Giant Octopus May Have Ruled Cretaceous Oceans
AI analysis of fossil jaws suggests a giant octopus up to 19 meters (62 ft) long could once have topped marine food chains in the Late Cretaceous.
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In the oceans of the Late Cretaceous, roughly 100 to 72 million years ago, a gigantic octopus may have occupied the very top of the food chain. Reaching up to 19 meters (62 feet) in length, the creature was identified through AI-based analysis by a team that included researchers from Hokkaido University. The findings were published on April 24 in the journal Science.
The discovery challenges a long-standing assumption in paleontology: that apex marine predators over the past 400 million years were always vertebrates.
Octopuses are invertebrates, so their soft bodies rarely fossilize. Their hard, beak-like jaws are an exception, and these can be preserved. Working with 27 jaw fossils from the Late Cretaceous, the research team developed two techniques to study them in detail.
They ground the fossils down layer by layer along with the surrounding rock, capturing thousands of cross-sectional images. The team also used a technique known as "digital fossil mining," in which AI reconstructs three-dimensional images from the data.
Rivaling Top Predators
The largest jaw fossils measured about 10 centimeters (4 inches), and the full jaw likely reached around 15 centimeters when reconstructed—pointing to a ferocious carnivore capable of crushing hard-shelled or bony prey.
Estimates based on jaw size suggest earlier species ranged from 3 to 8 meters (around 10–26 feet) in length, while later species from around 86 million years ago may have reached 7 to 19 meters. That would put them on par with dominant predators of the era, including mosasaurs (up to 17 meters), plesiosaurs (up to 12 meters), and sharks (up to 10 meters).
Yasuhiro Iba, an associate professor of paleontology at Hokkaido University, said the findings mark a turning point for the field. "We are now able to see long spans of evolution and ancient ecosystems that we previously couldn't," he said. "Paleontology is entering a new phase."
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Author: Juichiro Ito, The Sankei Shimbun
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