Wednesday, 07 December 2011 15:10

New dinosaur species in Eastend highlights variety of pre-historic animal life

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By Matthew Liebenberg — This email address is being protected from spambots. You need JavaScript enabled to view it.

A partial skeleton discovered almost 40 years ago near Eastend has been confirmed as a new species of plant-eating dinosaur.

Called Thescelosaurus assiniboiensis in recognition of Saskatchewan’s historic District of Assiniboia where it was found, this 66-million-year-old specimen is quite different from the popular image of dinosaurs as flesh-eating monsters.

It measured about two metres from the tip of its snout to the end of its tail, which made it similar in size to a white-tailed deer.  It was bipedal, meaning it walked around on its two hind legs.

Caleb Brown studied and identified it as a new species as part of his Masters thesis at the University of Calgary. His supervisor was Dr. Anthony Russell and the co-author of the study was Clint Boyd of the University of Texas at Austin. The new species is described in a study published in the December 2011 edition of the Zoological Journal of the Linnean Society.

Brown said it lived during the Late Cretaceous period shortly before the mass extinction of dinosaurs.

“It was very small and this is at the very end of the time of the dinosaurs ... when we tend to see very large dinosaurs. So it’s interesting. It changes our idea that not everything was big during that time.”

Finding food was probably not a problem for Thescelosaurus, because the area where it lived was then a lowland forest environment with a lot of rivers and streams. It faced a much bigger challenge to avoid becoming prey to carnivores such as Tyrannosaurus rex and the raptor-type dinosaurs. Other dinosaurs had different ways to defend itself, such as horns, bony armour or simply its size. In comparison, this little plant-eater appeared to be vulnerable.

“This particular animal is small and has no obvious defence," Brown said. "So we’re not exactly sure how it coped. But it obviously was able to survive and actually was able to thrive during this time.”

There is generally still a lack of knowledge about small-bodied and plant-eating dinosaurs.

“We tend to know more about the big things because they tend to fossilize better,” he explained. “And then on top of that there tends to be a lot more research investigation into the meat-eating dinosaurs because they’re seen as more exciting and more important.”

Tim Tokaryk, who is the head of the paleontology program at the Royal Saskatchewan Museum (RSM), said Thescelosaurus is significant for the time period in which it lived.

“The ever-increasing diversity of the dinosaurs that we’re discovering just prior to their extinction illustrates even more how dramatic their eventual extinction was,” he emphasized. “It wasn’t a gradual decline of species to the point of extinction. It was a catastrophic sudden event that wiped out a very profitable diversity of ecosystems.”

After this specimen was collected from the Frenchman River Valley near Eastend in 1968 by Albert Swanston, it became part of the RSM fossil collection and it was used for comparative studies with other dinosaurs.

“Often new discoveries are not made in the field but are actually made in museums,” Tokaryk noted. "That sort of illustrates the importance of having museum collections because we continually go back to earlier collections and to comparisons utilizing new technologies, new advances in thinking and methodology.”

According to Brown more specimens have been found south of the border in North and South Dakota, Montana and Wyoming in recent years, which allowed them to have a better comparative framework.

“When we compared this specimen from Saskatchewan to those, we see that there are some consistent differences. Enough for us to suggest that this is a new species.”

He described it as a “pretty cool experience” to have been able to identify a new dinosaur species, even though there was no specific Eureka moment.

“In this particular case it was just the sum of all these different subtle changes between this particular specimen and those in the United States,” he said.

Brown is now a Ph.D. student at the University of Toronto’s Department of Ecology and Evolutionary Biology.

His research is focused on the horned dinosaurs that lived during the same time as the Thescelosaurus. He said there is still a lot to discover about the diversity of dinosaurs and their behaviour.

“The more we study about them the more complex they are and the more interesting and the more questions we actually have about them,” he noted.

The partial skeleton of the new dinosaur species can be seen at the T.rex Discovery Centre in Eastend and an exact cast is also on display at the RSM in Regina.

Sean Bell, the general manager at the T.rex Discovery Centre, said the actual fossil is on display there.

“Within our lab, we’ve got a glassed area. When you look in there’s a big table and it’s got all the bones laid out in roughly life position.”

He felt the discovery will focus attention on the work done at the centre.

“It helps us get our message out about there’s more than just a T.rex at our centre ... and it gives something new for people to see. I think most people aren’t really aware of this kind of dinosaur. It’s fairly small; it’s not your big, toothy gigantic animal.”

The centre is open every day from 9 a.m. to 5 p.m., except Dec. 25 and 26 and Jan. 1.

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