Oldest Octopus Fossil Reclassified as Nautiloid

A fossil previously identified as the oldest octopus, Pohlsepia mazonensis, has been re-examined and determined to be a decomposed nautiloid. This specimen, found in Illinois and dated to the late Carboniferous period, had challenged existing theories on cephalopod evolution. Advanced imaging techniques, including X-ray fluorescence and micro-CT scanning, revealed that features initially interpreted as octopus anatomy were actually mineral deposits and body outlines. The reclassification suggests that crown coleoids, which include octopuses, squid, and cuttlefish, likely diverged much later in evolutionary history.