Unio rotundus Spix, 1827 accepted as Diplodon rotundus (Spix, 1827) (unaccepted)
  » Species Unio rowellii I. Lea, 1859 accepted as Nephronaias rowellii (I. Lea, 1859) (unaccepted, basionym)
  » Species Unio rubellinus I. Lea, 1857 accepted as Medionidus acutissimus (I. Lea, 1831) (unaccepted)
  » Species Unio rubellus Conrad, 1834 accepted as Pleurobema rubellum (Conrad, 1834) (unaccepted)
  » Species Unio rubicundus Martens, 1900 accepted as Martensnaias rubicunda (Martens, 1900) (unaccepted, original combination)
  » Species Unio rubidus I. Lea, 1861 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio rubiginosus I. Lea, 1829 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio rudis Conrad, 1837 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio rufescens Heude, 1874 accepted as Cuneopsis rufescens (Heude, 1874) (unaccepted, basionym)
  » Species Unio ruffonii Adami, 1886 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio rufus I. Lea, 1857 accepted as Elliptio arca (Conrad, 1834) (unaccepted)
  » Species Unio rufusculus I. Lea, 1852 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio rugososulcatus I. Lea, 1866 accepted as Pachynaias rugososulcata (I. Lea, 1866) (unaccepted, a junior synonym)
  » Species Unio rugosus Barnes, 1823 accepted as Quadrula quadrula (Rafinesque, 1820) (unaccepted)
  » Species Unio rugulosus Küster, 1856 accepted as Nephronaias rugulosa (Küster, 1856) (unaccepted, basionym)
  » Species Unio rumphianus I. Lea, 1852 accepted as Quadrula rumphiana (I. Lea, 1852) (unaccepted)
  » Species Unio rusticus I. Lea, 1856 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio rusticus Pini, 1885 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted, invalid: junior homonym of Unio rusticus I. Lea, 1856)
  » Species Unio rutersvillensis I. Lea, 1859 accepted as Ligumia subrostrata (Say, 1831) (unaccepted, synonym)
  » Species Unio rutilans I. Lea, 1857 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio saccatus Küster, 1862 accepted as Epioblasma florentina (I. Lea, 1857) (unaccepted)
  » Species Unio saccellus Drouet & Chaper, 1892 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio sacculus Reeve, 1864 accepted as Epioblasma florentina (I. Lea, 1857) (unaccepted)
  » Species Unio sacellus Simpson, 1900 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, in error for Unio saccellus Drouet & Chaper, 1892)
  » Species Unio sageri Conrad, 1836 accepted as Ligumia recta (Lamarck, 1819) (unaccepted)
  » Species Unio sagittarius I. Lea, 1856 accepted as Ensidens sagittarius (I. Lea, 1856) (unaccepted, basionym)
  » Species Unio sagittiformis I. Lea, 1852 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio saladoensis Lea, 1860 accepted as Cyrtonaias saladoensis (Lea, 1860) (unaccepted, original combination)
  » Species Unio salebrosus I. Lea, 1859 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio sallei Crosse & P. Fischer, 1893 accepted as Barynaias sallei (Crosse & P. Fischer, 1893) (unaccepted, basionym)
  » Species Unio sampsonii I. Lea, 1862 accepted as Epioblasma sampsonii (I. Lea, 1862) (unaccepted)
  » Species Unio sandrii Rossmässler, 1844 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio santeensis I. Lea, 1871 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio sapotalensis I. Lea, 1841 accepted as Actinonaias sapotalensis (I. Lea, 1841) (unaccepted, original combination)
  » Species Unio sapperi Ihering, 1901 accepted as Cyrtonaias sapperi (Ihering, 1901) (unaccepted, original combination)
  » Species Unio satillaensis I. Lea, 1858 accepted as Elliptio downiei (I. Lea, 1858) (unaccepted)
  » Species Unio satur I. Lea, 1852 accepted as Lampsilis satura (I. Lea, 1852) (unaccepted, original combination)
  » Species Unio savannahensis I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio saxeus Conrad, 1838 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio sayii Ward in Tappan, 1839 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio scalenius (Rafinesque, 1820) accepted as Pleurobema clava (Lamarck, 1819) (unaccepted)
  » Species Unio scamnatus Morelet, 1849 accepted as Nephronaias scamnata (Morelet, 1849) (unaccepted)
  » Species Unio schoolcraftensis I. Lea, 1834 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted)
  » Species Unio schrencki Westerlund, 1897 accepted as Nodularia douglasiae (Gray, 1833) (unaccepted)
  » Species Unio scitulus I. Lea, 1860 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio scobinatus I. Lea, 1856 accepted as Scabies scobinatus (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio scriptus Heude, 1875 accepted as Aculamprotula scripta (Heude, 1875) (unaccepted, basionym)
  » Species Unio scutulatus Morelet, 1849 accepted as Delphinonaias scutulata (Morelet, 1849) (unaccepted, basionym)
  » Species Unio scutum G. B. Sowerby II, 1868 accepted as Trapezidens scutum (G. B. Sowerby II, 1868) (unaccepted, original combination)
  » Species Unio securiformis Conrad, 1849 accepted as Rotundaria infucata (Conrad, 1834) (unaccepted)
  » Species Unio securis I. Lea, 1829 accepted as Ellipsaria lineolata (Rafinesque, 1820) (unaccepted)
  » Species Unio segregatus Drouët, 1896 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio semidecoratus Morlet, 1889 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio semigranosus Philippi, 1843 accepted as Psoronaias semigranosa (Philippi, 1843) (unaccepted, basionym)
  » Species Unio semiplicatus Küster, 1862 accepted as Medionidus acutissimus (I. Lea, 1831) (unaccepted)
  » Species Unio semirugata Lamarck, 1819 accepted as Potomida semirugata (Lamarck, 1819) (unaccepted, original combination)
  » Species Unio semmelinki von Martens, 1891 accepted as Contradens semmelinki (von Martens, 1891) (unaccepted, basionym)
  » Species Unio shepardianus I. Lea, 1834 accepted as Elliptio shepardiana (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio showalterii I. Lea, 1860 accepted as Pleurobema hartmanianum (I. Lea, 1860) (unaccepted)
  » Species Unio shurtleffianus I. Lea, 1856 accepted as Indonaia shurtleffiana (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio shuttleworthii I. Lea, 1856 accepted as Alathyria pertexta Iredale, 1934 (unaccepted, invalid, junior homonym of Unio shuttleworthi Küster, 1856)
  » Species Unio siamensis Morlet, 1889 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio sibiricus Lindholm, 1932 † accepted as Cuneopsis sibiricus (Lindholm, 1932) † (unaccepted, basionym)
  » Species Unio sikkimensis I. Lea, 1859 accepted as Parreysia sikkimensis (I. Lea, 1859) (unaccepted, basionym)
  » Species Unio siliquatus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio siliquoideus Barnes, 1823 accepted as Lampsilis siliquoidea (Barnes, 1823) (unaccepted, original combination)
  » Species Unio similis I. Lea, 1857 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio simplex I. Lea, 1845 accepted as Ptychobranchus greenii (Conrad, 1834) (unaccepted)
  » Species Unio simpsoni Wright, B.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio simulans I. Lea, 1871 accepted as Pleurobema perovatum (Conrad, 1834) (unaccepted)
  » Species Unio simus I. Lea, 1838 accepted as Villosa sima (Lea, 1838) (unaccepted, original combination)
  » Species Unio singleyanus Marsh, 1891 accepted as Villosa amygdalum (I. Lea, 1843) (unaccepted, synonym)
  » Species Unio singularis Wright, B.H., 1899 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio sinuatus Lamarck, 1819 accepted as Margaritifera auricularia (Spengler, 1793) (unaccepted)
  » Species Unio sloatianus I. Lea, 1840 accepted as Elliptoideus sloatianus (I. Lea, 1840) (unaccepted, original combination)
  » Species Unio smaragdinus Anton, 1838 accepted as Cristaria plicata (Leach, 1814) (unaccepted, junior synonym)
  » Species Unio smaragdites Benson, 1862 accepted as Parreysia smaragdites (Benson, 1862) (unaccepted, basionym)
  » Species Unio smithii Gray in Griffith & Pidgeon, 1833 accepted as Diplodon chilensis (Gray, 1828) (unaccepted, junior synonym)
  » Species Unio soboles Fischer, 1891 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio solandri J. de C. Sowerby, 1826 † accepted as Palindonaia solandri (J. de C. Sowerby, 1826) † (unaccepted, original combination)
  » Species Unio soleniformis I. Lea, 1831 accepted as Margaritifera monodonta (Say, 1829) (unaccepted)
  » Species Unio solidulus Philippi, 1869 accepted as Diplodon solidulus (Philippi, 1869) (unaccepted, basionym)
  » Species Unio solidus I. Lea, 1838 accepted as Pleurobema sintoxia (Rafinesque, 1820) (unaccepted)
  » Species Unio solisiana d'Orbigny, 1835 accepted as Diplodon solisianus (d'Orbigny, 1835) (unaccepted, basionym)
  » Species Unio sordidis I. Lea, 1852 accepted as Unio sordidus I. Lea, 1852 (unaccepted, incorrect original spelling)
  » Species Unio sordidus I. Lea, 1852 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio sowerbianus I. Lea, 1834 accepted as Epioblasma haysiana (I. Lea, 1834) (unaccepted)
  » Species Unio spadiceus I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio sparsus I. Lea, 1841 accepted as Theliderma sparsa (I. Lea, 1841) (unaccepted, original combination)
  » Species Unio sparsus Küster, 1861 accepted as Rotundaria kleiniana (I. Lea, 1852) (unaccepted, invalid, a junior homonym of Unio sparsus I. Lea, 1841)
  » Species Unio sparus I. Lea, 1868 accepted as Cambarunio jonesii (Lea, I., 1859) (unaccepted, synonym)
  » Species Unio spatulatus I. Lea, 1845 accepted as Venustaconcha ellipsiformis (Conrad, 1836) (unaccepted, synonym)
  » Species Unio speciosus I. Lea, 1862 accepted as Quadrula apiculata (Say, 1829) (unaccepted)
  » Species Unio sphaericus I. Lea, 1868 accepted as Rotundaria refulgens (I. Lea, 1868) (unaccepted)
  » Species Unio spheniopsis Morelet, 1849 accepted as Pachynaias spheniopsis (Morelet, 1849) (unaccepted, original combination)
  » Species Unio sphenorhynchus Crosse & P. Fischer, 1893 accepted as Nephronaias sphenorhyncha (Crosse & P. Fischer, 1893) (unaccepted)
  » Species Unio spillmanii I. Lea, 1861 accepted as Hamiota perovalis (Conrad, 1834) (unaccepted)
  » Species Unio spinellii Spinelli, 1852 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio spinosus I. Lea, 1836 accepted as Elliptio spinosa (I. Lea, 1836) (unaccepted, original combination)
  » Species Unio spissus I. Lea, 1859 accepted as Elliptio downiei (I. Lea, 1858) (unaccepted)
  » Species Unio squalidus I. Lea, 1863 accepted as Uniomerus carolinianus (Bosc, 1801) (unaccepted)
  » Species Unio squameus I. Lea, 1862 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio stabilis I. Lea, 1861 accepted as Pleurobema stabilis (I. Lea, 1861) (unaccepted)
  » Species Unio stagnalis Conrad, 1849 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio stagnorum Dautzenberg, 1890 accepted as Coelatura stagnorum (Dautzenberg, 1890) (unaccepted, original combination)
  » Species Unio stapes I. Lea, 1831 accepted as Theliderma stapes (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio stephaninii Adami, 1882 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio stewardsonii I. Lea, 1852 accepted as Epioblasma stewardsonii (I. Lea, 1852) (unaccepted)
  » Species Unio stolatus von Martens, 1900 accepted as Prohyriopsis stolata (von Martens, 1900) (unaccepted, basionym)
  » Species Unio stonensis I. Lea, 1840 accepted as Eurynia dilatata (Rafinesque, 1820) (unaccepted)
  » Species Unio stramineus Conrad, 1834 accepted as Lampsilis straminea (Conrad, 1834) (unaccepted, original combination)
  » Species Unio striatissimus J. G. Anthony, 1865 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio striatulus I. Lea, 1857 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio striatus I. Lea, 1840 accepted as Pleurobema pyriforme (I. Lea, 1857) (unaccepted)
  » Species Unio strictiplicatus Noulet, 1864 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio strigosus I. Lea, 1840 accepted as Elliptio arctata (Conrad, 1834) (unaccepted)
  » Species Unio strobeli Bourguignat, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio strodeanus Wright, B.H., 1898 accepted as Pleurobema strodeanum (Wright, B.H., 1898) (unaccepted)
  » Species Unio strumosus I. Lea, 1872 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio strumosus I. Lea, 1874 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio stuhlmanni von Martens, 1897 accepted as Coelatura stuhlmanni (von Martens, 1897) (unaccepted, original combination)
  » Species Unio suavidicus I. Lea, 1856 accepted as Diplodon suavidicus (I. Lea, 1856) (unaccepted, basionym)
  » Species Unio subangulatus I. Lea, 1840 accepted as Hamiota subangulata (I. Lea, 1840) (unaccepted, original combination)
  » Species Unio subcroceus Conrad, 1854 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio subcylindraceus I. Lea, 1874 accepted as Elliptio angustata (I. Lea, 1831) (unaccepted)
  » Species Unio subcylindricus Drouët, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio subellipsis I. Lea, 1857 accepted as Villosa lienosa (Conrad, 1834) (unaccepted, synonym)
  » Species Unio subellipticus Lindholm, 1932 † accepted as Betekeia subelliptica (Lindholm, 1932) † (unaccepted, original combination)
  » Species Unio subflavus I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio subgibbosus I. Lea, 1857 accepted as Elliptio arca (Conrad, 1834) (unaccepted)
  » Species Unio subglobatus I. Lea, 1871 accepted as Pleuronaia dolabelloides (I. Lea, 1840) (unaccepted)
  » Species Unio subglobosus I. Lea, 1834 accepted as Glebula rotundata (Lamarck, 1819) (unaccepted)
  » Species Unio subinflatus (Conrad, 1835) accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio sublatus I. Lea, 1857 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio subluridus Simpson, 1892 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio subniger I. Lea, 1857 accepted as Elliptio fumata (I. Lea, 1857) (unaccepted)
  » Species Unio subolivaceus I. Lea, 1874 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio suborbiculata Lamarck, 1819 accepted as Glebula rotundata (Lamarck, 1819) (unaccepted)
  » Species Unio subovatus I. Lea, 1831 accepted as Lampsilis cardium Rafinesque, 1820 (unaccepted)
  » Species Unio subparallelus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio subplanus Conrad, 1837 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio subrostratus Say, 1831 accepted as Ligumia subrostrata (Say, 1831) (unaccepted, original combination)
  » Species Unio subrotundus I. Lea, 1831 accepted as Fusconaia subrotunda (I. Lea, 1831) (unaccepted, original combination)
  » Species Unio subsquamosus I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio substriatus I. Lea, 1856 accepted as Indonaia substriata (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio subtentus Say, 1825 accepted as Ptychobranchus subtentus (Say, 1825) (unaccepted)
  » Species Unio subteritus (Say, 1825) accepted as Ptychobranchus subtentus (Say, 1825) (unaccepted)
  » Species Unio subtontus Say, 1825 accepted as Ptychobranchus subtentus (Say, 1825) (unaccepted)
  » Species Unio subtrigonus Noulet, 1864 † accepted as Margaritifera (Pseudunio) flabellata (Goldfuss, 1837) † (unaccepted)
  » Species Unio subviridis Conrad, 1835 accepted as Lasmigona subviridis (Conrad, 1835) (unaccepted)
  » Species Unio succineus Drouët, 1881 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio succissus I. Lea, 1852 accepted as Cyclonaias succissa (Lea, 1852) (unaccepted, original combination)
  » Species Unio sudus I. Lea, 1857 accepted as Villosa vibex (Conrad, 1834) (unaccepted, synonym)
  » Species Unio sulcatus I. Lea, 1829 accepted as Epioblasma obliquata (Rafinesque, 1820) (unaccepted)
  » Species Unio sulcidens Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio sumatrensis I. Lea, 1859 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio sumatrensis Dunker, 1852 accepted as Rectidens sumatrensis (Dunker, 1852) (unaccepted, basionym)
  » Species Unio superbus I. Lea, 1843 accepted as Physunio superbus (I. Lea, 1843) (unaccepted)
  » Species Unio superiorensis Marsh, 1897 accepted as Lampsilis siliquoidea (Barnes, 1823) (unaccepted)
  » Species Unio superstes Neumayr, 1899 accepted as Rhombuniopsis superstes (Neumayr, 1899) (unaccepted)
  » Species Unio suttoni Wright, B.H., 1897 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio swainsoni Sowerby, 1868 accepted as Alasmidonta undulata (Say, 1817) (unaccepted)
  » Species Unio swananoensis Hanley, 1843 accepted as Alasmidonta raveneliana (I. Lea, 1834) (unaccepted)
  » Species Unio swordianus Wright, S.H., 1897 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio symmetricus I. Lea, 1845 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio tabascoensis Küster, 1856 accepted as Nephronaias tabascoensis (Küster, 1856) (unaccepted, basionym)
  » Species Unio taeniatus Conrad, 1834 accepted as Villosa taeniata (Conrad, 1834) (unaccepted, original combination)
  » Species Unio tahetianus (I. Lea, 1834) accepted as Pleurobema taitianum (I. Lea, 1834) (unaccepted)
  » Species Unio taitianus I. Lea, 1834 accepted as Pleurobema taitianum (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio tamaulipasensis Crosse & P. Fischer, 1894 accepted as Sphenonaias taumilapana (Conrad, 1855) (unaccepted)
  » Species Unio tampicoensis I. Lea, 1838 accepted as Cyrtonaias tampicoensis (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio tanganyicensis E. A. Smith, 1880 accepted as Grandidieria burtoni (Woodward, 1859) (unaccepted, junior synonym)
  » Species Unio tappanianus I. Lea, 1838 accepted as Lasmigona subviridis (Conrad, 1835) (unaccepted)
  » Species Unio taumilapanus Conrad, 1855 accepted as Sphenonaias taumilapana (Conrad, 1855) (unaccepted)
  » Species Unio tavoyensis Gould, 1843 accepted as Leoparreysia tavoyensis (Gould, 1843) (unaccepted, original combination)
  » Species Unio tecomatensis I. Lea, 1841 accepted as Cyrtonaias tampicoensis (I. Lea, 1838) (unaccepted)
  » Species Unio tecomensis (I. Lea, 1841) accepted as Cyrtonaias tampicoensis (I. Lea, 1838) (unaccepted, incorrect subsequent spelling)
  » Species Unio tehuantepecensis Crosse & P. Fischer, 1893 accepted as Popenaias tehuantepecensis (Crosse & P. Fischer, 1893) (unaccepted, basionym)
  » Species Unio tellicoensis I. Lea, 1872 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio tenebricus I. Lea, 1857 accepted as Villosa umbrans (I. Lea, 1857) (unaccepted, synonym)
  » Species Unio tenebrosus Conrad, 1834 accepted as Lampsilis radiata (Gmelin, 1791) (unaccepted)
  » Species Unio tener I. Lea, 1840 accepted as Villosa iris (I. Lea, 1829) (unaccepted, synonym)
  » Species Unio tenerus Simpson, 1892 accepted as Villosa delumbis (Conrad, 1834) (unaccepted, synonym)
  » Species Unio tennesseensis I. Lea, 1840 accepted as Cambarunio taeniatus pictus (I. Lea, 1834) (unaccepted, synonym)
  » Species Unio tenuis Griffith & Pidgeon, 1833 accepted as Pletholophus tenuis (Gray in Griffith & Pidgeon, 1833) (unaccepted, basionym)
  » Species Unio tenuisculus Frierson, 1911 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio tenuissimus (I. Lea, 1829) accepted as Leptodea leptodon (Rafinesque, 1820) (unaccepted, recombination)
  » Species Unio teretiusculus Philippi, 1847 accepted as Nitia teretiuscula Philippi, 1847 (unaccepted, basionym)
  » Species Unio tesserulae I. Lea, 1862 accepted as Pleurobema oviforme (Conrad, 1834) (unaccepted)
  » Species Unio tetralasmus Say, 1831 accepted as Uniomerus tetralasmus (Say, 1831) (unaccepted)
  » Species Unio tetricus I. Lea, 1857 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio texasensis I. Lea, 1857 accepted as Toxolasma texasiense (I. Lea, 1857) (unaccepted, incorrect subsequent spelling)
  » Species Unio texasiensis I. Lea, 1857 accepted as Toxolasma texasiense (I. Lea, 1857) (unaccepted)
  » Species Unio thaiensis Habe, 1964 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio theca Benson, 1862 accepted as Lamellidens theca (Benson, 1862) (unaccepted)
  » Species Unio thermalis Drouët, 1896 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio thorntonii I. Lea, 1857 accepted as Pleuronaia dolabelloides (I. Lea, 1840) (unaccepted)
  » Species Unio tientsinensis Crosse & Debeaux, 1863 accepted as Aculamprotula tientsinensis (Crosse & Debeaux, 1863) (unaccepted, basionym)
  » Species Unio tinkeri Wright, B.H., 1899 accepted as Obovaria unicolor (I. Lea, 1845) (unaccepted)
  » Species Unio tommasii Adami, 1886 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio topekaensis I. Lea, 1868 accepted as Ligumia subrostrata (Say, 1831) (unaccepted, synonym)
  » Species Unio tortivus I. Lea, 1840 accepted as Elliptio arctata (Conrad, 1834) (unaccepted)
  » Species Unio tortuosus Sowerby, 1868 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio tortuosus I. Lea, 1865 accepted as Aculamprotula tortuosa (Lea, 1865) (unaccepted, basionym)
  » Species Unio trabalis Conrad, 1834 accepted as Villosa trabalis (Conrad, 1834) (unaccepted, original combination)
  » Species Unio tracheae Kobelt & Rolle, 1895 accepted as Potomida semirugata (Lamarck, 1819) (unaccepted)
  » Species Unio trapezoides I. Lea, 1831 accepted as Plectomerus dombeyanus (Valenciennes, 1827) (unaccepted)
  » Species Unio triangularis Barnes, 1823 accepted as Epioblasma triquetra (Rafinesque, 1820) (unaccepted)
  » Species Unio triclavus Heude, 1877 accepted as Lamprotula triclava (Heude, 1877) (unaccepted, basionym)
  » Species Unio triembolus Benson, 1862 accepted as Parreysia triembola (Benson, 1862) (unaccepted, basionym)
  » Species Unio triformis Heude, 1877 accepted as Lanceolaria triformis (Heude, 1877) (unaccepted, basionym)
  » Species Unio trigonus I. Lea, 1831 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio trinacrus I. Lea, 1861 accepted as Ptychobranchus foremanianus (I. Lea, 1842) (unaccepted)
  » Species Unio trisulcatus Heude, 1883 accepted as Acuticosta trisulcata (Heude, 1883) (unaccepted, basionym)
  » Species Unio triumphans Wright, B.H., 1898 accepted as Megalonaias nervosa (Rafinesque, 1820) (unaccepted)
  » Species Unio trompi Drouёt & Chaper, 1892 accepted as Elongaria trompi (Drouёt & Chaper, 1892) (unaccepted)
  » Species Unio troostensis I. Lea, 1834 accepted as Venustaconcha troostensis (I. Lea, 1834) (unaccepted, original combination)
  » Species Unio troschelianus I. Lea, 1852 accepted as Pleurobema georgianum (I. Lea, 1841) (unaccepted)
  » Species Unio trosculus I. Lea, 1843 accepted as Unio trossulus I. Lea, 1843 (unaccepted, incorrect original spelling)
  » Species Unio trossulus I. Lea, 1843 accepted as Villosa amygdalum (I. Lea, 1843) (unaccepted, synonym)
  » Species Unio tryoni Wright, B.H., 1888 accepted as Elliptio jayensis (I. Lea, 1838) (unaccepted)
  » Species Unio tuberculatus Barnes, 1823 accepted as Tritogonia verrucosa (Rafinesque, 1820) (unaccepted)
  » Species Unio tuberosus I. Lea, 1840 accepted as Theliderma metanevra (Rafinesque, 1820) (unaccepted)
  » Species Unio tumescens I. Lea, 1845 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio tumidiformis Lindholm, 1932 accepted as Heterunio tumidiformis (Lindholm, 1932) † (unaccepted, original combination)
  » Species Unio tumidulus I. Lea, 1856 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio tuomeyi I. Lea, 1852 accepted as Elliptio cylindracea Frierson, 1927 (unaccepted)
  » Species Unio turgidulus I. Lea, 1858 accepted as Epioblasma turgidula (I. Lea, 1858) (unaccepted)
  » Species Unio turgidus I. Lea, 1838 accepted as Rotundaria pustulosa (I. Lea, 1831) (unaccepted)
  » Species Unio turtonii Payraudeau, 1826 accepted as Unio mancus turtonii Payraudeau, 1826 (unaccepted, original rank)
  » Species Unio tuscumbiensis I. Lea, 1871 accepted as Fusconaia cuneolus (I. Lea, 1840) (unaccepted)
  » Species Unio uber Conrad, 1866 accepted as Obovaria unicolor (I. Lea, 1845) (unaccepted)
  » Species Unio uhareensis I. Lea, 1868 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio umbrans I. Lea, 1857 accepted as Villosa umbrans (I. Lea, 1857) (unaccepted, original combination)
  » Species Unio umbrosus I. Lea, 1857 accepted as Villosa umbrans (I. Lea, 1857) (unaccepted, invalid, a junior homonym of Unio umbrosus I. Lea, 1856; replaced by Unio umbrans)
  » Species Unio umbrosus I. Lea, 1856 accepted as Cyrtonaias umbrosa (I. Lea, 1856) (unaccepted, original combination)
  » Species Unio undatus Barnes, 1823 accepted as Fusconaia flava (Rafinesque, 1820) (unaccepted)
  » Species Unio undulata Say, 1817 accepted as Alasmidonta undulata (Say, 1817) (unaccepted, original combination)
  » Species Unio undulatus Barnes, 1823 accepted as Amblema plicata (Say, 1817) (unaccepted, invalid: junior homonym of Unio undulata Say, 1817)
  » Species Unio unicolor I. Lea, 1845 accepted as Obovaria unicolor (I. Lea, 1845) (unaccepted, original combination)
  » Species Unio unicostatus Wright, B.H., 1899 accepted as Leaunio lienosus unicostatus (Wright, B.H., 1899) (unaccepted, original combination)
  » Species Unio upsonii Marsh, 1887 accepted as Ortmanniana ligamentina (Lamarck, 1819) (unaccepted)
  » Species Unio uruguayensis I. Lea, 1860 accepted as Diplodon uruguayensis (I. Lea, 1860) (unaccepted, basionym)
  » Species Unio usumasintae Crosse & P. Fischer, 1892 accepted as Psoronaias usumasintae (Crosse & P. Fischer, 1892) (unaccepted, basionym)
  » Species Unio utriculus I. Lea, 1845 accepted as Fusconaia masoni (Conrad, 1834) (unaccepted)
  » Species Unio validus I. Lea, 1871 accepted as Pleuronaia barnesiana (I. Lea, 1838) (unaccepted)
  » Species Unio vallatus I. Lea, 1868 accepted as Rotundaria asperata (I. Lea, 1861) (unaccepted)
  » Species Unio vanuxemensis I. Lea, 1838 accepted as Villosa vanuxemensis (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio varicosa Lamarck, 1819 accepted as Alasmidonta varicosa (Lamarck, 1819) (unaccepted)
  » Species Unio varicosus I. Lea, 1831 accepted as Plethobasus cicatricosus (Say, 1829) (unaccepted)
  » Species Unio vaughanianus I. Lea, 1838 accepted as Villosa vaughaniana (I. Lea, 1838) (unaccepted, original combination)
  » Species Unio veillanicus Bourguignat, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio velatus Conrad, 1854 accepted as Ptychobranchus foremanianus (I. Lea, 1842) (unaccepted)
  » Species Unio velthuizeni Schepman, 1896 accepted as Hyriopsis velthuizeni (Schepman, 1896) (unaccepted, basionym)
  » Species Unio velum Say, 1829 accepted as Leptodea leptodon (Rafinesque, 1820) (unaccepted)
  » Species Unio ventricosus Barnes, 1823 accepted as Lampsilis cardium Rafinesque, 1820 (unaccepted)
  » Species Unio venustus I. Lea, 1838 accepted as Venustaconcha ellipsiformis (Conrad, 1836) (unaccepted, synonym)
  » Species Unio veracruzensis I. Lea, 1868 accepted as Cyrtonaias umbrosa (I. Lea, 1856) (unaccepted)
  » Species Unio veraepacis Tristram, 1863 accepted as Popenaias popeii (I. Lea, 1857) (unaccepted)
  » Species Unio verbanicus Bourguignat, 1883 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio verbecki Martens, 1897 accepted as Contradens contradens (I. Lea, 1838) (unaccepted, junior synonym)
  » Species Unio verreauianus I. Lea, 1856 accepted as Unio caffer F. Krauss, 1848 (unaccepted, junior synonym)
  » Species Unio verrucosa Barnes, 1823 accepted as Unio verrucosus Barnes, 1823 (unaccepted, incorrect gender ending)
  » Species Unio verrucosus Barnes, 1823 accepted as Rotundaria tuberculata (Rafinesque, 1820) (unaccepted)
  » Species Unio verus I. Lea, 1861 accepted as Pleurobema verum (I. Lea, 1861) (unaccepted)
  » Species Unio verutus I. Lea, 1859 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio vesicularis I. Lea, 1872 accepted as Villosa amygdalum (I. Lea, 1843) (unaccepted, synonym)
  » Species Unio vestitus I. Lea, 1862 accepted as Elliptio congaraea (I. Lea, 1831) (unaccepted)
  » Species Unio vibex Conrad, 1834 accepted as Villosa vibex (Conrad, 1834) (unaccepted, original combination)
  » Species Unio vicinus I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio villosus B. H. Wright, 1898 accepted as Villosa villosa (B. H. Wright, 1898) (unaccepted, original combination)
  » Species Unio violaceus Spengler, 1793 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio virens I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio virescens I. Lea, 1858 accepted as Lampsilis virescens (I. Lea, 1858) (unaccepted, original combination)
  » Species Unio virginiana Lamarck, 1819 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio viridans I. Lea, 1859 accepted as Elliptio arctata (Conrad, 1834) (unaccepted)
  » Species Unio viridicatus I. Lea, 1857 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio viridiflavus Küster, 1854 accepted as Unio elongatulus C. Pfeiffer, 1825 (unaccepted)
  » Species Unio viridiradiatus I. Lea, 1859 accepted as Elliptio pullata (I. Lea, 1857) (unaccepted)
  » Species Unio viridulus I. Lea, 1863 accepted as Elliptio lanceolata (I. Lea, 1827) (unaccepted)
  » Species Unio vittatus I. Lea, 1859 accepted as Velesunio ambiguus (Philippi, 1847) (unaccepted, junior synonym)
  » Species Unio vulcanus Hanley, 1876 accepted as Leoparreysia vulcanus (Hanley, 1876) (unaccepted, original combination)
  » Species Unio waccamawensis I. Lea, 1863 accepted as Elliptio waccamawensis (I. Lea, 1863) (unaccepted)
  » Species Unio waikarensis Colenso, 1845 accepted as Echyridella menziesii (Gray, 1843) (unaccepted)
  » Species Unio walkeri Wright, S.H., 1897 accepted as Medionidus walkeri (Wright, S.H., 1897) (unaccepted)
  » Species Unio waltoni Wright, B.H., 1888 accepted as Elliptio ahenea (I. Lea, 1843) (unaccepted)
  » Species Unio wardii I. Lea, 1862 accepted as Theliderma metanevra (Rafinesque, 1820) (unaccepted)
  » Species Unio websterii Wright, B.H., 1888 accepted as Elliptio monroensis (I. Lea, 1843) (unaccepted)
  » Species Unio weldonensis I. Lea, 1863 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio wheatleyanus I. Lea, 1856 accepted as Diplodon (Rhipidodonta) burroughianus (I. Lea, 1834) (unaccepted, junior synonym)
  » Species Unio wheatleyi I. Lea, 1857 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio whiteianus I. Lea, 1852 accepted as Elliptio icterina (Conrad, 1834) (unaccepted)
  » Species Unio wilsonii I. Lea, 1859 accepted as Velesunio wilsonii (I. Lea, 1859) (unaccepted, original combination)
  » Species Unio woodwardius I. Lea, 1857 accepted as Ptychobranchus foremanianus (I. Lea, 1842) (unaccepted)
  » Species Unio wymanii I. Lea, 1860 accepted as Diplodon wymanii (I. Lea, 1860) (unaccepted, basionym)
  » Species Unio yadkinensis I. Lea, 1872 accepted as Elliptio complanata (Lightfoot, 1786) (unaccepted)
  » Species Unio yzabalensis Crosse & P. Fischer, 1892 accepted as Nephronaias yzabalensis (Crosse & P. Fischer, 1892) (unaccepted, basionym)
  » Species Unio zambesiensis Preston, 1905 accepted as Coelatura kunenensis (Mousson, 1888) (unaccepted, junior synonym)
  » Species Unio zeiglerianus I. Lea, 1838 accepted as Leaunio vanuxemensis (I. Lea, 1838) (unaccepted, synonym)
  » Species Unio zelebori Dunker, 1866 accepted as Cafferia caffra (Krauss, 1848) (unaccepted)
  » Species Unio zigzag I. Lea, 1829 accepted as Truncilla donaciformis (I. Lea, 1827) (unaccepted)
  » Species Unio zonatus Heude, 1883 accepted as Aculamprotula zonata (Heude, 1883) (unaccepted, basionym)
  » Subgenus Unio (Crassiana) Servain, 1882
  » Subgenus Unio (Limnium) Oken, 1815 (unavailable; incorrect subsequent spelling of Lymnium Oken, 1815)
    » Species Unio (Lymnium) foucauldiana Pallary, 1936 accepted as Unio foucauldianus Pallary, 1936 (original combination)
  » Species Unio phillipsii Williamson, 1836 † (invalid: a junior homonym of Unio phillip