Mystery Dino

North Carolina Museum of Natural Sciences researchers discovered fossils of an unknown dinosaur while working in Utah. Using only a few bones, they'll learn the creature's size, diet, age and other features, and this mystery dinosaur could become the museum's first holotype, the example with which other species are described.

RALEIGH — For all of the difficulty and challenges involved in hiking through deserts, dry riverbeds and other remote places looking for fossils, there is also the thrill of adventure for paleontologists. That’s because for all of the study and planning that is put into each fossil hunting expedition, the thrill of the unknown remains. Researchers don’t know what they will discover in the field, and the anticipation of discovering the 'big find' is pretty exciting.

And that’s what makes the discovery in Utah during the summer of 2014 by researchers with the North Carolina Museum of Natural Sciences all the more extraordinary.

"This is the amount of material we found just on the surface, and we just stumbled on this,” says Dr. Lindsay Zanno, Director of Paleontology and Geology at the North Carolina Museum of Natural Sciences Nature Research Center in Raleigh, N.C. She’s standing next to a rolling cart that has shelves overloaded with fossils of all sizes. There’s a box on the top shelf that is filled with what appears to be broken pieces of fossilized bone.

"We were just walking around looking for fossils and all of these bones were trailing down the hill, so we found one at the top and just kept walking down and collecting bones, and we picked up more and more," Dr. Zanno adds. She admits that because the bones were all at the surface, many were broken. That explains the box of broken bones.

What makes this expedition even more amazing, in addition to the convenience of fossil hunting when all of the bones are sitting on the surface, is that the fossil collection forms the nearly complete skeleton of a dinosaur that lived about 98 million years ago. That’s right, the skeleton is almost intact.

“We already know our new beastie was a juvenile because of the vertebrae,” explains Zanno, still standing at the cart and holding several bones of the vertebrae together. “If this were an adult these would be fused, but because they aren’t we know this animal had a lot of growing to do.”

The expedition also recovered much of the juvenile dinosaur’s skull and jawbone. That’s a good thing, because those bones contain the most information for a paleontologist. The skull contains what are called signaling structures, which include horns, frills and other display features. Sometimes, those structures are the only differences that are really pronounced and unique to a species. The jawbone reveals the creature’s diet.

“We’ve already been cleaning the jawbone and removing the sediment, and we found that the jaw has a series of holes where teeth would have been as well as a couple of tooth crowns still embedded in the jaw,” Zanno says as she points out the crowns. For a tooth that is 98 million years old, the remaining teeth are in relatively good condition. The prehistoric molars have higher points, much like a molar you see today.

“The teeth that remain are important because by looking at them we can tell it’s a plant eater and not a predator,” says Zanno. “These are leaf shaped teeth with dentacles and ridges and these are common with plant eaters that we find.”

Researchers also discovered a bone from the front of the dinosaur’s face that contained three little holes where teeth would be. The bone would likely sit in front of the jawbone. Researchers believe these teeth were used to grab plants and then move them back to the cheek teeth for shredding and chewing.

And if all of this good luck wasn't enough, there’s something even more remarkable with this discovery. It turns out that all of those easily recoverable fossils are from a completely new dinosaur. That means researchers around the world will look to the North Carolina Museum of Natural Sciences for guidance about this dinosaur.

“The museum does not have what scientists call a dinosaur holotype, which is a specimen where there has been a new species described,” explains Dr. Zanno. “We give it a name and we attach that name to a particular specimen and this would be the museum’s first dinosauriun holotype.”

The challenge now is to discover what this new dinosaur looked like. So to better understand the past, scientists look to the present and extrapolate from the skeletons of close relatives.

“Dinosaurs aren’t extinct, we just call them birds now,” says Mark Norell, Chairman of the Division of Paleontology at the American Museum of Natural History in New York. “Lots of these animals, including the T-Rex, were incredibly bird like. We know it had a wishbone, it had hollow bones just like modern birds and it walked in that position you see ducks and chickens, where the backbone is parallel to the ground and the bird has an s-shaped neck.”

Norell adds that by comparing the skeletons and behavior of modern descendants of dinosaurs, scientists can understand a lot more about dinosaurs.

“The more we compare dinosaurs to modern birds, the more we learn, and the more we realize that dinosaurs were closer to birds than we ever could have imagined,” says Norell.

There is, however, one sad note to this story.

A close examination of the jawbone reveals several holes in the bone, which is a sign of a serious infection. It is not known yet whether the infection was a tooth abscess or some other type of infection. Since the holes are large, it could be one of the reasons the dinosaur died. But once again, scientists will look to the present to find out what happened.

“Because these animals are extinct and we can’t observe them directly, we have to look to living animals and see how diseases progress in closely related animals that are alive today, including birds and crocodiles,” says Dr. Zanno. “We’ll examine how their bones look when they have diseases, and then we can make a hypothesis about what these animals suffered from.”

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