Parictis

Parictis is the earliest genus of bears known.[1] It was a very small and graceful ursid with a skull only 7 cm long. Parictis first appeared in North America in the Late Eocene (around 38 million years ago), but it did not arrive in Eurasia until the Miocene.[2] Some suggest that Parictis may have emigrated from Asia into North America during the major sea level low about 37 mya, because of the continued evolution of the Amphicynodontinae into the Hemicyoninae in Asia.[3] Although no Parictis fossils have been found in East Asia, Parictis does appear in Eurasia and Africa, but not until the Miocene.[2]

Parictis Temporal range: Eocene–Miocene PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Ursidae
Subfamily:	†Amphicynodontinae
Genus:	†Parictis Scott, 1893
Species
See text

Species

• P. dakotensis Clark 1936 37 Million years old
• P. gilpini Clark & Guensburg 1972 35 Million years old
• P. major Clark & Guensburg 1972
• P. montanus Clark & Guensburg 1972 36 Million years old
• P. parvus Clark & Beerbower, 1967 38 Million years old
• P. personi Chaffee 1954[4] 33 Million years old
• P. primaevus, Scott 1893 Although Hall (1931) thought to reassign this species to the Canidae,[5] Hunt (1998) clearly places it within the Ursidae, under Parictis.[6]

Formerly classed under Parictis

• P. bathygenus White 1947 is no longer considered a species of Parictis, having been reassigned to the genus Cynelos, in the Amphicyonidae ("bear dog") family.[7][8]

References

1. While originally classified as a bear (Ursidae), Hunt, R. M. Jr. (1998). "Ursidae". In Janis, Christine M.; Scott, Kathleen M.; Jacobs, Louis L. (eds.). Evolution of Tertiary Mammals of North America, volume 1: Terrestrial carnivores, ungulates, and ungulatelike mammals. Cambridge, England: Cambridge University Press. pp. 174–195. ISBN 978-0-521-35519-3., others consider the entire Amphicynodontinae family to be at most bear-dogs. McLellan, Bruce & Reiner, David C. (1994). "A review of bear evolution". In Claar, James J.; et al. (eds.). Bears: Their Biology and Management: Ninth International Conference on Bear Research and Management. International Association for Bear Research and Management. pp. 85–96. ISBN 978-0-944740-04-0.
2. Kemp, T. S. (2005). The Origin and Evolution of Mammals. Oxford University Press. p. 260. ISBN 978-0-19-850760-4.
3. Several students (Erdbrink 1953, Kurten 1966, Mitchell and Tedford 1973, Thenius 1979) suggested that the evolutionary line between the canid subfamily Amphicynodontinae and the ursid subfamily Hemicyoninae was through the genera Cephalogale and Ursavus. McLellan, Bruce & Reiner, David C. (1994). "A review of bear evolution". In Claar, James J.; et al. (eds.). Bears: Their Biology and Management: Ninth International Conference on Bear Research and Management. International Association for Bear Research and Management. pp. 85–96. ISBN 978-0-944740-04-0.
4. Chafee, R. F. (1954). "Campylocynodon personi, a new Oligocene carnivore from the Beaver Divide, Wyoming". Journal of Paleontology. 28 (1): 43–46.
5. Hall, E. Raymond (1931). "Description of a New Mustelid from the Later Tertiary of Oregon, with Assignment of Parictis primaevus to the Canidae". Journal of Mammalogy. 12 (2): 156–158. doi:10.2307/1373915. JSTOR 1373915.
6. Hunt, R. M. Jr. (1998). "Ursidae". In Janis, Christine M.; Scott, Kathleen M.; Jacobs, Louis L. (eds.). Evolution of Tertiary Mammals of North America, volume 1: Terrestrial carnivores, ungulates, and ungulatelike mammals. Cambridge, England: Cambridge University Press. pp. 174–195. ISBN 978-0-521-35519-3.
7. Olsen, Stanley J. (1958). "Some problematical carnivores from the Florida Miocene". Journal of Paleontology. 32 (3): 595–602. JSTOR 1300686.
8. Tedford, Richard H. & Frailey, David (1976). Review of some Carnivora (Mammalia) from the Thomas Farm local fauna (Hemingfordian, Gilchrist County, Florida) (PDF). American Museum Novitates; no. 2610. New York: American Museum of Natural History. p. 2.