[ad_1]
Pterosaurs were winged flying reptiles that lived at the same time as dinosaurs, between 210 million and 65 million years ago. Previously, it was thought that they could only take flight when they would have almost become normal size, just like birds or bats. This hypothesis was based on fossilized pterosaur embryos discovered in China whose wings were poorly developed. However, a team of paleontologists from the universities of Leicester and Lincoln was able to refute this hypothesis.
One summer day in the lower Cretaceous, 124 million years ago, a nascent pterosaur emerges from the sand and looks at the sky for the first time. The other newborns are exhausted by their struggles or crawl to shelter in the trees along the beach. The less fortunate are caught and eaten by small theropods (Sinosauropteryx). From tree safety, the lamellae make their first flight. Inexperience means that many are killed in accidents or storms, their bodies drifting into nearby lakes where a few tiny ones are preserved as fossils in fine, muddy sediments that now form rocks that fall in Liaoning Province. in China. Image credit: James Brown.
David Unwin of the University of Leicester and Dr. Charles Deeming of the University of Lincoln have 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 in an early stage of development and away from hatching.
"Theoretically, what pterosaurs did, grow and fly, is impossible, but they did not know it, so they did it anyway," said Dr. Unwin.
"Another fundamental difference between pterosaur babies, also known as flaplings, and baby birds or bats, is that they had no parental care and had to feed and care for themselves from birth."
"Their ability to fly gave them a survival mechanism that allowed them to escape the carnivorous dinosaurs."
"This ability has also proven to be one of their deadliest because the demanding and dangerous flight process has led many of them to die very early."
Since slats could fly and grow from birth, this provides a possible explanation of why they were able to reach huge wings, much larger than any historical or current bird or bat species .
The way in which they have been able to carry out this process will require further research, but it is an issue that would not have been asked without these recent developments in our understanding.
"Our technique shows that pterosaurs were different from birds and bats and that comparative anatomy can reveal new patterns of development in extinct species," said Dr. Deeming.
The research was published in the Acts of the Royal Society B.
_____
David Michael Unwin & Charles Deeming. 2019. Prenatal development in pterosaurs and its consequences on their postnatal locomotor capacity. Proc. R. Soc. B 286 (1904); doi: 10.1098 / rspb.2019.0409
[ad_2]
Source link