A comprehensive taxonomic list of brittle stars (Echinodermata: Ophiuroidea) from submarine caves of the Ryukyu Islands, southwestern Japan, with a description of a rare species, Dougaloplus echinatus (Amphiuridae) Author Okanishi, Masanori Author Fujita, Yoshihisa text Zootaxa 2019 2019-03-25 4571 1 73 98 journal article 28099 10.11646/zootaxa.4571.1.5 4b455544-f490-4283-b51f-3bab0af22419 1175-5326 2605976 40B4CF49-C6F0-4392-B971-C90AC4768DF1 Ophiomastix ? sp. (juvenile?) Material examined. Shimoji Island (RUMF-ZE-02084[1]): “middle zone” of the “Akuma no Yakata” cave, under coral rubble, approximately 20 m depth, 5 February 2017 . Remarks. Blunt disc spines of this specimen suggest an affinity to the genus Ophiomastix . However, its assignation to species is difficult because of its immaturity; it has small arms and few arm spines. To determine the species, examination based on more specimens is required.