A pair of a gravid female and a male of Ceratothoa oxyrrhynchaena Koelbel, 1878 (Isopoda: Cymothoi- dae) were collected from the buccal cavity of a black- throat seaperch, Doederleinia berycoides (Hilgendorf, 1879) (Perciformes: Acropomatidae), in the western North Pacific Ocean off Kinkasan Island, Miyagi Pre – fecture, northeastern Japan. This expands the geo- graphical distribution range of C. oxyrrhynchaena from off Onahama (ca. 37°N), Fukushima Prefecture, northward to off Kinkasan Island (38°17′N) and repre – sents the first record of the species from the southern subarctic waters. Based on the previous and present records of C. oxyrrhynchaena from Japan, the species is suggested to occur in a wide area ranging from the subtropical through temperate to southern subarctic waters.

Northward range extension of the cymothoid isopod Ceratothoa oxyrrhynchaena, a buccal cavity parasite of marine demersal fishes, in Japan (Kazuya Nagasawa and Masafumi Kodama)