The wings of ancient birds and feathered dinosaurs that lived some 150 million years ago may have been less like those of modern birds than previously thought.

Credit: CARL BUELL/J. VINTHER/BRISTOL UNIV.

Contemporary birds share a common wing design, with a single feather layer. But Nicholas Longrich of Yale University in New Haven, Connecticut, and his colleagues identify separate layers in their fossil analyses of the wings of the Jurassic bird Archaeopteryx lithographica (pictured) and the Cretaceous feathered dinosaur Anchiornis huxleyi.

The slender feather shafts found in these prehistoric plumages would make the feathers weak by modern standards but, when stacked, may have formed a structure strong enough to generate lift. However, the layers would have limited the airflow through the wing, which is used by modern birds for take-off and low-speed flight, so these prehistoric flyers probably glided or parachuted down from trees, the authors say.

Curr. Biol. http://dx.doi.org/10.1016/j.cub.2012.09.052 (2012)