Finds force scientists to rethink the evolution of dinosaur eggs
Eggs from the earliest dinosaurs were more like leathery turtle eggs than rigid bird eggs.Studies of fossilized embryos from two kinds of dinosaurs, one from early in dinosaur history and the other living about 150 million years later.
Further analyses of these and other dinosaur eggs suggest that hard eggshells evolved independently for each of the three main dinosaur lineages: the long-necked sauropods, plant-eating ornithischians and fierce theropods.
Until now, paleontologists thought that all dinosaurs had hard, mineralized eggshells. But scientists couldn’t explain why eggs from the earliest dinosaurs haven’t appeared in the fossil record or why microstructures within eggshells are so different for each of the main dinosaur lineages.
