Ancient sea reptiles are finally showing their true colors. Researchers investigated skin remnants from ancient leatherback turtles and ichthyosaurs and mosasaurs, which resembled fish. The researchers found that all three creatures were covered in black skin or scales, with reason: The coloration may have helped camouflage them and protect them from UV rays, and may also have acted as a method of temperature control, grabbing the sun's heat much like black asphalt does in the sunshine, lead author Johan Lindgren explains to LiveScience.
The scientists probed the fossil samples using "complex techniques" including energy-dispersive X-ray microanalysis; they found the appearance of "oval bodies" that were verified as melanosomes. The Los Angeles Times explains that eumelanin was most heavily present in these pigment packets; it results in black and gray color. "Every living animal out there has eumelanin, so that by itself is not surprising," says Lindgren. "What is surprising is the sheer concentration of these fossilized melanosomes." In the future, similar techniques might be used to figure out the coloration of land animals, too, he noted.