The Isle of Skye, which sits off the northwest coast of Scotland, is today known for its windswept mountain ranges, rugged sea cliffs and crumbling castles. But millions of years ago, the landscape was very different—part of a subtropical island filled with beaches, shallow lagoons and dinosaurs. The richness of Skye’s prehistoric past came to light with the recent discovery of two fossil sites that preserve some 50 dinosaur footprints, among them a type of track that has never before been documented on the island.
According to the Guardian’s Nicola Davis, the prints were found at the cliffs of Rubha nam Brathairean, or Brothers’ Point. One of the track sites had been explored before, but its paleontological treasures remained hidden until storms shifted some boulders, revealing footprints among sedimentary rocks that are about 170 million years old. During the Middle Jurassic period, which spanned from 161 to 176 million years ago, this site consisted of mudflats bordering a lagoon, where an array of dinosaurs ambled about, leaving tracks that were preserved across the ages.
Among the footprints, a team of researchers reveal in the journal PLOS One, were three-toed tracks belonging to various sizes of carnivorous theropods, a bipedal dino subgroup. Other tracks have been tentatively connected to large-bodied, herbivorous ornithopods, a group that includes the hadrosauridae (or duck-billed dinosaurs).
But perhaps the most exciting among the prints were Deltapodus tracks—a general descriptor for delta-shaped tracks likely left by plated or armored dinosaurs. (As Gizmodo’s George Dvorsky points out, paleontologists are sometimes wary of ascribing prints to specific species, opting instead for broad morphotypes.) In this case, researchers believe that the prints belonged to a stegosaur, a subgroup of plate-backed, beaked dinosaurs that included the iconic Stegosaurus. These Deltapodus prints are the oldest ever found, and provide the first strong evidence that stegosaurian dinosaurs were part of the Middle Jurassic landscape on Skye.
The discovery of a dinosaur “stomping ground” on the island enhances experts’ understanding of prehistoric life in Scotland, where dinosaur fossils are “so rare,” Stephen Brusatte, paleontologist at the University of Edinburgh and co-author of the new study, tells Nina Pullano of Inverse. The prints thus help researchers “get a better sense of the variety of dinosaurs that lived near the coast of Skye during the Middle Jurassic,” explains Paige dePolo, a PhD student at the University of Edinburgh and lead author of the report.
The find has broader implications, too. Around the world, according to the study authors, body fossil remains from the Middle Jurassic are sparse, which is unfortunate, because this was an important period of evolutionary diversification for many dinosaur groups. Footprints, as the track sites show, can offer a compelling glimpse into the prehistoric past when other types of remains do not survive. Skye has proven itself to be a particularly fruitful location in that regard; previously, the same research team documented prints left by both carnivorous theropods and towering sauropods were found there.
“We knew there were giant long-necked sauropods and jeep-sized carnivores, but we can now add plate-backed stegosaurs to that roster, and maybe even primitive cousins of the duck-billed dinosaurs too,” Brusatte says. “These discoveries are making Skye one of the best places in the world for understanding dinosaur evolution in the Middle Jurassic."