The unique Acrotholus dinosaur was discovered in the fertile Milk River Formation that stretched from Alberta, Canada to Montana and Kansas. This dinosaur is known for its sizeable dome-shaped head and bipedal movement. Research shows that it used its sturdy dome head in combat with other dinosaurs.
Discovered in 2013, the Acrotholus was roughly six feet long and weighed about 90 pounds. The acrotholus’ dome skull was more than two inches thick, making it useful when battling other animals. This species is known as the oldest bone-headed dinosaur in America. Acrotholus dinosaurs walked around on two legs and had short arms like a Tyrannosaurus ex. Like many other dinosaurs, this species ate a plant-based diet. Acrotholus walked the Earth more than 85 million years ago.