Agkistrodon contortrix (the copperhead, a snake), Dinemellia dinemelli (the white-faced buffalo-weaver, a bird), various extinct ornithischian dinosaurs, Chelonia mydas (the green sea turtle), Anurognathus (an extinct pterosaur), and Alligator mississippiensis (the american alligator, a crocodilian) Sauria is the clade of diapsids containing the most recent common ancestor of Archosauria (which includes crocodilians and birds) and Lepidosauria (which includes squamates and the tuatara), and all its descendants.

[1] Since most molecular phylogenies recover turtles as more closely related to archosaurs than to lepidosaurs as part of Archelosauria, Sauria can be considered the crown group of diapsids, or reptiles in general.

[4] Sauria lies within the larger total group Sauropsida, which also contains various stem-reptiles which are more closely related to reptiles than to mammals.

[5] The redefinition to cover the last common ancestor of archosaurs and lepidosaurs was the result of papers by Jacques A. Gauthier and colleagues in the 1980s.

[10] †Araeoscelidia †Claudiosaurus †Younginiformes Lepidosauromorpha †Eosauropterygia †Placodontia †Sinosaurosphargis †Odontochelys †Proganochelys Testudines †Choristodera †Prolacertiformes †Rhynchosauria †Trilophosaurus Archosauriformes The cladogram below follows the most likely result found by another analysis of turtle relationships, this one using only fossil evidence, published by Rainer Schoch and Hans-Dieter Sues in 2015.