Fossil fills a critical gap in avian evolution and offers evidence concerning the early evolution of birds
New York.January 10, 2001.Mark A. Norell, curator and chair of the Division of Paleontology at the American Museum of Natural History, and Julia Clarke, doctoral candidate in paleontology at Yale University, announced this week in Nature the discovery of a new dinosaur in the Gobi Desert of Mongolia. Named Apsaravis ukhaana, the fossil is the best-preserved specimen of a Mesozoic ornithurine (bird of modern aspects) bird found in over a century, and offers critical insight into a key stage of avian evolution, near the time when all living bird groups diversified. The fossil, which is about 80 million years old, was collected in 1998 by the American Museum of Natural History/Mongolian Academy of Sciences Paleontological Expedition at Ukhaa Tolgod, the site that has proved to be one of the worlds richest locations for vertebrate fossils from near the end of the age of dinosaurs.
Apsaravis ukhaana, the size of a small pigeon, was found buried in sandstone deposited from adjacent sand dunes, and yields a great deal of data important for assessing the early evolution of modern birds. Very few bird fossils have been found at Ukhaa Tolgod, which is virtually unparalleled in the extraordinary preservation of the hundreds of fossil mammals, lizards, and small dinosaur specimens.
Through phylogenetic analysis of the fossil, Dr. Norell and Ms. Clarke found strong evidence refuting the theory that early birds were divided into two groups the Saururae, thought to be the dominant landbirds of the Cretaceous period, and the Ornithurae, thought to be transitional shorebirds restricted to near-shore environments and shorebird ecologies. The analysis by Dr. Norell and Ms. Clarke reveals, in fact, that early modern birds were not restricted to a near shore marine or wading bird habitat, but were, rather, small terrestrial flyers. Discove
Contact: Holly Evarts
American Museum of Natural History