For centuries, we've only known dinosaurs through the fossilized bones they've left behind.  Now, researchers have found other  - more dramatic - remains.

Examples of ancient feathers ranging from the simple to the complex are now being studied. They were preserved in amber found in western Canada, researchers led by Ryan C. McKellar of the University of Alberta report in Friday's edition of the journal Science.

The amber-sealed dinosaur feathers range in age from 70 to 90-million years old.

Specimens include simple filament structures similar to the earliest feathers of non-flying dinosaurs — a form unknown in modern birds — and more complicated bird feathers "displaying pigmentation and adaptations for flight and diving," the researchers reported.

Indications of feathers have been found on much older fossils, and the new discoveries indicate feathers continued to develop into modern form before the extinction of dinosaurs, explained Norell, who was not part of the research team.