Paleontologists, reporting in the journal Nature Communications, have identified a new species of bone-headed, plant-eating dinosaur that lived about 85 million years ago in what is now Alberta, Canada.
Reconstruction of Acrotholus audeti (Julius Csotonyi)
The newly discovered dinosaur, named Acrotholus audeti, was 6 feet long and weighed about 40 kg.
Acrotholus means ‘high dome,’ referring to its dome-shaped skull, which is composed of solid bone over 2 inches (10 cm) thick. The species name ‘audeti’ honors Alberta rancher Roy Audet, on whose land the best specimen was discovered in 2008.
According to the scientists, Acrotholus represents the oldest bone-headed dinosaur in North America, and possibly the world.
The dinosaur walked on two legs and had a greatly thickened, domed skull above its eyes, which was used for display to other members of its species, and may have also been used in head-butting contests.
“Acrotholus provides a wealth of new information on the evolution of bone-headed dinosaurs. Although it is one of the earliest known members this group, its thickened skull dome is surprisingly well-developed for its geological age. More importantly, the unique fossil record of these animals suggests that we are only beginning to understand the diversity of small-bodied plant-eating dinosaurs,” explained lead author Dr David Evans of the Royal Ontario Museum and University of Toronto.
Small mammals and reptiles can be very diverse and abundant in modern ecosystems, but small dinosaurs (less than 100 kg) are considerably less common than large ones in the fossil record. Whether this pattern is a true reflection of dinosaur communities, or is related to the greater potential for small bones to be destroyed by carnivores and natural decay, has been debated.
The massively constructed skull domes of bone-headed dinosaurs (pachycephalosaurs) are resistant to destruction, and are much more common than their relatively delicate skeletons – which resemble those of other small plant-eating dinosaurs. Therefore, the researchers suggest that the pachycephalosaur fossil record can provide valuable insights into the diversity of small, plant-eating dinosaurs as a whole.
“We can predict that many new small dinosaur species like Acrotholus are waiting to be discovered by researchers willing to sort through the many small bones that they pick up in the field. This fully domed and mature individual suggests that there is an undiscovered, hidden diversity of small-bodied dinosaurs. So when we look back, we need to reimagine the paleoenvironment.
There is an evolutionary history that we just don’t know because the fossil record is incomplete. This discovery also highlights the importance of landowners, like Roy Audet, who grant access to their land and allow scientifically important finds to be made,” said co-author Dr Michael Ryan of the Cleveland Museum of Natural History.
Source: sci.news
