In Depth
Platytholus was a dome-headed dinosaur from the Late Cretaceous Hell Creek Formation of Montana, about 66 million years ago.
It belonged to the pachycephalosaurids, a group of small, plant-eating ornithischians best known for their thick, rounded skull roofs.
Unlike most of its relatives, Platytholus had a broad, flattened dome, which is what inspired its name.
Platytholus was a small herbivore, probably around 2–3 meters long. Like other pachycephalosaurs, it would have walked on two legs, with short arms and a stiff tail.
Its most striking feature was the top of its skull: instead of being strongly domed like Pachycephalosaurus, it was lower and wider, with a flattened crown.
The flattened dome of Platytholus may have been used in display or recognition within its species, or possibly for head-to-head shoving contests, though its exact purpose is still debated.
Further Reading
A new pachycephalosaurid from the Hell Creek Formation, Garfield County, Montana, U.S.A. Horner, John R.; Goodwin, Mark B.; Evans, David C. (2023-04-14). Journal of Vertebrate Paleontology. 42 (4): e2190369.