Elliptio angustata I. Lea, 1831 Potomac River
Anodontoides angustifrons (FOSSIL) (F. McCoy, 1851 †) UK, England, Westmorland
Parreysia annandalei H.B. Preston, 1912 India, Assam
Quadrula apiculata T. Say, 1829 USA, Texas106,1 mm
Elliptio aquila (I. Lea, 1857) USA, Georgia51 mm
Micronaias arata (I. Lea, 1845) Nicaragua
Elliptio arca T.A. Conrad, 1834 Mississipi51 mm
Epioblasma arcaeformis (I. Lea, 1831) Alabama, Florence
Anemina arcaeformis (P.M. Heude, 1877) Poyang Lake, Jiangxi, China78 mm
Anemina arcaeformis flavotincta (E.C. Von Martens, 1905) Poyang Lake, Jiangxi, China
Elliptio arctata T.A. Conrad, 1834 Alabama
Unio arcuatus N.R. Bouchard-Chantereaux, 1838 France, La Saône59,3 mm
Alasmidonta arcula I. Lea, 1838 Michigan55,4 mm
Obovaria arkansasensis (I. Lea, 1862) Alabama38 mm
Fusconaia askewi (W.A. Marsh, 1896) Kansas59 mm
Amphinaias asperata (I. Lea, 1861) Alabama57 mm
Unio asturianus (FOSSIL) G. Delvene & al., 2016 † Spain, Asturias
Pleurobema athearni Gangloff, G.C. Williams& Feminella, 2006 Alabama
Alasmidonta atropurpurea C.S. Rafinesque, 1831 USA, Kentucky
Amphinaias aurea (I. Lea, 1859) USA, Texas
Pseudodon aureus P.M. Heude, 1885 Anhui, China
Acuticosta aurorea (P.M. Heude, 1883) China, Yangtze River
Hamiota australis (C.T. Simpson, 1900) Alabama
Pseudodon avae (W. Theobald, 1873) Mandalay, Myanmar
Prisodontopsis aviculaeformis F.R. Woodward, 1991 Congo, Pointe Noire39 mm
Nephronaias aztecorum (R.A. Philippi, 1847) Mexico, Veracruz
Coelatura bakeri (C.B. Adams, 1866) Uganda
Lithodomina bakhensis (FOSSIL) Reed, 1944 † Pakistan, Punjab, Sargodha
Fusconaia barnesiana (I. Lea, 1829) Alabama74 mm
Lamprotula bazini (P.M. Heude, 1877) Poyang Lake, Jiangxi, China104,9 mm
Pleurobema beadleianum (I. Lea, 1861) Mississippi, Lincoln County
Cristaria beirensis Y.Y. Liu & W.Z. Zhang,1982 Mongolia
Unionelloides bellalensis (FOSSIL) D. Van Damme& A. Bogan, 2015 † Niger76 mm
Anodonta beringiana (A.T. von Middendorff,1851) Alaska39 mm
Parreysia bhamoensis W. Theobald, 1873 Myanmar, Bhamo