T. rex and the World of the Tyrannosaurs Wiki

An illustration of Peck's Rex, the only specimen attributed to Tyrannosaurus "imperator", with Trichomonas-like parasites infesting the back of its jaw.

Tyrannosaurus "imperator" is a proposed species of Tyrannosaurus that was believed to be around 20% larger than Sue. It is now known to be a larger-than-usual Tyrannosaurus rex. The specimen which was attributed to this species is now known as Peck's Rex or Peckrex. It is supposed to be 51 feet long and 15 and a half feet tall in its juvenile form.