Researchers have discovered a new species of small plant-eating dinosaur on the Isle of Wight in southern England. The species, named Vectidromeusinsularis, is the second heterodontosaurid dinosaur discovered on the island. This suggests that Europe also had its own family of small plant-eating dinosaurs, distinct from those in Asia and North America.
Heterodontosauridae were a group of flexible, bipedal, herbivorous dinosaurs that lived about 125 million years ago. These animals lived alongside early Tyrannosaurus and Spinosaurus. The new fossil represents an animal about the size of a chicken, but it was still a juvenile and could have grown larger.
Vectidromeus is a close relative of Hypsilophodonfoxii, a dinosaur first described in the Victorian era and one of the first to be described based on relatively complete remains. The famous scientist Thomas Henry Huxley once used the dactylosaurus as evidence of the relationship between birds and dinosaurs.
Hypsilophodon is also found on the Isle of Wight, but it was found in taller rocks and is probably two to three million years younger than Vectidromeus. Vectidromeus differs in the details of its hip bones, suggesting it is a closely related but distinct species.
Dr Nicholas Longridge from the Milner Center for Evolution at the University of Bath led the research. He said: "Paleontologists have been working on the Isle of Wight for more than a century and these fossils have played an important role in the history of vertebrate paleontology, but we are still discovering new discoveries about the dinosaur fauna as the sea erodes new fossils from the cliffs."
The Cretaceous strata on the Isle of Wight are hundreds of meters thick and may have spanned millions of years - scientific consensus is still not entirely clear on how old they are - so the fossils may be samples of a series of evolving ecosystems, each with different species.
The discovery was made by the University of Bath in collaboration with the University of Portsmouth, the Isle of Wight Dinosaur Museum in Sandtown and local fossil collectors.
"Collaboration with amateurs is very important," Longrich said. "It's good to have a diverse team; everyone brings something different to the table. These are people who have spent their lives collecting and preparing these fossils, and they know details about the rocks, geology and bones that others don't. Everyone can see a different piece of the puzzle."
Professor Dave Martial, of the University of Portsmouth and co-author of the study, said: "It's absolutely bizarre that so many new dinosaurs have been discovered on the Isle of Wight. Vectidromeus is the seventh new dinosaur discovered in the last four years. It's all thanks to amateur collectors."
Over the years, dozens of species of small herbivorous dinosaurs were classified as Heterodontosaurus, but revisions to the dinosaur family tree led to them being reclassified to other branches of the family tree, leaving Heterodontosaurus as the only remaining species in the family tree.
Dr Longrich said: "We have a strange situation where the first dinosaur families to be identified only had one species. Now, we have two species. Intriguingly, they are not particularly closely related to any species found in North America, Asia or the southern hemisphere.
"We're still piecing together how all of these dinosaurs were related and how they moved between continents. After the breakup of Pangea, there was a lot of isolation that led to different species of dinosaurs evolving on each continent."
Co-author Dr Martin Munt, Director of the Dinosaur Island Museum, said: "This exciting new discovery is the latest in a series of new discoveries on the Isle of Wight. We are enjoying a wonderful time of collaboration between collectors, researchers and the museum. There are new finds on the coast, in private collections and in the museum shop. The museum's mission is to work hard to ensure that as many new finds as possible stay on the Isle of Wight for the benefit of the island community; we expect this dinosaur to be on display at the museum during the October school holidays."