Albertosaurus sarcophagus Osborn 1905

Figs. 2 D, 5 D

= Laelaps incrassatus Cope 1892

= Dryptosaurus incrassatus (Cope) 1892

= Albertosaurus arctunguis Parks 1928

Holotype: NMC 5600 nearly complete skull from the Horseshoe Canyon Formation, Alberta, Canada .

Diagnosis: (Cranial) premaxilla anteroposteriorly very short and broad so that littie of it is visible in lateral view; pro-maxillary fenestra set well in advance of maxillary fenestra,and visible in lateral'view;maxillary fenestra taller than long,and separated from antorbital fenestra by a thin bar of the maxillary; lacrymal horn moderately developed;surangular foramen small for tyrannosaurid. (Postcranial) Body appears to be shorter than in A. libratus; distal end of scapular blade strongly inflected forward; tibia more gracile than in A. libratus .

Stratigraphic and Palaeobiogeographic Distribution: Horseshoe Canyon Formation, Alberta, Canada.