The Case of the Headless Hadrosaur

Out of all the parts of a dinosaur’s skeleton, nothing is as prized as the skull. While an entire Tyrannosaurus is a frightening visage, the jaws are what we fear the most. Triceratops is a stout herbivore, but the highly decorated skull is what makes the dinosaur a fan favorite. And the entire character of Apatosaurus, née “Brontosaurus,” changed when paleontologists recognized that they had mounted the wrong head on the dinosaur’s body. No surprise, then, that many paleontologists have been dinosaur head-hunters.

Royal Tyrrell Museum paleontologists Darren Tanke and Rhian Russell recently solved one case of a decapitated dinosaur, they explained at the 16th annual symposium of the Alberta Palaeontological Society. In 1992, paleontologists prospecting in Alberta’s Dinosaur Provincial Park came across an abandoned dinosaur quarry. The site was one of many unrecorded quarries scattered throughout the park—remnants of early 20th century expeditions that did not necessary excavate or record data to modern scientific standards. But the early fossil hunters hadn’t collected everything in the rock. The 75-million-year-old site still contained the parts of the hips legs, and tail of a large hadrosaur, while the front half of the skeleton seemed to have eroded away. For whatever reason, the fossil collectors decided to abandon the quarry without collecting the whole dinosaur.

Paleontologist Phil Currie found a hadrosaur lower jaw at the site in 1992, but this did not seem remarkable since the site was part of a bonebed with many fossils. The site was recorded and sometimes visited, but who dug the quarry and when remained a mystery. Then, last year, someone found a hadrosaur toe bone and a scrap of newspaper at the quarry. The newspaper carried a 1920 date, and there was only one person working in the area at that time: George F. Sternberg.

With a little historical detective work, Tanke and Russell found that Sternberg, accompanied by his wife and young son, collected a single hadrosaur specimen in 1920. The fossil was a skull of Corythosaurus, although the specimen was missing the lower jaws. The skull is on display at the University of Alberta in Edmonton, while the jaw and toe bone are at the Royal Tyrrell Museum and the remainder of the skeleton is in the field.

But why did Sternberg leave so much of the fossil in the ground? Maybe, Tanke and Russell propose, he thought that the skull was the only part worth collecting. The dinosaur’s body between the skull and the hips—including the neck, chest and arms—was disarticulated, and lacking a trained field crew to excavate what remained, maybe Sternberg decided to pick up the skull and leave the body. We may never know for sure.

Still, the fact remains that a single dinosaur is now split among several places—two museums and a field site. This is not an isolated case. Other headless dinosaur bodies undoubtedly exist in the field, and these fossils might be collected and stored in different museums. And even sites that have been carefully excavated may yield additional bones as erosion scrapes away at the rock, and different paleontologists may eventually find parts of skeletons that have already been mostly collected. This is why detailed records are so important in paleontology. Even if a skeleton is scattered hither and yon, there is at least the hope that the parts can be reunited someday.

References:

Tanke, D., Russell, R. 2012. Headless wonder: Possible evidence of a head-hunted dinosaur skeleton in Dinosaur Provincial Park, Alberta. Alberta Palaeontological Society Sixteenth Annual Symposium Abstracts. 14-17

Riley Black | | READ MORE

Riley Black is a freelance science writer specializing in evolution, paleontology and natural history who blogs regularly for Scientific American.