New Haven, Conn. The discovery in Mongolia of the fossil of a new bird, Apsaravis ukhaana, that lived about 80 million years ago, sheds new light on the evolution of birds.
The nearly complete specimen of the small pigeon-sized bird was found at the locality Ukhaa Tolgod in the Gobi Desert of Southern Mongolia as part of the ongoing joint expeditions of the American Museum of Natural History in New York and the Mongolian Academy of Sciences.
The find, announced this week in the journal Nature, was analyzed by Julia Clarke, a doctoral candidate in vertebrate paleontology atYale University, and Mark Norell, chair and curator of the Division of Paleontology at the American Museum of Natural History. The discovery is particularly important because the new bird comes from a part of the evolutionary tree close to the origin of all living birds and that is not well represented in the fossil record.
"All of the birds living today have a most recent common ancestor that they share," said Clarke, who is in Yales Department of Geology. "This fossil is just outside the group or clade that includes the decendants of that common ancestor. It is the best preserved specimen of a fossil from close to the radiation of all living birds discovered in over 100 years."
The finding is the most significant from this part of the avian tree since the discovery of specimens of the closest relative to living birds, Ichthyornis, first discovered more than 100 years ago in Kansas. These specimens of Ichthyornis are part of the permanent collection at Yales Peabody Museum of Natural History.
Clarke said the fossil dispels the notion that the ornithurines, or nearest relatives to todays existing birds, were restricted to near shore environments while the interior was dominated by another lineage of fossil birds known as the "opposite birds" or Enantiornithes. The Enantiornithes are comparatively abundant in terrestrial deposits in the fossil record of Mesozoic, but went e
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