Squalus blainville (Risso) is described for the first time from Japan.Two closely allied species, S.mitsukurii Jordan et Fowler and S.japonicus Ishikawa, are redescribed and reviewed to clarify the classification of the genus Squalus in Japan.The three species are separable by a combination of differences in snout length, mouth width, dorsal fin height, dorsal fin spine length, and vertebral counts.
