The fossilized species has been named Erpetonyx arsenaultorum after the family of Michael Arsenault of Prince County, P.E.I., who found the fossil at Cape Egmont, said a study published this week in the Proceedings of Royal Society B: Biological Sciences.
"Our animal is the only reptile known from this time period called the Gzhelian," said Sean Modesto, a paleontologist at Cape Breton University who was the lead author of the new paper about the fossil, now in the collection of the Royal Ontario Museum in Toronto.
The Gzhelian Age was a five-million-year span that started about 304 million years ago, just 10 million years after the first reptiles appeared.
Erpetonyx helps fill a big gap in the fossil record, revealing that there were nearly twice as many kinds of reptiles living around that time as scientists previously believed, Modesto said.
The animal was about 25 centimetres long — about the size of a chameleon — and would have looked like an average modern-day lizard, even though it isn't closely related to them. Its sharp, peg-like teeth showed it likely ate insects and small amphibians rather than plants.
"Anything that it could catch or stuff down its throat it probably ate," said Modesto.
Its narrow claws suggest it moved easily across the ground, and the first part of its name means "claw crawler," the study says.
A couple of decades ago, Michael Arsenault was vacationing with his family at a cottage in western P.E.I. when he spotted the fossil on a rock on a beach, said Bette Sheen, a family friend.
His father, Ed Arsenault, got a farm tractor and used it to help chop the fossil out of the rock it was in.
"They built a box and Michael kept it under his bed for many years," Sheen said. "He knew it was very valuable. I don't think it was about the money so much. He knew it was really important to Prince Edward Island."
The family tried to sell it to a museum, including the Nova Scotia Museum and the Royal Ontario Museum, without success.
Then years later, Sheen connected with Kevin Seymour, assistant curator of vertebrate paleontology at the Royal Ontario Museum. The museum had recently received a large endowment from Louise Hawley Stone, a former museum board member and volunteer who died in 1997. It was dedicated to helping the museum buy artifacts for its collection. Meanwhile, the Arsenault family was looking for money to pay for Michael's post-secondary education.
Sheen helped the museum buy the fossil in 2004, but couldn't get it shipped to Toronto.
"Because you couldn't insure it," she said. In the end, she and her brother drove it across the country themselves.
Being in a museum collection made it available for scientists to study, and Seymour invited Modesto to do so, since he was an expert in ancient reptiles.
In the years that followed, Seymour said, the Arsenault family occasionally called to ask how research on the fossil was going.
"I'm really happy to see that the study is finally completed," he added.
The earliest reptiles first evolved during the Carboniferous Era, at a time when much of the world was covered in swampy forests that gave rise to the coal beds that we mine today.
By the time Erpetonyx lived, the world had grown much drier and the coal forests had largely broken up, giving way to less swampy coniferous forests. It's a period that paleontologists know very little about, Modesto said.
"This animal provides a unique window into what's happening to reptiles evolving just after the coal swamps disappear."
He added that he hopes to go to P.E.I. this summer to explore the area where the fossil was found. He hopes to learn more about the other plants and animals that lived alongside Erpetonyx — including what it ate — and to find other fossils like it.
"There's got to be more," he said. "It's just that no one is looking for them."
Meanwhile, Sheen credits Michael Arsenault for safeguarding the unique fossil until it could be made available to scientists.
"The Arsenault family deserves a pat on the back because their little boy knew it was an important find," she said. "He wasn't going to let it go unless somebody else could keep it safe."