A description is given of Benedenia hoshinai sp. nov.(Monogenea, Capsalidae)on the body surface and fins of the Japanese striped knifejaw, Oplegnathus fasciatus(Japanese name“ishi-dai”), cultured in Nagasaki Prefecture. The new species is separated from previously known species of the genus by the shape of the opisthohaptoral hard parts and/or of the male copulatory organ.
