Daspletosaurus

Daspletosaurus ( das-PLEET-ə-SOR-əs; meaning "frightful lizard") is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 79 and 74.4 million years ago, during the Late Cretaceous Period. The genus Daspletosaurus contains three named species. Fossils of the earlier type species, D. torosus, have been found in Alberta, while fossils of a later species, D. horneri, have been found in Montana and Alberta. D. wilsoni has been suggested as an intermediate species between D. torosus and D. horneri that evolved through anagenesis, though further research may be required to definitively support the theory. There are also multiple specimens which may represent new species of Daspletosaurus from Alberta and Montana, but these have not been formally described. The taxon Thanatotheristes has been suggested to represent a species of Daspletosaurus, D. degrootorum, but this has not been widely supported. Daspletosaurus is closely related to the much larger and more recent tyrannosaurid Tyrannosaurus. Like most tyrannosaurids, Daspletosaurus was a large bipedal predator, with the average adult measuring 8.5–9 m (28–30 ft) and weighing 2–3 metric tons (2.2–3.3 short tons). Daspletosaurus had the small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera. As an apex predator equipped with dozens of large, sharp teeth, Daspletosaurus was at the top of the food chain, probably preying on large dinosaurs like the ceratopsid Centrosaurus and the hadrosaur Hypacrosaurus. In some areas, Daspletosaurus coexisted with another tyrannosaurid, Gorgosaurus, though there is some evidence of niche differentiation between the two. While Daspletosaurus fossils are not as common as other tyrannosaurid fossils, the available specimens allow some analysis of the biology of these animals, including social behavior, diet, and life history.