Recent benthonic ostracod assemblages as indicators of the Tsushima warm current in the southwestern sea of Japan

One hundred and sixty-seven species of podocopid ostracods are reported from 26 recent surface sediment samples collected on the shelf of the Tsushima Strait in the southwestern Sea of Japan. Four biofacies (A-D) are recognised based on Q-mode cluster analysis. Among these, biofacies B is distributed along the Tsushima Warm Current and includes typical East China Sea species. This fact suggests that the migration of the shelf-living ostracods between the open sea and the adjacent semi-enclosed marginal sea mainly occurs in association with the inflow of this sea current. The distribution of the recent ostracod assemblages from the Tsushima Strait are expected to be a sensitive indicator of past and future changes in the Tsushima Warm Current. One new ostracod species of the family Trachyleberididae, Trachyleberis ikeyai, is described and illustrated herein.