X-rays of an extinct mouse fossil that is three million years old have revealed an old red-colored pigment for the first time.
Researchers discovered that the well-preserved animal looked a lot like a common field mouse but had a reddish fur on its back and sides and a small white belly.
Unlike a field mouse, it is thought that the creature – by the research team as & # 39; Mighty mouse & # 39; – lived in what is now the German village of Willershausen.
Figuring out the colors of petrified animals was a guesswork for scientists, even if they encountered fossils that contained feather feathers, scales or fur.
Using a new technique, the team was able to identify the chemical signature of the pigment that gives red hair its color.
Color is an important part of how animals have adapted to survive for millions of years and has played a key role in evolution. It is now hoped that the traces of red pigment discovered in the old fossils could lead to a new dimension in the study of evolution.
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Researchers were able to untangle the story of the most important pigments in the old mouse fossil to show that it probably had a reddish and brown fur on its back and sides and a white belly. On the left, an artist's view of the creature that lived three million years ago
Ten years ago, scientists used high-energy X-rays to identify a pigment called eumelanin that colors skin, hair, and other tissues black, brown, and gray.
But a pigment, called pheomelanin, that gives skin and hair a pink or red tint is hard to identify.
The team, led by scientists from the University of Manchester, looked at trace metals found in the pigment of modern feathers.
They found that eumalanine contained copper while pheomelanin, which contained a reddish hue, contained sulfur and zinc.
When they scanned the mouse fossils, they found the characteristic overlap of sulfur and zinc in areas where it was visible on the fossil.
They used X-ray spectroscopy and multiple imaging techniques to detect the delicate chemical signature of pigments in the mouse.
Study co-leader Professor Phil Manning, from the University of Manchester, said: “Life on Earth has littered the fossil record with a wealth of information that has only recently become accessible to science.
& # 39; A series of new imaging techniques can now be used, allowing us to look deeply into the chemical history of a fossil organism and the processes that have preserved its tissues.
The most important fossil investigated in this study is a 3 million year old, extinct species of field mouse from Germany. The mouse is approximately 7 cm long
X-rays reveal an extinct mouse. It is the first time – an exceptionally well-preserved mouse, not like a field mouse, that lived around three million years ago. Pictured, a pigment scan with mouse colors.
& # 39; Where we once just saw minerals, we now carefully get the & # 39; biochemical spirits & # 39; of long extinct species. & # 39;
He explained that color plays a vital role in the selective processes that have driven evolution for hundreds of millions of years.
But until recently, the techniques used to study fossils were unable to investigate the pigmentation of ancient animals that is essential in reconstructing exactly what they looked like.
Professor Manning said the new study represents a breakthrough in the ability to dissolve petrified color pigments in long-extinct species by mapping these elements, the dominant pigment in animals.
HOW DO THEY FIND THE CHEMICAL TRACKS OF RED PIGMENT?
The key to their work was to identify trace metals that were absorbed into their soft tissues by ancient organisms and to compare them with the ways of incorporation into living species.
The chemistry shows that the trace metals in the mouse fur are bound to organic chemicals in exactly the same way that these metals are bound to organic pigments in animals with high concentrations of red pigment in their tissue.
The scientists have also translated the chemical findings into sound waves, so that people hear frequencies of sound associated with different pigment colors that occur in the fossils.
To be absolutely certain of their findings, modern comparison standards were analyzed, both by synchrotron radiation and by pigment chemistry specialists based at Fujita Health University in Japan.
& # 39; 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, & # 39; he said.
To reveal the fossil patterns in the mouse, the team bathed the fossils in intense X-rays.
The interaction of those X-rays with trace elements in pigments enabled the team to reconstruct the reddish coloring in the fur of the mouse.
The geochemistry of Manchester Professor Roy Wogelius, who co-led the research, said: & # 39; The fossils that were used preserve amazing structural details, but our work emphasizes that such exceptional conservation can also lead to extraordinary chemical details which change our understanding of what is possible to solve. fossils.
Along the way we learned so much more about the chemistry of pigmentation throughout the animal kingdom. & # 39;
He explained that the key to their work was to establish that trace elements were absorbed in the fossilized mouse fur in exactly the same way as they bind to pigments in animals with high concentrations of red pigment in their tissue.
Professor Wogelius said: & # 39; Our hope is that these results will increase our confidence in reconstructing extinct animals and thereby add a new dimension to the study of evolution. & # 39;
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