Cork researchers helped solve a long-standing conundrum about dinosaur parenting
Not much is known about dinosaur parenting styles.
Now new research by scientists from University College Cork, China (Nanjing and Yunnan Universities) and the UK (University of Bristol and Queen Mary University of London) shows that pterosaurs were indeed caring parents – but only the larger species.
“This was a difficult project,” says the study leader, Dr Zixiao Yang from University College Cork (UCC).
“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.”
“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.”
The research focussed on testing the allometry, or how the creatures’ characteristics changed with size.
“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 body.” Dr Yang said.
“But 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.”
“This 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 – 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.”
The paper ‘Allometric Wing Growth Links Parental Care to Pterosaur Giantism’ is published in the journal Proceedings of the Royal Society B.
