Published: Sun, December 03, 2017
Research | By Raquel Erickson

Baby Pterosaurs Couldn't Fly as Hatchlings

Baby Pterosaurs Couldn't Fly as Hatchlings

About 215 eggs of the pterosaur, which flew and have jagged teeth, were found in the Xinjiang Uygur Autonomous Region in China.

Researchers have reported the discovery of hundreds of prehistoric eggs in China that were laid by pterosaurs, the world's first flying vertebrates that appeared before the birds and bats.

The researchers consider a tornado might have hit a large group of pterosaur nests hidden in mud and washed them into a lake.

An worldwide team of paleontologists has discovered a fossil-rich site with more than 200 fossilized eggs of the Cretaceous pterosaur species Hamipterus tianshanensis in China.

The CT scans meant the researchers could use X-rays to see inside the eggs and embryos without destroying them, the first time this has been done with pterosaur eggs (although dinosaur eggs have been studied like this before).

The partial remains of pterosaur embryos were found in 16 of the eggs, allow scientists to examine the beasties in unprecedented detail.

The first pterosaur embryo was found in China in 2004, but the egg and embryo were flattened, and exactly what type of pterosaur it was was unclear.

A life reconstruction of Hamipterus tianshanensis, a species of pterosaur that lived in what's now China more than a hundred million years ago. Could raise their young together mean pterosaurs were social and nurtured approaching one another?

"The site is in the Gobi desert, and there are strong winds, a lot of sand, with few plants and animals", says study coauthor Shunxing Jiang of the Chinese Academy of Sciences.

The species that laid the recently discovered eggs is known as Hamipterus tianshanensis. The fossilised eggs found at the nesting ground look more like deflated balloons than eggs cracked for an omelette.

"I remember looking at the specimens and saying that's not possible", said Alexander W.A. Kellner, a palaeontologist at the Federal University of Rio de Janeiro and an author on the paper. Bones are distributed along the egg, and mostly disarticulated and displaced from their natural position.

"Thus, newborns were likely to move around but were not able to fly, leading to the hypothesis that Hamipterus might have been less precocious than advocated for flying reptiles in general ... and probably needed some parental care", the paper reads.

Inside one of the eggs that contained remains of a pterosaur embryo.

Since at least some other pterosaur embryos possess teeth, this might indicate that the Hamipterus embryos are of an earlier developmental stage, before tooth development.

The discovery could help paleontologists understand how pterosaurs reproduced and nested. But with paleontologists working more and more on the case, it only seems like only a matter of time now. And in at least 16 of these eggs, the sediments also cradled the delicate skeletons of developing pterosaur embryos, including one bone that the team thinks belonged to a hatchling. Others boasted wild and insane crests, which may have been used to attract the opposite sex, as has been suggested with H. tianshanensis. Thanks to the hard work of paleontologists, we are starting to develop a good understanding of the entire life history, from before hatching to death, of these fascinating creatures.

So why did they find 215 eggs in one place?

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