Recently discovered dinosaur-era reptile gave birth to babies


Mammals give birth to babies, reptiles pop out eggs, right? An ancient fossil unearthed in China suggests the latter wasn't always true.

Paleontologists have found a 245-million-year-old fossil of a pregnant reptile and her curled-up embryo.

The discovery suggests this long-necked reptile may have ditched its egg-bearing ways over time to gain a biological advantage, according to a study published Wednesday in the journal Nature Communications.

In its day, the Dinocephalosaurus could grow to be at least 13 feet long — with the neck making up about half that length. The aquatic reptile was a relative of dinosaurs and is a distant ancestor of modern crocodiles and birds, all of which belong to the major clade Archosauromorpha.

While live birth has evolved many times in mammals and diverse groups of lizards and snakes, scientists had not yet observed live birth among archosauromorphs.

Jun Liu, a paleontologist at the Hefei University of Technology in China, said he and his colleagues have found the first known example of an Archosauromorpha member giving birth to live young.

The team found their ancient fossil inside a chunk of limestone in Southwest China nearly a decade ago. As they steadily chipped away at the stone surrounding the skeleton, they encountered a surprise in the reptile's stomach: another reptile.

Liu, the study's co-author, said at first they though it might be just an unlucky meal. But the creature was curled, and it was facing forward. The Dinocephalosaurus preferred to eat its prey head-first.

"If an animal is ingested by something else, there's no way to preserve that shape," he told National Geographic.

The scientists suggested the marine reptile may have evolved to deliver live babies because producing and nesting eggs was too hazardous. Its neck-to-body ratio made it harder to walk on land and burrow its progeny, like turtles do. Reptilian eggs also can't be incubated underwater, as they need oxygen.

RELATED: See more of the latest dinosaur discoveries

19 PHOTOS
Largest Dinosaur print found
See Gallery
Largest Dinosaur print found
People stand next to a footprint made by a meat-eating predator some 80 million years ago and one of the largest of its kind ever found, at the Maragua Syncline, Bolivia, July 20, 2016. REUTERS/David Mercado
Paleontologist Sebastian Apesteguia measures the footprint made by a meat-eating predator some 80 million years ago and one of the largest of its kind ever found, at the Maragua Syncline, Bolivia, July 21, 2016. REUTERS/David Mercado
Visitors look at dinosaur footprints while visiting with a tour guide the Cal Orcko cliff in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
Paleontologist Sebastian Apesteguia touches a dinosaur's footprint at the Maragua Syncline, Bolivia, July 20, 2016. REUTERS/David Mercado
Visitors look at dinosaur footprints while visiting the Cal Orcko cliff in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado
A man walks next to dinosaur footprints at the Maragua Syncline, Bolivia, July 21, 2016. REUTERS/David Mercado
Visitors look at dinosaur footprints while visiting the Cal Orcko cliff in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado
Children play with the replica of a dinosaur fossil at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
A child walks up a playground climber with dinosaur footprints at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
A mother takes a photograph of her children while they pose in front of the replica of a Tyrannosaurus rex at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
Children have a snack while sitting next to the replica of a Tyrannosaurus rex at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
The replica of a Titanosaur is seen at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
Visitors walk underneath a replica of a Titanosaur at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
A visitor walks underneath a replica of a Titanosaur at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
The replica of a Titanosaur is seen at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
Visitors walk underneath a replica of a Titanosaur at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado 
Paleontologist Sebastian Apesteguia measures the footprint made by a meat-eating predator some 80 million years ago and one of the largest of its kind ever found, at the Maragua Syncline, Bolivia, July 21, 2016. REUTERS/David Mercado
A truck unloads rocks next to the Cal Orko cliff where thousands of dinosaur's footprints can be seen, in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. REUTERS/David Mercado
HIDE CAPTION
SHOW CAPTION
of
SEE ALL
BACK TO SLIDE

Read Full Story