Borophaginae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Borophaginae
Temporal range: 40–2.5Ma
Oligocene to Pliocene
Aelurodon stirtoni.jpg
Strobodon stirtoni, Cat Tooth
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Subfamily: Borophaginae
Genera

See text

The subfamily Borophaginae is an extinct group of canids called "bone-crushing dogs"[1] that were endemic to North America during the Oligocene to Pliocene and lived roughly 36—2.5 million years ago and existing for about 33.5 million years.[2]

Origin[edit]

The Borophaginae apparently descended from the subfamily Hesperocyoninae. The earliest and most primitive borophagine is the genus Archaeocyon, which is a small fox-sized animal mostly found in the fossil beds in western North America. The borophagines soon diversified into several major groups. They evolved to become considerably larger than their predecessors, and filled a wide range of niches in late Cenozoic North America, from small omnivores to powerful, bear-sized carnivores such as Epicyon.[2][3]

Species[edit]

Borophagines are a total of 66 species that includes 18 new species which range from Orellan through Blancan ages. A phylogenetic analysis using cladistic methods with Hesperocyoninae as an archaic group of canids, as the outgroup. Most of the Borophaginae, aside from some transitional forms, can be organized in four major clades: Phlaocyonini, Cynarctina, Aelurodontina, and Borophagina (all erected from as new tribes or subtribes). The Borophaginae begins with a group of small fox-sized genera, such as Archaeocyon, Oxetocyon, Otarocyon, and Rhizocyon, in the Orellan through early Arikareean stages.[4] These canids reached their maximum diversity of species around 28 million years ago.

Often generically referred to as "bone-crushing dogs" for their powerful teeth and jaws, and hyena-like features (although their dentition was more primitive than that of hyenas), their fossils are abundant and widespread; in all likelihood, they were probably one of the top predators of their ecosystems.[3][5] Their good fossil record has also allowed a detailed reconstruction of their phylogeny, showing that the group was highly diverse in its heyday.[3] All Borophaginae had a small fifth toe on their rear feet (similar to the toes that bear dew claws on the front feet), where as all modern Caninae have only four toes normally.[6]

Noteworthy genera in this group are Aelurodon, Epicyon, and Borophagus (=Osteoborus). According to Xiaoming Wang, the Borophaginae played broad ecological roles that are performed by at least three living carnivoran families, Canidae, Hyaenidae, and Procyonidae.

Phylogeny of borophagines by R.L. Tedford, 1977
Fluctuation of species within Canidae over 40 million years

Classification[edit]

Borophagine taxonomy, following Wang et al.[3]

(million years=in existence)

Cladogram showing borophagine interrelationships, following Wang et al., figure 141:[3]

Canidae

Hesperocyoninae




Caninae


Borophaginae

Archaeocyon



Oxetocyon



Otarocyon




Rhizocyon



Phlaocyonini

Cynarctoides



Phlaocyon



Borophagini

Cormocyon




Desmocyon



Cynarctina

Paracynarctus



Cynarctus





Metatomarctus




Euoplocyon




Psalidocyon




Microtomarctus




Protomarctus




Tephrocyon


Aelurodontina

Tomarctus



Aelurodon



Borophagina

Paratomarctus




Carpocyon




Protepicyon




Epicyon



Borophagus




















References[edit]

  1. ^ http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=83323&is_real_user=1 Paleobiology Database: Borophaginae
  2. ^ a b Postanowicz, Rebecca. "Lioncrusher's Domain: Canidae". Retrieved 2006-04-12. 
  3. ^ a b c d e Wang, Xiaoming; Richard Tedford; Beryl Taylor (1999-11-17). "Phylogenetic systematics of the borophaginae". Bulletin of the American Museum of Natural History 243. hdl:2246/1588. 
  4. ^ ANMH Scientific Library, Wang, X.
  5. ^ Alan Turner, "National Geographic: Prehistoric Mammals" (Washington, D.C.: Firecrest Books Ltd., 2004), pp. 112–114. ISBN 0-7922-7134-3
  6. ^ Wang, Xiaoming; and Tedford, Richard H. Dogs: Their Fossil Relatives and Evolutionary History. New York: Columbia University Press, 2008. p44

Additional 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