Rank Subfamily | Phylum Chordata Higher classification Canidae | |
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Taxonomic history
The subfamily Hesperocyoninae was named by Martin (1989). The members were reassigned to the family Canidae (with no subfamily) by Xiaoming Wang in 1999.
Hesperocyoninae are basal canids that, according to Wang and Tedford, gave rise to the other canid groups, such as the Borophaginae and Caninae.
This disused subfamily was endemic to North America, living from the Duchesnean stage of the Late Eocene through to the early Barstovian stage of the Miocene, lasting around 20 million years. It comprises 10 recognized genera and 26 recognized species; among these, four genera and species are new. Four major lineages can be defined based on shared characteristics:
The genus Caedocyon probably forms a distinct clade of its own.
Hesperocyon, which lacks the shared derived characters that would include it within any of the aforementioned clades, is possibly ancestral to many of the lineages. Some evidence indicates the Paraenhydrocyon clade may be directly descended from Hesperocyon gregarius. According to Xiaoming Wang, Hesperocyon coloradensis provides an important link between H. gregarius and the Mesocyon-Enhydrocyon clade.
Extinction
According to an analysis of the fossil record of North American fossil carnivorans, the decline of hesperocyonines to extinction during the period from about 20 to 10 million years ago was driven by competition with felids and borophagines.