Nerocila phaiopleura Bleeker, 1857 was collected from the body surface of gnomefish, Scombrops boops (Houttuyn, 1782) (Perciformes: Scombropidae), in the Kowaura Fishing Port, part of Kowaura Bay facing the western North Pacific Ocean, Mie Prefecture, central Japan. This represents a new host record for N. phaio- pleura. The collected specimens of N. phaiopleura, consisting of 10 ovigerous females, 3 transitional-stage individuals, and 5 juveniles, are briefly described. The gnomefish examined were young fish, which are con – sidered to have become infected by N. phaiopleura dur- ing their stay in coastal waters of the bay. Skin wounds caused by N. phaiopleura were found at some attach- ment sites. This paper also provides an updated list of the Japanese hosts of N. phaiopleura, including 11 nominal species of fishes in three clupeiform families (Clupeidae, 3 spp.; Dussumieriidae, 1 sp.; Engraulidae, 1 sp.) and four perciform families (Carangidae, 1 sp.; Scombridae, 3 spp.; Scombropidae, 1 sp.; Sphyraeni- dae, 1 sp.).

The cymothoid isopod Nerocila phaiopleura parasitic on gnomefish, Scombrops boops, in coastal Pacific waters of central Japan, with an updated list of the hosts reported from Japan (Kazuya Nagasawa and Susumu Isozaki)