コレクション: Mammal-like Reptiles Synapsids / Pelycosauria
Synapsids[a]—not to be confused with therapsids,[b] which are a subordinate group to synapsids—are a group of animals that includes mammals and every animal more closely related to mammals than to the other members of the amniote clade, such as reptiles and birds.[2] They are easily separated from other amniotes by having a temporal fenestra, an opening low in the skull roof behind each eye, leaving a bony arch beneath each; this accounts for their name.[3] Primitive synapsids are usually called pelycosaurs or pelycosaur-grade synapsids. This informal term consists of all synapsids that are not therapsids, a monophyletic, more advanced, mammal-like group. The non-mammalian synapsids were described as mammal-like reptiles in classical systematics, but this misleading terminology is no longer in use[4][5] as synapsids as a whole are no longer considered reptiles.[6] They are now more correctly referred to as stem mammals or proto-mammals.
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