The study, which was conducted by Virginia Tech and University of Bristol researchers, was able to determine the reddish-brown shade of two extinct bat species. Researchers took fossils from these two bat species, both dating back some 50 million years ago, and were able to use fossil analysis to deduce what color the bats were back when they were still on Earth. The scientists also believe that their technique can be used to deduce the color of animals that roamed the earth up to 300 million years ago, provided that the fossils are well-preserved.
“We have now studied the tissues from fish, frogs, and tadpoles, hair from mammals, feathers from birds, and ink from octopus and squids,” said lead author Caitlin Colleary of the College of Science at Virginia Tech. “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.”
Delving into the above mentioned findings, the researchers said microscopic structures that were once thought to be fossilized bacteria are actually melanosomes. These are tiny organisms within cells that contain melanin, the pigment that gives skin its brown color, while also colorizing hair, feathers, and eyes.
Senior author Jakob Vinther of the University of Bristol had first found fossilized melanosomes in a fossil feather some seven years ago, and in the time since then, melanosome shapes have been utilized to see how marine reptiles are related to each other, and to detect colors in dinosaurs. Now the process has successfully been done in determining the color of an extinct mammal.
“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 Vinther in a statement, adding that the correlation of melanosome shape to melanin color is an “ancient invention” that can be used to find out an extinct animal’s color.
The researchers used a special instrument called a time-of-flight secondary ion mass spectrometer in order to spot the fossil makeup of the melanosomes and compare it against that of modern-day melanosomes. They also simulated the conditions that informed the formation of the fossils, in order to identify how melanin is chemically altered; specifically, they placed modern feathers in high temperatures to see how chemical signatures may have been altered in the millions of years that had since passed.
According to Colleary, the above methods were instrumental in helping her team see how melanin “chemically changes over millions of years,” which could be the key in determining previously unknown and inaccessible information in fossils.
Colleary and Vinther had carried out the study at the University of Bristol and the University of Texas-Austin, receiving funding from UT, the University of Bristol, and National Geographic.