The Pachycephalosaurus from the Schleich® DINOSAURS themed world is the largest platypus dinosaur discovered to date. It was about 4 -5 meters long, weighed 450 kg and moved on two legs. He lived in North America in the late Cretaceous Period. Its skull, strongly arched upwards, was 20-25 cm thick. Scientists suspect he used his skull to ram or impress rivals. Pachycephalosaurus means as much as thickhead phagedis.