Cynodesmus is an extinct genus of omnivorous canine which inhabited North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 during the Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 living from 33.3—-26.3 Ma and existed for approximately .
Cynodemus was one of the first canids

Canidae

Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...

 to truly look dog-like. At around 1 metres (3.3 ft) in length, it was about the same size as a modern coyote

Coyote

The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...

, but had a shorter skull

Skull

The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

, heavier tail, and longer rump. The shape of its limbs suggests that Cynodesmus was not a very good runner compared to most other canids; it probably attacked prey from an ambush. Unlike modern dogs, it had five toes on each foot, bearing partially retractable claw

Claw

A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...

s.

Taxonomy

Cynodesmus once included numerous species of Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 and Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 canid with highly carnivorous (hypercarnivorous

Hypercarnivore

A hypercarnivore is an animal which has a diet that is more than 70% meat, with the balance consisting of non-animal foods such as fungi, fruits or other plant material. Some examples include the big cats, dolphins, eagles, snakes, marlin, most sharks, and such invertebrates as octopuses and sea...

) dentition

Dentition

Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, the characteristic arrangement, kind, and number of teeth in a given species at a given age...

s. A revision of the genus by Wang (1994) indicates that most species previously placed in Cynodesmus are unrelated to the type

Biological type

In biology, a type is one particular specimen of an organism to which the scientific name of that organism is formally attached...

 species, C. thooides. These other species have been placed the genera Carpocyon

Carpocyon

Carpocyon is an extinct member of the Borophaginae, and a terrestrial canine which inhabited most of North America during the Barstovian stage of the Middle Miocene through the Hemphillian stage of the Late Miocene epoch 20.4—3.9 Mya. Carpocyon existed for approximately .-Taxonomy:Carpocyon was...

, Desmocyon

Desmocyon

Desmocyon is an extinct genus of the Borophaginae and a terrestrial canine which inhabited most of North America during the Harrisonian stage of the Late Oligocene through Early Hemingfordian stage of the Early Miocene epoch living 24.8—16.3 Mya existing for approximately .-Fossil record:It is a...

, Leptocyon

Leptocyon

Leptocyon is a small extinct genus of canidae endemic to North America during the Oligocene through Miocene living from 24.8—10.3 mya, existing for approximately .Leptocyon was a small bodied, fox-like animal with a slender jaw.-Taxonomy:...

, Metatomarctus

Metatomarctus

Metatomarctus is an extinct genus of Borophaginae and a terrestrial canine which inhabited most of North America during the Early Hemingfordian stage of the Miocene epoch living 23.0—5.3 Mya, existing for approximately -Taxonomy:...

, Osbornodon

Osbornodon

Osbornodon is an extinct genus of bone-crushing canid that were endemic to North America and which lived from the Orellan age of the Early Oligocene to Early Miocene epoch 33.9—15.97 Ma and existed for approximately ....

, Otarocyon

Otarocyon

Otarocyon is an extinct genus "bone crushing dog" of the family Borophaginae and a terrestrial canine which was small in size endemic to North America during of the Oligocene epoch, ~33.9—20.6 Ma...

, Paracynarctus

Paracynarctus

Paracynarctus is an extinct genus of the Borophaginae and a terrestrial canine which inhabited most of North America during the Early Hemingfordian stage of the Early Miocene subepoch through the Early Barstovian stage of the Middle Miocene subepoch 20.6—13.6 Ma, existing for approximately .As...

, Paratomarctus

Paratomarctus

Paratomarctus an extinct member of the Borophaginae, subtribe Borophagina, a terrestrial canine which inhabited most of North America from the Harrisonian stage to Early Barstovian stage of the Miocene epoch living 16.3—5.3 mya, existed for approximately .-Canid competitors:Paratomarctus was one...

, and Phlaocyon

Phlaocyon

Phlaocyon is an extinct genus of the Borophaginae and a terrestrial canine which inhabited most of North America during the Whitneyan stage of the Early Oligocene through Late Hemingfordian stage of the Early Miocene epoch 33.3—16.3 Mya existing for approximately .-Taxonomy:Phlaocyon was about in...

(Wang, 1994; Wang et al., 1999). Of these, only Osbornodon belongs in the same subfamily as Cynodesmus, Hesperocyoninae

Hesperocyoninae

Hesperocyoninae is a subfamily of extinct canids.-Taxonomic history:Hesperocyoninae was named by Martin . The members of this subfamily were reassigned to the family Canidae by Xiaoming Wang in 1999....

. The remaining genera are placed in the subfamilies Borophaginae

Borophaginae

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 approximately .-Origin:...

 and Caninae

Caninae

Caninae is the only living subfamily of Canidae. Many extinct species of Caninae were endemic to North America, living from 34 Ma—11,000 years ago. Some members of the endemic North American canines survived to the present time. This subfamily was recently revised by Tedford, Wang, and Taylor...

.

With unrelated species removed, Cynodesmus is currently restricted to the type species and the closely related C. martini (Wang, 1994).
Studies using the old conception of Cynodesmus considered it to be the ancestor of Tomarctus

Tomarctus

Tomarctus is a canine of the extinct subfamily Borophaginae which inhabited most of North America during the late Early Miocene to the Early Barstovian age of the Middle Miocene . Tomarctus existed for approximately ....

(16-23 Ma) from which wolves, dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

s, fox

Fox

Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...

es and fennec

Fennec

The fennec fox is a small nocturnal fox found in the Sahara of North Africa. Its most distinctive feature is unusually large ears. The name "fennec" comes from the Arabic word for fox, and the species name zerda has a Greek origin that refers to its habitat...

s developed. The Cynodesmus is a good example of convergent evolution

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

 because of other species such as the Borophagus

Borophagus

Borophagus 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 .-Overview:Borophagus, like other borophagines, are loosely...

, the largest and most dominant canids of this Pliocene

Pliocene

The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

epoch, both of which evolved from it.