Sauria

Saurians Temporal range: Ma PreꞒ Ꞓ O S D C P T J K Pg N
clockwise from top left: crocodilian )
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Neodiapsida
Clade:	Sauria Macartney, 1802
Groups
snakes , and various extinct taxa) Archelosauria dinosaurs (including birds), and various extinct taxa) Pantestudines (includes turtles) †Kuehneosauridae †Choristodera? †Sauropterygia? †Ichthyosauromorpha? †Thalattosauria?

Sauria is the

Sauria lies within the larger total group Sauropsida, which also contains various stem-reptiles which are more closely related to reptiles than to mammals.^[3] Prior to its modern usage, "Sauria" was used as a name for the suborder occupied by lizards, which before 1800 were considered crocodilians.

Systematics

Genomic studies^[5][6][7] and comprehensive studies in the fossil record^[8] suggest that turtles are closely related to archosaurs, not to the pre-Saurian parareptiles as previously thought. In a 2018 cladistic analysis, Pantestudines (turtles and close relatives) were placed within Diapsida but outside of Sauria.^[4]

Synapomorphies

The synapomorphies or characters that unite the clade Sauria also help them be distinguished from stem-saurians in

However, some of these characters might be lost or modified in several lineages, particularly among birds and turtles; it is best to see these characters as the ancestral features that were present in the ancestral saurian.[9]

Phylogeny

The cladogram shown below follows the most likely result found by an analysis of turtle relationships using both fossil and genetic evidence by M.S. Lee, in 2013. This study found Eunotosaurus, usually regarded as a turtle relative, to be only very distantly related to turtles in the clade Parareptilia.^[8]

	Diapsida †Araeoscelidia Neodiapsida †Claudiosaurus †Younginiformes Sauria Lepidosauromorpha  Archosauromorpha   Pantestudines  † Eosauropterygia †Placodontia †Sinosaurosphargis †Odontochelys  Testudinata  †Proganochelys Testudines †Choristodera † Prolacertiformes † Rhynchosauria †Trilophosaurus Archosauriformes (=Archelosauria)

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. This study found Eunotosaurus to be an actual early stem-turtle, though other versions of the analysis found weak support for it as a parareptile.^[12]

Sauria	Ankylopoda  †Kuehneosauridae Lepidosauria Rhynchocephalia Squamata  Pantestudines  †Sauropterygia † Eosauropterygia †Placodontia †Sinosaurosphargis †Eunotosaurus †Pappochelys †Odontochelys  Testudinata  †Proganochelys Testudines (=Lepidosauromorpha) Archosauromorpha

The cladogram below follows the analysis of Li et al. (2018). It places turtles within Diapsida but outside of Sauria (the Lepidosauromorpha + Archosauromorpha clade).^[4]

	†Parareptilia
Eureptilia	†Captorhinidae †Paleothyris Diapsida †Araeoscelidia †Hovasaurus †Youngina crown‑group Pantestudines †Acerosodontosaurus †Claudiosaurus †Eunotosaurus †Pappochelys †Eorhynchochelys †Odontochelys Testudinata Sauria Lepidosauromorpha †Kuehneosauridae †Saurosphargidae † Eosauropterygia †Placodus Lepidosauria Rhynchocephalia Squamata Archosauromorpha † Rhynchosauria †Trilophosaurus †Prolacerta Archosauriformes

The following cladogram was found by Simões et al. (2022):^[13]

Neoreptilia

†Procolophonomorpha Neodiapsida †Younginiformes †Eunotosaurus †Weigeltisauridae Sauria Lepidosauromorpha Rhynchocephalia (tuatara and their extinct relatives) Squamata (lizards and snakes) Archelosauria Pantestudines (turtles and extinct relatives) Archosauromorpha †Ichthyosauromorpha †Sauropterygia †Thalattosauria †Protorosauria †Protorosaurus †Tanystropheidae † Drepanosauromorpha †Kuehneosauridae †Allokotosauria †Rhynchosauria Archosauriformes (crocodiles, birds, and their extinct relatives)

References

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Sauria.