Scotland's Isle of Sky hosted rich dinosaur diversity during middle Jurassic

Dinosaur remains from the Middle Jurassic Period are rare, but the new Scottish fossils sites -- described this week in the journal PLOS One -- suggests many dinosaur groups were rapidly diversifying during this period.

The 50 dinosaur tracks found at the two sites included footprints made by Deltapodus, the first to be found on the Isle of Skye. Researchers also found tracks they estimate were made by a stegosaurian, a plate-backed dinosaur.

Several three-toed footprints suggest early carnivorous theropods walked across the ancient mudflats. Some of the prints appear to have been made by large-bodied herbivorous ornithopod dinosaurs -- the oldest of their kind.

"These new tracksites help us get a better sense of the variety of dinosaurs that lived near the coast of Skye during the Middle Jurassic than what we can glean from the island's body fossil record," lead study author Paige dePolo, scientist at the University of Edinburgh in Scotland, said in a news release. "In particular, Deltapodus tracks give good evidence that stegosaurs lived on Skye at this time."

Analysis of ancient dinosaur footprints can help paleontologists provide context for body fossils. Scientists hope their discoveries will inspire other paleontologist to revisit known fossil sites, as the latest footprint collections were found near popular fossil-hunting destinations.

"These new tracksites give us a much clearer picture of the dinosaurs that lived in Scotland 170 million years ago," said study co-author Stephen Brusatte, researcher at Edinburgh. "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. These discoveries are making Skye one of the best places in the world for understanding dinosaur evolution in the Middle Jurassic."