| Albertosaurus Temporal range:Upper Cretaceous | |
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| Albertosaurus sarcophagus | |
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| Genus: | Albertosaurus Osborn, 1905 |
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Albertosaurus was a relative ofTyrannosaurus. It was smaller thanT. rex and lived a few million years earlier.Albertosaurus walked on two legs and had a large head with sharp, saw-toothedteeth. It had two-fingered hands on shortarms. Its long tail provided balance and quick turning. It had powerful back legs with clawed, three-toed feet.
Albertosaurus was about 30 feet (9 m) long, about 11 feet (3.4 m) tall at the hips, and up to 3 tons in weight (averaging roughly 2500 kg). Its lowerjaw had 14 to 16 teeth; the upper jaw had 17-19 teeth. It had one row of teeth in each jaw and had at least one replacement tooth growing up under each working tooth.
Albertosaurus was more lightly built thanTyrannosaurus. MostAlbertosaurus specimens were found in a single place.[1]
Compared with the robust tyrannosaurines (such asTarbosaurus andTyrannosaurus), albertosaurines had slender builds, with proportionately smaller skulls and longer bones of the lower leg (tibia) and feet (metatarsals andphalanges).[2] That suggests they were taking smaller or younger prey thanTyrannosaurus, and were able to run faster to do so.
