Seven 100-million-year-old feathers have been found perfectly preserved in amber in western France.
The feathers have features of both feather-like fibers found with some two-legged dinosaurs known as theropods and of modern bird feathers and they could fill in 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 Néraudeau 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, Perrichot said.
"It is entirely plausible that the feathers come from a dinosaur rather than from a bird," he said.