US EditionResearchers Reclassify 300-Million-Year-Old Octopus Fossil as Nautiloid Relative
Synchrotron scans found 11 tooth-like structures and a radula, leading researchers to say the fossil is a nautiloid relative, not an octopus.
- On Wednesday, April 8, 2026, researchers published findings in the Proceedings of the Royal Society reclassifying the 300 million year old fossil Pohlsepia as a nautiloid relative rather than an octopus.
- Originally discovered in Illinois and described in 2000, scientists interpreted the fossil's decayed features as evidence of an octopus, pushing the known origin of octopuses back by at least 150 million years.
- Thomas Clements and his team used synchrotron imaging to uncover a radula with at least 11 teeth, which matched those of the nautiloid Paleocadmus rather than octopuses, which typically have seven or nine.
- This reclassification removes Pohlsepia from the Guinness Book and World Records as the oldest octopus, while extending the nautiloid soft tissue record back by around 220 million years.
- The discovery redraws the cephalopod family tree, suggesting octopuses appeared much later during the Jurassic period, while the split between octopuses and their ten-armed relatives occurred in the Mesozoic era.
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The story of an old 300 million years fossil has been cited after scientists have discovered that it does not actually belong to the oldest characteristics of the world, as it was previously believed, to CNN. In fact, fossil belongs to a modern-born animal that has its tentacles and a cochille ...
The oldest known octopus fossil may have been a nautilus, suggesting the marine creature may have belonged to a different group than initially thought, scientists say.
Tiny teeth allow scientists to determine that 300 million-year-old fossil is not an octopus
World's oldest octopus isn't really an octopus
A reconstruction drawing of the species Pohlsepia mazonensis, originally believed to be an ancient octopus but reclassifed after new research (Picture: Dr Thomas Clements, University of Reading/Cover Media) It’s one of the world’s most famous octopus that turned out not to be an octopus at all. This 300-million-year-old fossil was thought to be the earliest known example of one of the eight-legged sea-dwellers, and even features in the Guinness …
"Weird blob" creature thought to be the world's oldest octopus isn't an octopus after all. Here's what scientists found.
Scientists have found evidence that a 300-million-year-old sea creature previously thought to be the world's oldest octopus is actually a nautilus relative.
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