Proterosuchidae

Proterosuchidae Temporal range: Late Permian to Early Triassic
Proterosuchus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Node:	Archosauriformes
Family:	†Proterosuchidae Huene, 1914
Genera
†Archosaurus †Blomosuchus †Chasmatosuchus †Exilisuchus †Kalisuchus †Proterosuchus †Tasmaniosaurus †Vonhuenia
Synonyms
Proterosuchinae Huene, 1914 Chasmatosauridae Haughton, 1924 Chasmatosaurinae Haughton, 1924 Pelycosimiidae Abel, 1919

Proterosuchidae is an early, possibly paraphyletic, assemblage of basal archosauriformes whose fossils are known from the Latest Permian of Russia and the Early Triassic of southern Africa, Russia, China, Australia, and Antarctica. They were slender, medium-sized (about 1.5 meters long), long-snouted and superficially crocodile-like animals, although they lack the armoured scutes of true crocodiles, and in their skeletal features are much more primitive. Their most characteristic feature is a distinct down-turning of the premaxilla (the front of the upper jaw, which overhangs the lower jaw). The limbs are short and indicate a sprawling posture, like contemporary lizards but unlike most later archosaurs.

Archosaurus rossicus - Permian proterosuchid

The proterosuchids represent perhaps the earliest adaptive radiation of the archosaurs. They gave rise to the Erythrosuchidae some time in the Early Triassic.

Classification

Some studies consider Proterosuchidae to be a paraphyletic grouping, meaning that it does not form a true clade with a single common ancestor and proterosuchids as its only descendants. Instead, they are a chain of successively basal archosauriforms. Below is a cladogram from Ezcurra et al. (2010):^[1]

Archosauriformes  Proterosuchus  Sarmatosuchus  Fugusuchus  Osmolskina Koilamasuchus  Erythrosuchidae  Shansisuchus Vjushkovia Erythrosuchus Euparkeria Chanaresuchus Vancleavea Doswellia  Archosauria  Pseudosuchia Avemetatarsalia

Proterosuchids

References

1. ^ Ezcurra, M.D.; Lecuona, A.; and Martinelli, A. (2010). "A new basal archosauriform diapsid from the Lower Triassic of Argentina". Journal of Vertebrate Paleontology 30 (5): 1433–1450. doi:10.1080/02724634.2010.501446. 

• Benton, M. J. (2000), Vertebrate Paleontology, 2nd Ed.; (2004) 3rd edition Blackwell Science Ltd
• Carroll, R. L. (1988), Vertebrate Paleontology and Evolution, WH Freeman & Co.

External links

• Proterosuchidae
• Proterosuchidae - list of species (Mikko's Phylogeny Archive)