A 66 million-year-old complete baby dinosaur fossil called "Baby Yingliang" discovered in China shows "remarkable similarities" to modern birds, scientists said in a study published Tuesday.
The fossil shows a theropod dinosaur apparently just a few days before it would have hatched. It can be seen inside a 6-inch elongated eggshell.
An unprecedented fossil of a baby dinosaur curled up perfectly inside its egg is shedding more light on the links between dinosaurs and birds https://t.co/doKgAZQQym
— CNN (@CNN) December 21, 2021
The fossil is named after the southern Chinese museum where it was found.
Fion Waisum Ma, one of the authors of a study on the fossil published in iScience, said the head shows a striking similarity to newly hatched bird heads.
"Some embryos are quite well preserved, but they don't show this posture," she said. "And some are very fragmentary, so it is difficult to see their posture clearly."
The posture includes "tucking" -- where the head is tucked beneath the right wing. Ma says that posture helps crack the eggshell.
Fossils of dinosaur embryos are very rare. They've been found at only about half a dozen sites.
Our little one has just arrived. Welcome Baby Yingliang, a gorgeous fossil dinosaur embryo preserved inside its egg!
— Steve Brusatte (@SteveBrusatte) December 21, 2021
You're looking here at a baby dinosaur, not too long before it would have hatched. pic.twitter.com/NtXE8XODjT
Baby Yingliang would have been roughly 10 inches when hatched. It might have grown an an adult length of 6 feet.
Modern birds take up a similar posture in their eggs.
Not all dinosaurs hatched in the same way. Plant-eating sauropod dinosaurs hatched from round eggs and were not so bird-like.
This article has been adapted from its original source.