The function of feathers on the Jurassic specimen, the Archaeopteryx, has left paleontologists scratching their heads for quite some time. The latest discovery of another skeleton of the organism is finally yielding some tentative answers.

Scientists constantly debate about the use of the Archaeopteryx's feathers on their hind limbs. Were they used for flight? Did they mostly just function as decorative plumage? Did the feathers work in conjunction with the feathered fore limbs to allow for a kind of four-winged gliding mechanism? Previous skeletons, many of them inadequately-preserved, hinted at these theories but never offered enough solid proof for one theory over the other. 

Now, an incredibly well preserved specimen is in the hands of German scientists who aim to find concrete evidence to put an end to the dispute. The paleontologists, from the Ludwig-Maximilians-Universität (LMU), have a fossil that shows the clearest representation of the 150-million-year-old's plumage. Their findings, however, show that the association between feather development and flight is more complex than scientists previously thought. They were published in Nature on July 2.

The findings suggest that the first Archaeopteryx feathers did not evolve for flight, but rather for display. The location and symmetry of the feathers on the hind limb show that the gliding theory is mostly likely incorrect, and that the primary function of these "trouser-like" feathers was for courtship behavior.

Since the specimen is considered a transition species between reptiles and birds, scientists compared the function and location of feathers on both to those on the Archaeopteryx. Predatory dinosaurs with feathers often used them for thermal insulation, while advanced predatory dinosaurs, primitive birds and, according to the new fossil findings, Archaeopteryx, likely used them for balancing, brooding, camouflage and display.

Yet the researcher's observations suggest that while Archaeopteryx feathers were not initially used for flight, they did evolve a secondary function for aviation. "Interestingly, the lateral feathers in the tail of Archaeopteryx had an aerodynamic form, and most probably played an important role in its aerial abilities," says first author Dr. Christian Foth. Thus, the specimen's ability to fly is not disproven, but more research must be done to figure out if, how, why and when this adaptation may have evolved.

This fossil is the 11th preserved specimen of the species found since the first intact fossil in 1861. It was found in Bavaria, like the other fossils, by a collector who registered it as a German Cultural Treasure and aims to keep it available for science. 

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