The earliest dromaeosaurid theropod from South America

Drifting apart Sickle-clawed predatory dinosaurs, known as dromaeosaurids, are close relatives of birds. Until a decade ago, members of this group such as Velociraptor were known only from northern continents, but a few fragmentary specimens have been found in the Southern Hemisphere in recent years. The cover shows a life reconstruction of Buitreraptor gonzalezorum, a newly discovered dromaeosaurid from La Buitrera in Patagonia, which is known from a nearly complete specimen. It is geologically oldest of the southern dromaeosaurids, and its completeness provides evidence that they are a distinct lineage that split from their northern relatives after the breakup of the supercontinent Pangaea towards the end of the Jurassic. The individual in the foreground is shown holding a juvenile Priosphenodon (see Nature 425, 609–612; 2003), a relative of the living tuatara, and another relict of a group with a global Jurassic distribution.