A dinosaur egg (illustration photo) - MARY EVANS / SIPA
Scientists have managed, thanks to X-rays, to unravel the mystery of the interior of dinosaur eggs 200 million years old. They revealed tiny skulls of embryos, similar in development to modern reptiles, according to a study published this Thursday in Scientific Reports .
These embryos of "Massospondylus carinatus", a herbivore 5 meters long, are among the oldest in the world. These had been discovered in 1976 in the Golden Gate Highlands National Park in South Africa, and because of their fragility and their very small size, they remained difficult to study for a long time, due to the lack of a non-scientific method. destructive.
Similarities to modern reptiles
In 2015, an international scientific team brought seven eggs (only three of which contained embryos) to the European synchrotron in Grenoble (ESRF) to scan them, the study explains. The powerful X-rays produced by the ESRF, via electrons accelerated at the speed of light in a ring more than 800 meters long, revealed an unprecedented level of detail, showing up to the bone cells.
These data notably made it possible to reconstruct a 3D model of the baby dinosaur skull, only about two centimeters long. Scientists compared their results to embryos of the modern closest relatives of dinosaurs (crocodiles, turtles, lizards), and found similarities in the stages of development.
The unchanged embryonic pattern
"What surprised me most was how younger the embryos were than we thought," said Kimberley Chapelle, lead author of the study. She explained that they were only 60% of their embryonic development.
They also had two types of teeth preserved in their jaws, the first of which "would have fallen out before hatching, just like geckos and crocodiles today". The study concludes that these dinosaurs "developed in their eggs in a similar way to their reptilian parents, whose embryonic development pattern has not changed in 200 million years".
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- South Africa