Ursavus
| Ursavus Temporal range: Oligocene–Miocene | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Suborder: | Caniformia |
| Superfamily: | Arctoidea |
| Family: | Ursidae |
| Subfamily: | Ursinae |
| Tribe: | †Ursavini[1][2] |
| Genus: | †Ursavus |
| Type species | |
| Ursavus brevirhinus | |
| Species | |
Ursavus is an extinct genus of ursid carnivoran mammals that existed in North America, Europe, and Asia during the Miocene, living from about 23—5.3 million years ago (Mya), existing for roughly 17.7 million years. It evolved from the bear-dog[3][4] The genus apparently dispersed from Asia into North America about 20 Mya, becoming the earliest member of the subfamily Ursinae in the New World.[5] 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.
Ursavus was named by Schlosser (1899). It was assigned to the family Ursidae by Schlosser (1899) and R. L. Carroll (1988); and to Ursavini by R.M. Hunt (1998) and Jin et al. (2007).[1][6]
In life, the various species would have been between cat-sized for the smaller species[7] and wolf-sized for the larger members of the genus and were mainly ground-dwelling omnivores or hypocarnivores.
U. elmensis, also known as the "dawn bear"[8] is generally taken to be the earliest undisputed bear species.[9][10]
Currently, only U. orientalis, from the Shanwang diatomite of Early Miocene China, is known from a complete skeleton.[7][11] However, U. orientalis may have been reassigned to the genus Ballusia, thus is no longer considered part of Ursavus.
Most other species are known from teeth and skull fragments. A complete skull has been found in the Gansu region of China of a new species dubbed U. tedfordi. From the late Miocene, it was about the size of a wolf and is believed to be nearest ancestor of most modern bear species apart from the giant panda and spectacled bear.
Fossil distribution
Sites (not complete) and specimen ages:
- Pawnee Buttes Site, Weld County, Colorado (U. pawniensis) ~23.03—5.3 Ma.
- Shanwang diatomite, Shanwang, China (U. orientalis[11]) ~17-16 Ma.[7] May belong to the genus Ballusia
- Pasalar site, Bursa, Turkey (U. primaevus) ~16—13.7 Ma.
- Baigneaux-en-Beauc, Alsac, France (U. brevirhinus) ~16.9—16.0 Ma.
- Hambach mine horizon 6C, Germany (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.[7]
- Linxia Basin Gansu, China (U. tedfordi) ~9-7 Ma.
In popular culture
Ursavus was featured briefly in the National Geographic documentary Evolutions: Bear Necessities.
References
- 1 2 Hunt, R. M. (1998). "Ursidae". In Jacobs, Louis; Janis, Christine M.; Scott, Kathleen L. Evolution of Tertiary Mammals of North America: Volume 1, Terrestrial Carnivores, Ungulates, and Ungulate like Mammals. Cambridge, UK: Cambridge University Press. pp. 174–195. ISBN 0-521-35519-2.
- ↑ C. Jin, R. L. Ciochon, W. Dong, R. M. Hunt, Jr., J. Liu, M. Jaeger, and Q. Zhu. 2007. The first skull of the earliest giant panda" Proceedings of the National Academy of Sciences 104:10932-10937
- ↑ Kurten, Bjorn. "Pleistocene bears of North America I, Genus Tremarctos, spectacled bears. 1966". Acta Zool. Fenn. 115: 1–120.
- ↑ Crusafont, M.; Kurten, B. "Bears and bear-dogs from the Vallesian of the Valles-Penedes basin, Spain". Acta Zool. Fenn. 1976 144: 1–29.
- ↑ Qiu Zhanxiang. 2003. Dispersals of Neogene Carnivorans between Asia and North America in Chapt 2, Bulletin of the American Museum of Natural History #279, pp18-31.
- ↑ R. L. Carroll. 1988. Vertebrate Paleontology and Evolution. W. H. Freeman and Company, New York 1-698
- 1 2 3 4 Lindburg, Donald G. (2004). Giant Pandas: Biology and Conservation. University of California Press. p. 308. ISBN 9780520238671.p 46
- ↑ Derocher, Andrew E.; Ian Stirling (February 1989 (1990)). "Factors Affecting the Evolution and Behavioral Ecology of the Modern Bears". Bears: Their Biology and Management A Selection of Papers from the Eighth International Conference on Bear Research and Management 8: 189–204. JSTOR 3872919. Check date values in:
|date=(help) - ↑ McLellan, Bruce (1994). "A REVIEW OF BEAR EVOLUTION" (PDF). International Conference Bear Research and Management 9 (1): 85–96. doi:10.1080/08897077.2011.540477.
- ↑ Derocher, A. E. & W. Lynch. 2012. Polar Bears: A Complete Guide to Their Biology and Behavior. The Johns Hopkins University Press, Baltimore
- 1 2 Yang, Hong; SHIPU YANG (December 1994). "The Shanwang fossil biota in eastern China: a Miocene Konservat-Lagerstätte in lacustrine deposits". Lethaia 27 (4): 345–354. doi:10.1111/j.1502-3931.1994.tb01585.x.