These days, they believe it was more likely around 36 feet. The pachycephalosaurus, or stygimoloch is the hard-headed dinosaur that uses its armored skull to break itself out of containment at the ...

Pachycephalosaurus wyomingensis was the largest of the pachycephalosaurids—"thick-headed dinosaurs"—which featured extremely thick skullcaps. The top of a Pachycephalosaurus skull could be 9 ...

Paleontologists have announced the discovery of "North America's oldest dinosaur." The find challenges the consensus view on the origins of these extinct reptiles. In a study published in the ...