This is an incredibly rare and almost perfectly preserved dinosaur embryo. Thought to be between 66 and 72 million years old, this little unborn represents a link between dinosaurs and modern birds.
According to the team of paleontologists led by the University of Birmingham (England) , the creature that was not born, belongs to a group of feathered theropods, oviraptors, measures about 27 centimeters long and marks the first discovery of a dinosaur embryo that It presents a typical posture of current bird embryos, curled up curving the body, with the legs placed on both sides and the head under the wing; a behavior that we had never seen in dinosaurs . It is a common position of the embryo of modern birds for a successful hatching (in fact, experts compare the fossil embryo with that of a chicken embryo about 17 days old), as it is believed that this position helps stabilize and direct the head when the chick embryo uses its beak to break the egg shell. The baby was preparing to be born. This discovery suggests that this type of posture is not unique to birds, but might have first evolved among non-avian theropod dinosaurs.
“This dinosaur embryo inside its egg is one of the most beautiful fossils I’ve ever seen,” said paleontologist and study author Steve Brusatte of the University of Edinburgh. “This tiny prenatal dinosaur looks like a baby bird nestled in its egg, further evidence that many characteristic features of today’s birds first evolved in their dinosaur ancestors.”
The link between modern birds and dinosaurs seems now more evident than ever
The embryo has been dubbed ‘Baby Yingliang’ and was found in the rocks of the ‘Hekou Formation’ in the Shahe Industrial Park in Ganzhou city, south China’s Jiangxi province. It is, without a doubt, one of the most complete dinosaur embryos known.
Like all other non-avian dinosaurs, oviraptorosaurs went extinct at the end of the Cretaceous, about 66 million years ago, when an asteroid hit Earth. Birds, which evolved from earlier theropods, somehow survived this dramatic event.
“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 the growth and reproduction of dinosaurs. It is interesting to see this dinosaur embryo and a chicken embryo pose similarly inside the egg, possibly indicating similar behaviors before hatching,” the authors comment.
However, because it is the only specimen of its kind, the study’s authors admit that no firm conclusions about the nature of dinosaur embryos can be drawn from their observations, and that more fossils like this one will need to be studied first. that any type of hypothesis can be confirmed.
Referencia: An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures
Lida Xing 8
Waisum Ma 8, 10
Darla K. Zelenitsky
Tzu-Ruei Yang 9
Stephen L. Brusatte
Open Access Published: December 21, 2021 DOI:https://doi.org/10.1016/j.isci.2021.103516