synapsids are more closely related to mammals than to any modern reptile. Sauropsids, on the other hand, include all amniotes more closely related to modern...

318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals...

Carboniferous period and further diverged into two groups, namely the sauropsids (including all reptiles and birds) and synapsids (including mammals and...

forms found in all vertebrates and harder, derived forms found only among sauropsids (reptiles and birds). Spider silk is classified as keratin, although production...

Archosauria (lit. 'ruling reptiles') is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only living representatives. Archosaurs...

vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid species, the cervical vertebrae bear cervical ribs. In lizards and saurischian...

amniotes including synapsids (the clade to which modern mammals belong) and sauropsids (which include modern reptiles and birds) during the late Carboniferous...

exploitation of the land by certain tetrapods. These included the earliest sauropsid reptiles (Hylonomus), and the earliest known "pelycosaur" synapsids (Archaeothyris)...

Mammals Sauropsids (reptiles, birds)...

and the birds, are still those considered reptiles today. The synapsid/sauropsid division supplemented another approach, one that split the reptiles into...