Albertosaurus libratus ( Lambe) 1914

Carpenter, K., 1992, Tyrannosaurids (Dinosauria) of Asia and North America, Aspects of Nonmarine Cretaceous Geology, Beijing: China Ocean Press, pp. 250-268 : 258

Albertosaurus libratus ( Lambe) 1914

Figs. 2E , 5E

= Gorgosaurus libratus Lambe 1914

Holotype: NMC 2120 nearly complete skeleton from the Judith River Formation, Alberta, Canada .

Diagnosis: (Cranial) pro-maxillary fenestra close to the maxillary fenestra; maxillary fenestra oval in shape and separated from the antorbital fenestra by a wide bar of maxillary; lacrymal horn very well developed; surangular very large. (Postcranial) distal end of scapula gradually broadens; acromion process of the scapula very deep; tibia more robust than in A. sarcophagus .

Stratigraphic and Palaeobiogeographic Distribution: Judith River Formation of Alberta, Canada, and Montana, U. S. A.. Also possibly the Horseshoe Canyon Formation of Alberta, the Two Medicine Formation of Montana, Fruitland Formation of New Mexico,and the Morreville Chalk of Alabama,U.S.A.

Figures

Figure 2. Comparison of tyrannosaurid skulls: A-Tyrannosaurus rex AMNH 5027 (modified from Osborn, 1912); B-Tyrannosaurus bataar holotype PIN 551-1, with missing areas restored after PIN 551-3 and GI SPS 100/59 (from photographs,Maleev, 1974 and Barsbold,1983);C-Maleevosaurus novojilovi holotype PIN 552-2 (modified from Maleev, 1974);D-Albertosaurus sarcophagus AMNH 5222, with lower jaws based on NMC 5600 and NMC 5601 (modified from photographs and Lambe, 1904);E-Albertosaurus libratus(modified from Russell, 1970); F-? Albertosaurus lancensis holotype CMNH 7541, composite of the left and right side (modified from photographs);G-Daspletosaurus torosus(modified from Russell, 1970 and photographs of NMC 8506). All drawn to scale;scale beneath Tyrannosaurus rex = 10 cm .

Figure 5. Comparison of tyrannosaurid skeletons: A-Tyrannosaurus rex(based on drawings and photographs of AMNH 5027 and CM 9380);B-Tyrannosaurus bataar (based on photographs of PIN 552-1,a young adult);C- Maleevosaurus novojilovi (modified from Maleev, 1974);D-Albertosaurus sarcophagus (skeleton based on photographs and drawings of ROM 807,with the skull based on photographs and drawings of AMNH 5222,NMC 5600 and NMC 5601); E- Albertosaurus libratus (skeleton modified from Lambe, 1914,and skull modified from Russell, 1970);F-Daspletosaurus torosus (modified from Russell, 1970). All drawn to scale;height of scale beneath Tyrannosaurus rex tail = 1 m .