Bite marks on tetrapod bones from the Upper Triassic Chinle Group representing a new ichnogenus

Naming and tracking bite mark ichnofossils and identifying bite makers is important in that it may ultimately help establish trophic structures in the fossil record. Heterodontichnites hunti, ichnogenus et ichnospecies nov. is a new form of bite mark that comprises both laterally compressed and round tooth impressions. A single, incomplete clavicle of the metoposaurid amphibian, Buettneria perfecta, from the Lamy Amphibian Quarry, Lamy, NM, shows seven such tooth marks on its interior side. The marks occur in two gently arcuate rows. Because the punctures show no sign of healing, they are assumed to result from scavenging or a fatal predation event. The size, shape, spacing, and heterodonty of the tooth marks implicate a phytosaur as the probable bite maker. This tooth-marked bone represents the first documented evidence of predation or scavenging from the Lamy Amphibian Quarry. At least 11 similar tooth marks on a dicynodont (cf. Ischigualastia) femur are also described. This femur shows a pattern of end-gnawing and fracturing that is similar to that seen in mammalian predation and scavenging and could possibly represent an early attempt at prey bone processing.