Akishima whale

{{Short description|Extinct species of whale}} {{Speciesbox | fossil_range = Early Pleistocene c. 1.77–1.95 Ma | image = | extinct = yes | genus = Eschrichtius | species = akishimaensis | authority = Kimura, Hasegawa and Kohno, 2017 }}

'''''Eschrichtius akishimaensis''''', described in 2017, is one of two species, with the modern day gray whale, of the genus ''Eschrichtius'', and is the first and only fossil species of the genus, dating to around 1.77–1.95 million years ago (mya) in the Early Pleistocene.

== History of discovery == thumb|180px|left|Full size fossil replica

The bones were first found in 1961 by a father and son, Masato and Yoshio Tajima, in a riverbed in Akishima, Tokyo, lending it the nickname of the '''Akishima whale'''.<ref>{{Cite journal |last=Ohmori |first=M |date=1977 |title=Sunday Geology [4]. On the Geology of Tokyo |journal=Tsukiji Shokan Publishing Co., Tokyo |pages=184}}</ref><ref name=":0">{{cite journal |last1=Kimura |first1=T. |last2=Hasegawa |first2=Y. |last3=Kohno |first3=N. |year=2017 |title=A New Species of the Genus ''Eschrichtius'' (Cetacea: Mysticeti) from the Early Pleistocene of Japan |url=https://www.researchgate.net/publication/322188537 |journal=Paleontological Research |volume=22 |issue=1 |pages=1–19 |doi=10.2517/2017PR007|s2cid=134494152 |doi-access=free }}</ref> It was prepared by locals, under the mentorship of Hiroshi Ozaki, and subsequently put into storage at the National Museum of Nature and Science until it was transferred to Gunma Museum of Natural History to be studied.<ref name=":0" /> The discovery generated local enthusiasm in the city, having both a ''Kujira matsuri'' (whale festival) and a ''Kujira Park'' (Whale Park) in its honor, and plans for a life-size replica skeleton in a new educational facility to open March 2020.<ref name=":0" />

Prior to its formal description, ''E. akishimaensis'' was referred to as "Japonocetus" ''akishimensis'', though the name was never used in any way that fulfils the International Code of Zoological Nomenclature's requirements for species description.<ref name=":0" /> The species name of ''Eschrichtius akishimaensis'' derives from Akishima, Tokyo, where the holotype was discovered.<ref name=":0" />

== Description == The only specimen of ''Eschrichtius akishimaensis'' consists of a skull, seven neck vertebrae, thirteen thoracic vertebrae, eight lumbar vertebrae, twelve tail vertebrae, chevrons, ribs, and arm bones, and has a total length of about {{convert|12|m|ft}}. ''E. akishimaensis'' can be distinguished from ''E. robustus'' based on a number of characteristics. The posterior border of the nasal is squared off, the ascending process of the maxilla is dorsolateral and narrower compared to that of the premaxilla, and the squamosal concavity is deep and large.<ref name=":0" />

==References== {{Reflist}}

Category:Fossil taxa described in 2017 Category:Pleistocene mammals of Asia Category:Eschrichtiidae Category:Pleistocene cetaceans