Well, we don't know because of what's known as the egg gap. Some of our earliest fossil records of amniote eggs are from dinosaurs, like mussaurus patagonicus, which lived around 250 million years ...

The age-old debate of whether the chicken or the egg came first is explored through historical and evolutionary contexts.

Despite evidence that the earliest examples of creatures such as mammals and reptiles gave birth to live young, they actually may have laid eggs, a scientist argues. IE 11 is not supported.

The amniotic egg consists of a suite of fetal membranes, including the amnion, chorion and allantois, as well as an external shell that can be either strongly mineralized (as in rigid-shelled eggs ...

Most biologists will answer confidently when asked "which came first, the chicken or the egg?" but the answer may depend on what type of egg you're talking about.

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 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, ...

— -- South American paleontologists report they have discovered fossilized embryos of the oldest aquatic reptiles, lagoon-dwelling "mesosaurs" that lived about 280 million years ago. Long ...

What came first - the chicken or the egg? Scientists think they've cracked it at last! A new study has found that the chicken's ancestor may not have laid eggs ...