The first record of the family Paramunnidae (Isopoda: Asellota) from the bathyal of the Bering Sea with descriptions of two new species of Munnogonium

Four species of paramunnids (Isopoda: Asellota) were found on the Koryak slope in the Bering Sea during 82-nd cruise of the R/V Akademik M.A. Lavrentyev with a remotely operated vehicle (ROV) Comanche-18 in 2018. The paramunnids were collected at depths 415???660 m in vicinity of methane seep area. One species, Notoxenoides cf. setosa Shimomura 2009, earlier was known from the bathyal off Kyushu Island; two species, Munnogonium longum sp. nov. and M. koryakiensis sp. nov., were described as new to science, and one more species, Pleurogonium sp., is supposedly a new species which we left in an open nomenclature. These are the northernmost findings of the genera Notoxenoides and Munnogonium and first records of paramunnids from the bathyal of the Bering Sea. Before only one paramunnids species, Pleurogonium sp., was reported on the shelf of the Bering Sea. Both new bathyal species of the genus Munnogonium, that so far are the deepest findings in the genus, most closely resemble three shelf species: M. falklandicum (Nordenstam, 1933) from the southwestern Atlantic off South America, and two species from the northeastern Pacific off North America, M. erratum (Schultz, 1964) and M. tillerae (Menzies and Barnard, 1959). The reduction of eyes and eyestalks, characterizing new species, can be an adaptation to deep-sea mode of life that convergently emerged within many other isopod families. It also confirms the hypothesis of multiple colonization of the deep-sea by paramunnids, which occurs independently in different genera. The composition of the North Pacific paramunnid fauna is discussed.