Arkansaurus

Arkansaurus is an extinct genus of ornithomimosaurian theropod dinosaur that roamed North America during the Aptian and Albian stages of the Early Cretaceous period. The sole recognized species is Arkansaurus fridayi, named in honor of Joe B. Friday, the individual who discovered its fossilized remains on his property in Arkansas in 1972. This discovery holds particular significance as it represents the only dinosaur fossil described to date from the state of Arkansas.

Discovery and Naming

The fossils, consisting of three metatarsals, four phalanges, and three claws, were found in a ditch on Friday's land, likely exposed by recent road construction. Initially, the bones were not recognized as dinosaurian but were eventually brought to the attention of paleontologist Dr. James H. Quinn. Quinn recognized their significance and presented them to the scientific community. The species was informally intended to be named Arkansaurus fridayi by Quinn, but it remained an invalid nomen nudum until its formal scientific description in 2018 by paleontologists ReBecca Hunt-Foster and James H. Quinn in the Journal of Vertebrate Paleontology. In 2017, Arkansaurus was officially designated as the state dinosaur of Arkansas.

Physical Characteristics and Paleobiology

Arkansaurus is estimated to have measured approximately 4.6 meters (15 ft) in length and weighed around 380.5 kilograms (839 lb). As an ornithomimosaur, it was a bipedal dinosaur. A distinctive feature noted from the holotype, which includes a nearly complete right foot, is the presence of strongly curved foot claws, differing from the flatter claws typically seen in most ornithomimosaurs. The fossil also revealed an unusual greenstick fracture, a first documented instance in dinosaur fossils, and evidence suggesting a potential case of gout.