Gorgosaurus

Gorgosaurus is a genus of theropod dinosaur that lived in western North America during the Upper Cretaceous, between about 76.5 and 75 million years ago.
Fossil remains have been found in the Canadian province of Alberta and possibly the U.S. state of Montana. It was closely related to "T. rex" and "Albertosaurus". "Gorgosaurus", like "T. rex", had huge jaws with large, sharp, cone-shaped teeth, powerful legs, tiny arms and two-fingered hands.
"Gorgosaurus" lived in a lush floodplain environment along the edge of an inland sea. It was an apex predator: it preyed on ceratopsids and hadrosaurs. 
"Gorgosaurus" spent as much as half its life in the juvenile phase before ballooning up to near-maximum size in only a few years.
Most specimens of "Gorgosaurus libratus" have been recovered from the Dinosaur Park Formation in Alberta. This formation was laid down in the later Cretaceous, between 76.5 and 74.8 million years ago.