Archaeopteryx Fossil Sheds Light on the Evolution of Feathers in Birds and Dinosaurs

Archaeopteryx is known as one of the oldest and most distinct species of early bird. Now, paleontologists have uncovered a new specimen that reveals surprisingly and previously unknown features of the creature's plumage.

So far, 11 specimens of Archaeopteryx have been discovered, revealing further insight into this so-called "basal bird." This latest specimen, though, shows a bit more about the evolution of feathers and its relationship to avian flight.

"For the first time, it has become possible to examine the detailed structure of the feathers on the body, the tail and, above all, on the legs," said Oliver Rauhut, one of the researchers, in a news release. In fact, it seems as if primordial feathers didn't actually evolve in connection to flight-related roles.

Predatory dinosaurs, known as therapods, once had body plumage to provide thermal insulation. These dinosaurs actually predated Archaeopteryx. Their feathers were not used for flight but, instead, may have been used for camouflage, brooding and display. In contrast, the feathers of Archaeopteryx appear to have an aerodynamic form and were probably important in its aerial abilities.

By examining the new specimen, the researchers have been able to clarify the taxonomical relationship between archaeopteryx and other species of feathered dinosaur.  The diversity in form and distribution of feather tracts is particularly striking. For example, among dinosaurs that had feathers on their legs, many had long feathers extending to their toes, while others had shorter down-like plumage. If the feathers evolved first for flight, there would have been more functional constraints that limited their range of variation.

"It is even possible that the ability to fly evolved more than once within the theropods," said Rauhut. "Since the feathers were already present, different groups of predatory dinosaurs and their descendants, the birds, could have exploited these structures in different ways."

The findings are published in the journal Nature.