Thread:Animalman57/@comment-6025261-20180218074905/@comment-23825763-20180218220709

Jack Horner's team couldn't use the real Dracorex skull for their study, as the first skull is still the only one of its kind, so they had to use a cast for the experiment. The real skull shows ossification, or a hardening of the bones, showing that it was close to maturity. How could a juvenile of Pachycephalosaurus be almost fully mature looking nothing like a Pachycephalosaurus?