Word: pterosaurs
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Dates: during 1990-1999
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...What did pterosaurs eat? Because pterosaur fossils and footprints have been found primarily in marine and freshwater environments, paleontologists believe many pterosaurs had tastes similar to modern sea- and shorebirds. For example, the ancient salt lakes in southwestern Texas in which Quetzalcoatlus was found contained lots of crustacean burrows but no bones from larger animals like crocodiles that might have fed a carrion eater. Some pterosaurs had beaks shaped like those of spoonbills. Pterodaustro had a mouthful of strainer-like teeth that it probably used to filter microscopic plankton from the water. Pteranodon is thought to have scooped...
Like birds, which evolved independently 70 million years later, pterosaurs had bones that were hollow and lightweight. (One scientist refers to pterosaur skeletons as "Styrofoam and mailing tubes.") But of all the trademarks of a pterosaur, one of the most peculiar was its hand, which boasted three clawlike fingers of normal size and a fourth digit that was outlandishly long. It was this fourth finger that provided structural support for the wings. Made of a skin-like membrane, the wings were supported by thousands of microscopic fibers that acted rather like the ribs of a folding umbrella, creating a flexible...
Berkeley's Padian, on the other hand, contends that pterosaurs did not have to walk on their wings, but were agile two-legged runners. He also disagrees with the explanation University of Bristol paleontologist David Unwin offers for the long fifth toe that juts out from pterosaur hind limbs. Unwin believes this toe served as the attachment site for a second skinlike membrane that stretched between the animals' hind limbs. "Why else would the fifth toe have been so elongated?" he asks. Padian responds that Unwin's membrane does not make anatomical sense: among other things, it would have hampered...
Endless debate also swirls around the question of how pterosaurs managed to become airborne. Some scientists think the beasts launched themselves from a running start, while others believe they were so clumsy on the ground that they would have had to drop from cliffs or trees to attain a flightlike glide. Lockley, for one, argues that pterosaurs had to be capable of birdlike takeoffs and landings if only because so many pterosaur footprints come from mudflats along the seashore. If they were incapable of flying off after landing in such areas, he says, they would have quickly died...
What researchers don't know about pterosaurs still far outweighs what they do know, but at least some of the dark corners of pterosaur life are beginning to divulge their secrets. A group of fossils discovered in Chile, for example, hints that pterosaurs may have nested in colonies. Some pterosaurs, like some birds, were crowned with dramatic crests that probably played a role in sexual display. But reconstructing their lost world is made difficult by the vagaries of fossil preservation and by the fact that these winged reptiles were evolutionary dead ends and left no descendants. Pterosaurs, for this reason...