They think this particular dinosaur would likely have been one metre long (3.3 ft) and weighed around 5.85 kg (about 12.9 pounds) – but it’s been described as a “teenager”, so a fully grown one would have been much larger.

Although the researchers can’t be sure, other pachycephalosaur species reached lengths of more than four metres and 400kg, which could suggest this one would also have grown to be much bigger.

These dinosaurs had rounded heads made of solid-bone, which they may have used to defend themselves or to help attract a mate.

The fossil also shows the skull covered in dimples, which could show it also had other unknown features on its head.

Experts think it could have been a fearsome sight, with a mouth full of sharp teeth and giant eye sockets.