In 2015, palaeontologists found hundreds of sauropod tracks on the Isle of Skye, making the rocky island Scotland’s most significant dinosaur site. Now, as Nicola Davis reports for the Guardian, researchers have unearthed around 50 more footprints at a nearby site, which, unlike the previous location, includes the tracks of carnivorous dinosaurs.
The large footprints, described in a paper in the Scottish Journal of Geology, were discovered near a scenic headland known as Brothers’ Point. They date to the Middle Jurassic period, around 170 million years ago, when Skye was part of a subtropical island near the equator. Today, Skye is known for its windswept, mountainous landscape, but during the Middle Jurassic, the region was dotted with beaches, lagoons and rivers. Stephen Brusatte, a paleontologist at the University of Edinburgh and co-author of the new paper, tells Davis that the prints were made by “dinosaurs walking in very shallow water.”
According to Michael Greshko of National Geographic, two researchers—Davide Foffa and Hong-Yu Yi—found the footprints in 2016, and Brusatte and his student Paige dePolo returned to the site the following year to further study the tracks. They used drones and cameras to map the site, explains a University of Edinburgh statement, and were able to make out many clear isolated footprints and two trackways.
Some of the prints were quite large (“as big as a car tire,” Davis writes), and appeared to have been made by a towering dinosaur walking on all fours. “[T]he dinosaur that fits the bill is a sauropod—one of these long-necked, pot bellied, brontosaurus-type dinosaurs,” Brusatte tells Davis. But other prints appeared to have been made by three-toed dinosaurs walking on their hind legs. Researchers believe that these tracks were left by theropods, a diverse group of bipedal dinosaurs that includes the Tyrannosaurus rex. The theropods roaming around on what is now Skye may have been a very early cousin of the T. rex, which lived during Cretaceous period.
In an interview with National Geographic’s Greshko, Brusatte explains that the Middle Jurassic was an important period in dinosaurs’ evolutionary history—a time when “the first birds took to the sky, the first tyrannosaurs were evolving, [and] the first really colossal sauropods were getting their start.” But fossils from the Middle Jurassic are rarely found, making Skye an important paleontological site.
The new discovery does add nuance to our understanding of how sauropods reptiles moved about. Paleontologists once believed that the gargantuan reptiles would have been unable to support their weight on land and were therefore amphibious. More recent research revealed that the animals did in fact lumber about on land—but the footprints on Skye indicate that at least some sauropods spent their time plodding through coastal waters.
“It wasn't that the water was the only place they could live and just had to languish,” Brusatte tells Greshko. “Instead, we're now saying that they were so dynamic and so energetic—that they were so successful—that they were probably exploring whatever environments they could.”