Taxonomic review of the genus Boreocingula (Gastropoda: Rissoidae) in the Arctic and cold temperate waters

Abstract

Rissoidae is a very diverse family of marine microgastropods; however, its Arctic representatives are poorly studied. Taxonomy of Arctic and Subarctic rissoids is still based exclusively on characters of shell, while internal morphology remains unknown for the majority of the species. The present paper provides a taxonomic revision of the genus Boreocingula Golikov et Kussakin, 1974 based on morphology of shell and soft body. The genus includes five species: three of them [B. martyni (Dall, 1887), B. alaskana (Bartsch, 1912), and B. sirenkoi sp.n.] are present in the extreme north of the Pacific Ocean and the adjacent Siberian Seas; and the other two [B. castanea (Moller, 1842) and B. globulus (Moller, 1842)] are known from the Arctic parts of the Atlantic Ocean. B. sirenkoi sp. n. is described as a new species; lectotype for B. martyni is designated. Imposex females are described for B. martyni for the first time. Also, general patterns of rissoid diversity in the Arctic are reviewed based on the results of the present study and published sources. Only 26 species of the family are reliably known from the Arctic seas. The highest species richness was observed in Greenland (16) and in Barents Sea, except for its southwestern part (11).