Baby pterosaurs could fly the moment they hatched from the egg, argues a new paper based on analysis of 19 fossil baby pterosaurs in China.
The study, published Wednesday in the Proceedings of the Royal Society B, also flouts earlier thinking that juvenile pterodactyls needed parental care because they would have had tiny wings and weak muscles when first born. No, they didn’t.
So the study also postulates that in contrast to earlier thinking, parental care in pterodactyls wasn’t a thing.
It turns out that baby pterodactyls are called flaplings. Until now, flaplings had been thought capable of running on their hind legs after birth, based on the development of their leg bones. But they hadn’t been thought able to fly.
Pterodactyls — and in fact all pterosaurs — were primitive flying reptiles, so the notion of independent flaplings isn’t entirely shocking. Anybody who has raised a litter of baby snakes knows that as soon as the snakelet pops from the egg, it is on its own and hunting. Given provocation and opportunity, it will bite you, though they are quite small and you probably wouldn't notice unless they are poisonous. Envenomation, you would notice.
Yet parental care is not unknown in reptilia. It seems to have originated in the archosaurs — the animals that lived a quarter-billion years ago and gave rise to everything from dinosaurs to crocodilians to pterosaurs to birds. A study published in Nature focusing on doting Nile crocodile mothers even found that the younger the squeaking baby, the more Mama responds. (Parental care in reptiles tends to be confined to protecting the eggs and the young, not feeding the kiddies chewed-up antelope.)
That Nature article postulated that since pterosaurs also feature rapid early growth, like crocodiles, the mother detaches as the kids grow up.
But the new article postulates that there was no pterodactylian parental care after all, given the evidence that the pterosaur would stagger from its egg, presumably let the goo dry off its down (pterosaurs were feathered) and then fly off into the great unknown.
"Flaplings were essentially tiny adults. So, the argument goes that on the basis of what we can infer from morphology they did not necessarily need any parental care (which is also the default setting for tetrapods). It may be that they did receive care, its just that there isn't any direct, or indeed indirect evidence to support this," coauthor David Michael Unwin of the University of Leicester told Haaretz.
In contrast to earlier thinking, right before hatching the wee ones already had the bone development necessary to take wing, explain Unwin and D. Charles Deeming from the University of Lincoln.
The previous assumption that, like birds and bats, pterosaurs couldn’t fly until they were quite large and developed was partly based on Chinese fossils of embryonic pterosaurs with underdeveloped wings.
Also, it had been thought that hatchling flaplings wouldn’t have had the necessary muscles to fly yet — just think of the helplessness of baby birds. But first, pterosaurs were reptiles, not birds; and second, muscle attachments don’t have to be ossified to work: Cartilage can do the trick, and cartilage does not typically fossilize.
The long and short is that while the baby wing proportions in birds and bats are not suitable to flight, they were in the baby pterosaurs that Unwin and Deeming checked.
Also, the embryonic pterosaurs on which the earlier research had been based, concluding they couldn't move and needed mommy, were very early in the development stage. Now, based on more advanced embryos found in China and Argentina that died just before they hatched, Unwin and Deeming concluded that likely, pterodactyls could fly right away.
“Theoretically what pterosaurs did, growing and flying, is impossible, but they didn’t know this, so they did it anyway,” Unwin stated.
So, if the babies could fly and thusly avoid predators and find food, they probably didn’t need parental care, the two suggest — but add that their discovery does not exclude that possibility. It is also possible that the flaplings could fly but didn't.
Pterosaurs were probably as terrifying a predator as even plied the skies: the dread Quetzalcoatlus northropi had a wingspan so large — up to 13 meters, or 43 feet — that some doubted whether the big ones could fly at all.
This study related to rather smaller species: Hamipterus tianshanensis, from the Lower Cretaceous of China, whose wing span was “just” 3.5 meters, as long as a minibus. Pfft. Another was the bizarrely-beaked Pterodaustro guinazui of Argentina, which another paper suggested built nests rather than burying their eggs in dirt.
Apropos of which, evidence that pterosaurs of a feather flocked together and laid eggs near one another doesn’t have to imply parental care, let alone attest to heartwarming behavior of co-parenting in any way. Think of turtles. They come together to lay eggs on the same beaches and nary a warm feeling did they ever demonstrate for one another.