Nav: Home

In a first, researchers identify reddish coloring in an ancient fossil

May 21, 2019

Menlo Park, CA - Researchers have for the first time detected chemical traces of red pigment in an ancient fossil - an exceptionally well-preserved mouse, not unlike today's field mice, that roamed the fields of what is now the German village of Willershausen around 3 million years ago.

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 that is pivotal when reconstructing exactly 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.

Building the foundation

Until recently, the researchers had focused on the traces of elements known to be associated with eumelanin, which in previous experiments revealed dark and light patterns in the feathers of the first birds, including Archaeopteryx the famous fossil that first offered a clear link between dinosaurs and birds.

In 2016, co-author Nick Edwards, scientist at SLAC, led a study that demonstrated the potential to differentiate between eumelanin and pheomelanin in modern bird feathers. That work provided a chemical benchmark for this most recent paper, which for the first time showed it's possible to detect the elusive red pigment, which is far less stable over geological time, in ancient fossils.

"We had to build up a strong foundation using modern animal tissue before we could apply the technique to these ancient animals," Edwards said. "It was really a tipping point in using chemical signatures to crack the coloring of ancient animals with soft tissue fossils."

To reveal the fossil patterns in the mighty mouse, the Manchester team used SSRL and DLS to bathe the fossils in intense X-rays. The interaction of those X-rays with trace metals found in pigments allowed the team to reconstruct the reddish coloring in the mouse's fur.

"The fossils used in this study preserve amazing structural detail, but our work emphasizes that such exceptional preservation may also lead to extraordinary chemical detail that changes our understanding of what is possible to resolve in fossils," said Manchester professor of geochemistry Roy Wogelius, who co-led the study. "Along the way we learned so much more about the chemistry of pigmentation throughout the animal kingdom"

Adding a new dimension

The key to their work was determining that trace metals were incorporated into the fossilized mouse fur in exactly the same way that they bond to pigments in animals with high concentrations of red pigment in their tissue.

"As you do research in a particular area, the scope of your techniques might evolve," says Uwe Bergmann, co-author and a distinguished staff scientist at SLAC who led the development of the x-ray fluorescence imaging used in this research. "The hope is that you can develop a tool that will become part of the standard arsenal when something new is studied, and I believe the application to fossils is a good example."

The effort, which involved physics, paleontology, organic chemistry and geochemistry, informs the scientists what to look for in the future.

"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," Wogelius says.
-end-
The team also included researchers from the Fujita Health University in Japan; the Stanford PULSE Institute; the College of Charleston in South Carolina; the Children's Museum of Indianapolis; the University of Southampton in the U.K.; and the Joint Paleontology Foundation in Spain. The fossils were made available to the study by the University of Go?ttingen in Germany.

SSRL is a DOE Office of Science user facility. Funding was provided by the U.K. Natural Environment Research Council.

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science. To learn more, please visit http://www.slac.stanford.edu.

SLAC National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

DOE/SLAC National Accelerator Laboratory

Related Evolution Articles:

Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.
Evolution of aesthetic dentistry
One of the main goals of dental treatment is to mimic teeth and design smiles in the most natural and aesthetic manner, based on the individual and specific needs of the patient.
An evolution in the understanding of evolution
In an open-source research paper, a UVA Engineering professor and her former Ph.D. student share a new, more accurate method for modeling evolutionary change.
Chemical evolution -- One-pot wonder
Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth -- under the same environmental conditions.
Catching evolution in the act
Researchers have produced some of the first evidence that shows that artificial selection and natural selection act on the same genes, a hypothesis predicted by Charles Darwin in 1859.
Guppies teach us why evolution happens
New study on guppies shows that animals evolve in response the the environment they create in the absence of predators, rather than in response to the risk of being eaten.
Undercover evolution
Our individuality is encrypted in our DNA, but it is deeper than expected.
Evolution designed by parasites
In 'Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation,' published in the September 2019 issue of The Quarterly Review of Biology, Marco Del Giudice explores an overlooked aspect of the relationship between parasites and their hosts by systematically discussing the ways in which parasitic behavior manipulation may encourage the evolution of mechanisms in the host's nervous and endocrine systems.
Tracing the evolution of vision
The function of the visual photopigment rhodopsin and its action in the retina to facilitate vision is well understood.
Directed evolution comes to plants
Accelerating plant evolution with CRISPR paves the way for breeders to engineer new crop varieties.
More Evolution News and Evolution Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.