Austrocardilanx antarctica (FOSSIL) (Quilty 1983) †
Parastarte antillensis (FOSSIL) W.P. Woodring, 1925 †
Leukoma antiqua (P.P. King, 1832)
Dosinia anus (R.A. Philippi, 1848)
Marcia apaturia (A. Römer, 1864)
Lioconcha arabaya S.E.T. Van der Meij, R.G. Moolenbeek& H. Dekker, 2010
Gafrarium arabicum (J.B.P.A. Lamarck, 1818)
Timoclea arakana (G. Nevill & H. Nevill,1871)
Timoclea arakana lavrani E. Fischer-Piette, 1974
Tapes araneosus (R.A. Philippi, 1847)
Callistalox arata (FOSSIL) (W.M. Gabb, 1864 †)
Venus arcotensis E. Forbes, 1846
Macrocallista arenophila (FOSSIL) H.F.A. von Ihering,1907 †
Dosinia areolata A. Römer, 1870
Agriopoma arestum (W.H. Dall & C.T. Simpson,1901)
Pitar arestus (W.H. Dall & C.T. Simpson,1901)
Leukoma argentina (FOSSIL) (H.F.A. von Ihering,1897 †)
Tivela argentina (G.B. I Sowerby, 1835)
Pitar arisanensis (FOSSIL) (Yokoyama †)
Marcia armoricensis (FOSSIL) (Vasseur, 1881 †)
Katherinella arnoldi (FOSSIL) (C.S. Weaver, 1916 †)
Clementia asiatica (J.C. Melvill, 1899)
Dosinia aspera (L.A. Reeve, 1850)
Venerupis aspera (J.R.C. Quoy& J.P. Gaimard, 1835)
Venerupis aspera kioroshiensis (FOSSIL) K. Hirayama & Y. Ando,1954 †
Leukoma asperrima (Sowerby, 1835)
Tawera assimilis (FOSSIL) (F.W. Hutton, 1873 †)
Rhabdopitaria astartoides (FOSSIL) (J. Gardner, 1923 †)
Venerupis astensis (FOSSIL) (G. Bonelli, 1827 †)
Meretrix astricta (L.A. Reeve, 1864)
Cooperella atlantica H.A. Rehder, 1943
Venerupis atlantica (FOSSIL) C.J. Maury, 1912 †
Chione atlanticana (FOSSIL) Anderson, 1929 †
Meretrix attenuata R.W. Dunker, 1863
Sunetta aturi (FOSSIL) (C. Mayer, 1858 †)