The pachycephalosaurus (" lizard with the cranium épais") ornithischien Herbivore of the family of the pachycephalosauridés which lived with the late Crétacé, in North America was a .

A long time, the scientists believed that the very thick cranium of the animal (until a score of centimetres at the top) was used for ritual combat like those of the Musk ox, during which the animals sank head inside first. However, the morphology of their cranium does not allow it by really, because if they had been tested there, the round shape of craniums would have deviated the blows, returning serious wounds with the neck of the two extremely possible combatants.

One discovered whole skeleton of pachycéphalosaure forever; all that one knows about it comes from a cranium from this species and skeletons from the same family. Put aside the thick cranium, some characteristics of the animal confer a strange air to him. In spite of the fact that he lived at the end of the Cretaceous among kinds and species rather evolved/moved, he always had five fingers with his hands, a rather primitive feature in the dinosaurs, just like his teeth, similar to those of Stegosaurus , which however lived 100 million years before him.

Reference

• http://yahooligans.yahoo.com/content/science/dinosaurs/dino_card/33.html

Simple: Pachycephalosaurus