PREY BONE UTILIZATION BY PREDATORY DINOSAURS IN THE LATE JURASSIC OF NORTH AMERICA, WITH COMMENTS ON PREY BONE USE BY DINOSAURS THROUGHOUT THE MESOZOIC

Abstract

The frequency of tooth-marked bone in the Mesozoic is decidedly lower than the frequency found in the Cenozoic, although most ofthe previous work has focused on Creta­ ceous dinosaur faunas. This report describes two new examples oftooth-marked bone from the Jurassic Morrison Formation of western North America. The pubic foot of a specimen of Allosaurus from the Morrison Formation is missing a large section of its right side as the re­ sult of a single bite of a large theropod. Based on the size ofthe bite and known tooth size in large Morrison theropods, either Ceratosaurus or Torvosaurus can be responsible for the bite. Because of the large size of the Allosaurus and the location of the bite, it is suggested thatthe bite occurred during scavenging ratherthan during an attack by a predator. The pat­ tern of tooth marks on this specimen are supportive of the hypothesis that predatory dino­ saurs did not routinely chew the bones of their prey. Similarly, the tooth marks on a Camarasaurus ilium can be attributed to accidental contact with the teeth of a large preda­ tory dinosaur as it removed the flesh of its prey, rather than the result of intentional chewing of the bone. As with mammalian predators, patterns of tooth-marked bone provide insight into the behavior of predatory dinosaurs.