https://en.wikipedia.org/wiki/Synapsid https://en.wikipedia.org/wiki/Synapsid > Synapsids[a] are one of the two major clades of vertebrate animals that evolved

https://en.wikipedia.org/wiki/Synapsid https://en.wikipedia.org/wiki/Synapsid > Synapsids[a] are one of the two major clades of vertebrate animals that evolved from basal amniotes, the other being the sauropsids, which include reptiles (turtles, crocodilians and lepidosaurs) and birds. > the only extant group that survived into the Cenozoic are the mammals. > The animals (basal amniotes) from which non-mammalian synapsids evolved were traditionally called "reptiles". > It is now known that all extant animals traditionally called "reptiles" are more closely related to each other than to synapsids, so the word "reptile" has been re-defined to mean only members of Sauropsida (bird-line Amniota) or even just an under-clade thereof