First record of the deep-sea isopod family Dendrotionidae (Isopoda: Asellota) from the Northwest Pacific with description of two new species of Dendromunna

Two new abyssal species of Dendrotionidae are described: Dendromunna kurilensis sp. nov. from the Northwest Pacific Basin to the east of the Kuril–Kamchatka Trench and D. okhotensis sp. nov. from the Kuril Basin of the Sea of Okhotsk. The new species represent the first records of the family for the Northwest Pacific and the first records of the genus for the North Pacific. The new species differ from the remaining species of Dendromunna by the extremely long antennae and pereopods (antenna I is about 0.7–0.8 body length, article 4 of antenna II is about 0.6–0.7 body length, bases of pereopods are about 0.2–0.3 body length), the male pereopod I with concave lateral margins, short pereonite 1 (<0.03 body length), and the lack of mandibular palp. D. okhotensis sp. nov. differs from D. kurilensis sp. nov. by the more slender body, presence of stout setae on the pereonites 1–4 ventral surface, by different number of maxilliped retinaculae, and by number of spines of the mandibular spine row. The key to the species of Dendromunna is presented.