Scientists reclassify Pohlsepia mazonensis as a nautiloid relative
Updated
Updated · SciTechDaily · May 10
Scientists reclassify Pohlsepia mazonensis as a nautiloid relative
14 articles · Updated · SciTechDaily · May 10
Using synchrotron imaging, researchers found tiny teeth in the 300-million-year-old Illinois fossil, first described in 2000, and reported the findings in Proceedings of the Royal Society B.
The scans showed a radula with at least 11 teeth per row, ruling out an octopus and indicating a decomposed nautiloid related to Paleocadmus pohli.
The reclassification removes the fossil's record as the oldest octopus, sets a new oldest soft-tissue nautiloid record by about 220 million years, and suggests octopuses arose later, in the Jurassic.
After decades of misidentification, what tiny hidden feature revealed the 'oldest octopus' was actually a completely different ancient creature?
If the world's oldest octopus fossil is a fake, when did these intelligent predators actually first appear on Earth?
*Pohlsepia* Is Not an Octopus: New Technology Forces Rewrite of Cephalopod Evolution Timeline
Overview
In April 2026, a major scientific re-evaluation overturned the long-held belief that Pohlsepia mazonensis was the world's oldest octopus. New research revealed that this fossil, first identified as an octopus in 2000 and accepted for 25 years, is actually a relative of the nautiloid group. This discovery dramatically reshaped our understanding of cephalopod evolution, showing that octopuses appeared much later in Earth's history than previously thought. The reclassification of Pohlsepia fundamentally changed the timeline for octopus origins and highlights how new evidence can transform scientific knowledge.