Leteci praistorijski guster veci od Spitfirea

Leteci praistorijski guster veci od Spitfirea

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Lizard of the skies that was bigger than a Spitfire
By Mark Henderson, Science Correspondent


A PTEROSAUR with a wingspan almost twice that of the Typhoon Eurofighter is the largest known creature to have flown, scientists said yesterday.

The flying cousins of the dinosaurs, one of which seized Raquel Welch in the 1966 film One Million Years BC, have long been known to have dwarfed all modern birds. Fossils discovered recently in Mexico, however, suggest that the very largest were even bigger than had been thought possible.

The size of a set of newly identified pterosaur footprints indicates that some of the airborne behemoths had wings that stretched at least 59ft (18m) from tip to tip, and its true dimensions may have been larger still.

Previous estimates had put the biggest pterosaurs, of a species known as Quetzalcoatlus after an Aztec god, at a span of 38ft — as wide as the wings of a Spitfire, but a mere pigeon in comparison with the new beast. Among modern fighter aircraft, the F15’s wingspan is 42ft and the Typhoon’s 34ft.

Fossilised bones found in Israel, Jordan, Brazil and Romania have also provided evidence of pterosaurs measuring 42ft to 46ft across, suggesting that truly huge individuals may not have been altogether rare.

David Martill, of the University of Portsmouth, a leading authority on pterosaurs, told the BA Science Festival in Dublin that the footprints belonged to the largest flying animal yet discovered.

“Quetzalcoatlus was an animal the size of an aeroplane, with each wing five metres long, but we now have a lot of evidence that these things were even bigger than that,” he said. “The largest may have been nearly twice that size. Experts have come up with estimates that are in excess of 18 metres.”

The fossils were discovered in Mexico by Eberhard “Dino” Frey, of the State Natural History Museum in Karlsruhe, Germany, but details have yet to be published. It is not yet known whether they belong to a new species or a large example of a known one.

Pterosaurs were not dinosaurs, but they lived during the same Triassic, Jurassic and Cretaceous periods from about 220 million years ago to the mass extinction that took place 65 million years ago. The vast flying lizards, of which the most famous are the pterodactyl and the crested pteranodon, lived all over the world.

Dr Martill’s research has shed light on how pterosaurs managed to fly, despite their great size. Their secret was a remarkable, almost paper-thin membrane stretched tightly between light, hollow fore and hind limb bones. It gave them highly aerodynamic wings more similar to those of a modern bat than of a bird.

“This membrane was a very, very sophisticated structure,” Dr Martill said. “It was not just a piece of skin. It was a tissue that enabled thermoregulation by acting as a heat exchanger, and was very, very thin — it was not thick and scaly like a crocodile’s skin.”

He said that the bone was phenomenally structured, giving very low weight.

Unlike those of modern bats or birds, pterosaur wings were not attached to the upper body but to its lower part, rather as the wings of a jumbo jet protrude from its belly. This would have improved their manoevrability, as would the reptiles’ joint configuration.

The creatures were probably capable of powered flight and not just gliding, but would have exploited thermal currents in the same way as large, modern birds such as albatrosses and condors. They may have taken off by jumping — their pelvises show structural similarities to those of frogs — and most probably spent most of their lives in the air.

Three fossilised embryos have shown that pterosaur young were born with wings in the same proportions as zabranjenos, indicating that they started flying soon after they hatched. Modern birds do not fly until almost fully grown.

Dalje



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  • MRKY 
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Ako orao ptica može da zgrabi i ponese kokošku, onda ovaj gušter-ptica može da ponese medveda Confused



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A kravu?

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  • Pridružio: 18 Dec 2003
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Ovo su leteci gusteri, ne dinosaurusi, jeli su ribu vecinom.

Jednostavno su izumrli, nisu od njih postale ptice, vec od dinosaurusa mesozdera.

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Cuo sam za njih

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