Two New Species of Microloxoconcha (Crustacea: Ostracoda) from the Sublittoral Zone in Western Japan

Abstract

In the present study, we describe two new marine species, Microloxoconcha toyoshioae n. sp. and M. sublittoralis n. sp., collected from the sandy bottom in the western part of Japan, from the depths of approximately 20 to 30 m and 50 m, respectively. This represents the first record of this genus from such depths, since all 10 previously described species are known from the beach interstitial waters. We suspect the two new species are most probably also inhabiting spaces between sand grains since they have very small body and have been collected with other common interstitial ostracods belonging to Cobanocythere Hartmann, 1959; Parvocythere Hartmann, 1959; Paracobanocythere Gottwald, 1983; Parapolycope Klie, 1936; and Psammocythere Klie, 1936. Owing to their small body and fragile carapace, previous studies might have overlooked the existence of interstitial ostracods from habitats other than beach interstitial. In addition, a key to all species of the genus Microloxoconcha is provided.