Lamprotula similaris (C.T. Simpson, 1900)
Medionidus simpsonianus B. Walker, 1905
Unionelloides sinensis (FOSSIL) (Gu, 1976 †)
Pleurobema sintoxia C.S. Rafinesque, 1820
Elliptoideus sloatianus (I. Lea, 1840)
Parreysia smaragdites W.H. Benson, 1862
Unio solandrei (FOSSIL) Sowerby, 1826 †
Solenaia soleniformis (W.H. Benson, 1836)
Pseudodon solidus F. Haas, 1911
Harmandia somboriensis A. de Rochebrune, 1882
Harmandia somboriensis castelneaui A. de Rochebrune, 1904
Scabies songkramensis Kongim & S. Panha, 2015
Theliderma sparsa (I. Lea, 1841)
Pachynaias spheniopsis (P.M.A. Morelet, 1849)
Nephronaias sphenorhyncha (J.C.H. Crosse& P.H. Fischer, 1893)
Elliptio spinosa I. Lea, 1836
Schistodesmus spinosus C.T. Simpson, 1900
Lampsilis splendida I. Lea, 1838
Pleurobema stabilis (I. Lea, 1861)
Coelatura stagnorum (P. Dautzenberg, 1890)
Theliderma stapes (I. Lea, 1831)
Cyprogenia stegaria (C.S. Rafinesque, 1820)
Elliptio steinstansana R.I. Johnson & A.H. Clarke,1983
Epioblasma stewardsonii I. Lea, 1852
Prohyriopsis stolata (E.C. Von Martens, 1900)
Lampsilis straminea T.A. Conrad, 1834
Lampsilis straminea claibornensis I. Lea, 1838
Lampsilis streckeri L.S. Frierson, 1927
Unio stricklandii (FOSSIL) B. Phillips, 1871 †
Pleurobema strodeanum B.H. Wright, 1898
Coelatura stuhlmanni (E.C. Von Martens, 1897)
Hamiota subangulata (I. Lea, 1840)
Contradens subcircularis (R.A.M. Brandt, 1974)
Utterbackiana suborbiculata (T. Say, 1831)
Unionelloides subquadrata (FOSSIL) (X.T. Ma, 1999 †)