Samplings: May 2008

Print

Email

Three-dimensional reconstruction of a primitive feather 

© Perrichot/European Synchrotron Radiation Facility

A two-inch piece of amber discovered among thousands of others at the muddy bottom of a French quarry is helping scientists bridge a gap in their knowledge of the early development of feathers. The fossil dates to the Middle Cretaceous, around 100 million years ago, and encases seven beautifully preserved primitive feathers of a type never before seen, together with various arthropods and several types of microorganisms. Vincent Perrichot of the Museum of Natural History in Berlin, Germany, and four colleagues carefully cut the piece into twenty-two fragments. From one of the fragments, they isolated the ancient feathers and observed them in three dimensions, using scans, microtomography, and other sophisticated X-ray imaging techniques at the European Synchrotron in Grenoble, France. The feathers’ primitive feature—a flattened central shaft composed of not-yet-fused barbs—differs from those of all other feathers, both modern and fossilized, providing evidence for a key step in the evolution of feathers and thus the ability to fly. So whose feathers were they? Teeth from two species belonging to a group of feathered dinosaurs known as theropods were found in the same quarry as the amber, raising the possibility that the feathers came from a dinosaur. But the researchers would rather not make that call based on isolated feathers alone, since the feathers may well belong to a primitive bird. (Proceedings of the Royal Society B)