The 70-million-year-old fossil preserves the embryonic skeleton of an overhauled dinosaur, nicknamed Baby Yingliang by the Chinese Museum that holds the fossil. Baby dinosaur bones are so small and fragile that they are rarely preserved as fossils, making it a very fortunate discovery, said Darla Zhelenitsky, an associate professor in the Department of Geography at the University of Calgary in Canada.
“This is an amazing model … I have been working on dinosaur eggs for 25 years and have not seen anything like it yet,” said Zelenitsky, co-author of the research published in iScience magazine on Tuesday.
“So far, not much is known about what happens before a dinosaur’s egg hatches, because there are so few embryonic skeletons, especially those that are complete and preserved in a living pose,” he said in an email.
The egg is approximately 17 centimeters (7 inches) long and is estimated to be 27 centimeters (11 inches) long from dinosaur head to tail. If it had been an adult, the researchers believe it would have been two to three meters long.
Researchers from China, the United Kingdom and Canada studied the conditions of Baby Yingliang and other previously discovered eggs. They decided that the dinosaurs would move and change poses before hatching and look like little birds.
In modern birds, such movements are associated with a behavior called ducking, which is controlled by the central nervous system and is critical to the success of hatching.
“Most known non-bird dinosaur embryos are incomplete with decomposed skeletons (Bones are separated in the joints), “said Wise Ma, the lead author of the study and a researcher at the University of Birmingham in the UK.
“We were amazed to see this embryo so beautifully preserved inside a dinosaur egg, lying in a bird-like position. This pose has not been previously recognized in non-bird dinosaurs.”
All birds are descended directly from a group of two-legged dinosaurs called theropods, whose members include the tall dinosaur Rex and small velociraptors.
Pre-hatching behavior is not the only behavior modern birds have inherited from their dinosaur ancestors. The same type of dinosaurs are known to sit on top of their eggs to incubate like birds, Zhelenitsky said.
The fossil was discovered in Jiangxi Province, China, and was obtained in 2000 by Liang Liu, director of the Chinese stone company Yingliang Group. About 10 years after the construction of the Yingliang Stone Nature History Museum, when museum staff lined up the boxes and discovered the fossil, it was completed in storage. This museum is funded by the company.