New Report on Two Species of the Genus Nipponomysis (Crustacea: Mysida: Mysidae) from Korean Waters

Two species of mysid, Nipponomysis fusca (Ii, 1936) and N. tenuiculus (Ii, 1940), are newly recorded in Korean fauna. These two species were collected using a light or a bait trap from all coasts of the Korean peninsula. The genus Nipponomysis can be distinguished from allied genus by the following morphological characteristics: third to eighth thoracic endopods with carpopropodus divided into five to six subsegments compared to three subsegments, and anterior four pairs of pleopod in female subequal in length and fifth pair elongated. Nipponomysis fusca is characterized by its acute rostral plate and armature of telson, and N. tenuiculus differs from other species by the number of spine in ventral statocyst region and the shape of the fourth pleopod in male. Herein, we present detailed descriptions of two species from Korean waters with illustrations of morphology. In addition, an identification key to the Korean species of the genus is provided.