CompuServe Thread

Scientists have discovered a dramatic fossil trove in Mongolia's Gobi Desert, including some unknown meat-eating dinosaurs and several dinosaur "nurseries" with extremely well preserved eggs. The finding represents the best-preserved assemblage of backboned animals ever found from the Cretaceous period, 130 million to 65 million years ago, the American Museum of Natural History said. The fossils will be "extraordinarily important" for understanding the evolutionary changes from dinosaurs to birds, and in shedding light on the early days of mammals, said Michael J. Novacek of the museum, one of the expedition's leaders. In just 10 days last July, researchers discovered nearly 100 dinosaur fossils, 175 fossil lizards and skulls and skeletons of 147 very rare mammals, the museum said Monday (4-4-94) in a statement. The fossils, collected from a square-mile site at Ukhaa Tolgod, are thought to be about 80 million years old. Apart from the dinosaur eggs in their nurseries, the museum said finds included: –six skeletons of the armored ankylosaur dinosaurs, some with perfectly preserved tails and tail spikes. –more than a dozen skeletons of small meat-eating dinosaurs called theropods, several of which are new types of the three-toed creatures. The museum called it the most diverse assemblage of theropods from any single location. –an excellent skull and complete skeleton of one theropod, Oviraptor. That beast is now known from only one or two skeletons, Novacek said. –six skeletons of the recently discovered creature Mononykus, perhaps including the first skull or significant portion of a skull, Novacek said. The creature represents a transition between birds and dinosaurs, Novacek said. Altogether, the finding provides an unusually diverse and well-preserved snapshot of life at the site, said Novacek, the museum's curator of vertebrate paleontology. "We're picking up … an extraordinarily rich picture of a dinosaur community toward the end of the dinosaur empire, that captures both the decline of the dinosaurs and the … rise of the diversity of mammals," Novacek said in a telephone interview. Mammals represented by the findings ranged from shrew-sized to possibly as big as squirrels, he said. Novacek said the remains of lizards, mammals and more delicate dinosaurs show anatomical details and completenesss not generally seen elsewhere. That is due to the blowing sands of the desert, which quickly buried animals after death and may even have killed some of them, he said. "The site is a remarkable site," said Willam Clemens, curator of mammals at the Museum of Paleontology at the University of California, Berkeley. It will provide "new windows of understanding relating to the evolution of mammals and other animals in Asia," he said. ++++++++++++++++++++++++++++++++++++