Teacher's decades-old find on a Northern Ireland beach turns out to be the island's first-ever dinosaur discovery

Mike Simms, who led the research team, holds the theropod tibia on the left and the Scelidosaurus femur on the right. (From University of Portsmouth, via CNN)

You never know what you might find while walking along the beach.

People often come across coins, shells and trash, but a teacher in Northern Ireland made a discovery that will go down in history.

In the 1980s, the late Roger Byrne, a schoolteacher and fossil collector, found several unidentified fossils on the east coast of County Antrim. He held onto them for several years before donating them to the Ulster Museum in Belfast.

Mystery swirled around what the fossils could be until a team of researchers with the University of Portsmouth and Queen's University Belfast confirmed they are fossilized dinosaur bones.

The 200-million-year-old fossils are the "first dinosaur remains reported from anywhere in Ireland," according to the article by the research team, published this month in the Proceedings of the Geologists' Association.

"This is a hugely significant discovery," Mike Simms, a paleontologist at National Museums NI who led the team of researchers, said in a news release Tuesday. "The great rarity of such fossils here is because most of Ireland's rocks are the wrong age for dinosaurs, either too old or too young, making it nearly impossible to confirm dinosaurs existed on these shores."

The researchers wrote in their article that folklore attributes the apparent absence of dinosaur remains from Ireland to the activities of St. Patrick, who is credited with having driven the snakes out of Ireland. But the lack of fossilized dinosaur bones is simply due to geology, they said. The rocks around the country are either the wrong age or type.

"Finding an Irish dinosaur might seem a hopeless task but, nonetheless, several potential candidates have been identified and are described for the first time here," the article says.

Researcher Robert Smyth and Professor David Martill of the University of Portsmouth analyzed the bone fragments with high-resolution 3D digital models of the fossils, produced by Dr. Patrick Collins of Queens University Belfast.

Originally researchers believed the bones were from the same animal but then determined they were from two different dinosaurs.

"Analyzing the shape and internal structure of the bones, we realized that they belonged to two very different animals," said Smyth in the news release.

"One is very dense and robust, typical of an armored plant-eater. The other is slender, with thin bone walls and characteristics found only in fast-moving two-legged predatory dinosaurs called theropods."

Both fossils were pieces of the animal's leg bones, according to the researchers. One was part of a femur of a four-legged plant-eater called Scelidosaurus. The other was part of the tibia belonging to a two-legged meat-eater similar to Sarcosaurus.

The beach where the fossils were found is covered in rounded fragments of basalt and white limestone, according the journal article. It noted that fossils in that area are usually sparse and heavily abraded.

"The two dinosaur fossils that Roger Byrne found were perhaps swept out to sea, alive or dead, sinking to the Jurassic seabed where they were buried and fossilized," said Simms.

This discovery helps shine light onto the life of dinosaurs that roamed millions of years ago.

"Scelidosaurus keeps on turning up in marine strata, and I am beginning to think that it may have been a coastal animal, perhaps even eating seaweed like marine iguanas do today," said Martill.

The Ulster Museum, which is closed because of coronavirus restrictions, plans to display the bones when those restrictions are lifted, the news release said.