Crosbysaurus

Crosbysaurus is an extinct genus of archosauromorph that roamed the Earth during the Late Triassic period. Its fossil record is sparse, consisting solely of individual teeth, which has led to its classification as a dinosaur known only from its dentition. These teeth are small, typically measuring between 3 and 5 millimeters in height, and are characterized by a triangular outline with serrations along both edges. Many of these serrations exhibit further subdivisions, known as compound denticles, with those on the trailing edge being more pronounced than those on the leading edge.

Classification and Diet

When first described in 2004 by Andrew Heckert, Crosbysaurus was identified as an ornithischian dinosaur. However, subsequent research based on the distinctive features of its teeth has led to its reclassification as a likely archosauromorph, potentially belonging to the Archosauriformes clade. The morphology of its teeth, particularly their blunt outline, strongly suggests that Crosbysaurus was a herbivore, subsisting on plant matter. Despite the limited fossil evidence, the genus is considered valid due to its differentiation from other tooth-based genera found in the same geological formations, such as Revueltosaurus and Tecovasaurus.

Geographic and Temporal Distribution

Fossil evidence of Crosbysaurus has been recovered from several states in the southwestern United States, including Arizona, New Mexico, Texas, and Utah, as well as from North Carolina. These finds are predominantly associated with rock units such as the Chinle Formation and the Dockum Group, which are chronologically situated within the Late Triassic epoch. The discovery of eleven specimens, each comprising a single tooth, provides the entirety of our current understanding of this ancient creature.