Nature & Environment

Oldest Fossilized Dinosaur Embryos Ever Discovered Unearthed in China

Catherine Griffin
First Posted: Apr 10, 2013 02:16 PM EDT

Paleontologists in China have unearthed some of the oldest fossilized dinosaur embryos every discovered. The treasure trove of baby dinosaur remains contains individuals at different developmental stages, and could provide insight into how dinosaurs may have grown during these early stages.

Researchers first discovered the embryos in a bone bed in Lufeng County. The remains, which include eggshells and more than 200 disarticulated bones, come from the Early Jurassic period, which occurred 197 to 190 million years ago. This would make the fossils the oldest detailed record of dinosaur embryology to date.

The dinosaurs that the team discovered were most likely sauropodomorphs, since they're very similar to intact embryonic skeletons of  sauropodomorphs that were unearthed in South Africa in 2005. These giant, herbivorous dinosaurs possessed long necks that allowed them to gain access to high tree foliage. They had weak teeth and most likely possessed stomach stones that aided in the grinding of tough plant fibers.

The age of the remains isn't the only thing that's exciting researchers, though. Spectroscopic analysis of the bone-tissue samples from the site have also revealed some of the oldest organic material ever seen. This in particular was surprising because the fossilized femur bones that were analyzed were both delicate and porous, which means that they were especially vulnerable to the corrosive effects of weathering over the years.

"That suggests to us that other dinosaur fossils might have organic remains," said David Evans, one of the researchers, in an interview with Nature. "We just haven't looked at them in the right ways."

The bones that the researchers examined revealed that the dinosaurs experienced very rapid growth, doubling in length within the eggs. This in turn showed that the dinosaur had a very short incubation period. The scientists also found that the bones were reshaped while they were in the shell, which means that the dinosaurs moved around inside their eggs like modern birds.

In fact, the scientists believe that this rapid growth probably continued after the dinosaur hatched, aiding their ability to survive. It's also possible that this adaptation could explain why dinosaurs in this group grew to be so large. 

The details of the findings are published in the journal Nature.

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