Archosauromorpha

Archosauromorphs Temporal range: Lopingian–Present, 254.7–0 Ma PreЄ Є O S D C P T J K Pg N
Mounted skeleton of a primitive archosauromorph (Trilophosaurus buettneri)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Sauria
Clade:	Archosauromorpha von Huene, 1946
Subgroups
†Aenigmastropheus †Protorosauria †Drepanosauridae †Protorosauridae †Sharovipterygidae †Tanystropheidae †Choristodera (disputed) Pantestudines (disputed) Crocopoda †Boreopricea †Allokotosauria †Rhynchosauria †Prolacertidae Archosauriformes
Synonyms
Archelosauria Crawford et al., 2014

Archelosauria Crawford et al., 2014

Archosauromorpha (Greek for "ruling lizard forms") is an infraclass of diapsid reptiles that first appeared during the late Permian and became more common during the Triassic. It was defined by Jacques Gauthier, Arnold G. Kluge and Timothy Rowe (1988) as the group containing "archosaurs [i.e. Crocodylia, dinosaurs, birds, and several extinct orders] and all other saurians that are closer to archosaurs (s.s.) than they are to lepidosaurs (s.s.)" [i.e. tuataras, lizards, and snakes]. In a later publication, Michel Laurin (1991) defined Archosauromorpha as the clade containing the most recent common ancestor of Prolacerta, Trilophosaurus, Hyperodapedon and archosaurs and all its descendants; David Dilkes (1998) formulated a more inclusive definition of Archosauromorpha, defining it as the clade containing Protorosaurus and all other saurians that are more closely related to Protorosaurus than to Lepidosauria.

Included in this infraclass are the groups Rhynchosauria, Trilophosauridae, Prolacertiformes and Archosauriformes. While superficially these reptiles vary in appearance (at one time they were even included in different subclasses – the trilophosaurs were considered euryapsids and the rhynchosaurs were considered lepidosaurs and were included in the same order as the tuatara), they are actually united by a number of small skeletal and skull-related details that suggest they form a clade that descended from a single common ancestor. Additional groups with uncertain phylogenetic position that are included in Archosauromorpha by some authors (and excluded from it by others) are Choristodera, drepanosaurs,thalattosaurs, ichthyopterygians, sauropterygians and turtles.