A New Species of the Genus Caprella (Crustacea: Amphipoda: Caprellidae) Collected from a Gorgonian at 1497 m Depth off Boso Peninsula, Central Japan

抄録

Caprella nojimaensis sp. nov. (Crustacea: Amphipoda: Caprellidae), inhabiting the gorgonian Calcigorgia gracilis Matsumoto, van Ofwegen, and Bayer, 2019, is described based on a specimen from 1497 m depth in the Nojima Submarine Canyon, off Boso Peninsula, central Japan. The species is closely related to C. gracillima Mayer, 1890, but differs from the latter in gnathopod 2 being positioned near the anterior margin of pereonite 2 and in the presence of paired small mid-dorsal projections on pereonites 2 and 5. The body colour of live material is pale pink, with mouth parts and gnathopod 2 fringed with darker pink, revealing protective colouration that matches that of the host gorgonian. The clinging behaviour in situ is “upright” as recorded by the remotely operated vehicle Hyper-Dolphin, and the presence of dense swimming setae on antenna 2 suggests that the caprellid feeds by filtering material suspended in the bathyal zone.