Ancient sea monsters had black skins or scales and these served critical purposes, such as for camouflage and sexual display, a new research suggests.
The study published January 8 in the journal Nature suggests that three reptiles that lived in the oceans millions of years ago, the ancient leatherback turtle, the toothy predator called mosasaurs and the dolphin-like reptile called ichthyosaurs, were near black.
The international team of researchers analyzed three exquisitely preserved fossils of an 86-million-year-old mosasaur; a 55-million-year-old leatherback turtle; and a 190-million-year-old ichthyosaur and found melanin preserved in the animals' fossilized skins. Melanin is the light absorbing pigment responsible for color in humans and animals.
According to Johan Lindgren, a mosasaur expert at Lund University in Sweden and lead researcher of the study, the animals' blackness likely helped them in a variety of ways. "The most sensational aspect of the study is that it can now be established that the analyzed ancient marine reptiles were, at least partially, dark-colored in life, something that probably contributed to more efficient thermoregulation, as well as providing means for camouflage and protection against harmful UV radiation," Lindgren said.
"The fossil leatherback turtle probably had a similar colour scheme and lifestyle as does Dermochelys. Similarly, mosasaurs and ichthyosaurs, which also had worldwide distributions, may have used their darkly coloured skin to heat up quickly between dives," the scientist added.
"Our results really are amazing. The pigment melanin is almost unbelievably stable. Our discovery enables us to make a journey through time and to revisit these ancient reptiles using their own biomolecules. Now, we can finally use sophisticated molecular and imaging techniques to learn what these animals looked like and how they lived," said Per Uvdal, one of the co-authors of the study. Uvdal works at the MAX IV Laboratory.
The study also suggests that darker-colored hides have long provided advantages to ocean dwellers for survival in diverse environments." While the presence of other undetected pigments cannot be ruled out, particularly dark pigmentation in these fossils suggests that they might have been able to live in more [extremely hot] environments or have used pigmentation patterns as camouflage in dark waters," shared evolutionary behavioral ecologist Ted Stankowich of California State University in Long Beach. "This work is a really cool first step to both understanding the external appearance of extinct marine creatures and using that information to make inferences about their lifestyle and behavior, which, unfortunately for behavioral ecologists, do not fossilize."
Mike Benton, professor of vertebrate palaeontology from the University of Bristol, said the findings were a fascinating discovery. "Determining colour in an ancient organism is more than a smart trick. For many animals, colour is crucial for sexual signalling, for camouflage, or for warning - think of stripy snakes - and so contributes hugely to the success of the evolution of the groups," he said.
