Additions to the Pacific Fauna of Haplomunnidae (Isopoda: Asellota) with Descriptions of Three New Species from the Kuril–Kamchatka Trench Region

Three new species of the rare deep-sea family Haplomunnidae are described from the abyssal of the Northwestern (NW) Pacific adjacent to the Kuril–Kamchatka Trench (KKT) based on material collected during the deep-sea expeditions KuramBio (2012) and SokhoBio (2015). Previously, only three species of the genus Haplomunna Richardson, 1908 were described in the whole North Pacific, including one species from its western part. Haplomunna kurilensis Golovan and Malyutina sp. nov., closely resembling H. japonica (Gamô, 1983) from the upper hadal of the Japan Trench, was the most numerous haplomunnid species in the studied region. Thylakogaster wilsoni Malyutina and Golovan sp. nov., and Abyssaranea minuta Golovan and Malyutina sp. nov., are the first species of their genera described from the Pacific Ocean. For H. kurilensis sp. nov. and T. wilsoni sp. nov., DNA sequences were obtained for 18S rRNA and 28S rRNA genes. The phylogenetic relationship between these species, as well as their position within the Haplomunnidae, were reconstructed using 18S rDNA.