Cynodontia

Cynodontia is a therapsid clade that includes mammals and their extinct close relatives. Its members evolved increasingly mammal-like jaws and teeth, including a dentary lower jaw and differentiated tooth rows.

Therapsida: Therapsida is a synapsid clade that includes mammals and several groups of extinct mammal-like reptiles. Cynodontia is one of the major therapsid lineages.
Dentary-squamosal jaw joint: The dentary-squamosal jaw joint is the articulation between the lower jaw's dentary and the skull's squamosal bone. Its emergence marks a major stage in the transformation of the cynodont jaw.
Thrinaxodon: Thrinaxodon is an Early Triassic cynodont known from fossils in southern Africa and Antarctica. Its skull and skeleton preserve an early combination of ancestral and mammal-like features.
Permian: The Permian is the geologic period preceding the Triassic, lasting from about 299 to 252 million years ago. Early cynodont lineages emerged during the later part of this period.
Dicynodontia: Dicynodontia is an extinct therapsid clade whose members commonly had beaked jaws and tusks. Dicynodonts were a major therapsid lineage distinct from cynodonts.
Synapsida: Synapsida is the amniote lineage that includes mammals and their extinct relatives, traditionally identified by a temporal opening in the skull. Cynodonts belong to the synapsid branch of amniote evolution.
Mammalian middle ear: The mammalian middle ear transmits sound through the malleus, incus, and stapes. Bones that once formed part of the cynodont jaw joint became middle-ear bones.
Cynognathus: Cynognathus is a large-bodied Early Triassic cynodont genus found in several southern continents. Its broad distribution records cynodont success after the end-Permian extinction.
Gorgonopsia: Gorgonopsia is an extinct group of predatory therapsids that lived during the Permian. Its members represent other therapsid branches that shared ancestry with cynodonts.
Dinocephalia: Dinocephalia is an extinct group of large-bodied Permian therapsids. Dinocephalians show a different early therapsid body plan from cynodonts.

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