X-Rays Give a New Look at Archaeopteryx

Scientists have known about the feathered dinosaur Archaeopteryx for over a century and a half, but scientists are using new techniques to get a better look at this creature and its close relatives. Within the past few months alone, paleontologists have described how they have used laboratory techniques to determine what color some feathered dinosaurs might have been, how Archaeopteryx grew, how feathers were arrayed around the body of Microraptor and, in a new study published in PNAS, how some Archaeopteryx fossils may contain more fine detail than was previously appreciated.

Specimens of Archaeopteryx are rare and vary greatly in terms of their preservation, and one way in which paleontologists keep track of these fossils is by giving them informal names. The first skeleton to be discovered, the one which was purchased for the British Museum of Natural History (now the Natural History Museum) and described by Richard Owen, is known as the "London specimen," and one of the more recent specimens to come to the attention of scientists has been called the "Thermopolis specimen" after its home at the Wyoming Dinosaur Center in Thermopolis, Wyoming. This latter specimen formed the basis of the new study in which an interdisciplinary team of scientists used X-ray technology to try and detect the chemical composition of the fossil.

By using a kind of scanning technology called SRS-XRF, the scientists expected to detect the distribution of chemicals in the skeleton and the surrounding rock. This would allow them to get a better idea of how the skeleton became fossilized and what it may have looked like in life. When the scientists ran a scan looking for phosphorous, for example, the shafts of the dinosaur's arm feathers became highlighted, showing the chemical traces of the structures that were otherwise missed. A different scan also showed that the skeleton preserved a high amount of zinc, meaning that at least some of the original bone chemistry of the dinosaur had been preserved. Despite being over 145 million years old, some of the original chemical material of the fossil remained intact.

This study, like the report of the use of UV light to detect otherwise hidden patterns on fossils, is significant because it provides a new way for scientists to look at fossils. By using SRS-XRF technology, paleontologists can achieve a better understanding of how much original material might remain in a fossil and how that skeleton came to be preserved. Likewise, this method can help illuminate structures on slabs which are invisible to the naked eye, something that will no doubt have important applications for the exceptionally preserved specimens of feathered dinosaurs in China. Through such interdisciplinary work, paleontologists are better able to understand the life of the past and how it came to be preserved, and hopefully this study will help spur further research on other fossils.

Bergmann, U., Morton, R., Manning, P., Sellers, W., Farrar, S., Huntley, K., Wogelius, R., & Larson, P. (2010). Archaeopteryx feathers and bone chemistry fully revealed via synchrotron imaging Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1001569107

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Riley Black is a freelance science writer specializing in evolution, paleontology and natural history who blogs regularly for Scientific American.