Toothless dinosaurs give researchers much to digest

Daren Zomerman, Edmonton Journal 


EDMONTON - The image of a dinosaur in most people’s mind is that of a towering monster, snarling and baring a mouthful of teeth.

But an undergraduate researcher at the University of Alberta is shedding light on a Labrador retriever-sized toothless dinosaur found in Horseshoe Canyon near Drumheller.

Greg Funston, working under renowned paleontologist Phillip Currie, is trying to find out what and how the caenagnathidae (pronounced: kay-no-nay-thid) ate.

“One of the big questions in theropods is ‘why did they lose their teeth?’ There are two or three groups that do it, and most importantly is the birds,” Funston said.

According to Funston, the caenagnathidae, a theropod or “beast feet” dinosaur related to velociraptors and Tyrannosaurus rex, lost its teeth in the late cretaceous era, 70 million years ago. Before that, the species had small teeth in the front of their beaks.

By studying jaw fragments, Funston and other researchers are trying to determine whether the creature ate only plants or also consumed small prey.

The metre-tall caenagnathidae had ridges that protruded from the jaw that may have been used like scissors to shear plants and small animals.

“By looking at the lower jaw, we can figure out that they’re actually adapted for shearing plants, kind of like a scissor-like action to chop up plants, but they’ve actually got long claws on their forelimbs so they would have been able to eat small prey as well,” he said.

Funston compared a few jaw fragments with other toothless animals such as modern-day turtles and an early mammal known as a dicynodonts to help describe the jaw’s function.

“The study I did was comparative anatomy. So, figuring out what these different bones are in the jaw ... how they are adapted differently from what they evolved from, and what those adaptations mean,” he said.

Debate also continues about where these dinosaurs lived.

The majority of caenagnathidae fossil locations are found near what used to be water, leading paleontologists to believe they would wade through the water, much like modern-day herons, Funston said.

“We’re really not sure where these guys live, exactly, but we tend to find them near water,” he said.

Funston will also be examining differences between caenagnathidaes found in Mongolia and North America.

“In Mongolia, we have a lot of the bigger group that this belongs to,” he said. “They belong to oviraptorosaurs, and for oviraptorosaurs, they show a split between these North American ones and the Mongolian ones. So it’s cool to see what their ancestors were like and why they split off in different directions.”

