Ever since preschool, we've all been taught that one of the main things that set reptiles apart from mammals is the fact that they lay eggs, and we give birth to live young. But it looks like things aren't always so cut-and-dry, at least according to the ancient Dinocephalosaurus reptile.
The Dinocephalosaurus roamed the oceans and stretched to at least 13 feet long. It's related to dinosaurs and is a great-great-great-grandparent of today's crocodiles and various bird species. Of the Dinocephalosaurus's 13 feet length, at least half of that was all neck. And although this extraordinarily long neck isn't a problem underwater, it would make walking on land nearly impossible. So if this ancient reptile couldn't go on land and couldn't lay eggs underwater (reptile eggs can only live on land), how did the Dinocephalosaurus reproduce?
A 240-million-year-old fossil of this unique reptile might finally provide scientists with an answer to this head-scratcher. The fossil was found in Southwest China eight years ago, and a Dinocephalosaurus embryo was recently discovered in the fossil. There was no eggshell surrounding the embryo, suggesting that it was being carried to full term in its mother's belly.
Since the fossil's soft tissue is long gone, scientists don't know for sure if the embryo was growing in the mother Dinocephalosaurus or if she had eaten the young. However, the live birth explanation makes the most sense. The embryo was discovered curled up in the easily recognizable fetal position, and if it had been eaten by the Dinocephalosaurus, its head would have been facing in the opposite direction.
It looks like we're still learning about early life on Earth every day.