Borophagus

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Borophagus[1]
Temporal range: late Miocene to late Pliocene
Borophagus cyonoides 1.jpg
Osteoborus cyonoides skull
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Subfamily: Borophaginae
Genus: Borophagus
Cope, 1892
Type species
Borophagus diversidens
Species
  • B. diversidens
  • B. dudleyi
  • B. hilli
  • B. littoralis
  • B. orc
  • B. parvus
  • B. pugnator
  • B. secundus
Synonyms
  • Borophagus Stirton & VanderHoof, 1933
  • Cynogulo' Kretzoi, 1968
  • Hyaenognathus Merriam, 1903
  • Porthocyon Merriam, 1903
  • Osteoborus

Borophagus ("gluttonous eater") is an extinct genus of the subfamily Borophaginae, a group of canids endemic to North America from the early Miocene epoch through the Zanclean stage of the Pliocene epoch 23.3—3.6 Mya. Borophagus existed for approximately 19.7 million years.[2]

Evolution[edit]

Restoration of two Borophagus preying on a camel

Borophagus, like other borophagines, are loosely known as "bone-crushing" or "hyena-like" dogs. Though not the most massive borophagine by size or weight, it had a more highly evolved capacity to crunch bone than earlier, larger genera such as Epicyon, which seems to be an evolutionary trend of the group (Turner, 2004). During the Pliocene epoch, Borophagus began being displaced by Canis genera such as Canis edwardii and later by Canis dirus. Early species of Borophagus were placed in the genus Osteoborus until recently, but the genera are now considered synonyms.[1]

Canidae competitors[edit]

Borophagus was one of the last of the Borophaginae and would have shared its North American habitat with other canids: Epicyon ((20.6—5.330 Ma), Paratomarctus (16.3—5.3 Ma), Carpocyon (20.4—3.9 Ma), Aelurodon (23.03—4.9 Ma), and the first emerging wolf, Canis lepophagus appearing 10.3 Ma.

Taxonomy[edit]

Typical features of this genus are a bulging forehead and powerful jaws; Borophagus has been considered to be probably a scavenger by paleontologists in the past.[3] Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. However, Borophagus fossils are so abundant and geographically widespread that some paleontologists now argue that Borophagus must have been both the dominant carnivore of its time, and thus an active predator because carrion feeding alone could not have sustained such a large population. [4] They note that not all carnivores with bone-cracking ability are scavengers, such as the modern spotted hyena; instead, they interpret the bone-cracking ability as an adaptation to social hunting where complete utilization of a carcass was favored. [5]

The adult animal is estimated to have been about 80 cm in length, similar to a coyote, although it was much more powerfully built.[6]

Morphology[edit]

Jaws of Borophagus diversidens

Two fossil specimens of Borophagus were measured by Legendre and Roth in 1988. They estimated that specimen one weighed 43.8 kilograms (97 lb) and the second weighed 35.8 kilograms (79 lb).[7]

Species[edit]

Restoration by Charles R. Knight, 1902

Existence based on age of fossil collections and recombination with other species.

Sister genera[edit]

Carpocyon, Epicyon, Paratomarctus, Protepicyon

References[edit]

  1. ^ a b Wang, Xiaoming; Richard Tedford; Beryl Taylor (1999-11-17). "Phylogenetic systematics of the Borophaginae". Bulletin of the American Museum of Natural History 243. Retrieved 2007-07-08. [dead link]
  2. ^ PaleoBiology Database: Borophagus, basic info
  3. ^ Lambert, David (1985). The Field Guide to Prehistoric Life. New York: Facts on File. p. 163. ISBN 0-8160-1125-7. 
  4. ^ Wang, Xiaoming; and Tedford, Richard H. Dogs: Their Fossil Relatives and Evolutionary History. New York: Columbia University Press, 2008. pp112-3
  5. ^ Wang, Xiaoming; and Tedford, Richard H. Dogs: Their Fossil Relatives and Evolutionary History. New York: Columbia University Press, 2008. pp112-3
  6. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 220. ISBN 1-84028-152-9. 
  7. ^ S. Legendre and C. Roth. 1988. Correlation of carnassial tooth size and body weight in recent carnivores (Mammalia). Historical Biology: p. 85-98
  • Alan Turner, "National Geographic: Prehistoric Mammals" (Washington, D.C.: Firecrest Books Ltd., 2004), pp. 112-114. ISBN 0-7922-7134-3

Further reading[edit]

  • Xiaoming Wang, Richard H. Tedford, Mauricio Antón, Dogs: Their Fossil Relatives and Evolutionary History, New York : Columbia University Press, 2008; ISBN 978-0-231-13528-3