Ruffling Dinosaur Feathers

Dinosaur and early bird feathers trapped in amber around 80 million years ago provide unprecedented insight into the evolution of plumage.

Sep 15, 2011
Cristina Luiggi

A feather barb within Late Cretaceous Canadian amber that shows some indication of original coloration. The oblong brown masses within the dark-field photomicrograph are concentrated regions of pigmentation within the barbules. In this specimen, the overall feather color appears to have been medium or dark-brown.IMAGE © SCIENCE/AAAS

After rummaging through thousands of amber inclusions housed at the University of Alberta and the Royal Tyrrell Museum of Paleontology in Canada, researchers discovered 11 amber encased-feather fossils that provide the most detailed picture yet of early feather evolution. The feathers, described in a Science paper published today (September 15), likely adorned early birds and non-avian dinosaurs living between 70 and 85 million years ago—back when the Western Canadian landscape was a wetland covered in coniferous forests—and they represent various stages of feather evolution: from primitive single filaments, to multiple filaments joined through a single stem, to the intricate hook-like barbules found in modern birds. The latter feather type was a surprising find, according to Mark A. Norell, curator of fossil reptiles, amphibians, and birds at the American Museum of Natural History, who wrote an accompanying Science perspective, since barbules are found in modern birds whose feathers are specialized for diving and swimming, such as in the freshwater diving birds, grebes. “Earlier examples of feathers from Late Cretaceous (90 to 94 Ma) amber did not display such diversity,” he explained.

In addition to preserving minute, structural details often not appreciated in traditional fossils, the amber inclusions also preserved color. “The amber filaments display a wide range of pigmentation, ranging from nearly transparent to dark,” the researchers, led by Ryan C. McKellar of the University of Alberta, stated in the paper. Such diversity in feather structures suggests “that complex modern feather adaptations had already appeared before the extinction of the non-avian dinosaurs” around 65 million years ago, Norell wrote.

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