Overview
- An international team’s study, published Wednesday in Proceedings of the Royal Society B, used ultra‑bright X‑ray scans to reveal a radula, a toothy tongue found only in mollusks, hidden inside the Pohlsepia fossil.
- The radula preserved at least 11 teeth per row, which does not fit octopuses that have seven or nine, and it matches the nautiloid Paleocadmus pohli known from the same Mazon Creek site in Illinois.
- The authors conclude the single Pohlsepia specimen is a decomposed nautiloid whose shell likely separated during decay, creating a shape that mimicked octopus traits in the rock.
- Removing Pohlsepia as an octopus erases a key Paleozoic data point and shifts support toward a Jurassic origin for modern octopuses, bringing fossil evidence and timing estimates into closer agreement.
- Guinness World Records says it will rest the “oldest octopus” title, and the Field Museum’s specimen now counts as the oldest known nautiloid soft tissue, highlighting how new imaging can overturn long‑held IDs.