Melanin, a black pigment, was responsible for the coloration of mosasaurs, ichthyosaurs, and ancient turtles according to new research published in the Jan. 8, 2014, edition of the journal Nature by Johan Lindgren from Lund University in Sweden and an international group of biologists and paleontologists.
The researchers found melanin in the soft tissue remains that were obtained from the skin of a 55 million-year-old leatherback turtle, the scales of an 85 million-year-old mosasaur, and the tail fin of a 196 to 190 million-year-old ichthyosaur. Melanin is extremely stable and has remained in the small bits of ancient reptile’s soft tissues for millions of years.
Melanin confers a black color. The researchers consider that the monasaur, a land and water living lizard, the ichthyosaur, a member of a group of large marine reptiles that had flippers, and the turtle were all or mostly black or shades of black in color.
The most likely color scheme was a dark back and a lighter and possibly white under side. The color scheme would have been an adaptation that served a functional purpose in species studied because the species are related.
The black color provided the potential for the animals to regulate their body temperature. The coloration also may have served as a protection from ultraviolet radiation and as camouflage protection from predators. The function of the pigment was verified in a modern species of leatherback turtle (Dermochelys) that is almost completely black.