They find a dinosaur egg in perfect condition: its posture reveals the connection with modern birds

A team of investigatorss has managed to describe an embryo between 72 and 66 million years old “exquisitely preserved” inside a fossilized dinosaur egg, which sheds new light on the relationship between the behavior of modern birds and these extinct animals.

The embryo, nicknamed “Bebé Yingliang”, was discovered in Ganzhou, in the on from China, and I belongedand a toothless theropod dinosaur or ovirraptorosaur; the fossil suggests that these dinosaurs developed postures similar to those of birds near hatching.

Scientists discovered that the posture of Baby Yingliang, one of the most complete dinosaur embryos ever found, is unique: your head is below the body, with your feet on either side and your back curled up along the blunt end of the egg.

This posture, hitherto unknown in dinosaurs, is similar to that of modern bird embryos, says a statement from the University of Birmingham (UK).

Until now, this posture was exclusive to birds.

In birds these postures are related to behavior controlled by the central nervous system and fundamental for the success of the hatching.

After studying the egg and the embryo, the researchers believe that this behavior prior to hatching, which until now it was considered exclusive to birds, may have originated between non-avian theropods.

Led by experts from the University of Birmingham and the Chinese University of Geosciences (Beijing), the team, also made up of scientists from Canada, publishes the details in the journal iScience.

A forgotten fossil in a box

The embryo is articulated without major alterations due to fossilization: with an estimated length of 27 centimeters from head to tail, the creature is inside a 17 centimeter egg.

According to the magazine, the specimen was acquired in 2000 by Liang Liu, a director of a company called Yingliang Group, who suspected it might contain egg fossils.

But it ended up in storage largely forgotten until about ten years later, when, during the construction of the Yingliang Stone Natural History Museum, the staff sorted the boxes and unearthed the fossils; now is where you are.

The relationship between a dinosaur and a chicken

“We are very excited about the discovery of Baby Yingliang as it has been preserved in a great state and helps us answer many questions about the growth and reproduction of dinosaurs“, emphasizes Fion Waisum Ma.

“It is interesting to see that this dinosaur embryo and a chicken embryo pose similarly inside the egg, possibly indicates similar behaviors before hatching“.

Baby Yingliang was identified as a ovirraptorosaur based on its deep, toothless skull; These are a group of feathered theropod dinosaurs, closely related to modern birds, known from the Cretaceous of Asia and North America.

An evolution of theropod dinosaurs

Birds are known to develop a series of tuck-in poses, in which the body is bent and the head is tucked under the brim shortly before hatching. Embryos that do not reach these positions are more likely to die because they were not born.

Comparing Baby Yingliang to someone else’s embryoss theropods, long-necked sauropod dinosaurs and birds, the team proposed that the retreat behavior, which was considered unique to birds, first evolved in theropod dinosaurs many tens or hundreds of millions of years ago.

Additional discoveries of embryo fossils would be very valuable to further test this hypothesis, summarize the researchers.