Preserved in amber.
The researchers combed through thousands of minuscule amber nuggets from nearly 80 million years ago. Among them they found 11 M&M-sized globules with traces of ancient feathers and fuzz. A number resembled modern feathers—some fit for flying and others designed to dive. And unlike fossils, the amber preserved colors too: white, gray, red and brown.The research was published in Science back in 2011:
The unusual find suggests a wide array of plumed creatures populated the time period—sporting everything from seemingly modern feathers to their filament-like forebears—and that even by this early date, feathers had become specialized, for example, for diving underwater...
The currently accepted evolutionary-developmental model for feathers consists of a stage I morphology characterized by a single filament: This unfurls into a tuft of filaments (barbs) in stage II. In stage III, either some tufted barbs coalesce to form a rachis (central shaft) (IIIa), or barbules (segmented secondary branches) stem from the barbs (IIIb); then, these features combine to produce tertiary branching (IIIa+b). Barbules later differentiate along the length of each barb, producing distal barbules with hooklets at each node to interlock adjacent barbs and form a closed pennaceous (vaned) feather (stage IV). Stage V encompasses a wide range of additional vane and subcomponent specializations. Most modern birds possess stage IV or V feathers or secondary reductions from these stages...Red-feathered underwater dinosaurs. I love it.
The snapshot of Campanian feather diversity from Canadian amber is biased toward smaller feathers, subcomponents of feathers, feathers that are molted frequently, and feathers in body positions that increase their likelihood of contacting resin on tree trunks. Despite these limitations, the assemblage demonstrates that numerous evolutionary stages were present in the Late Cretaceous, and that plumage already served a range of functions in both dinosaurs and birds.
Via Discover Magazine and Neatorama.