The world of paleontology has been shaken by a recent discovery that challenges our understanding of the ancient past. The fossil once hailed as the world's oldest octopus, dating back 300 million years, has been reclassified as a relative of the nautilus, a multi-tentacled mollusc with an external shell. This revelation, published in the journal Proceedings of the Royal Society B: Biological Sciences, solves a decades-old puzzle and provides the oldest preserved soft tissue from a nautiloid ever discovered.
The story begins with the fossil, Pohlsepia mazonensis, found in the US state of Illinois. It was initially celebrated as the world's oldest octopus, a claim that has now been retracted. The key to this discovery lies in the use of advanced technology, specifically a synchrotron, which fired X-rays deep into the specimen, revealing a set of teeth hidden within the rock for 300 million years. These dental structures were the deciding factor in ruling out any octopus classification.
Dr. Thomas Clements, a lecturer in invertebrate zoology at the University of Reading and lead author of the study, explains the significance of this finding. "It turns out the world's most famous octopus fossil was never an octopus at all," he says. "It was a nautilus relative that had been decomposing for weeks before it became buried and later preserved in rock, and that decomposition is what made it look so convincingly octopus-like. Using modern techniques showed us what was beneath the surface of the rock, which finally cracked the case. We now have the oldest soft tissue evidence of a nautiloid ever found, and a much clearer picture of when octopi actually first appeared on Earth."
The specimen's appearance was altered by partial decay before fossilization, which preserved it for millions of years looking different from its living form. Within a ribbon-like body part known as a radula, researchers counted 11 tooth-like structures per row, a configuration that ruled out an octopus entirely since octopi possess either seven or nine such structures. Instead, the tooth count pointed towards a mollusc classification, leading scientists to conclude that the creature was more closely related to the modern nautilus.
This discovery fundamentally reshapes our understanding of when octopi first appeared on Earth. An analysis published in 2000 had pushed octopus origins back 150 million years to the Palaeozoic era, but the new research refutes a Palaeozoic origin for eight-armed cephalopods. Instead, the evidence now suggests that octopi evolved during the Jurassic period, between 200 and 145 million years ago.
Dr. Clements further emphasizes the impact of this finding: "It's amazing to think a row of tiny hidden teeth, hidden in the rock for 300 million years, have fundamentally changed what we know about when and how octopi evolved."
The Guinness World Records, which had previously recognized the fossil as the world's oldest octopus, has acknowledged the new evidence and will be updating the record. Adam Millward, managing editor of Guinness World Records, stated, "This is a fascinating discovery and congratulations to the University of Reading on their research. We will be resting the original title and look forward to seeing the new evidence."
In conclusion, this discovery highlights the importance of scientific inquiry and the potential for groundbreaking revelations in the field of paleontology. It also serves as a reminder that our understanding of the past is constantly evolving, and new evidence can challenge and reshape our existing knowledge.
