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Scientists said today they had disproved claims that enormous prehistoric winged beasts could not fly, with new evidence that they "pole-vaulted'' themselves into the sky.
Dr Mark Witton, a palaeontologist from the University of Portsmouth and Dr Michael Habib from Chatham University USA, have studied how the giant pterosaur, which was as big as a giraffe, could fly.
They found that the reptiles took off by using the powerful muscles of their legs and arms to push off from the ground, effectively pole-vaulting over their wings.
Once airborne they could fly huge distances and even cross continents, the scientists claim.
Dr Witton said:
"Most birds take off either by running to pick up speed and jumping into the air before flapping wildly, or if they're small enough, they may simply launch themselves into the air from a standstill.
"Previous theories suggested that giant pterosaurs were too big and heavy to perform either of these manoeuvres and therefore they would have remained on the ground.
"But when examining pterosaurs the bird analogy can be stretched too far.
"These creatures were not birds, they were flying reptiles with a distinctly different skeletal structure, wing proportions and muscle mass.
"They would have achieved flight in a completely different way to birds and would have had a lower angle of take off and initial flight trajectory.
"The anatomy of these creatures is unique.''
Their research, published today in the international Public Library of Science journal, PLoS ONE, follows claims that pterosaurs were too heavy to take off like birds.
But Drs Witton and Habib suggest that the creatures, with up to 50kg of forelimb muscle, could easily have launched themselves into the air despite their massive size and weight.
Previous theories have asserted that giant pterosaurs could have been six metres tall with a wingspan of up to 12 metres but the researchers argue that five metres high with a 10 meter wingspan would have been more realistic.
Dr Witton said:
"The size of the flight muscles in a giant pterosaur would be incredible: they alone would be up to 50kg (110lbs) and account for 20% of the animal's total mass providing tremendous power and lift.''
Dr Habib added:
"Scientists have struggled for decades to figure out how giant pterosaurs could become airborne and some recent proposals have simply assumed it must have been impossible.
"But they may have approached the problem from the wrong end, instead of taking off with their legs alone, like birds, pterosaurs probably took off using all four of their limbs.
"By using their arms as the main engines for launching instead of their legs, they use the flight muscles, the strongest in their bodies, to take off and that gives them potential to launch much greater weight into the air.
"This may explain how pterosaurs became so much larger than any other flying animals known.''
The researchers examined every possible anatomical aspect of the prehistoric flying reptiles, which died out 65 million years ago along with the dinosaurs.
Using fossilised remains they estimated size and weight and calculated bone strength and mechanics and potential ``flap gliding'' performance.
They concluded that not only could pterosaurs fly, they could do so extremely well and could have travelled huge distances and even crossed continents.
They found that it was unlikely that they would need to flap continuously to remain aloft but would flap powerfully in short bursts with their large size allowing them to achieve rapid cruising speeds.
Dr Witton said:
"Pterosaurs had incredibly strong skeletons, for their weight, they're probably amongst the strongest ever evolved.
"And, unlike birds, where the wings become relatively weak as they grow in size, those of pterosaurs do the opposite: they become stronger.
"As pterosaurs became larger, they reinforced their wings and expanded their flight muscles to ensure they could keep flying.''