The study revealed that the extinct creature, affectionately nicknamed “mighty mouse” by the authors, was dressed in brown to reddish fur on its back and sides and had a tiny white tummy. The results were published today in Nature Communications.
The international collaboration, led by researchers at the University of Manchester in the U.K., used X-ray spectroscopy and multiple imaging techniques to detect the delicate chemical signature of pigments in this long-extinct mouse.
“Life on Earth has littered the fossil record with a wealth of information that has only recently been accessible to science,” says Phil Manning, a professor at Manchester who co-led the study. “A suite of new imaging techniques can now be deployed, which permit us to peer deep into the chemical history of a fossil organism and the processes that preserved its tissues. Where once we saw simply minerals, now we gently unpick the ‘biochemical ghosts’ of long extinct species.”
The research team, which includes scientists from the U.S. Department of Energy’s SLAC National Accelerator Laboratory, used X-ray beams from SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) and the Diamond Light Source (DLS) in the U.K.
Painting a picture of the past
Color plays a vital role in the selective processes that have steered evolution for hundreds of millions of years. But until recently, techniques used to study fossils weren’t capable of exploring the pigmentation of ancient animals, which is pivotal when reconstructing what they looked like.
This most recent paper marks a breakthrough in the ability to resolve fossilized color pigments in long-gone species by mapping key elements associated with the pigment melanin, the dominant pigment in animals. In the form of eumelanin, the pigment gives a black or dark brown color, but in the form of pheomelanin, it produces a reddish or yellow color.