New Mexico Geological Society Annual Spring Meeting — Abstracts

Two tyrannosaur specimens from the upper Campanian Kirtland Formation, San Juan Basin, New Mexico evidence of numerous injuries that were sustained during life.

NMMNH P-27469 represents an adult partial skeleton of a new genus and species of basal tyrannosauroid. 1) The left maxilla bears a lesion in the rostroventral corner of the antorbital fossa and on the caudolateral surface of the interfenestral strut; 2) the left ectopterygoid possesses a large cavity on the ventral surface at the distal end of the jugal process. 3) the left intercoronoid has a lesion that healed as a hemicircular perforation notches the ventral margin between the eleventh and twelfth alveoli; 4) the left prearticular and angular are coössified at the rostral extent of their contact along the ventral margin of the mandible; 5) the right dentary bears a large crater-like cavity in the lateral surface, below the eleventh and twelfth alveoli; and 6) a rib bears a large swelling that probably represents a healed fracture.

NMMNH P-25049 is a partial skeleton that represents a subadult of the same taxon represented by P-27469. A large lesion is present between the neck of the femur and the diaphysis.

The majority of the cranial lesions of P-27469 are associated with the oral cavity, pharynx, and the external margins of the mouth and may be related to prey capture and/or feeding. The femoral lesion of P-25049 is unique among tyrannosaurs, where healed fractures of the fibula are the most common injuries to the long bones of the hind limb.