Taxonomic review of the genus Sars (Copepoda, Harpacticoida, Cylindropsyllidae), with (re)descriptions of two species from the Far East.

The taxonomic concept of the genus Sars, 1909 is uncertain because none of the synapomorphies for the species of are defined. Detailed comparison of previous records of (T. Scott, 1892) from different localities reveals that this species represents a species complex composed of two species, . s. str. and . Cottarelli & Venanzetti, 1989. Because the latter species has fundamental differences in the nature of the fifth leg in females and the sexual dimorphism of the second leg in males, we propose a new species for . Cottarelli & Venanzetti, 1989, . sp. nov. We also suggest that . Apostolov, 1971, . Marinov, 1971, and . Apostolov & Marinov, 1988 from the Black Sea and . Wilson, 1932 from North America should be relegated to in the genus. Taxonomic review of the morphology of all species indicated that the generic concept must be restricted to accommodate . s. str., . Sars, 1909, . Itô, 1972, . sp. nov., and the South Korean new species, . sp. nov., based on the synapomorphic condition of the confluent fifth leg in males. As a result of our analysis, two species, . Arlt, 1983 and . Noodt, 1955, are transferred to the genus Kornev & Chertoprud, 2008 as . (Arlt, 1983) comb. nov. and . (Noodt, 1955) comb. nov. based on the synapomorphic characters of a reduced condition of the second and fifth legs. Additionally, . Wilson, 1932 and . (Kunz, 1938) are allocated to a new genus, gen. nov., mainly characterized by obvious caudal rami with a recurved dorsal spinous process and convex inner margins, as . (Wilson, 1932) comb. nov. and . (Kunz, 1938) comb. nov. A marine interstitial harpacticoid collected from the subtidal substrate off Dok-do Island in the East Sea of South Korea is proposed as . sp. nov. and the distribution of . , originally known from its type locality in Japanese waters only, is extended to the East Sea of Korea and Russia. We provide their detailed descriptions and illustrations and discuss the morphological characters supporting their identities.