Proterosuchidae

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Proterosuchidae
Temporal range: Late Permian to Early Triassic, 252–247Ma
Archosaurus rossicus skull.JPG
Restored skull of Archosaurus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauriformes
Family: Proterosuchidae
Huene, 1914
Genera

see below

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 and the Early Triassic of Europe, Asia, Africa, Australia and possibly South America. The name comes from Greek πρότερο- ("first") and σοῦχος ("crocodile").

Description[edit]

Proterosuchus fergusi from the Early Triassic of South Africa

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. The limbs are short and indicate a sprawling posture, like contemporary lizards but unlike most later archosaurs.

Their most characteristic feature is a distinct down-turning of the premaxilla (the front of the upper jaw, which overhangs the lower jaw).

Evolutionary history[edit]

The terminal Permian catastrophe, which killed off 95% of all types of life, cleared the world of all large therapsids and allowed the proterosuchids to take center stage as the top carnivore. Within the space of five million years the proterosuchids had evolved into a wide variety of terrestrial and semi-aquatic carnivores.[1] The proterosuchids represent perhaps the earliest adaptive radiation of the archosaurs. They gave rise to the Erythrosuchidae some time in the Early Triassic.

Classification[edit]

Genera[edit]

Genus Status Age Location Description Images

Ankistrodon

Valid Early Triassic India

Archosaurus

Valid Late Permian, Changhsingian Russia and Poland Archosaurus ross1DB.jpg

Blomosuchus

Valid Early Triassic, Induan Russia

Chasmatosuchus

Valid Early Triassic South Africa and China Chasmatosuchus1DB.jpg

Exilisuchus

Valid Early Triassic, Olenekian Russia

Gamosaurus?

Valid Early Triassic, Olenekian Russia

Kalisuchus

Valid Early Triassic Australia

Proterosuchus

Valid Early Triassic South Africa and China ProterosuchusDB.jpg

Tasmaniosaurus

Valid Early Triassic Australia

Vonhuenia

Valid Early Triassic, Induan Russia

Phylogeny[edit]

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):[2]

Archosauriformes 

 Proterosuchus 




 Sarmatosuchus 



 Fugusuchus 




 Osmolskina




 Koilamasuchus



 Erythrosuchidae 

 Shansisuchus




 Vjushkovia



 Erythrosuchus






 Euparkeria




 Chanaresuchus





 Vancleavea



 Doswellia



 Archosauria 

 Pseudosuchia



 Avemetatarsalia











Proterosuchids

References[edit]

  1. ^ "Archosauria: Archosauriformes". Palaeos. Retrieved 29 October 2014. 
  2. ^ Ezcurra, M.D.; Lecuona, A.; 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. 

Further reading[edit]

External links[edit]