Albertosaurus (/ælˌbɜ rtəˈsɔ rəs/; meaning "Alberta lizard") is a genus of tyrannosaurid theropod
dinosaur that lived in western North America during the
Late Cretaceous Period, about 70 million years ago. The
type species, Albertosaurus sarcophagus, was apparently restricted in range to the modern-day Canadian province of Alberta, after which the genus is named. Scientists disagree on the content of the genus, with some recognizing Gorgosaurus libratus as a second species.
As a tyrannosaurid, Albertosaurus was a bipedal predator with tiny,
two-fingered hands and a massive head that had dozens of large, sharp teeth. It may have been at the top of the food chain in its local ecosystem. While Albertosaurus was large for a theropod, it was much smaller than its larger and more famous relative Tyrannosaurus
rex, growing
nine to ten meters
long and possibly weighing less than 2 metric tons.
Since the
first discovery in 1884, fossils of more than
30 individuals have been recovered, providing scientists with a more detailed knowledge of Albertosaurus anatomy than is available for most other tyrannosaurids. The discovery of
26 individuals at
one site provides evidence of pack behaviour and allows studies of ontogeny and population biology, which are impossible with lesser-known dinosaurs.