Washington, March 12 : Scientists have found seven dino-era feathers preserved in amber in western France, which could fill a key gap in the puzzle of how dinosaurs gave rise to birds.
According to a report in National Geographic News, Vincent Perrichot of the University of Kansas's Paleontological Institute led the research team, which found the tiny feathers encased in a lump of amber, a fossilized tree resin, in a quarry in the Poitou-Charentes region of France in 2000.
The hundred-million-year-old plumage has features of both feather-like fibers found with some two-legged dinosaurs known as theropods and of modern bird feathers, according to the researchers.
This finding fuels speculation that the fossils could fill a key gap in the puzzle of how dinosaurs gave rise to birds.
The find provides a clear example "of the passage between primitive filamentous down and a modern feather," said team member Didier Neraudeau of the University of Rennes in France.
The study team isn't sure yet whether the feathers belonged to a dino or a bird.
"But fossil teeth from two dino families thought to have been feathered were excavated from rocks just above the layer that contained the amber," said Perrichot.
"It is entirely plausible that the feathers come from a dinosaur rather than from a bird," he added.
Studies have suggested that primitive feathers first evolved in flightless dinosaurs that generated heat internally and so would have benefited from the insulation that down can provide.
Feathers later evolved for use in flight, the theory holds, although experts debate whether birds' immediate ancestors were tree-dwelling, gliding dinosaurs or terrestrial dinos that ran at high speeds and eventually lifted off the ground.
"Either way, the amber-encased feathers show for the first time the transition from downy filaments toward an aerodynamic, planar shape that enabled flight," said Perrichot.
According to Nick Longrich, of the University of Calgary in Canada, a bird-fossil expert, the newfound feathers are around 50 million years younger than the first known flying bird, Archaeopteryx, which lived about 150 million years ago.
"Obviously this animal, from whom the feathers came from, isn't directly ancestral to anything except later dinosaurs, but it's quite likely that we are seeing aspects of the ancestral feather structure," he said.
"So the animal isn't transitional', but it may preserve a transitional structure," said Longrich.