A newly discovered dinosaur species that roamed the Earth about 200 million years ago may help explain how the creatures evolved into the largest animals on land, scientists in South Africa said Wednesday. The Aardonyx celestae was a 23-foot- (7-meter-) long small-headed herbivore with a huge barrel of a chest. It walked on its hind legs but also could drop to all fours, and scientists told reporters that could prove to be a missing evolutionary link. This is a species “that no one has seen before and one that has a very significant position in the family tree of dinosaurs,” said Australian paleontologist Adam Yates. He led the research with a number of other local and international scientists. The Aardonyx celestae species dates back to the early Jurassic period. Yates said the creature found in South Africa stood nearly 6 feet (about 1.7 meters) high at the hip and weighed about 1,100 pounds (500 kilograms). It was about 10 years old when it died, and its death may have been caused by drought. The newly discovered species shares many characteristics with the plant-eating herbivores that walked on two legs, Yates said. But the new species also has similar attributes to dinosaurs known as sauropods, or brontosaurs, that grew to massive sizes and went about on all fours with long necks and whip-like tails. Why and how dinosaurs grew into such massive creatures is a question that scientists have been trying to answer for a long time. The discovery of the new species was made by postgraduate student Marc Blackbeard, who was excavating two sites in central South Africa about five years ago. The discovery was made on the first day.
