Breaking Bone-Head News!

Recently, your HMNS curator of paleontology, Dr. Bob, along with some friends, announced a new bone-head dinosaur, a family with the technical name “pachycephalosaurid,” meaning “thick-headed reptile,” or “pachy” for short.

Our new pachy was based on a complete skull and some neck bones found by talented and dedicated amateurs and donated to the Indianapolis Childrens Museum. Since the new beast looked like a medieval dragon, we named the genus Dracorex, meaning “Dragon King.”

Most exciting was the fact that the skull came with several neck bones. Neck bones from pachys are very rare and the butting abilities of these dinos has been hotly debated. The Dracorex neck  had special anti-twist joints that would let the critter butt, shove and bang heads.

 Two Dracorexes butt heads
to score points in the mating game

We named the species in honor of J. K. Rowling’s magical academy, Hogwarts. So the full names is: Dracorex hogwartsia.  Has a nice ring, doesn’t it?

Dracorex hogwartsia at the
Indianapolis Childrens Museum

The new bone-head  dinosaur was way different from any other bone-headed dinosaur discovered so far. Unlike Pachycephalosaurus, Stegoceras and their kin, Dracorex had no dome of bone in the middle of the forehead but had, instead, all sorts of knobs surrounding two huge holes. Unlike Stygimoloch, another famous bone-head, Dracorex had big holes and horns that were shorter.

Another difference – so we thought – were the upper nipper teeth, the incisors in the premaxillary bone. Dracorex didn’t have any. Most other bone-heads did.

Well……we were wrong.

True, the Dracorex skull as preserved had no upper nipper teeth and no sockets for such teeth either. This condition wasn’t necessarily a surprise. Many advanced plant-eaters lose their upper nippers. Cows and antelope have no upper incisors. Instead they have a tough pad in the roof of the mouth – the lower nippers bite into the pad when the critter tears off a tuft of grass.

Therefore we concluded that our bone-head was doing the cow-thing in its snout.

But Victor Porter, head of the lab at the Indianapolis Museum, had cleaned a peculiar tooth found with the skull. It was bigger than the back teeth, more triangular, and didn’t show wear from lower teeth.

 Upper nipper of Dracorex hogwartsia
Snout of Dracorex hogwartsia
with upper incisors restored

Our colleague and friend Mike Triebold of the Dinosaur Resource Center showed other new skulls – and they had just this type of teeth in the snout tip. (Mike has the most important pachy collection in the country). There’s no doubt: Dracorex hogwartsia  had big upper incisors too.  Our bone-head must have used its formidable nippers to bite off bits of vegetation – and to bite other Dracorexes when the dinos got frisky.

Why didn’t the Indianapolis skull preserve the holes for the deep roots of the nippers? The sockets must have been huge, since the root on the tooth was very long. We don’t know.  After death, something or someone broke the bone along the front of the mouth, destroying the sockets and loosening all the front teeth.

In paleontology, there always surprises…..more on Butt-Heads again soon.