Prof Horner added: “What we see are these vertical canals coming to the surface, which suggests that there might be keratin on top, but it’s oriented vertically. The study in the Journal of Vertebrate Paleontology said blood vessels in the skull ended abruptly at the surface of the dome, indicating that the blood originally fed some tissue that was sitting atop the dome.

Dr Goodwin continued: “It’s reasonable to suggest that the covering over the dome may also have been brightly coloured or subject to colour change seasonally. We know the dome was covered with something, and we make a hypothesis that it had a vertical structural component, unlike Triceratops, T. rex and other dinosaurs, which had hard skin or keratin closely covering the bone.”Prof Horner said: “Something hit the top of this guy’s head and damaged it, and it was something that was severe. Palaeontologists say Platytholus clemensi, a type of pachycephalosaur was a plant-eating dinosaur that grew up to 15 feet long and walked on two legs.

Dr Goodwin also noted that the shape of the domed heads of pachycephalosaurs changed as the animals matured, becoming more prominent and elaborate as they approached adulthood. A bristly, flat-topped covering biologically makes sense. Animals change or use certain features, particularly on the skull, for multiple functions.

Dinosaur skulls sport an amazing variety of bony ornaments, ranging from the horns of Triceratops and the mohawk-like crests of hadrosaurs to the bumps and knobs covering the head of Tyrannosaurus rex. That, too, would suggest they were used for sexual display and courting, though they may have been used to butt the flanks, as opposed to the heads, of male rivals. I think these pachycephalosaurs had something on top of their head that we don’t know about. I don’t think they were just domes. I think there was some elaborate display on top of their head.” Dr Mark Goodwin of the University of California, Berkeley, said: “We don’t know the exact shape of what was covering the dome, but it had this vertical component that we interpret as covered with keratin.

Any features, any accoutrements that we find on the heads of dinosaurs, I think, are all display - it’s all about display.” Brightly coloured Using the X-Acto knife, cut through the top and bottom of the dinosaur. This can be a bit tough, so be careful not to cut yourself. A sharp blade is key here. The top hole should be slightly larger than the bottom hole. After you are done test out the fit of your toothbrush. If it's too small, shave off a little bit of plastic on the sides until it works. The key is to be tight enough to hold the toothbrush in place, but not so tight that it's hard to get the toothbrush in and out. There is a theory that the type of dinosaurs that pachycephalosaurs belonged to bashed heads in courtship rituals much like some mammals do today.Discovered in 2011 in Montana’s Hell Creek Formation, the partial skull has now undergone CT scans that have revealed the keratin bristles, described as looking like a “brush cut”.

Using the base of your toothbrush as a guide, mark the circumference on the top and bottom of the dinosaur. A couple of notes, you will want to go smaller than bigger. The flexiness of the cheap plastic is what is going to provide the tension to hold your toothbrush in place.