Originally created 07/22/02

Researchers find fossil of previously unknown flying reptile



WASHINGTON -- A previously unknown flying reptile that lived in the age of dinosaurs sported a bony crest more than two feet high and may have fed by skimming the surface of a lagoon to snatch fish in its long, sharp beak.

Researchers unearthed a nearly intact fossil skull of the animal near the town of Santan do Cariri in northeastern Brazil. The scientists said the animal lived about 110 million years ago, spending its life soaring on 15-foot wings over a land dominated by lumbering dinosaurs.

In a study appearing Friday in the journal Science, researchers Alexander W.A. Kellner and Diogenes de Almeida Campos say the animal is a new kind of pterosaur, a type of reptile that flew on large wings of furry skin, dipping and diving at speeds of up 25 mph to catch fish on the fly. Pterosaurs are the largest flying animals known.

The researchers named the new pterosaur Thalassodromeus sethi. The first word is Greek for "sea runner" and the second honors the ancient Egyptian god Seth.

The animal is thought to have lived on the shores of an ancient lagoon, called the Araripe, not far from the ocean.

Kellner and de Almeida Campos said in Science that the pterosaur's four-foot-long skull was topped with a hollow bony crest that rose 31 inches from the top of its head and may have acted like a rudder as the large animal flew.

The crest fossil is marked with grooves from blood vessels, suggesting that the top knot also helped keep the animal cool, the researchers say. The blood vessels would have been near the skin's surface, allowing body heat to escape easily into the atmosphere.

The sea runner's jaw structure resembles a modern bird, called a skimmer, that captures its prey by gliding across the surface of a pool and dipping its beak.

To feed, the authors suggest that Thalassodromeus dropped toward the water in a long swooping glide and then dipped its head and closed its toothed beak around an unwary fish swimming near the surface.

"The scissors-like bill of Thalassodromeus almost precludes any other method of capturing prey," the authors wrote.

Marks in the fossilized skull suggest the sea runner had powerful neck muscles, giving it the strength needed to capture a fish on the fly.

Kellner is with the National Museum in Rio de Janeiro. De Almeida Campos is with the Museum of Earth Sciences, also in Rio. Both are associate researchers at the American Museum of Natural History.

Alan Feduccia, a dinosaur expert at the University of North Carolina at Chapel Hill, said the authors "have done a splendid job of bringing this large and remarkable ... pterosaur back to life."

He agrees that the animal probably was a skimmer, but questions the authors' interpretation that Thalassodromeus' large crest was for body cooling. Feduccia said there are modern birds, such as the hornbill, with large bony crowns that contain blood vessels used to nourish the head and not for cooling.

But despite the disagreement, Feduccia marvels: "One can only imagine the incredible sight of these flying reptiles skimming the Araripe lagoon some 110 million years ago."

Fossils of pterosaurs are more uncommon than the remains of many other animals from the age of dinosaurs. As with modern flying birds, the bones of pterosaurs were thin and usually didn't survive as fossils. The Araripe Basin, where Thalassodromeus was found, contains one of the largest deposits in the world of pterosaur fossils.

Pterosaurs ranged in size from sparrow-sized creatures up to massive fliers like Thalassodromeus. Unlike birds, the wings of pterosaurs had no feathers. Instead, there was a single long finger-like bone extending from a wrist that stretched a thin membrane that provided the aerodynamic lift to give the animal flight.

The fossils of another large pterosaur, called Pteranodon, has been found in Texas and Kansas. That animal is thought to have had a wing span of 23 feet and it, too, had a bony head crest, although smaller than that of Thalassodromeus.

Pterosaurs became extinct at the same time as the dinosaurs, about 65 million years ago.

On the Net:

Science: www.sciencemag.org



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