Study: Pterosaurs Had Remarkable Ability to Fly from Birth

Thursday, June 13, 2019

On a summer day in the Early Cretaceous 124 million years ago, a hatchling (flapling) pterosaur emerges from the sand and gazes at the sky for the first time. Other hatchlings lie exhausted from their struggles or crawl to safety on trees fringing the beach. The less lucky are caught and eaten by small theropods (Sinosauropteryx). From the safety of the trees flaplings make their maiden flights. Inexperience means that many are killed in accidents or storms, their bodies drifting out into nearby lakes where a tiny few are preserved as fossils in fine muddy sediments that now form rocks that crop out in Liaoning Province China. Image credit: James Brown.

Pterosaurs were winged flying reptiles that lived at the same time as dinosaurs, between 210 million and 65 million years ago. Previously, they were thought to only be able to take to the air once they had grown to almost full size, just like birds or bats. This assumption was based on fossilized pterosaur embryos found in China that had poorly developed wings. However, a team of paleontologists from Universities of Leicester and Lincoln was able to disprove this hypothesis.

University of Leicester’s Dr. David Unwin and Dr. Charles Deeming from the University of Lincoln compared fossilized eggs and embryos of a pterosaur species called Hamipterus tianshanensis with data on prenatal growth in birds and crocodiles, finding that they were still at an early stage of development and a long way from hatching.

“Theoretically what pterosaurs did, growing and flying, is impossible, but they didn’t know this, so they did it anyway,” Dr. Unwin said.

“Another fundamental difference between baby pterosaurs, also known as flaplings, and baby birds or bats, is that they had no parental care and had to feed and look after themselves from birth.”

“Their ability to fly gave them a lifesaving survival mechanism which they used to evade carnivorous dinosaurs.”

“This ability also proved to be one of their biggest killers, as the demanding and dangerous process of flight led to many of them dying at a very early age.”

Since flaplings were able to both fly and grow from birth, this provides a possible explanation as to why they were able to reach enormous wingspans, far larger than any historic or current species of bird or bat.

How they were able to carry out this process will require further research, but it is a question that wouldn’t have been posed without these recent developments in our understanding.

“Our technique shows that pterosaurs were different from birds and bats and so comparative anatomy can reveal novel developmental modes in extinct species,” Dr. Deeming said.

The research was published in the Proceedings of the Royal Society B.


David Michael Unwin & D. Charles Deeming. 2019. Prenatal development in pterosaurs and its implications for their postnatal locomotory ability. Proc. R. Soc. B 286 (1904); doi: 10.1098/rspb.2019.0409