What the study found
The study found evidence that the earliest finned octopuses, called Cirrata, were invertebrate top predators in Late Cretaceous oceans. The authors report that these animals may have reached about 7 to 19 meters in total length and could have rivaled giant marine reptiles.
Why the authors say this matters
The authors conclude that their findings show cephalopods, a group that includes octopuses, and marine vertebrates independently evolved powerful jaws and the loss of external skeletons to become large, intelligent predators. They suggest this changes the picture of who occupied the top of marine food chains during the so-called age of vertebrates.
What the researchers tested
The researchers examined exceptionally well-preserved fossil jaws from Late Cretaceous sediments, dated to about 100 to 72 million years ago. They used the jaws' size and wear patterns to identify the animals as early finned octopuses and to infer aspects of feeding behavior.
What worked and what didn't
The fossil jaws were large enough to support a calculated total length of about 7 to 19 meters. Extensive wear suggests the animals crushed hard skeletons, and asymmetric wear patterns indicate lateralized behavior, which the authors interpret as a sign of advanced intelligence.
What to keep in mind
The conclusions are based on fossil jaws and their wear, not on complete animals, so the rest of the body form is inferred rather than directly observed. The abstract does not describe other limitations.
Key points
- The earliest finned octopuses are identified as top predators from the Late Cretaceous.
- Fossil jaws show extensive wear consistent with crushing hard skeletons.
- Asymmetric wear patterns are reported as evidence of lateralized behavior.
- The animals are estimated to have been about 7 to 19 meters long.
- The authors say cephalopods and marine vertebrates convergently evolved powerful jaws and loss of superficial skeletons.
Disclosure
- Research title:
- Earliest octopuses were giant Cretaceous marine 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
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