The fossil, about 70 million years old, shows the same posture as birds before hatching.
Researchers in southern China have discovered a 70-million-year-old dinosaur embryo exquisitely well preserved inside its egg. The finding is a rarity in itself since it is not easy to find these practically intact specimens, but the fact is that the embryo is also folded on itself in a position that until now was considered exclusive to birds.
The dinosaur embryo, nicknamed ‘Baby Yingliang’, comes from the Late Cretaceous rocks of Ganzhou, Jiangxi province. It is an oviraptorosaur, a toothless theropod, a feathered animal, closely related to modern birds, known in what is now Asia and North America. They probably adopted a wide range of diets.
The fossil had been purchased in 2000 by the director of a business group, who suspected it might contain egg fossils. But it eventually ended up in storage, largely forgotten until about ten years later, when experts from the Yingliang Stone Natural History Museum sorted through the boxes and unearthed the fossils. When analyzing them, the embryo hidden inside appeared.
Folded to be born
Scientists noticed that Baby Yingliang maintained a unique posture among known dinosaur embryos: its head is below its body, with its feet on either side, and its back bent along the blunt end of the egg. It is very similar to the postures that modern birds adopt before birth, bending the body and placing the head low. This behavior is controlled by the central nervous system and embryos that do not display it have a higher chance of dying due to failed hatching.
After studying the egg and embryo, the researchers believe the ‘folding’ thought to be unique to birds may have originated among non-avian theropods many tens to hundreds of millions of years ago.
The embryo is about 27 cm long from head to tail. It lies inside an egg 17 cm long. “Dinosaur embryos are some of the rarest fossils and most of them are incomplete with dislocated bones. We are very excited about the discovery of Baby Yingliang – it is preserved in excellent condition and helps us answer many questions about dinosaur growth and reproduction,” said Fion Waisum Ma of the University of Birmingham and the first author of the study. , published in ‘science’.
“This dinosaur embryo inside its egg is one of the most beautiful fossils I have ever seen. This tiny prenatal dinosaur looks like a baby bird nestled in its egg, which is further evidence that many characteristic features of today’s birds first evolved in their dinosaur ancestors,” says Steve Brusatte, Professor at the University of Edinburgh.
Researchers will continue to study this rare specimen in even greater depth, using various imaging techniques to reveal its internal anatomies, such as the skull bones and other body parts that are still covered in rock.
