Xing Xu and Mark A. Norell of the American Museum of Natural History recovered the new fossil from China's famed Yixian Formation in Liaoning Province. Dubbed Mei long, which means soundly sleeping dragon, the specimen represents a two-legged troodontid that measures less than two feet long and is a relative of Tyrannosaurus rex. We're excited to have discovered this rare evidence of behavior, in this case sleeping or resting in an early fossilized dinosaur with birdlike features, Xu remarks. To be preserved in such a pose the creature must have been buried alive. The researchers describe the find in a report published today in the journal Nature.
The discovery strengthens the ties between dinosaurs and modern birds. This specific heat-conserving pose that Mei long was found in provides support for the hypothesis that at least some nonavian dinosaurs, including this animal and its troodontid relatives, were warm-blooded as are today's birds, Norell explains.