To be able to fly soon after hatching from the egg, a bird or pterosaur must have well-developed wings. Studies of small-bodies pterosaur species from the Jurassic period showed that their babies already had large wings when they hatched and they could have wobbled into flight within a few days of birth. But did this work for the later pterosaurs which were much larger in size? In the Cretaceous period, pterosaurs usually had wingspans of 5 m, and some even reached 10-15 m, the size of a small glider.
“This was a difficult project. We needed examples of pterosaurs where we had at least one hatchling or very young specimen as well as adults so we could study their growth rates. But baby pterosaurs are really rare,” said Dr. Zixiao Yang, a paleontologist at University College Cork.
“Luckily, we were able to use some classic specimens from the Jurassic of Europe and the Cretaceous of North America, together with new finds from China,” added Nanjing University’s Professor Baoyu Jiang.
“By measuring the skulls, backbones, wings, and hind legs, we were able to test for differences in the relative growth of different parts of the body.”
In their study, Dr. Yang, Professor Jiang and their colleagues focused on testing the allometry, or how the creatures’ characteristics changed with size.
“We are all familiar with allometry in human babies, puppies and kittens — their heads, eyes and knees are huge, and the rest of the body grows faster to get to adult proportions,” Dr. Yang said.
“It’s the same with many animals, including dinosaurs and pterosaurs. The babies have cute faces, with short noses, big eyes, and big heads.”
“The small, bird-sized, Jurassic pterosaurs were born with large wings and strong arms and legs, evidence that the babies could fly from birth.”
“As they grew from baby to adult, their arms and legs showed negative allometry, meaning they started large and were then growing more slowly than the rest of the…
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