Curled Up (IMAGE) Columbia Climate School Caption Two perfectly articulated skeletons of the sheep-size dinosaur Psittacosaurus, found in China's Yixian Formation. New research suggests they died in burrow collapses, not via volcanism, as previously thought. Credit Jun Liu, Institute of Paleontology and Paleoanthropology, Chinese Academy of Sciences Usage Restrictions Credit must be given. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.