One of the oldest and most complete plesiosaur fossils recovered in North America, and the oldest yet discovered from the Cretaceous Period, represents a new genus of the prehistoric aquatic predator according to University of Calgary palaeontologists who have formally described the creature after its remains were uncovered in a Syncrude Canada Ltd. mine near Fort McMurray in 1994.
In a paper published in the German research journal Palaeontographica Abteilung A, former U of C graduate student Patrick Druckenmiller and biological sciences professor Anthony Russell have named the 2.6-metre-long plesiosaur Nichollsia borealis in memory of the late Elizabeth (Betsy) Nicholls.*
The fossil was discovered by machine operators Greg Fisher and Lorne Cundal in 1994 during routine mining operations at Syncrude’s Base Mine, about 35 kilometres north of Fort McMurray near the Athabasca River. Amazingly, the specimen was serendipitously exposed by one of Syncrude’s 100-ton electric shovels approximately 60 metres below ground surface. It is complete except for its left forelimb and shoulder blade. It was transported to the Royal Tyrrell Museum, where it was prepared for research observations and exhibit and studied by Druckenmiller and Russell.
Nichollsia borealis is one of the most complete and best preserved North American plesiosaurs from the Cretaceous Period and lived approximately 112-million years ago. Although not classified as dinosaurs, plesiosaurs lived in the seas at the same time that dinosaurs roamed the land throughout the Jurassic and Cretaceous Periods (205 million – 65 million years ago).
They were a diverse group of carnivorous aquatic reptiles that reached lengths of over 12 metres. Fossil remains of dozens of plesiosaurs have been recovered around the world since the early 1800s and are among the first fossil vertebrates to be scientifically described.
Nichollsia is also very significant because it fills a 40-million-year gap in the plesiosaur fossil record and greatly increases the understanding of the ancient seaway that once split North America in two and whose shores abounded with dinosaurs.
“This individual was a pioneer in the marine waters that would eventually become the Cretaceous Western Interior Seaway, which ran the length of North America during much of the Cretaceous and was home to one of the world’s most diverse communities of marine reptiles,” Druckenmiller said. “It represents the oldest known forerunner of this amazing period in North American prehistory.”
The excellent condition of the fossil has also proven to be a gold mine for palaeontologists, who often rely on scattered and incomplete examples for classifying and reconstructing plesiosaur prehistory.
“This specimen was preserved in sandstone and was not crushed as much as most specimens, which have typically been found in shale,” Druckenmiller explained. “Because of this, I was able to have its three-dimensional skull CT-scanned so we can see the details of the insides of its braincase. This has helped us understand this animal in more detail than almost any other plesiosaur ever found.”
Russell said researchers continue to work with Syncrude to study the ancient sea floor that is now being mined for oil sands, in order to better understand the prehistoric ecosystem and to help predict where future fossil finds might occur.
“We are getting to look at a relatively large area of the ancient sea bed over many hectares, which is very unusual for a field site,” he said. “It allows us to create models and hopefully predict where other remains might turn up, which Syncrude and other oil sands operators can be aware of when working in a certain area.”
Nichollsia borealis is currently on display in the Discoveries Gallery at the Royal Tyrrell Museum.
*Nicholls was a renowned palaeontologist and U of C alumna who is credited with transforming the understanding of prehistoric ocean life by describing the largest-ever marine reptile, a 23-metre-long ichthyosaur, discovered in northern British Columbia in 1999. “We chose this name because Betsy was a key player in the study of marine reptiles, a mentor to me, a former student of Tony, and a great person,” said Druckenmiller, who is now Curator of Earth Sciences at the University of Alaska Museum of the North in Fairbanks, Alaska. “We felt it was a fitting way to honour both her memory and her accomplishments in palaeontology.”
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