An eagle-eyed shovel operator at Syncrude’s Mildred Lake mine has found the remains of Alberta’s oldest plesiosaur. The marine reptile lived 115 million years ago in an ancient seaway covering North America.
Jenna Plamondon said she was using a hydraulic shovel during a March 12 shift when an unusual shape caught her eye.
“I kept staring at this little chunk of dirt. As a shovel operator, we’re trained to see things that are out of the ordinary. We take a lot of pride in our pit and keeping the area clean,” said Plamondon in a statement. “I called my leader and asked to have geology look and confirm. We made the decision to move the shovel just in case it was an actual fossil.”
Geologists studied Plamondon’s find and called the Royal Tyrrell Museum of Paleontology in Drumheller. After more study, they determined Plamondon found the fossilized tail of a plesiosaur.
Plesiosaurs are noted for their long necks and four flippers on their barrelled bodies. They swam like penguins or turtles, and spent most of their lives in the oceans. They had no gills and came to the surface to breathe. Despite their long necks, they had a limited range of motion that was not snake-like.
Most of Fort McMurray Wood Buffalo’s history was underwater. For millions of years, it was the Western Interior Seaway. The ancient seaway stretched from the Yukon and Hudson’s Bay to the Gulf of Mexico.
The closest shoreline from what would become Fort McMurray was somewhere around the Alberta-Saskatchewan border. On land, temperatures were like the coast of Vancouver Island. The environment was forested, warmer and covered in ferns. There were no flowering plants and grass did not exist.
While plesiosaurs shared the Earth with dinosaurs, they are considered marine reptiles. Paleontologists believe the plesiosaur died in the inland sea and washed into shallow waters. The carcass was likely scavenged by predators, including dinosaurs.
Donald Henderson, curator of dinosaurs at the museum, speculates a storm may have buried the plesiosaur in sand.
“This presents very unusual preservation conditions,” Henderson said in a statement. “It’s so rare for things to become fossils, especially big things such as marine reptiles and dinosaurs. It’s only the fact that we’re shifting so much rock here that we’re fortunate to see this small piece of fossil.”
The plesiosaur’s final resting place will be in Drumheller at the Royal Tyrell Museum. It arrived at the museum using a similar method to transport a human bone cast. This allows a close fit of plaster to protect the fossil without touching the bone.
The first major marine reptile fossil was found at Syncrude in 1994. Dozens of other plesiosaurs have been found in the oilsands. A different long-necked marine reptile called an elasmosaur was found in 2012 during construction of the Parsons Creek Interchange.
The most significant find was at Syncrude’s Millennium mine in 2011 when the preserved remains of a nodosaur, an armoured land-based dinosaur, was found.
Fossil remains of a plesiosaur at the Mildred Lake site on March 12
