University of Virginia

The discovery of preserved ink sacs from a Jurassic-era giant cephalopod has revealed that the squid's inky escape mechanism hasn't changed much in the last 160 million years.

The cephalopod fossils were discovered two years ago in England. An international team of researchers, who published their finds in Proceedings of the National Academy of Sciences, used a combination of direct, high-resolution chemical techniques to determine if the pigment melanin had been preserved.

It had, so the team compared the chemical composition of the fossil melanin to the melanin in the ink of a modern day cuttlefish -- and they found a match.

"It's close enough that I would argue that the pigmentation in this class of animals has not evolved in 160 million years," said John Simon, chemistry professor at University of Virginia.

It proves that nature adheres to the age-old mantra "if it's not broken, don't fix it." Simon says, "the whole machinery apparently has been locked in time and passed down through succeeding generations of cuttlefish. It's a very optimised system for this animal and has been optimised for a long time."

Organic material is rarely preserved for hundreds of millions of years -- in fact, one of the the ink sacs studied is the only intact prehistoric ink bag that's ever been found -- but melanin is highly resilient to degradation over the course of vast amounts of time.

"Out of all of the organic pigments in living systems, melanin has the highest odds of being found in the fossil record," explains Simon. "That attribute also makes it a challenge to study. We had to use innovative methods from chemistry, biology and physics to isolate the melanin from the inorganic material."


Latest on