Scientists have unveiled the skin color of three, ancient marine reptiles, suggesting that the pigment that is preserved in fossilized skin analysed at SP Technical Research Institute of Sweden and MAX IV Laboratory, Lund University, Sweden, proves that these animals were, not completely but somewhat, dark-coloured.
The new findings “are marvelous, so cool,” says Anne Schulp, a vertebrate paleontologist at the Naturalis Biodiversity Center in Leiden, the Netherlands, who was not the part of the research. “This is paleontology well beyond the bones, and the team’s arguments make perfect sense.”
“This is great! When I commenced finding out at Lund College in 1993, the film Jurassic Park had just been produced, and that was just one of the most important reasons why I obtained fascinated in biology and palaeontology. Then, twenty years ago, it was unthinkable that we would at any time uncover biological stays from animals that have been extinct for lots of thousands and thousands of years, but now we are there and I am very pleased to be an aspect of it,” said Johan Lindgren, scientist at Lund University in Sweden, and leader of the international research team that has studied the fossils.
Scientists have now evolved a new technique to map the chemical traces of soft tissues in the rocks surrounding fossils. Previously soft tissues were not mostly preserved in the record. The chemical traces aid in visualizing the residual pigments. Previously the attention was given on fossil birds and preserved remains of their feathers, said Lindgren. Now, he and his colleagues are utilizing the same techniques to analyze the fossils of ancient marine reptiles.
The three sets of fossils are presently in museums in Denmark, England, and Texas. The fossils are made up of skeletal remains, along with dark skin patches that have masses of micrometre-sized, oblate bodies. The fossils refers to creatures from different eras, a leatherback turtle that lived about 55 million years ago, a giant marine lizard mosasaur a 98-66 million years old creature, and an ichthyosaur that used to swam the seas around 190 million and 196 million years ago. All three were air-breathers, thus they can be said to have spent enough time at the surface or in the shallow, well-lit portions of the seas.
At a close observation with a scanning electron microscope dense layers of tiny, rugby ball–shaped structures ranging between 0.5 and 0.8 micrometers long can be seen clearly. These tiny bits resemble the pigment-bearing structures (called melanosomes) in shape and size found in the skin and scales of modern-day lizards and in the feathers of birds. Their shape suggests the pigments were black; melanosomes that lend a red or yellow color are typically spherical, according to Lindgren.
The leatherback turtle and the mosasaur, had pigments on the upper surfaces of their bodies. Studies suggest that this dark-above-and-light-below color scheme, known as countershading, helps provide camouflage and UV protection. The ichthyosaur was found to have dark pigments all over its body.
The team’s research “is very interesting, and it’s not trivial,” says Mike Benton, a vertebrate paleontologist at the University of Bristol in the United Kingdom. “Several years ago, people would have said we’d never be able to tell what colors ancient creatures were,” he notes. “But here we are.”