On the Hawaiian Scallops of the Genus Pecten Muller (Pelecypoda)

Abstract

Strongly inequivalve scallops of the genus Pecten (s.str.) are represented in the western and central Pacific by relatively few living forms, most of which have widely separated distribution areas in Japanese and Australasian seas. Their fossil record and morphological affinities have suggested a rather unusual history of late Cenozoic' dispersal and speciation, at least for the majority of Western Pacific species, which are discussed in a recent publication (Fleming, 1957). The most isolated of all Pacific scallops, recorded from the Hawaiian Islands as two new species, Pecten waikikius and P. diomedeus, by Dall, Bartsch, and Rehder (1938), were known only from left valves, and as a consequence their relationships have been difficult to interpret.