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A specimen of Microraptor gui under UV light. The white arrows point to preserved tissue, the black arrows point to a "halo" around the body where feathers are not present, and the gray arrows point to preserved feathers. From the PLoS One paper.

Since 1996 paleontologists have found so many feathered dinosaurs that it has been impossible to keep up with them all. There are scores of exceptionally preserved specimens that have yet to be fully studied and published upon, but, according to a new study in PLoS One,  there is still plenty to learn about the few that have already been introduced in the literature.

Of the feathered dinosaurs discovered so far, Microraptor gui is among the most famous. Long flight feathers which were attached to its arms and legs and are plainly visible to the naked eye, made it a four-winged dinosaur. But until now scientists have been unsure whether some of the other preserved feathered around the body remained in their natural position (i.e. attached to the body) or had been moved around afterwards. To resolve this question, paleontologists David Hone, Helmut Tischlinger, Xing Xu and Fucheng Zhang decided to use UV light to see how the preserved feathers related to the rest of the body.

Paleontologists have been using UV light to study the details of fossils for a long time, but the practice had not yet been extended to the feathered dinosaurs of China. Under this light details that might elude scientists under normal lighting can more clearly be seen, and what the paleontologists found was that the feathers of Microraptor did indeed extend into the “halo” around the fossil that represented its body, and sometimes the feathers extended almost all the way to the skeleton. The feathers were not just strewn about as if they had fallen off after death; they were preserved in their natural positions.

This finding is important for two reasons. The first is that paleontologists can now be confident that the Microraptor specimen that was studied provides a good look at the external anatomy of the animal. More importantly, however, this sort of technique can be extended to the scores of similarly-preserved fossils from the same region. Using UV light, paleontologists will be able to better understand how feathers were attached to the bodies of dinosaurs, and added to new findings about the colors of feathered dinosaurs, scientists will be able to bring the past to life like never before.

For more on this study see the blog of its lead author, David Hone, called Archosaur Musings.

Hone, D., Tischlinger, H., Xu, X., & Zhang, F. (2010). The Extent of the Preserved Feathers on the Four-Winged Dinosaur Microraptor gui under Ultraviolet Light PLoS ONE, 5 (2) DOI: 10.1371/journal.pone.0009223