An unprecedented fossil of a baby dinosaur wrapped neatly in an egg helps to better understand the connection between dinosaurs and birds.
The fossil is 70 million years old and preserves the fetal skeleton of an oviraptorid dinosaur, which was christened baby yinglian because of the name of the Chinese museum that houses the fossil.
Baby dinosaur bones are small and fragile and are rarely preserved as fossils, making this a very fortunate find, said Darla Zelenitsky, an associate professor in the Department of Geosciences at the University of Calgary in Canada.
“It’s a fantastic specimen. […] I have been working with dinosaur eggs for 25 years and I have not seen anything like it yet, ”said Zelenitsky, co-author of the research published in iScience magazine this Tuesday (21).
“Until now, little was known about what happened inside a dinosaur egg before it hatched, as there are few embryonic skeletons, especially those that are complete and preserved in a life position,” the researcher added.
The egg is about 17 centimeters long and the dinosaur was estimated to be 27 centimeters from head to tail. The researchers believe that if it had lived to adulthood, it would have been about two to three feet long.
Researchers from China, the United Kingdom and Canada examined the positions of baby yinglian and from other oviraptoride embryos found previously. They concluded that the dinosaurs moved and changed position before hatching, in the same way as chicks.
In modern birds, these movements are associated with behaviors controlled by the central nervous system and fundamental to the successful hatching of the egg.
“Most known non-avian dinosaur embryos are incomplete, with incoherent skeletons (separated bones in the joints),” said Waisum Ma, lead author of the study and researcher at the University of Birmingham, UK, in a statement.
“We were surprised to see this embryo beautifully preserved inside a dinosaur egg, lying in a bird-like position. This posture had not been recognized in non-bird dinosaurs before,” Ma concluded.
All birds evolved directly from a group of bipedal dinosaurs known as theropods, whose members include the impressive Tyrannosaurus rex and the smaller velociraptors.
Pre-hatching behavior is not the only one that modern birds have inherited from their dinosaur ancestors. The same type of dinosaur is also known to sit on top of its eggs to hatch, just like birds, Zelentisky said.
The fossil was found in the Chinese province of Jiangxi and acquired in 2000 by Liang Liu, director of a Chinese stone company called the Yingliang Group. The find ended up being stored and forgotten until about 10 years later, when the museum team rummaged through the boxes and dug up the fossil during the construction of the Yingliang Stone Natural History Museum, which is backed by the company.
This content was originally created in English.