Photo: Mark Wilkinson/University of Edinburgh
Stephen Brusatte from the University of Edinburgh and his colleagues have discovered hundreds of giant dinosaur footprints in a coastal lagoon on the Isle of Skye. The researchers noticed the tracks at low tide one day in April on a slab of rock reaching out to sea on the north eastern tip of the island, where the remains of Duntulm castle stand in the distance. As the sun went down on the edge of the island, and the tide started to come in, the researchers saw pits in a huge slab of rock about 30 metres long that is submerged at high tide and covered with seaweed at some times of year.
The tracks, which number in the hundreds, date from the Middle Jurassic, 170 million years ago, and were left by many beasts over thousands of years. The prints are in several layers of rocks that formed from sediments at the bottom of a brackish lagoon, when the sea was farther away and more cut off from the land than it is today. The size of the prints – up to 70 centimetres across – and their structure suggest that they were left by early sauropods, distant relatives of Brontosaurus and Diplodocus. “They had a bigger footprint than T. rex,” says Brusatte. The largest creatures to ever have lived on land, these massive plant-eaters weighed around 20 tonnes, were up to 15 metres long and several storeys high.
This is the largest discovery of dinosaur footprints in Scotland, and it is also important globally because hardly any fossils from the that time in the middle of the Jurassic have been found anywhere else. The finding helps to piece together how and where these animals lived. “These dinosaurs weren’t swimmers but they would have been moving around knee-deep in this brackish lagoon. Maybe the plants there were a good food source or maybe they got some protection from other dinosaurs there,” says Brusatte.