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.