The ‘oldest octopus’ in the world isn’t an octopus after all, scientists find

The story of a 300 million-year-old fossil has been rewritten after scientists discovered it did not actually belong to the world’s oldest octopus as previously thought.

In fact, it belongs to an animal related to a modern nautilus, which has tentacles and an external shell, according to a study published Wednesday in the journal Proceedings of the Royal Society B.

“We basically used a broad selection of new analytical techniques to uncover hidden anatomical features in the rock,” lead study author Thomas Clements, a senior lecturer in invertebrate zoology at the University of Reading, England, told CNN on Thursday..

“And we were able to determine that this is not an octopus, but rather a very decomposed nautiloid, which is a relative of modern nautiluses.”

The fossil, named Pohlsepia mazonensis, was found at the Mazon Creek site just south of Chicago, Illinois.

Paleontologists have long been intrigued by this fossil because it is much older than the oldest known octopus, which dates back around 90 million years.

Clements explained that the animal decomposed for weeks before being buried, giving its fossil an octopus-like appearance, leading many scientists to conclude that octopuses had lived much earlier than previously thought.

However, others questioned whether that was actually the case because some features such as the length and shape of its arms weren’t what was expected, Clements said.

Mistaken identity

As a result, he decided to re-examine the fossil using new scientific techniques that were not available when the first analysis was published in 2000.

“We used a huge selection of new techniques,” he said, including using a scanning electron microscope and doing geochemistry work.

But the fossil still refused to reveal its true identity.

“We weren’t going anywhere,” Clements said. “I was pretty frustrated.”

Things changed when a colleague invited him to scan the fossil using synchrotron imaging, a technique described by the University of Reading as using beams of light brighter than the sun. This technique “generates the most powerful X-rays in the world,” Clements explained.

“This revealed anatomical characters hidden just beneath the surface of the rock, so you can’t see them visually when you look at the fossil,” Clements said.

The team had found a radula, a feeding structure with rows of teeth. There were at least 11 per row in the fossil, while octopuses only have seven or nine, according to a statement from the University of Reading.

“It was these little teeth that we found that allowed us to identify that it was not an octopus,” he added.

Clements said the research demonstrates the power of new technologies to advance our scientific understanding.

“Not only are they becoming more available, but they are also becoming more affordable, which is revolutionizing paleontological research,” he said, pointing to the use of synchrotrons to discover ancient proteins and biomolecules, as well as engineering techniques originally designed to test building materials to determine the force of a dinosaur bite.

“A lot of people think of paleontology as a very dusty science,” Clements said. “But in reality, we are an incredibly innovative science.”

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