Feeding Segregation of Eubranchus misakiensis Baba, 1960 and E. horii Baba, 1960 (Nudibranchia : Aeolidacea) in the Okhotsk Sea, Northern Japan with Range Extensions for Both Species

Abstract

Two Eubranchid nudibranchs, Eubranchus misakiensis Baba, 1960 and E. horii Baba, 1960 were found to occur sympatrically in the Okhotsk Sea area. The former fed only on Obelia plana (M. Sars, 1835) and the latter only on a subspecies of Plumularia filicaulis Kirchenpauer, 1876. The combinations of predator and prey species are discussed and compared with the results reported by Hirano & Hirano (1985). This occurrence also constitutes large northward range extensions for both species.