Bifurgaster, a new genus of Ascothoracida (Crustacea: Maxillopoda) parasitic in deep water asteroids

Abstract

A new genus of ascothoracid, Bifurgaster gen. nov., has been found parasitizing brisingid asteroids Freyella spp. The genus comprises two species, B. freyellae sp. nov. and B. kermadeca sp. nov., from the north-east Atlantic Ocean and south Pacific Ocean respectively, at depths of over 4000 m. The genus is characterized by the adult female having a bilobed mantle within which is a reduced main body with little or no segmentation. The only appendages are the first antennae and second maxillae. Each lobe of the mantle contains two branches of the gut and ovary and a distinctive gland. Males and larvae of B. freyellae are described. The genus is placed in the family Dendrogastridae, and is thought to be intermediate between Ulophysema and Dendrogaster.