At this point in ceratopsian evolution we’ve reached the ceratopsids – the big, elaborately horned and frilled group that includes famous names like Triceratops and Styracosaurus. First evolving from their smaller North American ancestors around 90-80 million years ago, these dinosaurs rapidly diversified and developed a huge variety of different head ornamentations during the last 20 million years or so of the Cretaceous.
Here the family tree gets a little more complicated, with two major subdivisions of the ceratopsids splitting off from a common ancestor: the centrosaurs and the chasmosaurs. We’ll be focusing on the centrosaurs to start off, and moving on to chasmosaurs later in the month.
The centrosaurs are known mainly from the northern region of western North America (Alaska, Alberta, and Montana) – although a few ranged further south with remains found as far away as Mexico, and one even made it into Asia. They often had prominent spikes on their frills, and many also developed large nose horns or nasal bosses.
Diabloceratops (“devil horned face”) was one of the earliest members of the group, dating to about 80 million years ago in the Late Cretaceous. Discovered in Utah, USA, it was probably around 5.5m long (18′), with a small nose horn, relatively short brow horns, and a pair of long “devil horn” spikes at the top of its frill that inspired its genus name.
Its skull was shorter and deeper than those of its later relatives, and retained a few “primitive” features from its ancestors. It was also the first centrosaur found further south than Montana, and with it being such a basal member it’s possible the group may have actually originated in the southern part of the continent with their descendants dispersing northwards.