Archosauriformes

Archosauriformes Temporal range: Lopingian–Present, 260–0 Ma PreЄ Є O S D C P T J K Pg N
Life restoration of a Proterosuchus fergusi
American alligator (A. mississippiensis)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Crocopoda
Clade:	Archosauriformes Gauthier, 1986
Subgroups[1]
†Cuyosuchus †Eorasaurus †Fugusuchus †Kalisuchus †Sarmatosuchus †Proterosuchidae †Erythrosuchidae Eucrocopoda Ezcurra, 2016 †Asperoris †Dongusuchus †Dorosuchus †Yarasuchus †Euparkeriidae[2] †Proterochampsia Archosauria

Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles that developed from archosauromorph ancestors some time in the Late Permian (roughly 250 million years ago). It was defined by Jacques Gauthier (1994) as the clade stemming from the last common ancestor of Proterosuchidae and Archosauria;^[3] Phil Senter (2005) defined it as the most exclusive clade containing Proterosuchus and Archosauria.^[4] These reptiles, which include members of the family Proterosuchidae and more advanced forms, were originally superficially crocodile-like predatory semi-aquatic animals about 1.5 meters (5 ft) long, with a sprawling elbows-out stance and long snouts. Unlike the bulk of their therapsid contemporaries, the proterosuchids survived the catastrophe at the end of the Permian, perhaps because they were opportunistic scavengers or because they could retreat into water to find respite from an overheated climate. Any such scenarios are hypothetical; what is clearer is that these animals were highly successful in their new environment, and evolved quickly. Within a few million years at the opening of the Triassic, the proterosuchids had given rise to the Erythrosuchidae (the first sauropsids to totally dominate their environment), which in turn were the ancestors of the small agile Euparkeriidae, from which a number of successfully more advanced families – the archosaurs proper – evolved rapidly to fill empty ecological niches in the devastated global system. The Archosauria includes crocodylians, birds, and their extinct relatives.

Pre-Euparkeria Archosauriformes have previously been included in the suborder Proterosuchia of the order Thecodontia. Under the cladistic methodology, Proterosuchia has been rejected as a paraphyletic assemblage, and the pre-archosaurian taxa are simply considered as basal Archosauriformes.

Relationships

Below is a cladogram from Nesbitt (2011):^[5]

Below is a cladogram from Ezcurra (2016), that reexamined all historical members of the "Proterosuchia" (a polyphyletic historical group including proterosuchids and erythrosuchids). The placement of fragmentary taxa that had to be removed to increase tree resolution are indicated by dashed lines (in the most derived position that they can be confidently assigned to). Taxa that are nomina dubia are indicated by the note "dubium". Bold terminal taxa are collapsed.^[1]

Sources

• Gauthier, J. A. (1986). "Saurischian monophyly and the origin of birds". In Padian, K. (ed.). The Origin of Birds and the Evolution of Flight. Memoirs of the California Academy of Sciences. 8. California Academy of Sciences. pp. 1–55. ISBN 0-940228-14-9. 
• Gauthier, J. A.; Kluge, A. G.; Rowe, T. (June 1988). "Amniote phylogeny and the importance of fossils". Cladistics. John Wiley & Sons. 4 (2): 105–209. doi:10.1111/j.1096-0031.1988.tb00514.x. 

References

External links

• Paleos
• Mikko's Phylogeny Archive

Basal archosauromorphs
Kingdom: Animalia Phylum: Chordata Class: Reptilia
Major clades Allokotosauria Archosauriformes Diapsida Drepanosauromorpha Sauropsida Rhynchosauria Tanystropheidae
Archosauromorpha Archosauromorpha Czatkowiella Aenigmastropheus Exilisuchus Cosesaurus Jesairosaurus Malerisaurus Mecistotrachelos Prolacertoides Protorosaurus Sharovipteryx Macrocnemus Drepanosauromorpha Tanystropheidae Amotosaurus Augustaburiania Dinocephalosaurus Gwyneddosaurus Tanytrachelos Protanystropheus Langobardisaurus Tanystropheus Crocopoda Allokotosauria Rhynchosauria Teyujagua Archosauriformes Prolacertidae Prolacerta Vritramimosaurus Malutinisuchus
Allokotosauria Basal allokotosaurs Pamelaria Azendohsauridae Azendohsaurus Trilophosauridae ?Anisodontosaurus ?Coelodontognathus Doniceps Spinosuchus Teraterpeton Tricuspisaurus Trilophosaurus Variodens ?Vitalia
Drepanosauromorpha Basal drepanosaurs Hypuronector Kyrgyzsaurus ?Longisquama Elyurosauria Vallesaurus Drepanosauridae Dolabrosaurus Megalancosaurinae Drepanosaurus Megalancosaurus
Rhynchosauria Basal rhynchosaurs Eohyosaurus Howesia Mesosuchus Noteosuchus Rhynchosauridae Otischalkia Rhynchosaurus Hyperodapedontidae Bentonyx Fodonyx Langeronyx Hyperodapedontinae Hyperodapedon Isalorhynchus Supradapedon Teyumbaita Stenaulorhynchinae Ammorhynchus Brasinorhynchus Mesodapedon Stenaulorhynchus
Related categories Archosaurs