Austinograea chubacarc n. sp. from the Manus and Woodlark Basins (western Pacific), and new records of A. alayseae Guinot, 1990 and A. hourdezi Guinot & Segonzac, 2018 (Crustacea, Decapoda, Brachyura, Bythograeidae)

Collected in the Woodlark Basin and Manus Basin during the French CHUBACARC 2019 cruise, a species of the genus Austinograea Hessler & Martin, 1989 (Bythograeidae Williams, 1980) was found to be distinct from its four congeners from the western Pacific: A. williamsi Hessler & Martin, 1989, A. alayseae Guinot, 1990, A. hourdezi Guinot & Segonzac, 2018, and A. jolliveti Guinot & Segonzac, 2018. Established here as A. chubacarc n. sp., it displays an original and unique character, which is regarded as having specific importance, namely in the male a narrow depression on the upper margin of the dactylus of the major chela (but not in the female). The presence of A. chubacarc n. sp. at a depth of around 1750 m in the Manus Basin and at a much greater depth, around 3388 m, in the Woodlark Basin reinforces the view that the brachyuran community of Woodlark, although very deep, can be connected to much shallower populations in the Manus Basin, as has already been demonstrated by the barcoding studies of vent gastropod species. New records of A. alayseae and of A. hourdezi are also reported.