London, Jan. 23 (Reuters): Chinese scientists have discovered fossils of a feathered, four-winged dinosaur which they say provides new evidence of the origin of avian flight.
The creature, called Microraptor gui, is less than a metre-long and is thought to have glided from tree to tree, similar to flying squirrels, in an intermediary step before full, flapping flight.
“The new fossils provide the best example of the transition from dinosaurs to birds,” Xing Xu, of the Chinese Academy of Sciences in Beijing, said yesterday. “They are the link between the flightless dinosaurs and (flying) birds,” he said in an interview. For more than a century, palaeontologists have been debating whether flight originated from tree-dwelling creatures that glided or from ground animals that propelled themselves by running and frantically flapping their wings. “The new discovery... requires us to re-evaluate some classical work in dinosaur evolution, in particular the evolution of dinosaur locomotion,” Xu said.
The four-winged dinosaur, which is described in the science journal Nature, was found in the northeastern province of Liaoning, a fossil-rich area of China. It is a dromaeosaur — a sub-group of small, two legged predator which scientists believe shares a common ancestor with birds that lived about 130 million years ago.
Dromaeosaurs themselves belong to a group of dinosaurs called theropods which share about 100 anatomical features with birds, including a wishbone, swivelling wrists and three forward-pointing toes.
Xu and his colleagues believe the earliest ancestors of birds and dromaeosaurs had four wings and that the hind wings were lost with the evolution of flight.