The 'mighty mouse', as affectionately named by its researchers for its similarity to today's field mouse, ran through the meadows of Germany's current Willerhausen village, three million years ago.
As published on Tuesday in Nature Communications, this incredibly well-preserved fossil of a mouse boasted reddish-brown fur on its main body and a snow-white belly.
Researchers know this thanks to a study led by UK-based scientists at the University of Manchester where an X-ray technique called spectroscopy as well as various imaging techniques were used.
This is the first time researchers have been able to discern the chemical signature of red fur or feathers in an ancient fossil. Chemical components for dark pigments such as black or brown, known as eumelanin, had previously been discovered.
However, this most recent paper has had a breakthrough in the ability to reconcile fossilized reddish or yellow pigment colors in the form of pheomelanin.
A colorful past
Until now, techniques for depicting the pigment of fossilized animals, integral when reconstructing extinct species, weren't able to identify different pigmentation such as the color red.
Phil Manning, professor at the University of Manchester and co-leader of the research, states "Life on Earth has littered the fossil record with a wealth of information that has only recently been accessible to science."
Manning continues, "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 study is a collaboration between researchers from the University of Manchester, and scientists from the U.S. Department of Energy’s SLAC National Accelerator Laboratory. The team used X-ray streaks from SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) and the Diamond Light Source (DLS) in the U.K. to assist them in their research.
"What we found is that the mouse is preserved in absolutely stunning detail, nearly all of the skeleton and most of the soft tissue of the body, head, feet, and tail can easily be recognized," stated Uwe Bergmann, research co-author and staff scientist at the SLAC National Accelerator Laboratory.
"The X-ray maps show that not only are structures preserved, but original biochemical information is resolvable. That was a wonderful surprise."
Red pigment is incredibly hard to preserve. But, it is not just about knowing that this mouse had reddish fur that is the important part, it is that "This has implications that there is hope of identifying pigments in many other fossils", as Bermann says.
Go back in order to move forward
It's not simply about looking into the past, as this revelation could also have a deep impact in the future of fossil research and preservation.
In a combined effort between physics, paleontology, geochemistry, and organic chemistry, from now on scientists will have a clearer idea of what to look for.
As Roy Wogelius, research co-author and geochemist at the University of Manchester, says "We understand now what to look for in the future and our hope is that these results will mean that we can become more confident in reconstructing extinct animals and thereby add another dimension to the study of evolution."