Evidence of a giant tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous (?Campanian) of Montana. 2007. M.A. Urban and M.C. Lamanna. Annals of Carnegie Museum 75: 231-235.
Right lacrimal of ?Tyrannosaurus sp., (CM 9401), in lateral (A) and (B) medial views. [figure modified from Hurum and Sabath 2003]
Michael and Matt report on an isolated right lacrimal from a tyrannosaurid, probably from the upper Campanian, Judith River Fm., Fergus County, Montana that was previously associated with the holotype of the giant crocodylian
Deinosuchus rugosus. Its size and shape make it comparable and tentatively referable to
T. rex. If correctly assigned it’s the oldest-known NA record of a
Tyrannosaurus-sized tyrannosaurid, and possibly the oldest occurrence of the genus.
