30 December 2011
Living at the same time and more than likely in some of the same areas as Daspletosaurus, Gorgosaurus was a slightly smaller tyrannosaurid of North America. The two animals both lived in western America and Canada with Daspletosaurus living mostly to the south of Gorgosaurus, however, they have been found together. It is believed, because of the more robust body of Daspletosaurus, that the animals could have easily coexisted and this theory explains some fossil finds in which both animals are found near one another without marks of predation or combat between skeletons. The sleeker Gorgosaurus it believed to have dined on large animals with fewer strong defensive attributes such as horns and tough armors. These, it is believed, Gorgosaurus left for Daspletosaurus who was tougher and more robust and more likely to take the punishment of an Ankylosaur or Chasmosaurus where it would more easily kill a Gorgosaurus.
Gorgosaurus is a genus that consists of one recognized species, Gorgosaurus libratus. Many other species have been named but have been eventually determined to either be a G. libratus or some other animal entirely, as happens (see last week's dinosaur). Though a tyrannosaur, Gorgosaurus was smaller than Tyrannosaurus Rex and even Tarbosaurus, weighing in around the same size as Daspletosaurus but closer to Albertosaurus, an animal that the remains of Gorgosaurus have been mistakenly assigned to in the past. At about 30 feet long and 2.7 tons, this dinosaur was still a very large predator despite being one of the smaller members of the family. Gorgosaurus, however, had many key differences in its body and these are well documented in the dozens of skeletons found. One such difference from its family was its brain shape, another being the shape of its eyes which rested in a circular cavity rather than an oval or key shaped area. Its skull was also longer and thinner than many tyrannosaurs and was fairly reminiscent of Albertosaurus' skull. Additionally, skin impressions found in the type fossils have led researchers to the conclusion that Gorgosaurus had smooth skin, rather than the scale covered skin found in most skin impressions of fossils.