At least three species of Tyrannosauridae seem to have lived in the area now known as Dinosaur Provincial Park. The first is a gracile tyrannosaurid (Fig. 1f) with a relatively long, narrow frontal. Isolated teeth identified as Aublysodon

are the premaxillary teeth of a small tyrannosaurid. They are relatively common, and can be distinguished from the teeth of juvenile specimens of large tyrannosaurids by their lack of serrations and more gracile appearance. Gracile, small maxillary and dentary teeth with serrations have also been identified as a small, Judithian tyrannosaurid. It would appear that a Lancian theropod described by Molnar (1978) is in fact a small tyrannosaurid, and that this animal is the same as the tooth genus Aublysodon (K. Carpenter and R.E. Molnar, personal communication, 1986). It seems possible then that TMP 80.16.485 (Fig. 1f) is Aublysodon or a closely related genus. It is conceivable that further preparation and study of the type specimen or Gorgosaurus sternbergi (AMNH 5664, Matthew and Brown 1923) will reveal that this is a valid species, and that this is the source of the aublysodont teeth.