Archosauromorpha

Taxobox|
name = Archosauromorphs
fossil_range = Middle Permian - Recent

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image_width = 250px
image_caption = "Trilophosaurus", a primitive archosauromorph
regnum = Animalia
phylum = Chordata
classis = Sauropsida
subclassis = Diapsida
infraclassis = Archosauromorpha
infraclassis_authority = von Huene, 1946
subdivision_ranks = Orders
subdivision = See text

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. Included in this infraclass are the orders Rhynchosauria, Trilophosauridae, Prolacertiformes, Archosauriformes, and, tentatively, the Choristodera. 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.

Of the five taxa mentioned above, the first three died out at or prior to the end Triassic extinction. The Choristoderans continued as a minor group until the Miocene, and the Archosauriformes were important factors in early Triassic environments before giving rise to the even more successful Archosauria.

Taxonomy

Classification

* Subclass Diapsida
** Infraclass ARCHOSAUROMORPHA
*** Family Euparkeriidae
*** Family Erythrosuchidae
*** Family Proterochampsidae
*** Family Proterosuchidae
*** Order Choristodera
*** Order Prolacertiformes
*** Order Rhynchosauria
*** Order Trilophosauria
*** Division Archosauria
**** Subdivision Crurotarsi
***** Family Ornithosuchidae
***** Order Aetosauria
***** Order Phytosauria
***** Order Rauisuchia
***** Superorder Crocodylomorpha
****** Order Crocodilia
**** Subdivision Avemetatarsalia
***** Order Pterosauria
***** Superorder Dinosauria
****** Order Ornithischia
****** Order Saurischia

Phylogeny

Archosauromorpha
--+--Rhynchosauria
`--+-?"Teraterpeton"
`--Trilophosauria `--+--Prolacertiformes `--Archosauriformes
-?"Uatchitodon"
--Proterosuchidae `--+-?Erythrosuchidae `--+-?"Heleosaurus" `--+--Euparkeriidae `--+--?"Turfanosuchus"
--Proterochampsidae `--+--"Yonghesuchus" `--Archosauria [Crown group Archosauria = Avesuchia]
--Crurotarsi (crocodiles and relatives) `--Ornithodira (dinosaurs, pterosaurs, and birds)

External links

* [http://www.palaeos.com/Vertebrates/Units/270Archosauromorpha/270.100.html Palaeos]
* [http://www.paleofile.com/Demo/Mainpage/Taxalist/Archosaurmorphs.htm Paleofiles] - lists taxa