Revoking the Title: The Oldest Octopus Fossil Isn’t an Octopus After All

For years, Pohlsepia mazonensis was celebrated as the oldest octopus fossil known to science, earning a mention in the Guinness World Records. However, new findings from researchers, led by University of Reading's zoologist Thomas Clements, reveal that the prehistoric creature is actually a relative of the nautilus.

The fossil's true identity came to light using synchrotron technology, which unveiled dental structures incompatible with those of an octopus. Instead, the teeth align with those found in a fossil nautiloid. This discovery has led to the retraction of its title, as confirmed by Guinness World Records.

Clements explains that earlier misidentifications occurred because the creature likely decomposed and lost its shell before fossilization. While it may no longer hold the octopus title, the finding enriches the Field Museum's collection as it now hosts the world's oldest soft tissue nautilus.