A new member of fossil balaenid (Mysticeti, Cetacea) from the early Pliocene of Hokkaido, Japan.

The family Balaenidae includes two genus and four extant species. Extinct balaenids are known for at least four genus and 10 species. The oldest known record of members of the Balaenidae is known from the early Miocene, but still need more early members of the family to provide better phylogenetic hypotheses.