Cynognathia ("dog jaw") is one of two major clades of

cynodont The cynodonts () (clade Cynodontia) are a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Cynodonts had a wide variety ...

s, the other being

Probainognathia Probainognathia is one of the two major subgroups of the clade Eucynodontia, the other being Cynognathia. The earliest forms were carnivorous and insectivorous, though some groups eventually also evolved herbivorous diets. The earliest and most ...

. Cynognathians included the large carnivorous genus ''

Cynognathus ''Cynognathus'' is an extinct genus of large-bodied cynodontian therapsids that lived in the Middle Triassic. It is known from a single species, ''Cynognathus crateronotus''. ''Cynognathus'' was a long predator closely related to mammals and ha ...

'' and the herbivorous

traversodontid Traversodontidae is an extinct family of herbivorous cynodonts. Traversodonts were primarily Gondwanan, with many species known from Africa and South America. Recently, traversodonts have also been found from Europe and eastern North America. Tra ...

s. Cynognathians can be identified by several

synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

including a very deep

zygomatic arch In anatomy, the zygomatic arch, or cheek bone, is a part of the skull formed by the zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the opening of the ear) and the temporal process of the zygomati ...

that extends above the middle of the

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a p ...

. Cynognathian fossils are currently known from

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

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 the Car ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

Taxonomy

*Suborder Cynodontia **Infraorder

Eucynodontia Eucynodontia ("true dog teeth") is a clade of cynodont therapsids including mammals and most non-mammalian cynodonts. The oldest eucynodonts are known from the Early Triassic and possibly Late Permian. Eucynodontia includes two major subgroups, ...

***(unranked) Cynognathia ****Family Cynognathidae *****''

'' ****(unranked)

Gomphodontia Gomphodontia is a clade of cynognathian cynodonts that includes the families Diademodontidae, Trirachodontidae, and Traversodontidae. Gomphodonts are distinguished by wide and closely spaced molar-like postcanine teeth, which are convergent wit ...

*****Family Diademodontidae ******''

Diademodon ''Diademodon'' is an extinct genus of cynodonts. It was about long. Discovery Harry Seeley had found his fossil in the Burgersdorp Formation of the Beaufort Group in the Karoo Basin of South Africa. As late as 1988, ''Diademodon'' had bee ...

'' ******'' Titanogomphodon'' *****(unranked)

Neogomphodontia Gomphodontia is a clade of cynognathian cynodonts that includes the families Diademodontidae, Trirachodontidae, and Traversodontidae. Gomphodonts are distinguished by wide and closely spaced molar-like postcanine teeth, which are convergent wit ...

******Family

Trirachodontidae Trirachodontidae is an extinct, possibly paraphyletic family of cynognathian cynodonts from the Triassic of China and southern Africa. Trirachodontids appeared during the Early Triassic soon after the Permian-Triassic extinction event and quickl ...

*******Subfamily

Trirachodontinae Trirachodontidae is an extinct, possibly paraphyletic family of cynognathian cynodonts from the Triassic of China and southern Africa. Trirachodontids appeared during the Early Triassic soon after the Permian-Triassic extinction event and quickl ...

********''

Langbergia ''Langbergia'' is an extinct genus of trirachodontid cynodont from the Early Triassic of South Africa. The type and only species ''L. modisei'' was named in 2006. ''Langbergia'' was found in the Burgersdorp Formation in the Beaufort Group, a pa ...

'' ********'' Trirachodon'' *******Subfamily

Sinognathinae Trirachodontidae is an extinct, possibly paraphyletic family of cynognathian cynodonts from the Triassic of China and southern Africa. Trirachodontids appeared during the Early Triassic soon after the Permian-Triassic extinction event and quickl ...

********''

Beishanodon ''Beishanodon'' is an extinct genus of eucynodonts from Lower Triassic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most p ...

'' ********'' Sinognathus'' ********''

Cricodon ''Cricodon'' is an extinct genus of trirachodontid cynodonts that lived during the Early Triassic and Middle Triassic periods of Africa.Abdala, F., J. Neveling, and J. Welman. 2006. A new trirachodontid cynodont from the lower levels of the Burg ...

'' ******Family

Traversodontidae Traversodontidae is an extinct family of herbivorous cynodonts. Traversodonts were primarily Gondwanan, with many species known from Africa and South America. Recently, traversodonts have also been found from Europe and eastern North America. Tra ...

*******'' Etjoia'' *******'' Nanogomphodon'' *******''

Scalenodon ''Scalenodon'' is an extinct genus of traversodontid cynodonts from the Middle Triassic of Africa and possibly Russia. The type species ''S. angustifrons'' was named in 1946 and several other species were named in the following years. Most of the ...

'' *******Subfamily Traversodontinae ********'' Traversodon'' ********'' Luangwa'' ******* Unnamed clade ********'' Andescynodon'' ********'' Pascualgnathus'' ********''

Mandagomphodon ''Mandagomphodon'' is an extinct genus of traversodontid cynodonts from the Middle Triassic Lifua Member of the Manda Beds of Ruhuhu Valley, Tanzania. The type species ''Mandagomphodon hirschsoni'' was named by Crompton in 1972 as a species refe ...

'' ********Subfamily Massetognathinae *********'' Dadadon'' *********'' Massetognathus'' *********'' Santacruzodon'' ********Subfamily

Arctotraversodontinae Arctotraversodontinae is a subfamily of Late Triassic cynodonts belonging to the family Traversodontidae. Members of the subfamily include '' Arctotraversodon'', '' Boreogomphodon'' and '' Plinthogomphodon'' from North America, and '' Habayia'' ...

*********'' Arctotraversodon'' *********'' Boreogomphodon'' *********'' Plinthogomphodon'' *********'' Habayia'' *********''

Maubeugia ''Maubeugia'' is an extinct genus of traversodontid cynodonts from the Late Triassic of France. Isolated postcanine teeth are known from Saint-Nicolas-de-Port Saint-Nicolas-de-Port () is a commune in the Meurthe-et-Moselle ''département'' ...

'' *********'' Microscalenodon'' *********''

'' *********''

Rosieria ''Rosieria'' is an extinct genus of dwarf cynodonts from the Late Triassic of France. It belongs to the family Traversodontidae, a herbivorous group known mainly from Gondwana. The type species ''R. delsatei'' was named in 1997 on the basis of a ...

'' ********Subfamily Gomphodontosuchinae *********''

Gomphodontosuchus ''Gomphodontosuchus'' is an extinct genus of cynodonts. It was created to describe the species ''Gomphodontosuchus brasiliensis''. Species ''Gomphodontosuchus brasiliensis'' was first collected in 1928 by Friedrich von Huene in Santa Maria Forma ...

'' *********'' Menadon'' *********'' Protuberum'' *********'' Ruberodon'' *********'' Scalenodontoides'' *********''

Exaeretodon ''Exaeretodon'' is an extinct genus of fairly large, low-slung traversodontid cynodonts from the southern parts of Pangea. Four species are known, from various formations. ''E. argentinus'' is from the Carnian-age (Late Triassic) Cancha de Boch ...

'' *********'' Siriusgnathus''

References

{{Taxonbar, from=Q5199968 Early Triassic first appearances Late Triassic extinctions Tetrapod unranked clades Taxa named by James Hopson

Taxonomy

See also

References