It is an extremely rare discovery that will allow us to better understand birds. Scientists said on Tuesday they had discovered a beautifully preserved dinosaur embryo, dating to at least 66 million years ago and preparing to emerge from its egg.
This oviraptorosaur fossil, found in Ganzhou, China, was named by researchers « Baby Yingliang ». « This is one of the best dinosaur embryos ever to be found, » said Fion Waisum Ma, of the University of Birmingham and co-author of the study, published in iScience.
An almost vital position for the chicks
« Baby Yingliang » was found with her back bent, her feet on either side of her head, with it tucked into her stomach. A position that had never before been seen in dinosaurs, but which is well known in birds. When the chicks prepare to hatch, they stabilize their heads under a wing, while piercing their shells with their beaks. Embryos that fail to position themselves have a greater chance of dying from a failed hatch.
According to Fion Waisum Ma, this position « indicates that such behavior in modern birds has its origin in their dinosaur ancestors. » An alternative could have resembled what crocodiles do, which adopt a seated posture, with their heads only tilted on their stomachs.
A fossil from the Late Cretaceous
Oviraptorosaurs, whose name means “egg-stealing lizard,” were feathered dinosaurs that lived in Asia and North America during the Late Cretaceous Period. They could have different beak shapes and diets, and ranged in size from monkeys to huge gigantoraptors, measuring eight meters in length.
“Baby Yingliang” measures 27 centimeters from head to tail and rests in a 17 centimeter long egg at the Yingliang Stone Nature History Museum. It is between 72 and 66 million years old, scientists say, and was probably so well preserved thanks to a mud slide that buried it and protected it from scavengers. It would have grown to two or three meters long if it had reached adulthood, and would have fed on plants.
This specimen was one of a group of several egg fossils, left out and forgotten for years. The researchers suspected that they might contain dinosaurs and scratched part of the shell to find « Baby Yingliang ».