"Long before it's in the papers"
July 05, 2011

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Metal traces help scientists “color in” fossilized animals

July 1, 2011
Courtesy of the University of Manchester
and World Science staff

Sci­en­tists say they have tak­en a big step in learn­ing the col­ors of the first birds and some oth­er an­cient an­i­mals, us­ing traces of cop­per found in the fos­sils.

A new anal­y­sis in­clud­ed the old­est beaked bird known, the 120 mil­lion year old Con­fu­ciu­sor­nis sanc­tus, and the 110 mil­lion year old Gan­sus yu­me­nen­sis, which looks like the mod­ern grebe and rep­re­sents the old­est ex­am­ple of mod­ern birds.

White shows the dis­tri­bu­tion of cal­ci­um in this bird's neck feath­ers, which in turn is con­trolled by met­al traces of dark pig­ments, re­search­ers say. This would mean the downy feath­ers were orig­i­nal­ly dark in this bird, Con­fuc­ius­or­nis sanc­tus.  (Im­age cre­at­ed by Greg­o­ry Stew­art/SLAC)

Scientists say they have taken a big step in learning the colors of the first birds and some other ancient animals, using traces of copper found in the fossils. A new analysis included the oldest beaked bird known, the 120 million year old Confuciusornis sanctus, and the 110 million year old Gansus yumenensis, which looks like the modern grebe and represents the oldest example of modern birds. “Copper can be mapped to reveal astonishing details about colour in animals that are over 100 million years old,” said University of Manchester, U.K. geochemist Roy Wogelius. He is the lead author of a paper on the findings published in the June 30 advance online edition of the journal Science. “Even more amazing is to realize that such biological pigments,” or molecules responsible for much biological coloring, “can now be studied throughout the fossil record,” he added. That can work “probably back much further than the 120 million years we show in this publication.” Wogelius and colleagues joined scientists at SLAC National Accelerator Laboratory in the U.S. and used a machine called the Stanford Synchrotron Radiation Lightsource to bathe fossils in intense X-rays. The interaction of these X-rays with the chemistry of each fossil let the recognise the chemistry of eumelanin, an dark pigment, in feathers from dino-birds and the eye of a 50-million-year-old fish. Eumelanin is probably the most important pigment in the animal kingdom and gives dark shading to human hair, reptile skin, and feathers, the researchers said. The key was identifying and imaging trace metals incorporated by ancient and living organisms into their soft tissues, in the same way that all living species do today, including humans. Without essential trace metals, key biological processes in life would fail and animals either become sick or die. Using a new technique called rapid scan X-ray fluorescence imaging, the team tracked down these essential trace metals, which survive even after pigment-containing compartments of cells break down. “The fossils we excavate have vast potential to un lock many secrets on the original organism’s life, death and subsequent events impacting its preservation before and after burial,” said Phil Manning, a senior author on the paper and Un ivers ity of Manchester palaeontologist. “To un pick the complicated chemical archive that fossils represent requires a multi disciplinary team that can bring in to focus many areas of science. In doing this, we un lock much more than just palaeontological information, we now have a chemical roadmap to track similar pigments in all life.”