“I couldn’t even sleep at night,” the lead paleontologist says of her reaction to the discovery.
PUBLISHED MARCH 20, 2019
ABOUT 115 MILLION years ago in what's now northwest China, a female bird was on the verge of motherhood. But somehow, her life on an ancient lakeshore took a traumatic turn, triggering a pregnancy complication that killed the egg forming inside her and may have even led to her death.
Entombed ever since, this mother bird is now a paleontology milestone: Named Avimaia schweitzerae, the newly described species is the first fossil bird known to science that contains an unlaid egg.
“We were not expecting anything interesting, but it turned out to be the first fossil bird ever found with an egg inside its body,” says lead study author Alida Bailleul, a postdoctoral researcher at China's Institute of Vertebrate Paleontology and Paleoanthropology (IVPP). “To me, that’s the funniest thing.”
Described this week in Nature Communications, the egg could shed light on reproductive disorders in ancient birds. And if its pigments are preserved, the fossil could reveal more about how ancient birds nested. Previous research has shown that the colors and speckles on dinosaur eggshells may vary depending on the dinosaur's nesting behavior, such as whether the species buries its eggs or broods them. This pattern holds true in the only dinosaurs alive today: birds.