March 19, 1998--A team of researchers from the American Museum of Natural History and George Washington University announced today in the journal Nature the discovery of the first known skulls of a bizarre group of ancient animals called the Alvarezsauridae. This group (which includes the creature called Mononykus), is of special interest because it provides further evidence in support of the theory that birds evolved from dinosaurs and reveals an advanced stage in this transition. Numerous physical characteristics in the fossil skulls show that these strange creatures were actually early birds, challenging the traditional view that all primitive birds looked similar to their modern-day cousins.
The new fossils, which date from the late Cretaceous Period and are approximately 70 million years old, were found in the Gobi Desert of Mongolia. They were discovered during one of a series of joint American Museum of Natural History/Mongolian Academy of Sciences expeditions to search for dinosaurs and other fossils.
The research team named their find Shuvuuia deserti, from the Mongolian word shuvuu, meaning "bird," and the Latin for desert, in reference to the ancient climate in which the animals lived. Shuvuuia deserti, which was about the size of a turkey, walked on two legs, had a long tail and neck, and quite unlike most primitive birds, had stubby forearms that ended in a single, blunt claw. How the animals used these strange appendages is a mystery, but they were clearly unable to fly.
While creatures similar to Shuvuuia deserti, including the early bird Mononykus, have been found in Mongolia, Argentina, and North America, none of the specimens was found with a skull. Fossil skulls are extremely important because they contain key physical characteristics that enable researchers to trace the evolutionary history of different lifeforms.
The Shuvuuia deserti skulls reveal an important physical characteristic
that is found only in birds:
Contact: Elizabeth Chapman
American Museum of Natural History