Petaurista tetyukhensis

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Petaurista tetyukhensis
Systematics
Subordination : Squirrel relatives (Sciuromorpha)
Family : Squirrel (Sciuridae)
Subfamily : Tree squirrel and flying squirrel (Sciurinae)
Tribe : Flying Squirrel (Pteromyini)
Genre : Giant Sliding Squirrel ( Petaurista )
Type : Petaurista tetyukhensis
Scientific name
Petaurista tetyukhensis
Tiunov & Gimranov , 2020

Petaurista tetyukhensis is an extinct and fossilized species of the flying squirrel from the genus of the giant flying squirrel ( Petaurista ). The species was described on the basis of a fragment of the upper jaw with two teeth and five isolated teeth from two cave locations near the town of Dalnegorsk in the Primorye region in Russia and assigned to the giant sliding squirrels as the northernmost fossil record. The finds were assigned to the late Pleistocene , which is evidenced by the accompanying fauna of the site.

features

Petaurista tetyukhensis was described on the basis of a fragment of the left upper jaw with two molars M1 and M2 as well as five further isolated teeth, premolars and molars of the lower and upper jaw. These correspond in their structure to those of more recent and other fossil Petaurista species, but also have species-specific features such as the lack of an elevation on the upper molar M2 and the mesoconus on the lower molars.

Way of life and paleoecology

In the way of life, Petaurista tetyukhensis probably corresponded to the giant sliding squirrels living today, which live as arboreal herbivores in forest habitats mostly in tropical to subtropical regions. The northern extent of the genus is mainly determined by the temperatures that have changed in the course of the earth's history due to various warm periods. It is assumed that the warming of the regions in northern China and southern Russia occurred during the warm period in the middle Pleistocene , which also enabled the forest regions and the animal species living in them to expand to the north. For today's Primorye region it is assumed that it was shaped by forests in which wolves , raccoon dogs , foxes , brown and Asiatic black bears , badgers , sables , wolverines , lynxes , leopards , tigers , steppe bison , woolly rhinos , wild boars and various There were deer and elk . It is assumed that the giant sliding squirrels were also able to spread to the north during this warm phase and survived there, especially in sheltered basins with forests, until the late Pleistocene, which isolated them from the species further south and Petaurista tetyukhensis to develop as a new species could.

The cooling and the spread of the steppe-like taiga led to habitats that corresponded to those of today's Chinese giant flying squirrels ( Petaurista xanthotis ) in the northern mountain regions of China. Like these, Petaurista tetyukhensis probably also fed on pine needles, seeds and sprouts, which indicates similarities in the dentition of both species. Further similarities of the teeth indicate a close relationship to the Japanese giant flying squirrel ( Petaurista leucogenys ), which is common on the northern islands of Japan.

Site and history

The fossil remains of Petaurista tetyukhensis were found in two caves, the Tetyukhinskaya Cave and the Sukhaya Cave, near Dalnegorsk in the Primorye region during paleontological investigations between 2003 and 2006. The fossil finds were dated to the late Pleistocene, into which other finds such as the evidence of the Asiatic black bear ( Ursus thibetanus ) from the caves were classified. The accumulation of bone debris in these caves was likely the result of the activity of predators who used the caves as habitation or shelter. All of Petaurista's fossils were found in the entrance to the caves.

Mikhail P. Tiunov , one of the two first descriptions of the species, presented the fossils as the remains of a Petaurista species at a conference of the Russian Theriological Society in 2016 . The first scientific description appeared in the journal Palaeoworld in March 2020, with a preliminary publication at the end of October 2019 that was picked up by the press.

Systematics

The first scientific description of the species comes from the Russian paleontologists Mikhail P. Tiunov and Dmitryi O. Gimranov , who presented the fossils in March 2020 and classified them in the genus Petaurista . These are the oldest fossil finds of a representative of this genus and Petaurista tetyukhensis is also the only known species of the genus that has only been proven in fossil form. Eight, nine or even 16 recent species are classified within the genus of the giant flying squirrel, depending on the system. The species are distributed over large parts of East and South Asia. Due to the similarities of the dentition and the geographical proximity, a closer relationship of Petaurista tetyukhensis to the Japanese giant flying squirrel ( Petaurista leucogenys ) is assumed.

The earliest records of fossil giant sliding squirrels come from the early Pleistocene from sites in Chongqing and Anhui in southern China . The northernmost finds up to the discovery of Petaurista tetyukhensis come from a warm phase in the middle Pleistocene from Zhoukoudian in the north of China and other finds of animals of the genus from the late Pleistocene come from Japan and China. In the Holocene , the genus was also found on the southern Japanese islands and on the island of Hainan, which belongs to China .

The species was named by the place where it was found , using the old name of the city of Dalnegorsk, Tetyukhe. The cave is also named after this city.

supporting documents

  1. ↑ a b c d e f g h i j k Mikhail P. Tiunov, Dmitryi O. Gimranov: The first fossil Petaurista (Mammalia: Sciuridae) from the Russian Far East and its paleogeographic significance. Palaeoworld 29 (1), March 2020; Pp. 176-181. doi : 10.1016 / j.palwor.2019.05.007
  2. ↑ a b P.A. Kosintsev, MP Tiunov, DO Gimranov, VS Panov: The First Finding of Asian Black Bear (Carnivora, Ursidae, Ursus (Euarctos) thibetanus G. Cuvier, 1823) in the Late Pleistocene of Northern Eurasia. Doklady Biological Sciences 471, 2016; Pp. 266-268. doi : 10.1134 / S0012496616060041 , full text .
  3. ↑ Mikhail P. Tiunov: First record of Petaurista Link, 1795 in the Late Pleistocene of the Far East of Russia. Proceedings of the International Conference “Theriofauna of Russia and Adjacent Territories” (X Congress of Russian Theriological Society RAS), Moscow 2016; P. 423.
  4. ↑ New species of a giant flying squirrel discovered in the Far East of Russia. The Siberian Times, October 31, 2019; accessed on April 4, 2020.
  5. ↑ PaleoMammalogy • 2019: Petaurista tetyukhensis • The First Fossil Petaurista (Mammalia: Sciuridae) from the Russian Far East and Its Paleogeographic Significance. novataxa.blogspot.com, November 1, 2019; accessed on April 4, 2020.
  6. ↑ Don E. Wilson & DeeAnn M. Reeder (eds.): Petaurista in Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed).
  7. ↑ a b Richard W. Thorington Jr., John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; P. 110 ff. ISBN 978-1-4214-0469-1
  8. ↑ a b J.L. Koprowski, EA Goldstein, KR Bennett, C. Pereira Mendes: Petaurista. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (Eds.): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6) Lynx Edicions, Barcelona 2016, ISBN 978- 84-941892-3-4 , p. 769 ff.

literature

  • Mikhail P. Tiunov, Dmitryi O. Gimranov: The first fossil Petaurista (Mammalia: Sciuridae) from the Russian Far East and its paleogeographic significance. Palaeoworld 29 (1), March 2020; Pp. 176-181. doi : 10.1016 / j.palwor.2019.05.007