Gorgosaurus libratus

Gorgosaurus libratus has proven itself a distinct tyrannosaurid. The evidence for it is mounting as better specimens of Albertosaurus are found. Russell (1970) got rid of this genus by putting it in with Albertosaurus (in 1992, Carpenter barely agreed with him). The name has become popular again as of late and I am told that it is valid (Holtz, personal communication and Olshevsky, personal communication). As I have stated, we will get a better understanding when the new study comes out (1998, I hope). There is to be a redescription based on the new juvenile specimen at the RTMP that will be most helpful. It can't come soon enough.

Tyrrell Gorgosaurus
The beautiful Gorgosaurus at the Royal Tyrrell Museum of Palaeontology.

The original skeleton is know from a fairly complete skeleton with a crushed skull. There seems to be some variation in the maxillary tooth count (from 13 in the type, to 15 in some specimens). Carr (1999) has said a lot of this is due to ontogenic variation (with good evidence to back it up.

Juvenile Gorgosaurus
A juvenile Gorgosaurus from the Ex-Terra Show.


  • Gorgosaurus libratus
    • 8-9 m (27-30 feet) long, 2.5 tonnes (3 tons)
    • Late Cretaceous (Campanian)
    • Known from over twenty skeletons. Known from virtually complete speciments.
    • Found in Western Canada and the United States, possible specimens from the Eastern United States.
    • The name means "Free dragon lizard".
    • Named By: Lambe, L.M. (1914) "On a new genus and species of carnivorous dinosaur from the Belly River Formation of Alberta with a description of the skull of Stephanosaurus marginatus from the same horizon". Ottawa Naturalist #28: 13-20.

Genera List.