Editing Therapsida (section)

{{Short description|Clade of tetrapods including mammals}}
{{Distinguish|Synapsid{{!}}Theropsida}}
{{Use dmy dates|date=November 2014}}
{{Automatic taxobox
| fossil_range = {{fossil range|272.5|0|[[Cisuralian]]–[[Holocene]] 279.5–0 Ma||PS=(Range includes [[mammal]]s)}}
| image = Therapsida 3.jpg
| image_caption = From top to bottom and left to right, several examples of non-mammalian therapsids: ''[[Biarmosuchus]]'' ([[Biarmosuchia]]), ''[[Moschops]]'' ([[Dinocephalia]]), ''[[Lystrosaurus]]'' ([[Anomodont]]ia), ''[[Inostrancevia]]'' ([[Gorgonopsia]]), a [[lycosuchid]] ([[Therocephalia]])  and ''[[Chiniquodon]]'' ([[Cynodont]]ia)
| image_upright = 1.2
| display_parents = 3
| taxon = Therapsida
| authority = [[Robert Broom|Broom]], 1905<ref name="Broom1905">{{cite journal|last=Broom|first=R.|author-link=Robert Broom|year=1905|title=On the use of the term Anomodontia|journal=Records of the Albany Museum|volume=1|issue=4|pages=266–269|url=https://www.biodiversitylibrary.org/page/7000255#page/292/mode/1up}}</ref>
| subdivision_ranks = [[Clade]]s
| subdivision = *{{extinct}}''[[Raranimus]]''
*†[[Biarmosuchia]]
*†[[Dinocephalia]]
*†[[Anomodont]]ia
**Various extinct taxa
**†[[Dicynodont]]ia
*[[Theriodontia]]
**†[[Gorgonopsia]]
**[[Eutheriodontia]]
***†[[Therocephalia]]
***[[Cynodont]]ia
****Various extinct taxa
****[[Mammal]]ia
}}

'''Therapsida'''{{efn|[[Greek language|Greek]]: 'beast-arch'}} is a clade comprising a major group of [[eupelycosauria]]n [[synapsid]]s that includes [[mammal]]s 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" [[quadrupedal]] posture, as opposed to the lower sprawling posture of many [[reptile]]s and [[amphibian]]s.

Therapsids evolved from earlier synapsids commonly called "[[pelycosaur]]s", 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]] [[sauropsid]]s ([[pseudosuchia]]ns, [[dinosaur]]s and [[pterosaur]]s, etc.) during the Middle Triassic.

The therapsids include the [[cynodont]]s, the group that gave rise to mammals ([[Mammaliaformes]]) in the Late Triassic around 225 million years ago, the 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 [[dicynodont]]s, became 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]].