''Miophocaena nishinoi'' is an extinct species of

porpoise Porpoises () are small Oceanic dolphin, dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and Beluga whale, belugas than to the Oceanic dolphi ...

from 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 ...

Koetoi Formation of Japan, dating to around 6.4–5.5

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

(mya), represented by a partial skull. the

genus name Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial spec ...

derives from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

''mio'' for the Miocene, and ''phocaena'' for "porpoise"; the

species name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...

honors the discoverer, Takanobu Nishino. ''Miophocaena'' resides in a clade with ''

Archaeophocaena ''Archaeophocaena teshioensis'' is a species of extinct porpoise from the Late Miocene Koetoi Formation of Japan living around 6.4–5.5 mya (unit), million years ago (mya). The holotype specimen comprises a partial skull. The animal, along with ...

'' discovered in the same area, and, along with '' Pterophocaena'', represents an intermediate phase between porpoises and dolphins.

References

Porpoises Mammals described in 2012 Pliocene mammals of Asia {{paleo-whale-stub