A new nodosaur specimen (Dinosauria: Nodosauridae) from the Smoky Hill Chalk (Upper Cretaceous) of western Kansas

Abstract

The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Upper Santonian) of the Niobrara Formation in October, 2000. Based on the similarity of the specimen in comparison with the holotype of Niobrarasaurus coleii, and the relatively small size of the remains, the bones are considered to be those of a juvenile N. coleii. The presence of two parallel scratch marks on the distal shaft of the radius, and the partially digested appearance of the proximal and distal ends of both bones, suggest that the lower limb had been detached from the carcass as the result of scavenging, most likely by the large lamniform shark, Cretoxyrhina mantelli. Although the remains of terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.