Therapsida

Therapsida Temporal range: Cisuralian–Holocene 279.5–0 Ma (Range includes mammals) PreꞒ Ꞓ O S D C P T J K Pg N
From top to bottom and left to right, several examples of non-mammalian therapsids: Biarmosuchus (Biarmosuchia), Moschops (Dinocephalia), Lystrosaurus (Anomodontia), Inostrancevia (Gorgonopsia), Glanosuchus (Therocephalia) and Chiniquodon (Cynodontia)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Sphenacodontia
Clade:	Pantherapsida
Clade:	Sphenacodontoidea
Clade:	Therapsida Broom, 1905[1]
Clades
†Raranimus †Biarmosuchia †Dinocephalia †Anomodontia Various extinct taxa †Dicynodontia Theriodontia †Gorgonopsia Eutheriodontia †Therocephalia Cynodontia Various extinct taxa Mammalia

Therapsida^[a] is a clade composing of a major group of eupelycosaurian synapsids that includes mammals and their ancestors and close relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more underneath the body, resulting in a more "standing" quadripedal posture, as opposed to the lower sprawling posture of many reptiles and amphibians.

Therapsids evolved from earlier synapsids commonly called "pelycosaurs", specifically within the Sphenacodontia, more than 279.5 million years ago. They replaced the pelycosaurs as the dominant large land animals in the Guadalupian through to the Early Triassic. In the aftermath of the Permian–Triassic extinction event, therapsids declined in relative importance to the rapidly diversifying archosaurian sauropsids (pseudosuchians, dinosaurs and pterosaurs, etc.) during the Middle Triassic.

The therapsids include the cynodonts, the group that gave rise to mammals (Mammaliaformes) in the Late Triassic around 225 million years ago, and only therapsid clade that survived beyond the end of the Triassic. The only other group of therapsids to have survived into the Late Triassic, the dicynodonts, becoming extinct towards the end of the period. The last surviving group of non-mammaliaform cynodonts were the Tritylodontidae, which became extinct during the Early Cretaceous.

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