Gonionucula aciloides (FOSSIL) Hautmann & al., 2011 †
Ennucula aegeensis (E. Forbes, 1844)
Ennucula agujana (W.H. Dall, 1908)
Leionucula albensis (FOSSIL) (A.V.M.D. D'Orbigny,1844 †)
Nucula alcocki (FOSSIL) Noetling, 1895 †
Palaeonucula aldanensis (FOSSIL) Kurushin, 1987 †
Truncacila allisoni (FOSSIL) R.L. Squires & Saul,2006 †
Nuculopsis alta (FOSSIL) Termier & Termier, 1959 †
Nucula amanoi (FOSSIL) Tashiro, 1976 †
Lamellinucula ambrosia (FOSSIL) (J.A. Bartrum & Powell,1928 †)
Nucula amica (FOSSIL) Gardner, 1916 †
Nucula andersoni (FOSSIL) Clark & J.W. Durham,1946 †
Economolopsis anodontoides (FOSSIL) (F.B. Meek, 1871 †)
Nuculopsis anthraconeiloides (FOSSIL) (Chao, 1927 †)
Linucula aptera (FOSSIL) (C.R. Laws, 1940 †)
Nucula archiaci (FOSSIL) A.E.M. Cossmann& G. Pissarro, 1927 †
Nuculavus arcuatus (FOSSIL) B.S. Kues, 1991 †
Austronucula arenaria (FOSSIL) Darragh 1997 †
Nucula assiniboiensis (FOSSIL) H.D. Russell & Landes,1937 †
Ennucula astricta T. Iredale, 1931
Nucula atacellana H.G. Schenck, 1939
Nucula athabaskensis (FOSSIL) McLearn, 1931 †
Pronucula atkinsoni (FOSSIL) (Johnston, 1880 †)
Austronucula australiensis (K.H.J. Thiele, 1930)
Nucula austrobenthalis R.K. Dell, 1990
Nucula axiniformis (FOSSIL) Phillips, 1829 †
Nuculavus bangarraensis (FOSSIL) Dickins, 1963 †
Leionucula barrosi (FOSSIL) (R.A. Philippi, 1887 †)
Ennucula bathybia (B. Prashad, 1932)
Nucula beachportensis J.C. Verco, 1907
Truncacila bellula (FOSSIL) Slodkewitsch, 1967 †
Ennucula bengalensis (E.A. Smith, 1895)
Nucula benguelana (A.H. Clarke, 1961)
Nucula bergmansi (P.A. Maxwell, 1988)
Nuculopsis beyrichi (FOSSIL) (K.C. Schauroth, 1854 †)