Four new species of the family Propeamussiidae (Mollusca: Bivalvia) from the abyssal zone of the northwestern Pacific, with notes on Catillopecten squamiformis (Bernard, 1978)

Abstract

Based on the material collected from 1949 to 2015 by nine deep-sea expeditions, four new species of the family Propeamussiidae (Mollusca: Bivalvia) and Catillopecten squamiformis (Bernard, 1978) were found in the abyssal zone (2,901-5,680 m depths) of the Bering Sea, the Sea of Okhotsk, and the northwestern Pacific. Parvamussium pacificum sp. nov., Catillopecten brandtae sp. nov., Catillopecten malyutinae sp. nov., and Catillopecten natalyae sp. nov. are described from the abyssal plain (4,860-5,680 m depths) adjacent to the Kuril-Kamchatka and Japan trenches (Pacific Ocean). Catillopecten squamiformis was found in the Bering Sea, the Sea of Okhotsk, and at the abyssal plain near the southeastern coast of Kamchatka and Aleutian Trench (Pacific Ocean) at 2,901-5,020 m depth. This is the first record of C. squamiformis from the northwestern Pacific. An expanded description of C. squamiformis with new data on its morphology and geographic distribution is given. To date, 12 species of the genus Catillopecten are known from the different regions of the World Ocean. A table with the main differences among all known species in the genus is provided.