"Arkansaurus fridayi" is the informal name of a dinosaur that was discovered in Lockesburg, Arkansas. "Arkansaurus fridayi" was a bipedal coelurosaurian dinosaur, a group of theropods that includes the Tyrannosauridae, Ornithomimidae, and Maniraptora. Its nearest relative was thought to be Ornithomimus, a bird or ostrich-like dinosaur. It is named for the state and its discoverer J. B. Friday, who found the dinosaur's fossilized foot on his farm in 1972.