Great Basin Naturalist


A diverse late Jurassic dinosaur fauna, discovered in western Colorado in 1963, contains many undescribed taxa that may represent evolutionary trends at the generic level not previously reported from the Morrison Formation. A preliminary faunal list is given. Bones of the largest known dinosaur, Ultrasaurus, are present as are a variety of small animals, including Pterosaurs, in which one sacrum displays avianlike fused sacral neural spines. A new family, the Torvosauridae, erected, based on the genus Torvosaurus that is redescribed.