Tyrannosaurus Rex 42 feet 18 feet 5-7 tons 25 mph Teeth Though the Tyrannosaurus had many different sizes of teeth, all were razor sharp and some grew to lengths of 9-13 inches. Broken teeth were replaced frequently by newer teeth. The powerful jaw exerted in excess of 3000 pounds of pressure! Osborn 1905 Canada Alberta &tyrannosaurus; Stegosaurus Armatus 25-40 feet 14 feet 2-4 tons &speed-not-known; Spikes The Stegosaurus had two long rows of armor along its back. At the end of its tail four large spikes were an excellent defense. Marsh 1877 United States Colorado &stegosaurus; Gallimimus Bullatus 18 feet 8 feet 1000 pounds 35-60 mph Osmólska Roniewicz Barsbold 1972 Mongolia Nemegtskaya Svita &gallimimus;