160-million-year-old skin pigment found

Well-preserved fossil

Scientists have discovered a well-preserved sac of the common skin pigment, melanin, from 160-million-year-old fossils of a well-known sea creature.

While rest of the giant squid’s body had been fossilised, two ink sacs containing the pigment magically survived the onslaught of time. This is the first ever isolation of preserved soft tissues from Jurassic era, which may throw new light on the subject.

The finding suggests that the ink-screen escape mechanism of the giant squid has not evolved since the Jurassic period, and that melanin could be preserved intact in the fossils of a range of organisms.

“It opens up a new window in paleontology. Globally, searches are going on to look for other soft tissues which may have been preserved for millions of years,” Suryendu Dutta, an assistant professor at the IIT and one of the members of the team that identified and analysed the sample said. Dutta alongwith his colleagues from eight institutes of from the US, UK and Japan detected an intact melanin in the 160 -million-year-old fossilised cephalopod ink sacs.

Cephalopods are a class of common marine animals that can throw inks at predators when attacked. The family includes octopus, squids and cuttlefish. The two giant squid ink sacs contain melanin, which is essentially identical to the melanin found in the ink sacs of modern-day squid.

Given that melanin appears to have survived fossilisation, the authors in their paper published in the “Proceedings of National Academy of Sciences” on Monday, reasoned that other biologically relevant organic compounds might lie undiscovered in the fossil record. In the Jurassic-age, deposits in the UK, they found eumelanin – one of the two forms of the common skin pigment.

A comparison of chemical signatures between the Jurassic era sample and modern age cuttlefish Sepia officinalis, found in the Mediterranean, North, and Baltic Seas, suggest close similarity between the two.