PARENTHOOD, DINO-STYLE

By MICHAEL D. LEMONICK

EVERYONE IN CAMP FELT SORRY FOR Luis Chiappe. He and other paleontologists from New York City's American Museum of Natural History had traveled halfway around the world to prospect one of the earth's richest fossil beds--a bowl-shaped valley called Ukhaa Tolgod in Mongolia's remote Gobi Desert. But Chiappe's foot had been so badly burned he could barely hobble, let alone stride around looking for ancient dinosaur bones. So Mark Norell, a leader of the joint U.S.-Mongolian expedition, gave him a consolation prize: digging out an unpromising specimen Norell had already found.

Within a few hours, all sympathy had evaporated. As Chiappe and a colleague chipped away the reddish sandstone, they realized that there was a nest of fossilized eggs beneath the bones, carefully laid out in a circle on two levels, with the narrow end of each egg pointing out. That alone was unusual enough to bring Norell running. And by the time the scientists had finished uncovering the fossil, they knew they had made a major scientific discovery. The dinosaur, an ostrich-size carnivore called Oviraptor, was perched protectively over its eggs, its legs tucked carefully under the body and its arms curled around the perimeter of the nest, just like a barnyard chicken.

And that's why the find is such big news. Paleontologists have been fighting for decades over how closely dinosaurs are related, in an evolutionary sense, to modern birds. Intimately, say the majority. Skeletal similarities, they argue, show that Oviraptor, Tyrannosaurus rex and other meat-eating dinos are closer kin to birds than to plant eaters like Stegosaurus or Triceratops. But a vocal minority disagree. They see no evolutionary connection between birds and dinos; any apparent similarities, they say, simply suggest that nature arrived at the same design by two different routes.

The new finding tips the balance steeply toward the bird-as-dinosaur camp. The new fossil makes it clear that these dinosaurs not only were built something like birds but acted like them as well. "It's rare that we get any insight into the behavior of animals that have been dead for 80 million years," says Norell. "This fossil demonstrates that brooding behavior evolved long before there were birds." This oviraptor was probably buried by a sudden sandstorm that preserved it just as it sat. Says Norell, who co-authored a report on the discovery that appears in the current Nature: "We don't know if dinosaurs used this posture to control the temperature of the eggs, to shade them from the sun or to protect the nest from predators."

Will this discovery win over the few paleontologists who still think dinosaurs and birds are only distantly related? Probably not. Paleontology is much like politics: passions run high, and it's easy to draw very different conclusions from the same set of facts. --By Michael D. Lemonick. Reported by Andrea Dorfman/New York

With reporting by Andrea Dorfman/New York