Albertosaurines Temporal range: Late Cretaceous, 76.6–68 Ma |
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Albertosaurus skull cast | |
Gorgosaurus skull | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Dinosauria |
Order: | Saurischia |
Suborder: | Theropoda |
Clade: | Coelurosauria |
Clade: | Tyrannoraptora |
Superfamily: | †Tyrannosauroidea |
Family: | Tyrannosauridae |
Subfamily: |
†Albertosaurinae Currie et al., 2003 |
Type species | |
Albertosaurus sarcophagus Osborn, 1905 |
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Genera | |
†Albertosaurus (type genus)
†Gorgosaurus
Albertosaurines, or dinosaurs of the subfamily Albertosaurinae, lived in the Late Cretaceous of United States and Canada. The subfamily was first used by Philip J. Currie, Jørn H. Hurum and Karol Sabath as a group of tyrannosaurid dinosaurs. It was originally defined as "(Albertosaurus + Gorgosaurus)", including only the two genera. The group is sister clade to Tyrannosaurinae. In 2007, it was found that the group also contained Maleevosaurus, often synonymized with Tarbosaurus. However, this classification has not been accepted, and Maleevosaurus is still considered a juvenile Tarbosaurus or Tyrannosaurus. Clevenger T. M. McLain found in an abstract, that Alioramus, commonly used as a derived tyrannosauroid, was an albertosaurine, or the sister taxon to the group.
Albertosaurines are large, lightly built tyrannosaurids. Compared to tyrannosaurines, they are lightly built, have shorter, flatter skulls, had shorter ilia, and had proportionally longer tibiae. Albertosaurines and tyrannosaurines share arms or about equal length, with the exception of Tarbosaurus, which had short arms for its size.
Albertosaurus was smaller than some other tyrannosaurids, such as Tarbosaurus and Tyrannosaurus. Typical adults of Albertosaurus and Gorgosaurus measured up to 8 to 9 m (26 to 30 ft) long, while rare individuals of Albertosaurus could grow to over 10 m (33 ft) in length. Several independent mass estimates, obtained by different methods, suggest that an adult Albertosaurus weighed between 1.3 tonnes (1.4 short tons; 1.3 long tons) and 1.7 tonnes (1.9 short tons; 1.7 long tons).Gorgosaurus estimates are higher, around 2.5 tonnes (2.8 short tons; 2.5 long tons), although greater estimates exist of about 2.8 tonnes (3.1 short tons; 2.8 long tons).