Fossil Pigment Shows Colors Of 50 Million-Year-Old Mammals

A team of researchers found that it is possible to find out pigment in mammal fossils that can help to locate the colors of extinct species.

With the technique, researchers concluded that two 50 million-year-old bat species were reddish-brown, reported Virginia Tech. It was a technique that could help to paint the pictures of species as old as 300 million years.

"We have now studied the tissues from fish, frogs, and tadpoles, hair from mammals, feathers from birds, and ink from octopus and squids," said Caitlin Colleary, a doctoral student of geosciences in the College of Science at Virginia Tech. and lead author of the study. "They all preserve melanin, so it's safe to say that melanin is really all over the place in the fossil record. Now we can confidently fill in some of the original color patterns of these ancient animals."

Earlier, scientists thought that melanosomes, or organelles within cells that contain melanin were fossilized bacteria. The first one of these were recognized in a dinosaur feather in 2008, whose shape is used to determine the color of marine reptiles and other dinosaurs. The first mammal was thus analysed.

"Very importantly, we see that the different melanins are found in organelles of different shapes: reddish melanosomes are shaped like little meatballs, while black melanosomes are shaped like little sausages and we can see that this trend is also present in the fossils," said Jakob Vinther, a molecular paleobiologist at the University of Bristol . "This means that this correlation of melanin color to shape is an ancient invention, which we can use to easily tell color from fossils by simply looking at the melanosomes shape."

Apart from just examining the shape of melanosomes, researchers can also determine colors with instruments called a "time-of-flight secondary ion mass spectrometer" that shows its chemical signature.

Hence, heat was used to recreate the environment of a fossil, as well as show how the melanin changes over time.

"By incorporating these experiments, we were able to see how melanin chemically changes over millions of years, establishing a really exciting new way of unlocking information previously inaccessible in fossils," Colleary said.

A recent edition of the journal Proceedings of the National Academy of Science  published the article.