April 11, 2008 -- Seven feathers that either belonged to a non-avian dinosaur or an early bird have been discovered encased in amber in a remarkably vivid state of preservation, according to a recent Proceedings of the Royal Society B study.

The 100-million-year-old amber, excavated from a Charente-Maritime quarry in western France, was found near the fossilized teeth of a troodontid dinosaur. Troodontidae is a family of bird-like, two-legged dinos that, other fossils suggest, had feathers and laid eggs in nests, just as birds do today.

The teeth of dromaeosaurids -- another bird-like group including the famed Velociraptor -- were also found near the amber.

"These two non-avian dinosaur [groups] are currently known to be feathered and are thus possibly related to the fossil feathers from France," concluded the archaeological team, led by Vincent Perrichot, a researcher at Humboldt University's Museum of Natural History in Berlin.

In a separate but related finding, Malvina Lak of the University of Rennes in France recently found 356 prehistoric creepy crawlies -- including wasps, flies, ants and spiders -- trapped in 100-million-year-old amber excavated from a different site in southwestern France.

Both teams used a sophisticated X-ray technique called synchronotron holotomography to "see" inside the hunks of ancient amber.

"Amber fossils are characterized by an exceptional quality of preservation that allows a detailed observation of all tiny structures," Perrichot and his colleagues wrote.

When X-rayed, the amber chunk with the seven feathers, now housed at the National Museum of Natural History in Paris, revealed the feathers were lying side by side and "very probably originate from a single individual."

The feathers show what the scientists describe as an "intermediate and critical stage in the incremental evolution of feathers, which has been predicted by developmental theories but hitherto undocumented by evidence from both the recent and the fossil records."

The first feathers, it is thought, consisted of a base shaft securing many loose barbs, sort of like strands of hair tied together at one end. Those feathers may have been followed evolutionarily by an intermediate stage, represented by the feathers found in the ancient amber.

The seven feathers "have a structure unknown in bird feathers," but they also have a flattened shaft, which the researchers say is a "prerequisite for using them to fly."

Feather impressions found in other fossils of the dromaeosaur Sinornithosaurus and a still unnamed Chinese theropod had a similar structure.

Kevin Padian, a professor in the Department of Integrative Biology at the University of California at Berkeley and a curator at the university's Museum of Paleontology, doesn't rule out that the feathers could have belonged to a dinosaur, but he told Discovery News "their structure does not allow us to conclusively determine the source."

While ancient amber provides a window into ancient life, it's an incomplete one, said Lak. Fossils of dinosaurs, birds and other large creatures will probably never be found in such a way, she noted, simply because they can "escape from the resin before becoming trapped."