On display at Chicago’s Field Museum of Natural History, it’s Daspletosaurus:
If you first thought this was a photograph of a Tyrannosaurus Rex, you were close — Daspletosaurus was an earlier, smaller relative of the T-rex (there is still some controversy over their exact relationship). Adults could grow to lengths of 8-9 meters (26-30 feet) from nose to tail, and weigh up to 3.8 metric tons — so, about 1/3 the size of a full grown T-rex.
So far, all the Daspletosaurus fossils that have been found date to the Late Cretaceous between 77 and 74 million years ago, and were located on what was once the western shoreline of North America’s Western Interior Seaway (now Montana and Alberta). This particular Daspletosaurus was found in southern Alberta (in the Dinosaur Park Formation) in 1914.