The phylogeny and taxonomy of the Tyrannosauridae Author Holtz, T. R. text 2001 2001-12-31 Indiana University Press Bloomington Editor Tanke D. H. Editor Carpenter K. Mesozoic Vertebrate Life 64 83 book chapter 10.5281/zenodo.3245327 9bf3a9f5-cd36-4be6-bba9-49607815bcd0 3245327 Daspletosaurus torosus , the Two Medicine tyrannosaurine, and Tyrannosaurus share several derived features lacking in other tyrannosaurids. Many of the synapomorphies of this clade suggest a more forcefully built and muscular skull and neck than in other tyrannosaurids, In some of the most parsimonious trees Daspletosaurus torosus and a presently unnamed tyrannosaurine from the upper Two Medicine Formation were united by a potential synapomorphy: 53.1 Lacrimal horn directly dorsal to descending ramus. However, in other trees Daspletosaurzs is closer to Tyrannosaurus than to the Two Medicine form, and in still others the Two Medicine form is closer to Tyrannosaurus . Daspletosaurus torosus Russell 1970 : From the Dinosaur Park Formation of Alberta, this form is more robustly and powerfully constructed than the sympatric Gorgosaurus libratus ( Russell 1970 ).