Gorgosaurus libratus

Currie, P. J., 1987, Theropods of the Judith River Formation of dinosaur Provincial Park, Alberta, Canada, Fourth Symposium on Mesozoic Terrestrial Ecosystems, Drumheller, Alberta: Tyrrell Museum of Paleontology, pp. 51-60 : 55

Gorgosaurus libratus

frontals are characterized by the presence of a prefrontal socket, the reduction of the orbital rim to a notch, and the retention of a relatively short (rostrocaudally), overlapping suture for the postorbital ( Fig. 1g ). immature frontals of Gorgosaurus libratus can be distinguished from that of cf. Aublysodon by their relatively greater thickness and width for a given length. in Daspletosaurus torosus , the shape of the frontal has been changed by the enlargement of the lacrimal and postorbital, causing an increase in the posterior width of the frontal ( Fig. 1h ), and a lengthening of the postorbital suture.

Figures

FIG. 1 Theropod frontals from Dinosaur Provincial Park. (a) Troodon formosus. TMP 86.49. 10; (b) Dromicelomimus samueli, TMP 85.56.62; (c) cf. Erilcosaurus sp., NMC 12355; (d) Saurornitholestes langstoni, TMP 86. 77. 57; (e) Dromaeosaurus albertensis, NMC 12349, AMNH 5356; (f) cf. Aublysodon sp., TMP 80.16.485; (g) cf. Gorgosaurus libratus, TMP 80.16.924; (h) Daspletosaurus torosus (after Russell. 1970). (1) Caudal limit of dorsalateral exposure of the lacrimal; (2) caudal limit of orbital rim; (3) caudal limit of postorbital suture; (4) lacrimal slot; (5) Postorbital buttress. Scale= 1cm.