Arctotraversodon is a genus

Genus

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...

 of traversodontid cynodont

Cynodont

Cynodontia or cynodonts are a taxon of therapsids which first appeared in the Late Permian and were eventually distributed throughout all seven continents by the Early Triassic . This clade includes modern mammals and their extinct close relatives. They were one of the most diverse groups of...

 from the Late Triassic

Late Triassic

The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...

 of Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. Fossils first described from the Wolfville Formation

Wolfville Formation

The Wolfville Formation is a Mesozoic geologic formation of Nova Scotia. The formation is late Carnian to early Norian in age. Fossils of small land vertebrates have been found in the formation, including procolophonid and early archosauromorph reptiles and cynodonts...

 in Nova Scotia

Nova Scotia

Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...

 in 1984 and represented the first known traversodontid from North America. The type

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 and only species is A. plemmyridon, represented by teeth and several dentary bones.

Description and history

Arctotraversodon was first tentatively placed in the genus Scalenodontoides as a new species, ?Scalenodontoides plemmyridon. Only dentary bones and a few teeth were known when it was first named. Postcanine teeth, the primary diagnostic material of most traversodontids, were not known for ?S. plemmyridon. Few available features could diagnose ?S. plemmyridon as its own species, but the bones and teeth were clearly different than those of other traversodontids. A traversodontid postcanine tooth was later found from the same formation that was distinct from those of all other species. Unlike other traversodontid lower postcanines which have two cusps on either side of their crowns, these teeth had three cusps. The traversodontid Boreogomphodon

Boreogomphodon

Boreogomphodon is a genus of traversodontid cynodont from the Late Triassic of the eastern United States. Fossils have been found from the Turkey Branch Formation in Virginia.-Description and history:...

from the Turkey Branch Formation of Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

 was later found to have three cusps on its lower postcanines, showing that North American traversodontids were distinct from those in Africa and South America.

The species was assigned to its own genus, Arctotraversodon, in 1992. Arctotraversodon means "northern Traversodon" in reference to its northern location and close relation with Traversodon. "Arcto" (from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 arktos) can also mean "bear", as the holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

specimen was once informally called the "bear jaw." Features of an upper postcanine tooth that was found on a sea cliff in Nova Scotia were used to diagnose the new genus.