New and Rare Species of the Deep-sea Gammaridea (Crustacea: Amphipoda) off Pacifi c Coast of Northern Honshu, Japan

Abstract: A new species of Trischizostomatidae and two rare species of Epimeriidae and Melitidae were col-lected from the deep sea off Pacifi c coast of northern Honshu, Japan: Trischizostoma tohokuense sp. nov., Uschakoviella echinophora Gurjanova, 1955, and Megaceradocus gigas Mukai, 1979. The genera Trischizos-toma and Uschakoviella are recorded from Japan for the fi rst time. Trischizostoma tohokuense differs from the known species of the genus by the combination of the following features: the accessory fl agellum of the an-tenna 1 reaches the end of the article 3 of the primary fl agellum; the palp of the maxilliped is developed, longer than the outer plate; the length of the propodus of the gnathopod 1 is almost same as the breadth; the ventral margin of the merus of the gnathopod 2 without setae; and the telson is entire, apically rounded