Oldest octopus fossil found to not be an octopus
Key Points:
- Pohlsepia mazonensis, once considered the oldest octopus fossil dating back 311-306 million years, has been reclassified as a decomposed, flattened nautiloid after advanced imaging techniques revealed no octopus-specific features.
- The fossil’s initial misidentification stemmed from its preservation as a two-dimensional stain in iron-rich nodules from the Mazon Creek Lagerstätte, which made interpreting its anatomy challenging and ambiguous.
- High-resolution synchrotron X-ray fluorescence, micro-CT scanning, and multispectral imaging showed the absence of octopus traits such as suckers, arm cirri, and ocular pigments, while revealing a radula with tooth patterns unique to nautiloids.
- This discovery makes Pohlsepia the oldest unequivocal evidence of nautiloid soft tissues in the Paleozoic fossil record and highlights the potential for re-examining other enigmatic fossils with modern imaging technologies.
- Researchers plan to continue applying these advanced methods to other Mazon Creek fossils, hoping to clarify the evolutionary history of ancient marine organisms and possibly uncover more surprising findings.