Scientists discover world’s oldest octopus fossil was basically catfishing us

The marine creature once hailed as the world’s oldest octopus has officially lost its title after new research revealed the 300-million-year-old fossil was not an octopus in the first place.

The specimen, long listed by Guinness World Records as the oldest known octopus, actually belonged to a shelled cephalopod that is more closely related to the nautilus, scientists say.

The Pohlsepia mazonensis fossil has been debated for decades, but a new study led by zoologist Dr Thomas Clements of the University of Reading has finally solved the mystery.

He explained: “It is a very difficult fossil to interpret.

“If you’re a cephalopod researcher, superficially it looks very similar to a deep-water octopus.”

The hand-sized fossil was discovered in Mazon Creek, Illinois; it was a treasure trove of prehistoric life dating back long before dinosaurs roamed the planet.

When researchers identified it as an octopus in 2000, they pushed back the evolutionary timeline of the eight-armed creatures significantly.

The next oldest confirmed octopus fossil is only 90 million years old, leaving a surprising gap that many scientists have difficulty reconciling.

To re-examine the fossil, Clements’ team used the synchrotron, a machine that fires electrons at extreme speeds to produce ultra-bright beams of light.

They discovered a radula in the rock: a ribbon-like structure covered in rows of tiny teeth.

Most importantly, there were 11 teeth in each row. While modern octopuses have seven or nine, ancient nautiloids had more; which immediately breaks the original classification.

Clements added: “This one has too many teeth, so it can’t be an octopus.”

The pattern matched another fossil from the same region of Paleocadmus pohli, a known nautiloid species.

Researchers believe the creature’s shell likely decomposed before fossilization, making misidentification more likely.

After the study was published in the Proceedings of the Royal Society B, Guinness World Records confirmed that the title of “oldest octopus fossil” would be retired.

Managing editor Adam Millward called the findings a “fascinating discovery” and said the organization would review the new evidence.