Two new species of the genus Chilibathynella Noodt, 1963 and Onychobathynella bifurcata gen. et sp. nov (Crustacea: Syncarida: Parabathynellidae) from New South Wales, Australia

Abstract

Two new species of the parabathynellid genus Chilibathynella Noodt, 1963 are described from Australia. Chilibathynella joshuai sp. nov. has a unique combination of morphological characters, which includes five-segmented antenna, no epipodite on thoracopod I, two setae on the endopod of the male thoracopod VIII, homonomous row of 17 spines on uropodal sympod, uropodal exopod with four distal spines and a flat anal operculum. Chilibathynella digitus sp. nov. has two exclusive characters: six teeth on the pars incisiva of the mandible and a large, elongated digitiform protuberance (resembling a finger) on the basipod of male thoracopod VIII. The species also displays a unique combination of morphological characters, which includes five-segmented antenna, no epipodite on thoracopod I, no outer marginal seta on the first and second segments of the endopod of thoracopod I to VII, two setae on the endopod of the male thoracopod VIII, homonomous row of 12 spines on uropodal sympod, uropodal exopod with three distal spines and an unprotruded anal operculum. The two new species extend the distribution of the Chilibathynella genus in Australia from Victoria to New South Wales. A new genus and species of the family Parabathynellidae, Onychobathynella bifurcata gen. nov. sp. nov., is described from New South Wales, Australia. The new genus displays an evolutionary novelty, for Parabathynellidae and the entire group of Bathynellacea: the antennule, antenna, thoracopods, pleopod I and uropod have setae that are strong, thick, short, barbed and claw-like. This new genus is the first in the family without smooth setae on the antennule and antenna. The new genus also has a combination of characters that makes it unique in Parabathynellidae: the antennule is eight-segmented like Octobathynella Camacho and Hancock, 2010; the antenna is five-segmented; the labrum has 20 teeth; the exopod of thoracopod I to VII has only one segment; the endopod lacks dorsal setae on the first segment and the epipod is absent from thoracopod I; first pleopods are present and resemble two barbed curved claws; there are 18 bifid spines on the sympod, two spines and four setae resembling strong barbed claws on the endopod and six robust setae on the exopod of the uropod.