New fossil on display at ROM predates dinosaurs and was discovered in Ontario

The Royal Ontario Museum says the very rare marine fossil species was discovered near Brechin in southern Ontario and is nearly half a billion years old.

By Ashima AgnihotriStaff Reporter

Wed., April 20, 2022

Royal Ontario Museum will display a very rare and recently discovered fossil of a 450 million year old marine animal found in southern Ontario.

Researchers with the ROM say the new “Tomlinsonus dimitrii” species is part of an extinct group of arthropods and is “exceptionally well preserved.”

The newly discovered marine animal fossil, which is nearly half a billion years old, appears to predate even the dinosaurs that first appeared around 240 million years ago.

This finding was announced on March 24, 2022, in the Journal of Paleontology.

Researchers are calling the fossil’s preservation “remarkable,” as typically only the hard parts of an organism are fossilized (bones and shells).

But not with this extinct group of arthropod. Defying the trend, this new species lacks any mineralized body parts and was entirely soft-bodied.

Lead author Joe Moysiuk, a PhD candidate in ecology and evolutionary biology at the University of Toronto, described the species as “an ornate head shield adorned with remarkable featherlike spines, possessing stilt-like limbs.”

George Kampouris, the discoverer and co-author, is also an independent paleontological technician who initiated a project to investigate fossil beds in 2014 at a stone quarry owned by Tomlinson Group, whom the fossil is named after. The quarry is located near Brechin, around Lake Simcoe in southern Ontario.

“Brechin has produced world-class fossils for over 100 years but our work here has revealed the role of catastrophic storm events in the burial and preservation of entire animal communities in their final moments,” Kampouris said.

Moysiuk told the Star that Kampouris was searching for “shelly” creatures like sea lilies and trilobites when he came across the rare fossil. Kampouris went to the active quarry with chisels and hammers and systematically excavated different layers of shale and limestone.

The species is known to have lived in a “shallow tropical marine sea,” which covered most of Ontario at the time of its existence, says researchers. It is said to be no longer than an index finger, in size, and most closely related to modern critters like spiders and scorpions.

“The finding of entirely soft-bodied species like Tomlinsonus allows a much better understanding of the diversity of life that really existed at that time,” said Dr. Jean-Bernard Caron, ROM Richard Ivey Curator of Invertebrate paleontology and co-author of the paper.

The Tomlinsonus will be displayed at the ROM in the newly opened Willner Madge Gallery, Dawn of Life’s burgess shale section, which contains various other soft-tissue preservation.

Ashima Agnihotri is a reporter for the Star's radio room based in Toronto.