What the study found
The study identifies the earliest finned octopuses (Cirrata, a group of octopuses with fins) from Late Cretaceous sediments as large invertebrate top predators. The authors report that these animals may have reached a total length of about 7 to 19 meters.
Why the authors say this matters
The authors conclude that their findings show that powerful jaws and the loss of superficial skeletons independently helped cephalopods and marine vertebrates become huge, intelligent predators. They also suggest these octopuses add an invertebrate example to an ocean food chain that was long thought to be dominated by large vertebrates.
What the researchers tested
The researchers studied exceptionally well-preserved fossil jaws from Late Cretaceous sediments dated to about 100 to 72 million years ago. They used the size and wear patterns on these jaws to identify the animals and infer how they fed.
What worked and what didn't
The fossil jaws were large and showed extensive wear, which the authors interpret as evidence of dynamic crushing of hard skeletons. Asymmetric wear patterns were also reported, and the authors interpret these as signs of lateralized behavior and advanced intelligence.
What to keep in mind
The abstract does not describe the full limitations of the study. The size estimate, behavioral interpretation, and predator role are all based on fossil jaws and their wear patterns from the available sediments.
Key points
- The study describes the earliest finned octopuses from Late Cretaceous sediments.
- The fossils are identified from huge, exceptionally preserved jaws and their wear patterns.
- The jaws show extensive wear consistent with crushing hard skeletons.
- Asymmetric wear is interpreted as evidence of lateralized behavior.
- The octopuses are estimated to have been about 7 to 19 meters long.
Disclosure
- Research title:
- Earliest octopuses were giant Cretaceous top predators
- Authors:
- Shin Ikegami, J. Mutterlose, Kanta Sugiura, Yusuke Takeda, Mehmet Oguz Derin, Aya Kubota, Kazuki Tainaka, Takahiro Harada, Harufumi Nishida, Yasuhiro Iba
- Institutions:
- Chuo University, DMG Mori (Japan), DMG Mori (Japan), Hokkaido University, Hokkaido University, Hokkaido University, Japan Synchrotron Radiation Research Institute, Niigata University, Osaka Metropolitan University, Ruhr University Bochum, Tokyo Metropolitan University
- Publication date:
- 2026-04-23
- OpenAlex record:
- View
- Image credit:
- Photo by ArtisticOperations on Pixabay · Pixabay License
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