Lamprotula similaris (C.T. Simpson, 1900) Vietnam, Tonkin
Medionidus simpsonianus B. Walker, 1905 USA, Georgia
Unionelloides sinensis (FOSSIL) (Gu, 1976 †)
Pleurobema sintoxia C.S. Rafinesque, 1820 Alabama68,7 mm
Elliptoideus sloatianus (I. Lea, 1840) USA, Georgia
Parreysia smaragdites W.H. Benson, 1862 Myanmar, Matu
Unio solandrei (FOSSIL) Sowerby, 1826 † UK, England
Solenaia soleniformis (W.H. Benson, 1836) India, Assam
Pseudodon solidus F. Haas, 1911 Hunan, China
Harmandia somboriensis A. de Rochebrune, 1882 Cambodia
Harmandia somboriensis castelneaui A. de Rochebrune, 1904 Cambodia
Scabies songkramensis Kongim & S. Panha, 2015
Theliderma sparsa (I. Lea, 1841) Tennessee, Holston River
Pachynaias spheniopsis (P.M.A. Morelet, 1849) Guatemala
Nephronaias sphenorhyncha (J.C.H. Crosse& P.H. Fischer, 1893) Guatemala
Elliptio spinosa I. Lea, 1836 South Carolina40 mm
Schistodesmus spinosus C.T. Simpson, 1900 China, Poyang Lake34 mm
Lampsilis splendida I. Lea, 1838 USA, Georgia70,6 mm
Pleurobema stabilis (I. Lea, 1861) USA, Georgia
Coelatura stagnorum (P. Dautzenberg, 1890) Congo river
Theliderma stapes (I. Lea, 1831) Alabama
Cyprogenia stegaria (C.S. Rafinesque, 1820) Illinois38 mm
Elliptio steinstansana R.I. Johnson& A.H. Clarke, 1983 USA, North Carolina
Epioblasma stewardsonii I. Lea, 1852 Tennessee, Chattanooga
Prohyriopsis stolata (E.C. Von Martens, 1900) Indonesia, Sumatra
Lampsilis straminea T.A. Conrad, 1834 Alabama69,5 mm
Lampsilis straminea claibornensis I. Lea, 1838 Alabama83,2 mm
Lampsilis streckeri L.S. Frierson, 1927 Arkansas
Unio stricklandii (FOSSIL) B. Phillips, 1871 † UK, England, Oxfordshire
Pleurobema strodeanum B.H. Wright, 1898 Florida, Escambia County
Coelatura stuhlmanni (E.C. Von Martens, 1897) Zaire, Edward Lake
Hamiota subangulata (I. Lea, 1840) Georgia, Columbus
Contradens subcircularis (R.A.M. Brandt, 1974) Thailand, Mekong River
Utterbackiana suborbiculata (T. Say, 1831) Alabama
Unionelloides subquadrata (FOSSIL) (X.T. Ma, 1999 †)