Pterosaurs were the first group of vertebrates to evolve flight, and became extinct at the same time as the dinosaurs. Some of these animals reached enormous sizes, with wingspans estimated to be more than 10 metres wide, comparable to the size of some small aircraft.
Pterosaurs are crucial for understanding the evolution of flight, however scientists trying to create reconstructions of pterosaurs are hindered by the fact that no pterosaur fossils preserve the full shape of the wing.
To determine how accurate these reconstructions are compared to what would be expected of flying animals, the researchers devised a test to examine nine popular pterosaurs including iconic animals like the Pteranodon (the pterosaurs featured in Jurassic Park) and Quetzalcoatlus (the largest animal ever to fly).
Using a method called theoretical morphospace, the researchers created a map of all the possible shapes or forms the wings could have. The team were then able to test the function of wing reconstructions, to answer how well shaped they were for flight.
Lead author, Benton Walters from Bristol's School of Earth Sciences explains: "In living flying animals, such as birds and bats, different lifestyles are associated with distinct wing shapes and flight abilities. The lack of comparable diversity in pterosaur reconstructions suggests that the reconstructions are missing important variation."
This study highlights the difficulties in reconstructing and studying extinct animals and shows that even for animals as iconic at the 'pterodactyl', there is still a lot scientists don't know about how they looked or lived.
"Reconstructions of pterosaur wings are commonly made using measurements of the bones which support the wing, and information about the soft tissues gleaned from a handful of exceptional fossils, but there is still a lot that cannot be definitively stated from these alone," Benton Walters said.
"For a group of animals that existed for over 100-million years and includes both palm-sized and plane-sized animals, you would expect diversity in shape," he added. "But wing shape was similar regardless of the pterosaur they depicted."
Overall, the research shows that the modern understanding of pterosaurs represents far less diversity than is expected in the group, both in terms of shape and flight performance.
However, Benton believes that as newer analysis techniques see wider adoption, like imaging fossils under specific sorts of light beyond what humans can see, our understanding of pterosaur wing shapes will improve in the future.
He added: "This research provides a helpful guide to show where the scientific understanding of pterosaur wings is lacking and will be used as a benchmark to test new and improved reconstructions of pterosaurs as our understanding of these amazing creatures improves."
Paper
"Exploring the limits of wing design in pterosaurs" by B. Walters et al. in Paleobiology
