''Pterophocaena nishinoi'' is an extinct species of

porpoise Porpoises are a group of fully aquatic marine mammals, all of which are classified under the family Phocoenidae, parvorder Odontoceti (toothed whales). Although similar in appearance to dolphins, they are more closely related to narwhals an ...

discovered in the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

Wakkanai Formation of Japan dating to 9.3–9.2 million years ago (mya), and may represent an intermediate phase between porpoises and dolphins. It is one of the oldest species discovered, after the

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...

'' Loxolithax'' 16–14.8 mya and the Late Miocene '' Salumiphocaena'' 12.6–9 mya. The holotype specimen comprises a partial skeleton. The genus name derives from Ancient Greek ''pteryx'', "wing," in reference to its unusually pronounced beak, and Latin ''phocaena'', "porpoise." The species name honors the discoverer of the holotype, Takanobu Nishino.

References

Porpoises Mammals described in 2012 Miocene mammals of Asia {{Paleo-whale-stub