nk from 160-million-year-old giant squid is essentially identical to today's squid ink.
The discovery suggests that the ink and the ink-screen escape mechanism of squid have not evolved much (if at all) since the Jurassic Period. The finding, published in the latest Proceedings of the National Academy of Sciences, might just prove that if it isn't broken, nature isn't going to fix it.
Researchers came to the determination after studying ink sacs from two giant squid fossils found two years ago in England. The primary component of squid ink is melanin, a substance that gives skin, hair and certain other things color. It's why squid ink is so dark in color. (On a side note, some studies show that squid ink has some anti-tumor properties.)
Since melanin hasn't changed much over the years, this research indicates that melanin could be preserved intact in the fossils of a range of organisms. Recent research has revealed, for example, the color of certain dinosaurs and other long-gone animals.
"Though the other organic components of the squid we studied are long gone, we've discovered through a variety of research methods that the melanin has remained in a condition that could be studied in exquisite detail," co-author John Simon said in a press release. He's a chemistry professor and the executive vice president and provost at the University of Virginia.
One of the ink sacs studied is the only intact prehistoric ink sac ever discovered.
Simon and his colleagues used a combination of direct, high-resolution chemical techniques to determine that the melanin had been preserved. The researchers also compared the chemical composition of the ancient squid ink remains to that of modern squid ink from Sepia officinalis, a squid common to the Mediterranean, North and Baltic seas.
"It's close enough that I would argue that the pigmentation in this class of animals has not evolved in 160 million years," Simon said. "The whole machinery apparently has been locked in time and passed down through succeeding generations of squid. It's a very optimized system for this animal and has been optimized for a long time."
Usually animal tissue, made up mostly of protein, degrades quickly. All that's then left of prehistoric animals is their skeletal remains -- or so we used to think. The preservation of melanin proves that some organic matter can survive.
"Out of all of the organic pigments in living systems, melanin has the highest odds of being found in the fossil record," Simon said.
Look for more such studies to come.