Chlamys argentinensis Z.J.A. De Castellanos,1973
Pecten argillensis (FOSSIL) T.A. Conrad, 1860 †
Dhondtichlamys arlesensis (FOSSIL) (Woods 1902) †
Lyropecten arnoldi (FOSSIL) (Aguerrevere, 1925 †)
Hyalopecten arntzi E.N. Egorova, 1999
Nodipecten arthriticus (L.A. Reeve, 1853)
Chlamys articulatus (FOSSIL) Sowerby, 1840 †
Nodipecten articulosus (FOSSIL) Cooke, 1919 †
Chlamys ashiyaensis (FOSSIL) S. Nomura, 1935 †
Chlamys asper Sowerby, 1847
Pecten asper (FOSSIL) J.B.P.A. Lamarck, 1819 †
Chlamys asperacrispata (FOSSIL) Tashiro, 1976 †
Mimachlamys asperrima (J.B.P.A. Lamarck, 1819)
Chlamys asperrimus (FOSSIL) †
Pecten assinboiensis (FOSSIL) H.D. Russell & Landes,1937 †
Neithea atava (FOSSIL) (F.A. Roemer, 1839 † †)
Athlopecten athleta (FOSSIL) (C.A. von Zittel, 1865 †)
Nodipecten atlanticola (FOSSIL) Anderson, 1929 †
Pecten atlanticus E.A. Smith, 1890
Pecten aurantiacus Roding, 1798
Adamussium auristriatum (FOSSIL) Quaglio, 2008 †
Camptonectes auritus (FOSSIL) (Schlotheim, 1813 †)
Leptopecten auroraensis (FOSSIL) Ward & B.W. Blackwelder,1987 †
Pecten aztecus (FOSSIL) Bose, 1906 †
Chlamys badenpowelli (FOSSIL) Weir, 1929 †
Talochlamys badioriva (FOSSIL) A.G. Beu & T.A. Darragh,2001 †
Lindapecten baitoanensis (FOSSIL) Waller, 2011 †
Leopecten bakeri (FOSSIL) (G.D. Hanna& L.G. Hertlein, 1927 †)
Ylistrum balloti (A.C. Bernardi, 1861)
Minnivola banakensis (FOSSIL) Eames & Cox 1956 †
Semipallium barnetti H.H. Dijkstra, 1989
Pecten barretti (FOSSIL) Seeley, 1861 †
Chlamys bartschi (FOSSIL) R. Arnold, 1906 †
Hyalopecten bavayi (H.H. Dijkstra, 1990)
Paraleptopecten bavayi (P. Dautzenberg, 1900)