Borophaginae Temporal range: 40–2.5 Ma Oligocene-Pliocene |
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Aelurodon stirtoni | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Family: | Canidae |
Subfamily: |
†Borophaginae G.G. Simpson (1945) |
Genera | |
See text |
See text
The subfamily Borophaginae is an extinct group of canids called "bone-crushing dogs" 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.
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.
There are 66 identified borophagine species, including 18 new ones that range from the Orellan to Blancan ages. A phylogenetic analysis of the species was conducted using cladistic methods, with Hesperocyoninae as an archaic group of canids, as the outgroup. Aside from some transitional forms, Borophaginae can be organized into four major clades: Phlaocyonini, Cynarctina, Aelurodontina, and Borophagina (all erected as new tribes or subtribes). The Borophaginae begins with a group of small fox-sized genera, such as Archaeocyon, , Otarocyon, and Rhizocyon, in the Orellan through early Arikareean stages. These canids reached their maximum diversity of species around 28 million years ago.