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With the help of electrons traveling close to the speed of light, scientists have reconstructed the skulls of some of the world's oldest known dinosaur embryos.
An international team of researchers took a cluster of fossilized dinosaur eggs to the stadium-sized particle accelerator at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Here, an 844-meter-long (2,769-foot-long) ring of electrons was accelerated close to the speed of light, making them emit high-powered X-ray beams to scan the fossils at an unrivaled level of microscopic detail, a technique known as synchrotron X-ray imaging. The specificity of the scans were so fine, it's said to be at the resolution of an individual bone cell.
"A synchrotron has several advantages over a laboratory CT scanner," Kimberley Chapelle, PhD, study author and vertebrate paleontologist at the University of the Witwatersrand in South Africa, told IFLScience.
"For example, a synchrotron source is one hundred billion times brighter than a hospital X-ray source. Secondly, properties of the synchrotron radiation also make it thousands of times more sensitive to density contrast, meaning that it makes it much easier to differentiate bones from the encasing rock matrix."
The results of the scans, published in the journal Scientific Reports today, were then used to craft 3D reconstructions of the skulls, providing unprecedented insight into the early life of dinosaurs.
The fossilized eggs in question were first discovered in 1976 in Golden Gate Highlands National Park, South Africa. The cluster of six eggs contains the fossilized remains of embryos belonging to a species known as Massospondylus carinatus, a bipedal herbivore from the Early Jurassic Period some 200 million years ago. Although this species could grow up to 5 meters long (16 feet long), the embryos are minuscule with skulls less than 2 centimeters long and teeth shorter than a millimeter.
The dinosaur embryos appear to have been fossilized around 60 percent of the way through their incubation period. By closely studying the scans, the researchers found that the dinosaur embryos seem to develop in the egg much like their living relatives, such as crocodiles, turtles, lizards, and – of course – the humble chicken. A significant similarity can be seen in the dinosaurs’ “baby teeth" that would have been lost before hatching, just like modern geckos and crocodiles. They also contain evidence of a second set of teeth, which appears to be structurally similar to the teeth found in freshly hatched reptiles.
"It's incredible that in more than 250 million years of reptile evolution, the way the skull develops in the egg remains more or less the same. Goes to show – you don't mess with a good thing!" concluded Jonah Choiniere, study co-author and professor at the University of Witwatersrand.
