A New Species of Asteroschema (Echinodermata: Ophiuroidea: Asteroschematidae) from Southwestern Japan

Abstract

A new species of brittle star, Asteroschema amamiense, is described from off Amami-oshima island, southwestern Japan. Asteroschema amamiense is distinguished from its congeners in having a single arm spine in each tentacle pore, both polygonal and elongated flat, plate-shaped dermal ossicles on the aboral periphery of the disc and basal portions of the arms, and radial shields composed of a single ossicle. Three species of Asteroschema, including this new species, and all the species of Astrocharis have plate-shaped dermal ossicles; a close relationship between all of these species is indicated. Moreover, single ossicle radial shields, which have not previously been reported for any species of Asteroschema, are found both in this new species and two species of Astrocharis.