''Ursavus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of bear that existed in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, and

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

during the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

period, about 23–5.3 million years ago (Mya), existing for roughly . The genus apparently dispersed from Asia into North America about 20 Mya, becoming the earliest member of the subfamily Ursinae in the New World. Qiu points out that if a questionable 29 million-year-old specimen of ''Ursavus'' reported in North America is validated, ''Ursavus'' may have evolved in North America and dispersed westward into Asia. The higher number of fossils in Europe grading toward eastern Asia make the westward dispersal unlikely. ''U. elmensis'', also known as the "dawn bear" is generally taken to be the earliest undisputed bear species.

Description

In life, the various species would have been between cat-sized for the smaller species and wolf-sized for the larger members of the genus phys.org news
/ref> and were mainly

omnivore An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize t ...

s or

hypocarnivore A hypocarnivore is an animal that consumes less than 30% meat for its diet, the majority of which consists of fungi, fruits, and other plant material. Examples of living hypocarnivores are the grizzly bear (''Ursus horribilis''), black bear (''U ...

s. Most other species are known from teeth and skull fragments. A complete skull has been found in the

Gansu Gansu is a provinces of China, province in Northwestern China. Its capital and largest city is Lanzhou, in the southeastern part of the province. The seventh-largest administrative district by area at , Gansu lies between the Tibetan Plateau, Ti ...

region of China of a new species from the late

, dubbed ''U. tedfordi''. It was about the size of a wolf and – except for the

giant panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear or simply panda, is a bear species endemic to China. It is characterised by its white animal coat, coat with black patches around the eyes, ears, legs and shoulders. ...

and the

spectacled bear The spectacled bear (''Tremarctos ornatus''), also known as the South American bear, Andean bear, Andean short-faced bear or mountain bear and locally as jukumari ( Aymara and Quechua), ukumari ( Quechua) or ukuku, is a species of bear native to ...

– is believed to be the nearest to the common ancestor of modern bears. Currently, the only member known from a complete skeleton is ''U. orientalis'', found in the Shanwang diatomite of Early Miocene

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. However, Qiu ''et.al.'' (2014) have suggested reassignment of ''U. orientalis'' to the genus '' Ballusia'', in which case it would no longer be considered part of ''Ursavus''.

Fossil distribution

A partial list of find sites and specimen ages: *Pawnee Buttes Site,

Weld County, Colorado Weld County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 328,981. The county seat is Greeley. Weld County comprises the Greeley, CO Metropolitan Statistical Area, which is included in the Denv ...

(''U. pawniensis'') ~23.03–5.3 Ma. *Shanwang

diatomite Diatomaceous earth ( ), also known as diatomite ( ), celite, or kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 ...

, Shanwang,

(''U. orientalis'') ~17-16 Ma. May belong to the genus '' Ballusia'' *Pasalar site, Bursa, Turkey (''U. primaevus'') ~16–13.7 Ma. *Baigneaux-en-Beauc, Alsac,

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

(''U. brevirhinus'') ~16.9–16.0 Ma. *Hambach mine horizon 6C,

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

(''U. elmensis'') ~16.9–13.7 Ma. *Yost Farm Site, Saskatchewan, Canada (''U. primaevus'') ~16.3–13.6 Ma. *Myers Farm Site, Valentine Formation, Webster County, Nebraska (''U. brevirhinus'') ~16.3–13.6 Ma. *Lufeng site, Yunnan, China (''U. depereti'') ~7-6 Ma. *Linxia Basin Gansu, China (''U. tedfordi'') ~9-7 Ma.

References

{{Taxonbar, from=Q3308205 Miocene bears Messinian extinctions Miocene mammals of North America Miocene mammals of Asia Miocene mammals of Europe Prehistoric carnivoran genera Aquitanian genus first appearances Fossil taxa described in 1899