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...