Gorgosaurus

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda > Tetanurae > Avetheropoda > Coelurosauria > Tyrannosauroidea > Pantyrannosauria > Eutyrannosauria > Tyrannosauridae > Albertosaurinae

Overview: Fossilized teeth possibly belonging to Gorgosaurus have been known to science since at least the 1850’s, referred to a now defunct genus called Deinodon. The holotype fossils, however, were discovered in 1913, in what is now Alberta, Canada. In the following year, a description of this find was published by the renowned Canadian paleontologist Lawrence M. Lambe, under the name Gorgosaurus – the “dreadful lizard”. In the decades to follow, numerous other specimens would be found, making Gorgosaurus one of the better known and well understood tyrannosaurs. Notably, the holotype was the first tyrannosaurid specimen found with intact arms and hands, revealing that they possessed only two digits. Other tyrannosaurids, including Tyrannosaurus itself, were restored in a similar fashion based on this discovery. Actual arm bones of Tyrannosaurus weren’t found until the 1980’s. Being fellow members of the family Tyrannosauridae, Gorgosaurus and Tyrannosaurus were closely related. Gorgosaurus, however, was closer to the genus Albertosaurus, which was the namesake of a distinct tyrannosaurid subfamily called the Albertosaurinae.

Members of the Albertosaurinae tended to be more lightly built than other tyrannosaurids, which is observable in Gorgosaurus itself. The two were highly similar, sporting large knobs in front of each eye, which in life probably supported keratinous crests. Said crests may’ve been used for courtship, to signal health and vitality. Gorgosaurus was so similar to Albertosaurus that some scientists have suggested they were the same genus. If this were true, then Albertosaurus would be the preferred name, as it was described first, with Gorgosaurus libratus actually being Albertosaurus libratus. The two did have enough differences for most researchers to treat them as distinct, however. The eye sockets of Gorgosaurus were more round, its body more slender, and its legs longer. Gorgosaurus fossils are known from the Dinosaur Park, Judith River, and Two Medicine formations. It may’ve preyed on hadrosaurs like Corythosaurus, Parasaurolophus, and Maiasaura, or ceratopsids like Centrosaurus. In many regions, Gorgosaurus appears to have coexisted with another large-bodied tyrannosaurid called Daspletosaurus, which was bulkier and may’ve went after tougher prey.