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Temporal range: Artinskian, 284.4–275.6 Ma
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Subclass: Diapsida
Order: Araeoscelida
Family: Araeoscelidae
Genus: Araeoscelis

Araeoscelis is an extinct genus of reptile, and one of the earliest diapsids. Fossils have been found in the United States, dating from the early Permian period.

1914 restoration by Samuel Wendell Williston

Araeoscelis was around 60 centimetres (2.0 ft) long, and superficially resembled a modern lizard. It differed from earlier forms, such as Petrolacosaurus, in that its teeth were larger and blunter; possibly they were used for cracking insect carapaces.[1]

Unlike its close relatives, which exhibit the two pairs of skull openings characteristic of diapsids, in Araeoscelis the lower pair of temporal fenestrae were closed with bone, resulting in an euryapsid condition. This would have made the skull more solid, presumably allowing a more powerful bite.[1]


  1. ^ a b Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 82. ISBN 1-84028-152-9. 
  • Carroll, Robert L. (1988). Vertebrate Paleontology and Evolution. New York: W.H. Freeman and Co. 
  • Benton, Michael J. (2000). Vertebrate Paleontology (2nd ed.). Oxford: Blackwell Science.