Ceratothoa oxyrrhynchaena Koelbel, 1878 was found in the buccal cavity of blackthroat seaperch, Do- ederleinia berycoides (Hilgendorf, 1879) (Perciformes: Acropomatidae), from the Kashima-nada Sea in the western North Pacific Ocean off southern Ibaraki Pre – fecture, central Japan. This represents the first record of C. oxyrrhynchaena from Ibaraki Prefecture, and the species is briefly described. While only eight fish were examined, four (50%) were infected by C. oxyr- rhynchaena.

茨城県鹿島灘産アカムツに寄生していた ソコウオノエ Ceratothoa oxyrrhynchaena(等脚目ウオノエ科)(長澤和也・栗原正彦・植松幸希)