An international team that includes Penn paleontologists is unearthing the appearance of ancient birds by using the world’s most powerful X-rays.

The Penn contingent includes Phillip Manning, an adjunct professor in the Department of Earth and Environmental Science, and Peter Dodson, a professor in both the Department of Earth and Environmental Science and the School of Veterinary Medicine’s Department of Animal Biology. They collaborated with Roy Wogelius of the University of Manchester, Uwe Bergmann of Stanford University and other researchers.

Manning and Dodson have long studied fossils of the earliest birds, which lived more than 100 million years ago, but their partnership with researchers from Manchester and Stanford opened a new avenue of investigation: an innovative technique based on synchrotron radiation to identify copper-bearing molecules in fossilized feathers.

“When you’re getting a good suntan, melanin forms in your skin. There are many forms of melanin, and some are found in the dark feathers of birds, but copper is always bound into its structure,” Manning says. “It’s only since we’ve been using a synchrotron—a vast accelerator that generates intense X-rays a hundred million times brighter than the sun—that we can see the chemical detail in fossils and show that the copper complexes we found were originally part of the animal.”  

To distinguish the copper that was bound in melanin from other kinds requires immense precision. By measuring the energy released from atoms when they are bombarded with high-powered X-rays, researchers can pinpoint the molecules in which they reside.

“While our work doesn’t yet allow you to diagnose color, you can get the concentration and distribution of pigments,” Dodson says. “In other words, you can work out monochrome patterns, which may tell us something about camouflage or other traits relevant to natural selection of the species.” 

The team is confident that further research with this technique will enable them to fully diagnose color via fossil chemistry. They also believe that this is only one of many applications the technique will have.