15 February 2011
I looked over and over for two opposing side pieces of the argument for and against Nanotyrannus. I came up with two for. One is a description of the new species authored by Bakker, Williams, and Currie (1988) entitled NANOTYRANNUS, A NEW GENUS OF PYGMY TYRANNOSAUR,FROM THE LATEST CRETACEOUS OF MONTANA. If anyone wishes to read this one Robert Taylor of The Theropod Archives was kind enough to email the pdf to me and I would gladly share it. However, I also found Currie, Hurum, and Sabath's article on tyrannosaurid skull structure and evolution here. The authors mention that Dr. Holtz of the University of Maryland argues that Nanotyrannus is congeneric with T. Rex and not distinct at generic or specific levels, but I guess that's as close as we're going to get to a solid paper refuting the existence of Nanotyrannus today.