New data on the Caprellidae (Amphipoda: Senticaudata) from the Koryak slope of the Bering Sea with description of Liropus beringi sp. nov.

During the expedition of the NSCMB FEB RAS aboard the R/V Akademik M.A. Lavrentyev to the Koryak slope of the Bering Sea, Northwest Pacific (NWP) in 2018, three species of the family Caprellidae were collected in a seep activity zone at a depth of 658–662 m using a remotely operated vehicle (ROV) Comanche-18. Two morphospecies of the genus Caprella Lamarck, 1801 were represented by a few juveniles or damaged specimens. The species of the genus Liropus Mayer, 1890 sampled at three stations appeared to be new to science. The genus Liropus is known from the shelf and bathyal zones of tropical and low-boreal waters of the Atlantic and Pacific Oceans. Thus, L. beringi sp. nov., described herein, is the northernmost record of the genus. The new species can be identified by the following combination of features: absence of eyes, three-segmented pereopod 5, presence of two proximal projections on the palmar margin of gnathopod 2 with two grasping spines on each projection. Data on the NWP bathyal fauna of Caprellidae is summarized and discussed. A key to the bathyal species of Caprellidae from the NWP is provided.