Pteroluter othnius (FOSSIL) Saul, 1973 †
Mactra ovalis Sowerby, 1817
Spisula ovalis (J. de C. Sowerby, 1817)
Cyclomactra ovata (J.E. Gray, 1843)
Pseudocardium pabloensis (FOSSIL) A. Packard in Clark,1915 †
Pseudocardium packardi (FOSSIL) R.E. Dickerson, 1917 †
Lutraria paeteli (FOSSIL) C. Mayer, 1889 †
Tresus pajaroanus (FOSSIL) (T.A. Conrad, 1857 †)
Mulinia pallida (W.J. Broderip& G.B. I Sowerby, 1829)
Mactra panchia R.B. Watson, 1886
Pseudocardium panzana (FOSSIL) (Loel & Corey, 1932 †)
Spisula paralis (FOSSIL) †
Austromactra parameces (FOSSIL) (A.E.M. Cossmann, 1886 †)
Spisula parilis (FOSSIL) (T.A. Conrad, 1833 †)
Oxyperas parinensis (FOSSIL) A.A. Olsson, 1928 †
Anatina parvula (FOSSIL) Thurmann & Etallon,1862 †
Mactra patagonica d'Orbigny, 1846
Raeta pellicula (L.A. Reeve, 1854)
Standella pellucida (J.F. Gmelin, 1791)
Standella pellucida hubbardi (T. Iredale, 1929)
Cryptomactra pesanseris (FOSSIL) (Mayer-Eymar †)
Mactra petitii (A.V.M.D. D'Orbigny,1846)
Eomactra piscinasina (FOSSIL) Garvie, 2013 †
Simomactra planulata (T.A. Conrad, 1837)
Mactrinula plicataria (C. Linnaeus, 1767)
Raeta plicatella (J.B.P.A. Lamarck, 1818)
Tumbeziconcha plicatilis (L.A. Reeve, 1854)
Mactra podolica (FOSSIL) K.E.I. von Eichwald,1830 †
Mactromeris polynyma (W. Stimpson, 1860)
Mactromeris polynyma alaskana (W.H. Dall, 1894)
Mactromeris polynyma voyi (W.M. Gabb, 1866)
Mactrodesma ponderosa (FOSSIL) (T.A. Conrad, 1830 †)
Mulinia pontchartrainensis J.P.E. Morrison, 1965
Willimactra popenoei (FOSSIL) Saul, 1973 †
Spisula praetenuis (FOSSIL) (T.A. Conrad, 1833 †)