An analysis of over three dozen specimens of Tyrannosaurus rex finds that they exhibit such a remarkable degree of proportional variations that the pattern favors multiple species at least partly separated by time. Tyrannosaurus rex holotype specimen at the Carnegie Museum of Natural History, Pittsburgh, the United States. Image credit: Scott Robert Anselmo / CC BY-SA 3.0. Tyrannosaurus rex, or T. rex for short, is the only recognized species of the...
