Papyridea clenchi spec. nov. and Papyridea curvicostata spec. nov., two new Paper Cockles from tropical America (Bivalvia, Cardiidae), with notes on evolution and dispersal

Papyridea clenchi spec. nov. (Cardiidae) is described from Martinique and compared with the related Papyridea lata (Born, 1778), Papyridea soleniformis (Bruguière, 1789) and Papyridea semisulcata (Gray, 1825). Papyridea curvicostata spec. nov. is described from Ecuador and compared with the related Papyridea hiulca (Reeve, 1845), Papyridea crock­eri (A.M. Strong & Hertlein, 1937) and Papyridea aspersa (G.B. Sowerby i, 1833). Taxonomic relations within the four tropical Atlantic and four tropical eastern Pacific species are analyzed. Distributions of the living species are given. Atlantic-Pacific geminate species pairs are discussed; a pre­dominantly one-way migration (from Atlantic to Pacific) through the Isthmus of Panama is hypothesized. The fossil record of Papyridea is reviewed and the taxonomic position of Profulvia is discussed.