Ursus rossicus
{{Short description|Extinct species of carnivore}}
{{speciesbox
| fossil_range = Middle to Late Pleistocene, {{fossil range|0.25|0.027}}
| image = Ursus rossicus.jpg
| image_caption = Skeleton in Zoological Museum, Saint Petersburg
| genus = Ursus
| species = rossicus
|extinct = yes
| authority = Borissiak, 1930
}}
Ursus rossicus is an extinct species of bear that lived in the steppe regions of northern Eurasia and Siberia during the Pleistocene. It is part of the cave bear species complex.
Discovery
Vereshchagin discovered the first U. rossicus remains in the Altai Mountains in 1973. Mandibles of the bear were found in Bachatsk Quarry, Krasni Yar (in Tomsk Province) and Mokhovo Quarry; skull fragments were found in Krasni Yar.{{cite journal|last1=Baryshnikov|first1=G.|last2=Foronova|first2=I.|year=2001|url=http://www.udc.gal/iux/almacen/articulos/cd26_art24.pdf|title=Pleistocene small cave bear (Ursus rossicus) from the South Siberia, Russia|journal=Cadernos Lab. Xeolóxico de Laxe|volume=26|pages=373–398|access-date=15 April 2015|archive-date=8 March 2021|archive-url=https://web.archive.org/web/20210308094429/https://www.udc.gal/iux/almacen/articulos/cd26_art24.pdf|url-status=dead}} More fossil remains of U. rossicus were discovered in the famous Denisova Cave.{{Cite journal |last=Puzachenko |first=A.Yu. |last2=Titov |first2=V.V. |last3=Kosintsev |first3=P.A. |date=20 December 2021 |title=Evolution of the European regional large mammals assemblages in the end of the Middle Pleistocene – The first half of the Late Pleistocene (MIS 6–MIS 4) |url=https://linkinghub.elsevier.com/retrieve/pii/S1040618220305024 |journal=Quaternary International |language=en |volume=605-606 |pages=155–191 |doi=10.1016/j.quaint.2020.08.038 |access-date=22 January 2024 |via=Elsevier Science Direct|url-access=subscription }}
Description
The small cave bear had a very broad, domed skull with a steep forehead. Its stout body had long thighs, massive shins and in-turning feet, making it similar in skeletal structure to the brown bear.{{cite book | author = Brown, Gary | title = Great Bear Almanac | year = 1996 | page = [https://archive.org/details/greatbearalmanac00gary/page/340 340] | publisher = Lyons & Burford | isbn = 1-55821-474-7 | url = https://archive.org/details/greatbearalmanac00gary/page/340 }} Cave bears were comparable in size to the largest modern-day bears.{{cite book | author= Macdonald, David | title= The Velvet Claw | year= 1992 | page= [https://archive.org/details/velvetclawnatura00macd/page/256 256] | isbn= 0-563-20844-9 | publisher= Parkwest | location= New York | url= https://archive.org/details/velvetclawnatura00macd/page/256 }}
Diet
U. rossicus dental specimens when separated into groups of different ontogenetic stages do not show significant variations in microwear, suggesting the diets of these bears stayed fairly constant over the course of their lifetimes.{{Cite journal |last=Ramírez Pedraza |first=Iván |last2=Baryshnikov |first2=Gennady F. |last3=Prilepskaya |first3=Natalya E. |last4=Belyaev |first4=Ruslan I. |last5=Pappa |first5=Spyridoula |last6=Rivals |first6=Florent |date=30 August 2021 |title=Paleodiet and niche partitioning among the easternmost European cave bears based on tooth wear analysis |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2021.1960324 |journal=Historical Biology |language=en |volume=34 |issue=6 |pages=1063–1071 |doi=10.1080/08912963.2021.1960324 |issn=0891-2963 |access-date=3 May 2024 |via=Taylor and Francis Online|url-access=subscription }}
Cave bear teeth show greater wear than most modern bear species, suggesting a diet of tough materials. However, tubers and other gritty food, which cause distinctive tooth wear in modern brown bears, do not appear to have constituted a major part of cave bears' diets on the basis of dental microwear analysis.Pinto Llona, A. C., Andrews, P. & Etxeberrı´a, P. 2005: Taphonomy and Palaeoecology of Cave Bears from the Quaternary of Cantabrian Spain. Fondacio´n de Asturias/Du Pont Ibe´rica/The Natural History Museum, Grafinsa, Oviedo.
The morphological features of the cave bear chewing apparatus, including loss of premolars, have long been suggested to indicate their diets displayed a higher degree of herbivory than the Eurasian brown bear. Indeed, a solely vegetarian diet has been inferred on the basis of tooth morphology. Results obtained on the stable isotopes of cave bear bones also point to a largely vegetarian diet in having low levels of nitrogen-15 and carbon-13,{{Cite journal|author= Bocherens, H.|title=Bears and humans in Chauvet Cave (Vallon-Pont-d'Arc, Ardeche, France): Insights from stable isotopes and radiocarbon dating of bone collagen |year=2006 |journal=Journal of Human Evolution |volume=50 |pages=370–376|pmid= 16442587|issue= 3|doi= 10.1016/j.jhevol.2005.12.002|display-authors=etal}} which are accumulated at a faster rate by carnivores as opposed to herbivores.
Cave bears of the last ice age lacked the usual two or three premolars present in other bears; to compensate, the last molar is very elongated, with supplementary cusps.[http://www.altabadia.it/orsispelei/nozioni_i.htm Gli orsi spelèi delle Conturines/ Ursus Spelaeus]. Altabadia.it. Retrieved on 2011-09-26.
References
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{{Ursidae extinct nav}}
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Category:Pleistocene mammals of Europe
Category:Pleistocene carnivorans
Category:Fossil taxa described in 1930
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