Hajime Ishihara

Two new North Pacific skates (Rajidae) and a revised key toBathyraja in the area

Two new species of the skates,Bathyraja hubbsi andB. pseudoisotrachys are described from the North Pacific. Among the North PacificBathyraja, B. hubbsi most closely resemblesB. violacea Suvorov in possessing a disc without thorns, a median tail thorns irregularly spaced, and minute fine prickles covering the entire dorsal surface. The two species are distinguished from each other by their dorsal color pattern, proportional measurement of tail in relation to total length, clasper components, and number of precaudal vertebrae.Bathyraja pseudoisotrachys has long been confused withB. isotrachys (Günther) by many Japanese authors, but is distinguished from other North PacificBathyraja by dorsal squamation and unique clasper components such as two clefts, terminal bridge and ridge.Bathyraja kincaidii Garman is synonymized with the valid speciesB. interrupta Gill et Townsend.Bathyraja abyssicola Gilbert andB. trachura Gilbert are redescribed in detail. Provisionally, 21 species of the genusBathyraja are recognized in the present study from this region, and a revised key is given to the North Pacific species of the genus.