More than 50 years after its discovery on Scotland’s Isle of Skye, scientists have unveiled a monster that would make Nessie blush: a 13-foot-long reptile that ruled the seas 170 million years ago.

The fossil, dubbed the Storr Lochs Monster, is a nearly intact skeleton of an ichthyosaur, a family of extinct marine reptiles that lived alongside the dinosaurs. The creatures were the dolphins of their time: fast swimmers with long, narrow snouts and cone-shaped teeth perfect for eating squid and fish.

Discovered by an amateur fossil collector, the Storr Lochs specimen is the most complete marine reptile ever recovered in Scotland from the age of dinosaurs. Yet for decades, the skeleton remained in storage because it was entombed in extremely hard rock.

Now, a partnership between the University of Edinburgh, National Museums Scotland, and energy company SSE has allowed paleontologists to expertly free the skeleton from its stony casing. On September 5, the freshly exposed remains made their triumphant public debut.

“Although some people think that sea monsters live here today in our lakes, there were actually real ones that lived here over a hundred million years ago,” says Stephen Brusatte of the University of Edinburgh, one of the lead researchers analyzing the fossil.

Norrie in (the) Skye With Fossils

The Storr Lochs Monster was discovered in the summer of 1966, when Norrie Gillies—the longtime manager of SSE’s hydroelectric Storr Lochs Power Station—took a Sunday afternoon stroll on a picturesque beach north of the station. There, he noticed something strange jutting out of the rocks: strings of vertebrae that looked like stacks of chocolate-brown ashtrays.

An amateur fossil collector, Gillies quickly realized the magnitude of what he had found. He dashed off a letter to the Royal Scottish Museum, which excitedly sent a team to the site several weeks later to remove the fossil. (The Royal Scottish Museum has since been absorbed into National Museums Scotland.)

“He was always interested in the environment ‘round about him,” says Allan Gillies, Norrie Gillies’s son and an electrical engineer with SSE. “When he discovered this, he realized it was a much bigger thing. This isn’t the sort of thing you find in your back garden.”

For decades, Norrie Gillies maintained periodic contact with the museum about the fossil, but the specimen remained in storage. He died in 2011 at the age of 93 without ever seeing the full creature he had discovered.

Keeping the Storr Lochs Monster entombed, however, was a matter of necessity. The fossil was trapped in sedimentary rock that had hardened when lava flows caked and baked the Isle of Skye during the Paleocene, about 66 to 56 million years ago. Exposing it without the right tools or expertise could have proved disastrous.

“He did the right thing [when] he got in touch with the museum; the museum did the right thing [and] kept it safe for decades,” says Brusatte.

View Images Conservator Nigel Larkin preparing the fossil for public display. Photograph courtesy of University of Edinburgh

The stars began to align in early 2015, when Brusatte and his colleagues came across the fossil in the museum’s collections. To the scientist’s surprise, Allan Gillies and his sisters contacted him several days later, after news stories highlighted Brusatte’s study of a different ichthyosaur. The siblings and Brusatte began corresponding, and he soon recruited the noted conservator Nigel Larkin to prepare the fossil for display.

They didn’t have sufficient funding, however, until Allan Gillies reached out to SSE, his and his late father’s employer. The company soon agreed to support the research.

“SSE is delighted to be playing its part in bringing the Storr Lochs Monster to life,” Martin Pibworth, an SSE managing director, says in a statement.

The Best-Ever Fish Story?

Now that the fossil has been fully revealed, paleontologists can see if the ichthyosaur bears resemblances to other known species or represents a first of its kind. The find also adds a key data point to the Middle Jurassic, a time noted for its scant fossil record.

“In the oceans [of the Middle Jurassic], it looks like there was a big turnover between smaller, more primitive reptiles and larger, more derived groups,” says Brusatte.

“It looks like that, though, because we don’t have that many fossils from that time period anywhere in the world. That’s what makes this potentially an internationally important specimen. It’s one of the few good fossils of an ichthyosaur that comes from this ‘dark’ period.”

For Allan Gillies, who was six years old when his father found the ichthyosaur, the fossil carries scientific—and personal—significance.

“Dad’s not around to see it himself, but I know he’d be very, very pleased to know that it’s finally being displayed, and he’d also be very pleased to know that it’s the company he worked for that helped to make it happen,” he says.