Balaenoptera siberi

Balaenoptera siberi is an extinct baleen whale of the rorqual genus Balaenoptera, known from Late Miocene fossils in the Pisco Formation of the Pisco Basin in southwestern Peru. It was described by Pilleri and Pilleri in 1989 from a complete skeleton that includes the skull, baleen, mandibles, flippers and vertebral column. The holotype is held in a private collection, and a paratype is kept at the State Museum of Natural History in Stuttgart. The skull is about 228 centimetres long and 111 centimetres wide, intermediate in size between the living common minke whale and the sei whale. Sediments at the Aguada de Loma locality were later dated to about 7 to 8 million years ago, in the late Tortonian to early Messinian.