New Mexico Geological Society Annual Spring Meeting — Abstracts

A partial skeleton of a tyrannosaurid is referred to Albertosaurus and represents the most complete skeleton of a theropod dinosaur to be collected from Upper Cretaceous deposits of New Mexico. Archer and Babiarz (1992) provided a preliminary description ofthis specimen (NMMNH P-25049) which was collected illegally from lands of the Navajo Nation and now resides at the New Mexico Museum of Natural History and Science. In May, 1995, the collection site of NMMNH P-25049 was relocated (NMMNH locality L-3097) in a fine-grained sandstone within the Farmington Sandstone Member of the Kirtland Formation. Additional portions of the skeleton, including a large articulated segment of the tail, were recovered.

NMMNH P-25049 includes parts of a disarticulated skull and many elements of the postcranial skeleton. Preserved skull elements include both frontals, both nasals, part ofthe left maxilla with several teeth, part of the left lachrymal, the left jugal, the right quadratojugal, part ofthe right quadrate, and a portion of the premaxilla as well as several isolated teeth and a portion of a premaxillary tooth. Parts of a mandible preserved include a partial dentary with several teeth, and the left articular. The postcranial skeleton includes a complete left scapula, the distal part ofthe right scapula, a partial humerus and fragments ofother forelimb elements, a partial ilium, fragments of the pubis?, a nearly complete right hindlimb, and parts of the left hindlimb. The right hindlimb was found largely articulated. The axial skeleton includes parts of a few cervi'cal vertebrae, part of the centrum of a dorsal vertebra, several ribs, a stomach rib, and a large articulated segment of the tail.

NMMNH P-25049 is referred to Albertosaurus based on the shape ofthe frontals and the presence ofserrations on a premaxillary tooth. The relatively small size and the relative proportions ofthe hind limb bones suggest that it represents a sub-adult.