The fossil foot of a ferocious flesh eating dinosaur has been uncovered in Argentina, it is reported in the weekly science journal Nature.
Neuquenraptor argentinus was a fierce meat-eater in the Late Cretaceous period
Neuquenraptor argentinus belonged to a group of dinosaurs called the deinonychosaurs, which are thought of as Northern Hemisphere animals.
The find suggests the creatures were more widespread than first thought.
"This is the first time an animal like this has been found in South America," said chief author Fernando Novas.
Deinonychosaurs were a close relative of birds. They included the famous Velociraptor, which was brought to life in the film Jurassic Park.
Generally, deinonychosaurs were small and lightly built, with deadly teeth and a distinctive sickle-shaped claw on their second toe, which was perfect for disembowelling prey.
So far, little is known about what N. argentinus looked like, but the characteristic sickle-shaped claw is present.
Given that this new deinonychosaur lived in the Late Cretaceous Period (about 75 million years ago), when the southern and northern continents had long since separated and were approaching their present day positions, the researchers think the animals must have been cosmopolitan creatures for millions of years.
In other words, they were probably roaming widely around Gondwana, the vast super-continent that began its split into our familiar southern and northern continents about 160 million years ago.
"What is new is the geographic distribution," said Dr Novas, a palaeontologist at the Argentine Museum of Natural Sciences in Buenos Aires. "This is the first time we can prove with firm evidence - here we have the foot - the presence of those animals in the Southern Hemisphere.
"Before it was thought that they were restricted to the Northern Hemisphere and Asia."
Neuquenraptor argentinus had the characteristic sickle-shaped claw
Neuquenraptor argentinus is slightly different from its Northern Hemisphere relatives, having had several million years of isolated evolution.
As the landmasses of Gondwana separated, populations of deinonychosaurs in the Northern and Southern hemispheres were very similar, although not identical. But as time passed, these populations gradually grew apart.
Dr Novas led an Argentine team who made the discovery while digging in a rocky, mountainous area in western Argentina, which has yielded many dinosaur fossils in recent years.
"This discovery modifies our understanding of the early evolutionary history of this group of dinosaurs and leads us to conclude that the northern and southern faunas during the Cretaceous were not as different as previously thought," co-author Diego Pol, of Ohio State University, US, told the BBC News website.
"This group, that previously characterised the dinosaur faunas of the Northern Hemisphere, has now to be reinterpreted as a worldwide distributed group, probably implying a much more ancient evolutionary history."