Overlooked biodiversity of brittle stars from the Upper Pleistocene of Japan: descriptions of fossil ossicle assemblage in Indo-West Pacific

Disarticulated fossil ossicles of brittle stars from the Upper Pleistocene Yokosuka Formation, Yokosuka, Kanagawa Prefecture, central Japan, are described. The ossicles of lateral arm plates and vertebrae are assigned to Gorgonocephalidae, Ophiocomidae, Ophiosphalmidae, Ophiopholis, Ophiothrix, Ophiarachnella, Stegophiura sladeni, Ophiuroglypha kinbergi and Ophiozonella longispina, on the basis of external morphology. This is the first faunal record mainly based on disarticulated fossil lateral arm plates of brittle stars from the Indo-Pacific region.