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Temporal range: Late Triassic, 205–200 Ma
Referred tooth, MNA V10666
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Genus: Crosbysaurus
Heckert, 2004
C. harrisae
Binomial name
Crosbysaurus harrisae
Heckert, 2004
Extremely hypothetical life restoration

Crosbysaurus is a genus of extinct archosauromorph that lived in the Late Triassic of Arizona, New Mexico, North Carolina, Texas, and Utah.[1] It is known from the Chinle Formation and Dockum Group rock units from the southwestern United States. The type species is C. harrisae, and the only known material includes teeth. 11 specimens are known, each including a single tooth.

Crosbysaurus was originally identified as an ornithischian dinosaur by Andrew Heckert when it was first described in 2004.[2] Further work has shown that it is likely an archosauromorph based on the features of its teeth, and it may belong to Archosauriformes.[3] The taxon is likely valid as it differs from other genera from the same region known from teeth like Revueltosaurus, Tecovasaurus, Krzyzanowskisaurus, Lucianosaurus, and Protecovasaurus.[1]


The teeth of Crosbysaurus are triangular in outline with serrations on both edges. Almost all specimens have "compound denticles"; serrations with their own subdivisions. The serrations on the trailing (posterior/distal) edge of the tooth are always larger than the leading (anterior/mesial) edge.[2] The teeth are small, approximately 3-5 millimeters tall. Owing to their blunt outline it is presumed that Crosbysaurus was a herbivore.


  1. ^ a b Gay, R. J.; Aude, I. S. (2015). "The first occurrence of the enigmatic archosauriform Crosbysaurus Heckert 2004 from the Chinle Formation of southern Utah". PeerJ. 3: e905. doi:10.7717/peerj.905. PMC 4411520. PMID 25922793.
  2. ^ a b Heckert, Andrew B. (2004). Late Triassic microvertebrates from the lower Chinle Group (Otischalkian-Adamanian: Carnian), southwestern U.S.A (27 ed.). Albuquerque: New Mexico Museum of Natural History and Science Bulletin.
  3. ^ Irmis, R. B.; Parker, W. G.; Nesbitt, S. J.; Liu, J. (2007). "Early ornithischian dinosaurs: The Triassic record". Historical Biology. 19: 3–22. CiteSeerX doi:10.1080/08912960600719988.