Ostracod genus Parapolycope (Crustacea): Diversity, distribution, and phylogeny, with description of the first representative from Korea

Parapolycope Klie, 1936 belongs to the family Polycopidae, one of the ecologically most diverse and mor-phologically most primitive ostracod families. Due to the small size of animals, polycopids are poorlystudied and unknown in many regions of the world. We describe a new species, Parapolycope koreanasp. nov., from marine beach interstitial in Gyeongsangnam-do, South Korea. This is the first representa-tive of the genus, and the first named polycopid species from Korea. It is very closely related to severalspecies from marine interstitial in Japan, but differs mainly in the shape and ornamentation of the shelland morphology of the male upper lip. A cladistic analysis of the genus Parapolycope is performed totest the phylogenetic relationships between species. Although Parapolycope presently encompasses 18species, only 15 are included in the analysis, because Parapolycope seridentata (Hartmann, 1959), Parapoly-cope ramunchensis (Hartmann-Schröder and Hartmann, 1962), and Parapolycope minutissima (Hartmann,1974) differ so much from other congeners that they should be excluded from the genus. The analysisis based on 27 morphological characters, with Parapolycopissa rossica (Chavtur, 1977) and Polycopiellamicrodentata Chavtur, 1979 as two outgroup taxa. In spite of the fact that descriptions of almost half ofspecies included in the analysis are based on a limited set of morphological characters, the majority ruleof the 15 equally parsimonious trees undoubtedly shows that there are at least two distinct lineages inthe genus, defined by the number of claws on the female uropodal lamellae. A close relationship betweenthe new species and the Japanese congeners is also strongly supported. We redescribe the type speciesof the genus, Parapolycope germanica Klie, 1936, based on the type material, and designate the lectotypeand paralectotypes. A key for identification of Parapolycope species is provided, along with a map of theirdistribution. This is a cosmopolitan taxon, with the centre of diversity in the Northwest Pacific region.