A new species of (Crustacea, Thecostraca, Ascothoracida) parasitic in an antipatharian from Green Island, Taiwan, with notes on its morphology.

A new ascothoracidan species has been discovered off Taiwan in the north part of the west Pacific at SCUBA depths. Twelve specimens including both sexes of the new species, described herein as , were collected from colonies of the antipatharian Myriopathes cf. japonica Brook, 1889. Three previously described species of , morphologically the least specialized ascothoracidan genus, have been found as ectoparasites of antipatharians and an alcyonarian, whereas all other records of this genus have been based on specimens collected from the marine plankton. This is the second study of a new form of to be based on more than a few mature specimens of a single sex or on a single juvenile. Furthermore, it is the second in which SEM has been used to document the fine-scale external morphology. The position of terminal pores in the anterior pairs of the lattice organs is different in than those in Kolbasov & Newman, 2018 and Grygier & Ohtsuka, 1995. Species of are small, host-specific predators or ectoparasites of antipatharians. This genus exhibits a major Tethyan reliction pattern.