New giant genus of Parabathynellidae (Crustacea: Bathynellacea): first record of Bathynellacea in an Australian cave

Abstract

A new genus and species of Parabathynellidae (Crustacea: Bathynellacea), Megabathynella totemensis Camacho & Abrams gen. et sp. nov., is described from the Northern Territory, Australia. This species is the first to be described from an Australian cave. It is a new giant species (4 to 6 mm). The new species displays several unique morphological character states within Parabathynellidae and is the only known species with: more than 12 articles on antennules, with a short, curved barbed seta on each article from the fifth; eight setae on the last article of antennae; more than three setae on the mandibular palp; up to 17 articles on the exopod of the thoracopods, without ctenidia but with a strong spine on each article at the base of the external seta; strong row of pair of spines on latero-external side of second article of endopod in all thoracopods; the male thoracopod VIII is different from all those known; more than 50 spines on the sympod of the uropod and more than 35 spines on the furcal rami. Specimens of the new species are morphologically different from all known species, but more closely resemble some giant species of the genera Kampucheabathynella (Asia), and Billibathynella and Brevisomabathynella (Australia).