Some of our earliest fossil records of amniote eggs are from dinosaurs, like mussaurus patagonicus, which lived around 250 million years ago in Argentina. And that's at least 100 million years ...

The chicken (or, rather its amniote ancestor) has beat the egg. Obviously, eggs of some form or another existed long before chickens—they are female sex cells, ...

Sander argues that egg-laying actually came first. He suggests that early leathery amniote eggs did not fossilize well. As such, evidence of egg-laying amniotes would be scarce at best, Sander said.

The evolution of the amniotic egg -- complete with membrane and shell -- was key to vertebrates leaving the oceans and colonizing the land and air but how bird eggs evolved into so many different ...

"Whether the first amniote babies were born in parchment eggs or as live, snapping little insect-eaters is unknown, but this adaptive parental protection gave them the advantage over spawning ...

The earliest reptiles, birds and mammals may have given birth to live young rather than laying eggs, new research suggests. Until now, the hard-shelled egg was thought to be the key to the success ...

image: The amniotic egg, showing the semipermeable shell and the extraembryonic membranes. view more Credit: Mike Benton. The earliest reptiles, birds and mammals may have borne live young ...