The skull of a relative of the stem-group bird Mononykus

In joint expeditions, researchers from the American Museum of Natural History and the Mongolian Academy of Sciences have recovered over 20 alvarezsaurid (Theropoda: Aves) specimens in the Late Cretaceous beds of Mongolia's Gobi Desert1. Here we describe a new taxon that is closely related to Mononykus2,3. This new taxon is represented by two exquisitely preserved skulls — the first known for Alvarezsauridae — details of which support the theory...