Professor makes a fossil breakthrough in the overlooked section of the Burgess Shale

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The world-famous Burgess Shale fossil layer in Yoho National Park has continued to uncover the mystery to scientists for more than a century since the site was first discovered.

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Two-dimensional fossil images of shale have confused scientists for years trying to determine what a 505 million-year-old creature would look like in the real world.

However, Dr. Paul Johnston and his associate professor at Mount Royal University’s School of Global Environmental Sciences used a unique technique to extract three-dimensional fossils from the most overlooked limestone deposits on the site.

“People tend not to care about the Burgess Shale limestone layer, as the best fossils tend to come from shale,” Johnston said.

“These fossils are so small that I had to lower my hands and knees. And when I saw that there were actually some fossils, with the lens of my hand, they had a long history of burial. I could see it replaced by silica in the meantime. “

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As a student, Johnston used hydrochloric acid to extract fossilized shells from young Australian limestone deposits. He realized that these old deposits could do the same and applied to Parks Canada to try it out.

“And it’s done-I was able to retrieve these things as 3D objects,” he said.

He discovered a new species of mysterious stenotecoid.Johnston named his discovery Stenothecoides rasettii In honor of Franco Rasetti, an Italian physicist who worked with Enrico Fermi on the issue of nuclear fission and had a secondary interest in paleontology.

“[Lassetti]came to Yoho National Park and found a stenotecoid in the formation beneath the Burgess Shale,” Johnston said, adding that his own work often relies on Lassetti’s previous work.

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Johnston owns about 200 examples of new stenotecoid species and has been able to break through the questions that have confused scientists since the first discovery of stenotecoid.

Previously, they were speculated to be a kind of mollusk, but some suggest that they may be brachiopods, while others want to create a new phyla to classify them. I was there.

“I’m working on the evolutionary history of mollusks. Like other paleontologists, I couldn’t fit them well into the evolutionary tree of mollusks,” Johnston said.

But one small hole common to his entire collection of fossilized shells is that Stenothecoids were actually more closely associated with brachiopods and were probably an early branch of their evolutionary branches. I made it clear.

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“I was able to solve it because it was very well preserved and I was able to see the anatomical details that actually tell the story,” he said.

He teamed up with brachiopod expert Michael Streng at Uppsala University in Sweden. Together they published their findings in the journal Acta Palaeontologica Polonica.

Coincidentally, the paleontologist who first discovered Stenothecoids in Nevada in the 1800s was the same person who discovered the Burgess Shale.

Paleontologist Charles Doolittle was the administrator of the Smithsonian Castle for 20 years. He pointed out that he discovered Stenothecoids in 1884, and later recorded the Burgess Shale in 1909.

Johnston’s discovery brings together Walcott’s two discoveries in a unique way that transcends time and geography.

“Obviously, Walcott was so busy with shale that he didn’t see the composition of the limestone,” Johnston said.

Johnston’s fossils are currently located at the Royal Tyrrell Museum and the Royal Ontario Museum in Toronto.

brthomas@postmedia.com

twitter: @brodie_thomas