Oxetocyon
Encyclopedia
Oxetocyon is an extinct genus of the subfamily Borophaginae
and a terrestrial
canine
which inhabited North America
during the Whitneyan
stage (33.3 Mya)—(30.8 Mya) of the Oligocene
epoch. Oxetocyon existed for approximately .
diet, as is found in the living Raccoon Dog
, and suggest a potential relationship to the unusual borophagine Otarocyon
. Oxetocyon is distinguished from Otarocyon by its own set of dental
specializations for an omnivorous diet, particularly by the presence of a cleft that divides each upper molar
into front and back halves.
is poorly known, and only the teeth, dentaries, and a fragmentary skull
have been reported.
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 a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
canine
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...
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 Whitneyan
Whitneyan
The Whitneyan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 33,300,000 to 30,800,000 years BP, a period of . It is usually considered to fall within the Early Oligocene...
stage (33.3 Mya)—(30.8 Mya) of 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...
epoch. Oxetocyon existed for approximately .
Taxonomy
The teeth of Oxetocyon indicate a more hypocarnivorousHypocarnivore
A hypocarnivore is an animal that consumes less than 30% meat for its diet, the majority of which consists of nonvertebrate foods that may include fungi, fruits, and other plant material...
diet, as is found in the living Raccoon Dog
Raccoon Dog
The raccoon dog , also known as the magnut or tanuki, is a canid indigenous to east Asia. It is the only extant species in the genus Nyctereutes...
, and suggest a potential relationship to the unusual borophagine 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...
. Oxetocyon is distinguished from Otarocyon by its own set of dental
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...
specializations for an omnivorous diet, particularly by the presence of a cleft that divides each upper molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
into front and back halves.
Morphology
Fossil specimens of two individuals' body mass were examined by Legendre and Roth. The first specimen was estimated to weigh 1.04 kg (2.29 lbs). The second specimen was estimated to weigh 1.1 kg (2.44 lbs).Species
Only a single species, O. cuspidatus, is known. Fossils of Oxetocyon are rare and, as a result, the genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
is poorly known, and only the teeth, dentaries, and a fragmentary 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...
have been reported.
Fossil distribution
- Roundhouse Rock, Brule Formation, Morrill County, NebraskaMorrill County, Nebraska-History:Morrill County was formed in 1908 "carved out of Cheyenne County". It was named after Charles Henry Morrill, a president of the Lincoln Land Company.-Demographics:...
~33.3—30.8 Ma. - UNSM Sx-28, Brule Formation, Sioux County, NebraskaSioux County, Nebraska-National protected areas:* Agate Fossil Beds National Monument* Nebraska National Forest * Oglala National Grassland -Demographics:...
~33.3—30.8 Ma. - Brule Formation, Shannon County, South DakotaShannon County, South DakotaAs of the census of 2000, there were 12,466 people, 2,785 households, and 2,353 families residing in the county. The population density was 6 people per square mile . There were 3,123 housing units at an average density of 2 per square mile...
~33.3—30.8 Ma. - Harris Ranch Unit C, Brule Formation, Fall River County, South DakotaFall River County, South DakotaAs of the census of 2000, there were 7,453 people, 3,127 households, and 1,976 families residing in the county. The population density was 4 people per square mile . There were 3,812 housing units at an average density of 2 per square mile...
~33.3—30.8 Ma.