Dinosaur Embryo Found Perfectly Preserved Inside Fossilized Egg From 66 Million Years Ago

A preserved dinosaur embryo was found inside a fossilized egg in China, according to researchers. The egg was found back in 2000, but it wasn't until this week that researchers went public with their findings in the journal iScience. It was discovered by the mining company Yingliang in southern China, but no one there knew how important it was until 15 years later when fragile bones were exposed by a crack in the egg.

Under the eggshell, scientists could see one of the most complete dinosaur embryos ever discovered, reports National Geographic. "I couldn't believe my eyes because it is so perfectly preserved," study author Darla Zelenitsky, a paleontologist who specializes in dinosaur eggs, said. The embryo, dubbed Baby Yingliang, is of a type of oviraptorosaur, beaked dinosaurs that lived between 130 million to 66 million years ago. The exact age of the egg is uncertain, but it was found among rocks estimated to be about 70 million years old.

"It's remarkable to get a glimpse into the very first stages of life of animals that lived more than 70 million years ago," Lindsay Zanno, head of paleontology at the North Carolina Museum of Natural Sciences and a researcher at NC State University told National Geographic. "The evidence that birds are living theropod dinosaurs is, at this point, overwhelming."

The egg can help researchers bridge the gap between dinosaurs and modern birds. It is longer than an ostrich egg but pill-shaped. Baby Yingliang's head is tucked in, laying on its belly, and knees bent where small forelimbs would grow. The embryo's curved back sits along one side of the egg, closing an area where the air gap may have been. The features of the embryo are very similar to how modern chicken embryos develop.

Many dinosaur eggs have been found around the world, but embryos as well preserved as Baby Yingliang are incredibly rare. "Most known non-avian dinosaur embryos are incomplete with skeletons disarticulated," Waisum Ma of the University of Birmingham, U.K. explained to CBS News. "We were surprised to see this embryo beautifully preserved inside a dinosaur egg, lying in a bird-like posture. This posture had not been recognized in non-avian dinosaurs before."

Research into Baby Yingliang has just started. Scientists also hope to image the dinosaur's internal anatomy, and some of the body parts are still covered in rocks. The mining company also found other eggs where Baby Yingliang was discovered, so scientists hold out hope there could be more embryos discovered.