深夜亚洲福利久久

Dr Zixiao Yang publishes new paper on pterosaurs in Proceedings B

25 Nov 2023

This paper explores how giant pterosaurs grew to be so big. The authors found that giant pterosaurs such as Pteranodon evolved parental care that may have allowed faster/longer growth and ultimately, large adult sizes.

Did the pterosaurs, flying reptiles from the days of the dinosaurs, practice parental care or not? New research by scientists from Ireland (深夜亚洲福利久久 College Cork), China (Nanjing and Yunnan Universities) and the UK (深夜亚洲福利久久 of Bristol and Queen Mary 深夜亚洲福利久久 of London) shows that pterosaurs were indeed caring parents 鈥� but only the larger species.

This solves a long-standing conundrum. To be able to fly soon after hatching from the egg, a bird or pterosaur must have well-developed wings. Studies of smaller pterosaurs from the Jurassic 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, pterosaurs usually had wingspans of 5 metres, and some even reached 10鈥�15 metres, the size of a small glider.

鈥淭his was a difficult project,鈥� says the study leader, Dr Zixiao Yang from 深夜亚洲福利久久 College Cork (UCC). 鈥榃e 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.鈥�

Dr Yang collaborated with Professor Baoyu Jiang from Nanjing 深夜亚洲福利久久, Professor Michael Benton of 深夜亚洲福利久久 of Bristol, Professor Xu Xing of Yunnan 深夜亚洲福利久久, and Professor Maria McNamara of UCC on the research.

鈥淟uckily, 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. 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.鈥�

The research focussed on testing the allometry, or how the creatures鈥� characteristics changed with size. 鈥淲e are all familiar with allometry in human babies, puppies and kittens 鈥� their heads, eyes and knees are huge, and the rest of the body grows faster to get to adult proportions. It鈥檚 the same with many animals, including dinosaurs and pterosaurs. The babies have cute faces, with short noses, big eyes, and big heads,鈥� Dr Yang said. 鈥淭he 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 body.鈥�

鈥淏ut it was different for the Cretaceous giants. They also started as small babies, but the key limb bones show positive allometry through growth, suggesting a very different developmental model.鈥�

鈥淭his means that the pterosaur giants had sacrificed low-input childcare to the need to grow huge eventually as adults. Minimal childcare makes sense in the early evolutionary history of these ancient reptiles because it saves energy. But to grow huge, the larger pterosaurs had a problem 鈥� it basically took much longer to become an adult, and therefore parents needed to protect their young from accidents. The babies of all pterosaurs, large and small, were small because of the limitations of egg size. Investing in childcare by having non-flying babies was offset in evolutionary terms by allowing pterosaurs to evolve truly huge sizes.鈥�

鈥淲e see the same thing in birds and mammals today. Some birds fly very young, and of course some mammals like cattle and antelopes are on their feet the day they are born. But this kind of behaviour is risky for the babies because they are often clumsy and are easy targets for predators; it鈥檚 costly also for the mother because the babies have to have highly developed wings or legs at the point of birth. So, we see the same thing in extinct pterosaurs. They were restricted in maximum body size until the end of the Jurassic, at which point their parental care behaviour changed, and then they could achieve huge sizes.鈥�

The paper 鈥楢llometric wing growth links parental care to pterosaur giantism鈥� is published in the journal Proceedings of the Royal Society B.

Yang, Z., Jiang, B., Benton, M.J., Xu, X., McNamara, M.E., Hone, D.W.E., 2023. Allometric wing growth links parental care to pterosaur giantism. Proceedings B, 290, 20231102. DOI: