Abstract A new podocerid amphipod, Leipsuropus seisuiae sp. nov., from 338-340 m depth in the Kumano Sea, Japan, Northwestern Pacific, is described. This is the deepest record of any Leipsuropus species. Leipsuropus seisuiae sp. nov. is distinguished from four other congeneric species in having: i) pereonites 2-5 each with five narrow spiniform projections on tergal plate, ii) one dorsal tubercle on the telson, and iii) one small, proximal, denticulate projection on gnathopod-2 palmar margin. A key to males of the species of Leipsuropus is provided.

Abstract We describe Kupellonura tamago sp. nov., collected from the North Pacific off the southern coast of the Boso Peninsula, Japan, at a depth of 445-407 m. This is the first record of Hyssuridae not only for Japan but also for the Temperate Northern Pacific ecoregion. Female K. tamago closely resembles Kupellonura gidgee Poore and Lew Ton, 1988 and Kupellonura indonesica Annisaqois and Wägele, 2021 in the shape of the uropodal exopod but differs from them in having a broader uropodal exopod (length/width ratio 1.47), a broader uropodal endopod (length/width ratio 1.64), and the telson margins smooth. We transfer Kupellonura flexibilis (Pasternak, 1982), originally described in Ananthura Barnard, 1925 but provisionally transferred to Kupellonura Barnard, 1925, to Anthelura Norman and Stebbing, 1886 in Antheluridae, as Anthelura flexibilis (Pasternak, 1982) comb. nov.