The extinct Hesperocyoninae are one of three subfamilies found within the canid family. The other two canid subfamilies are the extinct

Borophaginae The extinct Borophaginae form one of three subfamilies found within the canid family. The other two canid subfamilies are the extinct Hesperocyoninae and extant Caninae. Borophaginae, called "bone-crushing dogs", were endemic to North America dur ...

and extant Caninae.

Taxonomic history

Hesperocyoninae are basal canids that gave rise to the other two canid subfamilies, the Borophaginae and Caninae. This subfamily was endemic to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

, living from the Duchesnean stage of the

Late Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

through to the early

Barstovian The Barstovian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 16,300,000 to 13,600,000 years BP, a period of . It is u ...

stage of the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

, lasting around 20 million years. It comprises 10 recognized genera and 26 recognized species. Four major lineages can be defined based on shared characteristics: *''

Mesocyon ''Mesocyon'' ("middle dog") is an extinct genus of the Hesperocyoninae subfamily of early canid Canidae (; from Latin, ''canis'', "dog") is a biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a cla ...

''-''

Enhydrocyon ''Enhydrocyon'' is an extinct genus of bone crushing canid which inhabited North America during the Oligocene and Early Miocene, 30.8—20.4 Ma, existing for approximately . ''Enhydrocyon'' dentition suggests this animal was a hypercarnivo ...

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

(includes '' Cynodesmus, Sunkahetanka, Philotrox'') *''

Osbornodon ''Osbornodon'' (" Osborn's tooth") is an extinct genus of canid that were endemic to North America and which lived from the Oligocene to the Early Miocene, 33.9—15.97 Ma ( AEO), existing for approximately . Paraenhydrocyon ''Paraenhydrocyon'' ("beside ''Enhydrocyon''") is an extinct genus of bone crushing omnivorous early canid which inhabited North America during the Early Miocene, 24.8—20.4 Ma, existing for approximately . The dentition suggests that this ...

'' *''

Ectopocynus ''Ectopocynus'' ("strange dog") is an extinct genus of bone crushing canid which inhabited North America from the Oligocene to the Early Miocene. It lived from 33.3 to 16.0 Ma and existed for approximately . Remains of ''Ectopocynus'' are li ...

clade'' The genus '' Caedocyon'', which is only known from a single partial cranium that shows some ''Paraenhydrocyon'' affinities, probably represents another independent lineage. '' 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 ''Paraenhydrocyon'' ("beside ''Enhydrocyon''") is an extinct genus of bone crushing omnivorous early canid which inhabited North America during the Early Miocene, 24.8—20.4 Ma, existing for approximately . The dentition suggests that this ...

'' 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.Wang, X. 1994
Phylogenetic systematics of the Hesperocyoninae (Carnivora, Canidae)
Bulletin of the American Museum of Natural History, 221:1-207.

Extinction

According to an analysis of the fossil record of North American fossil

carnivora Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...

ns, 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. File:Canidae Species Divesity.png, Fluctuation of species within Canidae over 40 million years File:Wang Borophagine Construct.png, Phylogeny of Hesperocyoninae related to

and

canine Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** ''Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the surn ...

s by R.L. Tedford, 1977 File:Hesperocyoninae species.png, Hesperocyoninae species per unit of time

Taxonomic history

Extinction

References

Further reading