Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibi
Archaeothyris, one of the most basal synapsids, first appears in the fossil records about 306 million years ago.
By the Mesozoic, 150 million years ago, sauropsids included the largest animals anywhere. Shown are some late Jurassic dinosaurs, including the early bird Archaeopteryx perched on a tree stump.
Parareptilia is an extinct subclass of basal sauropsids. Traditionally considered the sister taxon to Eureptilia, its validity as a monophyletic clade has been disputed by modern cladistic analyses.
Skeleton of Kapes bentoni, a procolophonid from the Middle Triassic of England