Two new candonid species from South Korea (Ostracoda, Podocopida)

Abstract

Candonidae from South Korea are poorly studied, and only nine species have been recorded so far. Here we describe Cypria asiatica sp. nov. and Cryptocandona smithi sp. nov. The first species is the third representative of the genus reported from Korea and it belongs to a group of species of Cypria Zenker, 1854 with reduced swimming setae on the second antenna and without the marginal tubercles on the shell. The group comprises nine species distributed in the Holarctic. Cypria asiatica stands apart from eight other congeneric species by the presence of septa-like structures on the postero-dorsal end of the left valve. Based on the present observations and some previous studies of the subfamily Cyclocypridinae, we here draw attention to the chaetotaxy of the mandibular palp and the chaetotaxy of the fifth limb. The latter shows close similarity between Cyclocypridinae and Paracypridinae and urges further study of homology of setae on this leg between three candonid subfamilies. Cryptocandona smithi is the 14th known Recent species of its genus and the third reported from Korea. It is similar to C. tsukagoshii Smith, 2011 from Japan and C. pygmaea (Ekman, 1908) from Sweden. They all share a peculiar chaetotaxy of the seventh limb and an unusually long posterior seta on the uropodal ramus. The new species can be distinguished from the Swedish species by the morphology of the genital field, and from the Japanese by the shape of the carapace, the length of the f-seta on the seventh limb, and other details of the soft parts. We here report some abnormalities in the morphology of the antennule found in one specimen, and compare this with similar abnormalities reported for C. tsukagoshii and C. brehmi (Klie, 1934), and postulate that this may be a result of the regenerative process of the antennule after damage during development.