July 1, 2022

At least 66 million-year-old dinosaur embryo discovered

The excitement among scientists is at its height. A beautifully preserved dinosaur embryo, dating to at least 66 million years ago, has been discovered in Ganzhou, China. This oviraptorosaur fossil, named “Baby Yingliang” by researchers, was preparing to emerge from its egg, they explained when the discovery was announced on Tuesday, December 21.

“It is one of the best dinosaur embryos ever found”, said Agion France-Presse (AFP), Fion Waisum Ma, of the University of Birmingham and co-author of the study, published in iScience. « One of the most beautiful fossils I have ever seen ”, confirms Professor Steve Brusatte of the University of Edinburgh and member of the research team.

The specimen “Looks exactly like a baby bird coiled in its egg”, he specifies. 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 observed 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.

Preserved thanks to a slippage of mud

This discovery “Provides further evidence that many characteristics of birds today derive from their dinosaur ancestors”, explains Mr. Brusatte. An alternative could have resembled what crocodiles do, who adopt a seated posture, with their heads only tilted on their stomachs.

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.

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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 undated illustration, provided by the University of Birmingham, simulates a near-hatching oviraptorosaur dinosaur embryo, based on the “Baby Yingliang” specimen found in China.

This specimen was one of a group of several egg fossils, left out and forgotten for years. Researchers suspected that they might contain dinosaurs and scratched part of the shell to find Baby Yingliang. The researchers hope to be able to study the embryo with more precision using imaging techniques, in order to reveal its entire skeleton.

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The World with AFP