Juvenile Tyrannosaurus rex or adult pygmy tyrannosaur?
The Museum’s collections include the holotype of Nanotyrannus lancensis, a small Late Cretaceous tyrannosaur. Controversy persists about whether it is a juvenile Tyrannosaurus rex or an adult of a pygmy tyrannosaur species. Discovered in Montana in 1942 by Museum curator Dr. David Dunkle (of Dunkleosteus fame), this creature died close to the end of the Cretaceous, approximately 65 million years ago. In 2001, paleontologists discovered the remains of a partial skull and skeleton in the same general location where the Museum’s Nanotyrannus skull was found. Nicknamed “Jane,” this specimen was initially thought to be a Nanotyrannus. However, as preparation and study of the specimen progressed, Jane was referred to as a T. rex. At present, Jane is considered a juvenile tyrannosaur, and the debate over the true identity of Nanotyrannus lancensis continues.