Living cytheroid ostracod fauna from South Korea is very poorly known, and so far only 12 species have been reported in the taxonomic literature with detail description. We describe one new species, Xestoleberis hujeongensis n. sp., and report three other cytheroid ostracods: X. setouchiensis Okubo, 1979; X. sagamiensis Okubo, 1976; and Hemicytherura kajiyamai Hanai, 1957 from the east coast of Korea. The new species is most closely related to Xestoleberis hanaii Ishizaki, 1968, a widely distributed and ecologically versatile species. The two species have a very similar carapace shape and soft body parts morphology. Nevertheless, the new species has a distinctively different carapace ornament (presence of wart-like structures on the male carapace), as well as hemipenis morphology. The other three species were known so far only from Japan, and the South Korean populations differ from the Japanese ones only by carapace size, while the carapace shape and all soft body parts are very similar to their original descriptions. This is also the first record of a living representative of the genus Hemicytherura Elofson, 1941 from Korea.
Cytheroidea, Ostracoda, South Korea, East Asia, new species.