The South American discovery of embryonic dinosaur fossils that may be 90 million years older than any found previously could help scientists learn more about how animals moved from the sea to land, according to
USA Today.
Uruguayan paleontologist Graciela Piñeiro, who led the team, described the fossilized mesosaurs — crododile-like aquatic reptiles that lived 280 million years ago — as “an amazing discovery.”
The finds include mesosaur embryos, pointing to the possibility that the creatures laid their eggs on marshland or could even have given birth to live young according to the latest issue of the Historical Biology journal. That could be a significant piece in the evolutionary puzzle.
“We have to go back to the conquest of land by four-legged animals to explain why this is so very important,” said Martin Sander, a paleontologist at the University of Bonn in Germany. “A formal step in this transition was when eggs evolved to be deposited on dry land.”
Piñeiro initially dismissed one of the finds as just a piece of fossilized dung, USA Today reported. But closer study of what was pulled from a pile of debris in an abandoned quarry revealed that it was a 6-inch mesosaur embryo apparently still coiled in an egg. “I received a big shock,” Piñeiro said.
She and her colleagues plan to return to the same site to look for other fossils that could bolster their belief that the reptiles retained their eggs internally and gave birth to live young.
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