The Lujiatun Beds are the oldest layers of the famous Yixian Formation, which for more than 20 years has produced several hundred beautifully preserved skeletons of feathered dinosaurs in the Liaoning Province in north-eastern China. They date back to 125 million years ago.

Unlike the fossils found in the more recent parts of the Yixian Formation, two newly described dinosaur skeletons found in the Lujiatun Beds have not retained any traces of feathers; however, the two almost complete and articulated skeletons have been recovered posed in a way that truly looks like they are just sleeping. This is reflected in the name given to the species – Changmiania liaoningensis – meaning “The Eternal Sleeper from Liaoning” in Chinese.

The fossils were acquired by the Liaoning Paleontological Museum in Shenyang from local farmers. The fossils had already been somewhat prepared, causing at first concerns of a forgery. However, after being fully prepared by the staff at the museum and using x-ray analysis, experts were able to determine that the fossils, apart from a few restorations due to pieces being damaged during the original preparation, were indeed authentic.

Changmiania liaoningensis is the most basal ornithopod found to date. This group includes famous taxa as Iguanodon, the first herbivorous dinosaur ever found in 1822, and the duck-billed Hadrosaurus, the first American dinosaur. Unlike its relatives, Changmiania was a small animal, about 1.2 meters (less than 4 feet) long.

Based on the exceptional preservation in three dimensions, without their bones having been moved after the animals’ death, the researchers suggest that the two unearthed individuals were rapidly entombed while they were still alive, maybe killed inside their burrows by a volcanic eruption.