Lund University researchers have identified the color of three marine animals that swam the ancient waters millions of years ago.

The scans of fossilized skin from three aquatic reptiles - a 55 million-year-old leatherback turtle, an 86-million-year-old giant sea lizard, mosasaur, and a 190 to 196-million-year-old 'dolphin-like' creature called ichthyosaur, have revealed the color of their skin as black.

Researchers found melanin in the animal's soft tissue remains. The creature's dark color provided several benefits - regulation of body temperature, acting as a natural camouflage and protection against harmful UV radiation.

Previously, scientists could only speculate the colors of these species. But now, they conducted chemical tests on the soft tissues to determine the color. The tests were conducted at the SP Technical Research Institute of Sweden and MAX IV Laboratory, Lund University, Sweden.

The researchers said that both mosasaurs and leatherback turtles had an almost entirely black back. The giant sea lizards are relatives of the leatherback turtle. On the other hand, the ichthyosaurs were consistently dark-colored throughout their life.

This is the first time that the color of any extinct marine animal has been identified. The fossils comprised of skeletal remains, besides the dark skin patches.

"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," Per Uvdal, one of the co-authors of the study, and an employee at the MAX IV Laboratorym said in a press release.

During the era of dinosaurs, gigantic reptiles such as mosasaurs and ichthyosaurs dominated the seas. Both ichthyosaurs and mosasaurs became extinct during the Cretaceous Period, but leatherback turtles l survive till today.

The scans not only helped the researchers identify their color but also provided details of their appearance.

Mosasaurs might have grown up to 15 meters long while Ichthyosaurs are believed to have grown longer than the ancestors of lizards (Mosasaurs).

The study has been published in the journal Nature.