New Scientist reports on the best-preserved dinosaur embryo ever discovered, inside a 70 million-year-old egg that had been stored in Yingliang Stone Natural History Museum in Nan’an, China, for more than a decade – until 2015, when someone noticed what looked like tiny bones stuwhen someone noticed what looked like tiny bones sticking out of the broken shell:
The unhatched dinosaur’s 24-centimetre-long skeleton is curled inside the egg, with its head tucked tightly into its body. The egg is 17 centimetres long and 8 centimetres wide.
Features of the skeleton suggest it is an oviraptorid – a two-legged dinosaur that had a bird-like head and feathers.
The egg appears to be 72 to 66 million years old. It was probably buried rapidly in sand or mud to allow its remarkable preservation, says [the University of Birmingham’s Waisum] Ma. “It is very rare to find dinosaur embryos, especially ones that are intact,” she says.
The embryos of modern birds also adopt a tucked posture to protect themselves for hatching. This suggests the posture first evolved in dinosaurs, not in modern birds as was previously thought, says Ma.
You can see photos of what the embryo looks like now and what it probably looked like back when at the link, and you can read more about Ma’s findings here, at iScience.