A 90-MILLION-year-old dinosaur with striking bird-like features may force scientists to rewrite part of the family tree of the extinct reptiles, suggesting that flight evolved in two separate evolutionary paths. The creature found in Argentina is the earliest known dromaeosaur - a group of predator dinosaurs which includes the velociraptor, one of the stars of the movie Jurassic Park.

The discovery of an almost complete fossil skeleton at La Buitrera in Neuguen province in Patagonia has caused a stir among paleontologists.

It dates from before the break-up of the ancient super-landmass formed the northern and southern hemisphere continents of Laurasia and Gondwana.

Scientists now think dromaeosaurs in the separated continents took different evolutionary paths. That divergence might have led to flight evolving twice - once in birds and once among the Gondwanan dromaeosaurs.