Extinct ocean reptiles now appear in color

Dark patches in the fossilized tail fin of a nearly 200-million-year-old ichthyosaur show traces of skin pigmentation and suggest that the animal had dark coloration covering its entire body.

Johan A. Gren

When ichthyosaurs were alive, some of the dolphin-like sea creatures may have had dark-colored skin covering their entire bodies.

Many ocean-dwelling animals are darker on their upward-facing side and lighter on their underside. But chemical analyses of dark traces in fossilized tissue show that a 190-million- to 196-million-year-old ichthyosaur had skin pigments that made the animal uniformly dark, researchers suggest January 8 in Nature.

The team also found skin pigments, including melanin, in fossil tissue of a 55-million-year-old leatherback turtle and an 86-million-year-old mosasaur. The results help scientists understand how skin pigments may have helped animals live in colder parts of the world and expands the understanding of coloration in extinct animals beyond fossilized feathers.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.