The Paleontologist and the Three Different Dinosaurs

Three different dinosaurs Dracorex, Stygimoloch and Pachycephalosaurus (clockwise from top left) might really be the juvenile, teen and adult of the same dino.

Holly Woodward

A new twist in an old story about dinosaur bones sounds like a pixie tale for fossil fans: Once upon a time, scientists revealed three different dinosaur skulls in the northern United States. The first skull, found in 1931, was big and round. The second, found in 1983, was lesser and narrowerand had spikes sticking out of the back of its head. The third, which had horns on its nose, was found in 2006. This was the minimum skull of all.

Like all good tales, theres a revelation at the end of this dino story. Scientists have long thought that these three skulls belonged to three dissimilar kinds of dinosaurs. But dont inform that to Jack Horner, a paleontologist at the Museum of the Rockies in Bozeman, Montana. He says thats possibly not true. According to a new study by Horner and his team, the three skulls are more liable from a kid, teenager and adult of the similar kind of dinosaur.


All three dinosaurs lived about 65 million years past in an area now known as Hell Creek, in Montana and South Dakota. The technical name for the first, largest-skulled dinosaur is Pachycephalosaurus wyomingensis. The second, with the spikes, is Stygimoloch spinifer, which means horned mischievous sprite from the river of death. The third dinosaur takes its name from the globe of Harry Potterit is called Dracorex hogwartsia, which means dragon king from Hogwarts.

Horner began to suspect the fact about the three skulls after he heard about studies of duck-billed dinosaurs. In those studies, scientists found that a set of skulls that all looked dissimilar were found to be from different ages of the similar type of dinosaur. To investigate his hunch, Horner and his group studied bone fragments from the three thickheaded skulls.

Its real simple to tell young bone from old bone, Horner told Science News. Young bones are still growing and require a lot of blood flow, so they have more tunnels and passageways for blood vessels. (With all the tunnels and holes, the insides of these bones look a small like sponges.) Older bones are more dense, which means they look more solid and dont have as numerous tunnels and passageways going through.

Horner and his team found that the largest skull had few tunnels in it, which suggests the skull comes from an adult dinosaur. The two lesser skulls both had many tunnels, which suggest that those dinosaurs were younger when they died.


The scientists found other proof: They took CAT scans, or special pictures alike to X-rays, of the smaller skulls and saw that the bones had not yet grown entirely together, as they do in adults.

Horners method of studying the bone structure of skulls is a new way to seem at dinosaurs. In the past, people have been very unwilling to cut open skulls and look at their bone histology, he told Science News. This will show them you can get a terrible lot of information from doing that.

The Museum of the Rockies, where Horner works, has the biggest collection of dinosaur bones in the worldas well as the largest T. rex skull ever establish. With his new discovery, Horner fortuitously made a lot of work for himself.

I made a brand new dinosaur hall at the museum three years past, and now I have to alter it, he said. He may also have made a lot more work for other scientists. Future studies may reveal that some other dinosaur bones also came from the similar type of dinosaur at different ages, rather than from dissimilar types of dinosaurs.