The Mesozoic world of dinosaurs and birds was not black-and-white at all, it seems. Canadian researcher Ryan McKellar discovered samples of colorful feathers that possibly belonged to an unknown dinosaur species of the late Cretaceous period.

The report was published on Thursday in the journal Science.

For more than two decades, paleontologists have been searching for dinosaur fossils with feathers, which would help explain the evolution of dinosaur descendants and of the early birds.

The newly discovered colorful feathers are small in number, but will provide novel insights regarding feather formation, said  McKellar. The preserved filaments display a wide range of pigmentation from nearly transparent to dark, but no larger-scale patterns are apparent.

After exploring 4,000 specimens  preserved in tree resin that later became amber, McKellar considered only 11 samples, which the journal Science described as the richest amber feather find from the late Cretaceous period, which was about 80 million years ago and came after the Jurassic period.

The samples of feathers range from black to brown. All 11 samples show the presence of a wide diversity of feather types at that time. One type of proto-feathers had a single bristle-like filament and simple clusters, while others samples are complex in structure with hook-like barbules that act like velcro; in modern birds, this keeps feathers in place during dives.

The feathers had been preserved in amber dating back to 70 million years ago. In the study, parallels were drawn between the structures of the feathers and those of the earliest non-flying dinosaurs, however, the feathers could have still been of flying dinosaurs. The feathers display pigmentation and adaptations for flight and diving, researchers reported.

Although scientists are unable to decide which feathers of the 11 specimens belonged to birds or dinosaurs, the filament structures are similar to other non-avian dinosaur fossils found before.

One researcher said that feathers had been found on much older fossils, but the new samples suggest that feathers continued to develop into a modern form, even after the extinction of dinosaurs.

There were no fossils or dinosaurs found in the area near Grassy Lake in southwestern Alberta where the feathers were discovered, but what was found showcases four evolutionary stages for feathers, said the study, suggesting that a range of dinosaurs and birds once nested, flew and swam there.

Only now are we beginning to understand just how diverse feather types were in the Mesozoic, roughly the age of dinosaurs from 250 million to 65 million years ago, said Mark A. Norell, a dinosaur paleontologist, at the American Museum of Natural History in New York.

Meanwhile, a team at the University of Manchester in England is testing a new study, The New York Times reported. They are using an advanced X-ray method to detect geochemical traces that are biomarkers in feathered fossils.

This is an exciting technique, a powerful technique, Dr. Norell said in an interview, but it is in a very preliminary state and needs to be refined a bit.