Scientists have reclassified a 300-million-year-old fossil, previously thought to be the world's oldest octopus, as a relative of the modern nautilus. The discovery, published in the journal Proceedings of the Royal Society B, reshapes understanding of cephalopod evolution.
Core Findings
Researchers used synchrotron imaging to examine the fossil, Pohlsepia mazonensis, and found tiny teeth inside that confirmed it was not an octopus but a nautiloid. The fossil, discovered in Illinois's Mazon Creek fossil beds, now represents the oldest recorded evidence of nautiloid soft tissue preservation.
Evolutionary Implications
The reclassification shifts the timeline of octopus origins from the Carboniferous to the Jurassic period. The fossil's teeth, arranged in 11 rows, differ from the 7-9 rows typical of octopuses, leading scientists to conclude it was a nautilus relative.
Scientific Process
Lead researcher Thomas Clements of the University of Reading described the fossil as challenging to interpret. The synchrotron imaging technique allowed scientists to peer inside the fossil without damaging it, revealing the decisive teeth structure. The study highlights how scientific knowledge evolves with new evidence and technology.
Broader Context
Cephalopods, including octopuses, squids, and cuttlefish, are known for their advanced nervous systems and lack of rigid skeletons. The discovery underscores the importance of soft tissue preservation in understanding ancient marine life.