Researchers chipping away at marine reptile fossil found near Fort McMurray

Researchers at the Royal Tyrrell Museum are starting to chip off the stone surrounding the skeleton of a marine reptile that roamed the world's oceans while dinosaurs prowled the land.

In 2016, a group of Suncor workers were surveying a mining field north of Fort McMurray when they discovered parts of a shoulder and chest of a plesiosaur 33 metres down a hole,saidDon Henderson, a curator of dinosaurs at the museum.

"It's the type of reptile that was found all over the world, was fully adapted for life in the seas and went extinct along with dinosaurs," said Henderson.

Three years later,the mining phase advanced and Suncor was able to drill parts of the skeleton out of the ground and deliver it to the museum so the stone covering the skeleton can be delicately chipped off.

"Because the stone surrounding the skeleton is soft, there are still a few more pieces left behind that they're [Suncor] is digging in huge volumes of rock," said Henderson.

Plesiosaurs not uncommon

The discovery of the three-to-four-metre long marine reptileis not uncommon for Alberta.

So far, approximately 19 plesiosaurs have been discoveredin the province, according to Henderson.

"From the Fort McMurray area, I think we've got like 14 and in the south we've got about four or five," Henderson told the CBC.

Henderson said the three to four-metre plesiosaur discovered, on what may have been a gentle slope on a sea bed, is a few million years younger than the other plesiosaurs found in Alberta.

"We estimate the others are 110-to-112-million-years-old."

The plesiosaurs discovered in the southern part of Alberta are between 66 and 75 million-years-old.

"It's just part of the bigger picture of the changes of life on Earth quite and we can document that change in this part of the world quite well because we have a really good sedimentary rock record," Henderson said.

What are plesiosaurs?

Plesiosaurs were a successful speciesbefore they went extinct with the dinosaurs.

Their streamlined bodies indicate they were good at swimming, though they couldn't breathe underwater.

"Everything about them says efficient underwater movement but they're still reptiles and they still have to breathe. They don't have gills they had to come up to the surface to breathe. And so they're sort of tied to the surface a bit like seals and penguins today."

They also didn't lay eggs like other reptiles, said Henderson.

Unearthing an ancient creature

According to Henderson, when oilsands workers unearthed a rare dinosaur fossil in 2011 at this same Suncor mine, they moved about 1.2 billion cubic metres of rock.

"In all that rock, they only found one dinosaur. You need lots of patience in this game. It takes months to years to get things prepared and then it takes another several months to do the science on it."

Henderson says when he heard Suncor discovered another skeletonat the same mine he thought it was another dinosaur, but was surprised to learn a marine reptile's body was located.

"So, now all the rules have changed and we could tell that there was a lot more water currents on the seabed moving stuff around which we didn't know before," Henderson said.

"That probably explains why the carcass is a bit broken up but I'm always happy to get a fossil reptile. I don't care what it is, they're all so interesting and so yeah we'll take it."