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

cynodont Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extin ...

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 b ...

. Cynognathians included the large carnivorous genus '' Cynognathus'' and the herbivorous or omnivorous gomphodonts such as traversodontids. 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 ...

including a very deep

zygomatic arch In anatomy, the zygomatic arch (colloquially known as the cheek bone), is a part of the skull formed by the zygomatic process of temporal bone, zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the ...

that extends above the middle of the

orbit In celestial mechanics, an orbit (also known as orbital revolution) 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 ...

. Cynognathian fossils are currently known from

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

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

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Taxonomy

*Suborder

Cynodontia Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extinct ances ...

**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 *****'' Cynognathus'' ****(unranked) Gomphodontia *****Family Diademodontidae ******'' Diademodon'' ******'' Titanogomphodon'' *****(unranked) Neogomphodontia ******Family Trirachodontidae *******Subfamily Trirachodontinae ********'' Langbergia'' ********'' Trirachodon'' *******Subfamily Sinognathinae ********'' Beishanodon'' ********'' 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 Burge ...

'' ******Family Traversodontidae *******'' Etjoia'' *******'' Nanogomphodon'' *******'' Scalenodon'' *******Subfamily Traversodontinae ********'' Traversodon'' ********'' Luangwa'' ******* Unnamed clade ********'' Andescynodon'' ********'' Pascualgnathus'' ********'' Mandagomphodon'' ********Subfamily Massetognathinae *********'' Dadadon'' *********'' Massetognathus'' *********'' Santacruzodon'' ********Subfamily Arctotraversodontinae *********'' Arctotraversodon'' *********'' Boreogomphodon'' *********'' Plinthogomphodon'' *********'' Habayia'' *********'' Maubeugia'' *********'' Microscalenodon'' *********'' Mandagomphodon'' *********'' Rosieria'' ********Subfamily Gomphodontosuchinae *********'' Gomphodontosuchus'' *********'' Menadon'' *********'' Protuberum'' *********'' Ruberodon'' *********'' Scalenodontoides'' *********'' Exaeretodon'' *********'' Siriusgnathus''

Phylogeny

Cynognathians in a

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

after Stefanello ''et al''. (2023):

References

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

Taxonomy

Phylogeny

See also

References