Earliest octopuses were giant Cretaceous top predators

What the study found: The study reports that the earliest finned octopuses (Cirrata, a group of octopuses with fins) were invertebrate top predators in Late Cretaceous oceans. The authors describe these animals as huge, with estimated total lengths of about 7 to 19 meters.
Why the authors say this matters: The authors conclude that these findings show powerful jaws and the loss of superficial skeletons convergently transformed cephalopods and marine vertebrates into huge, intelligent predators. They also suggest these octopuses rivaled contemporaneous giant marine reptiles.
What the researchers tested: The researchers described Late Cretaceous fossils, focusing on exceptionally well-preserved fossil jaws and their wear, to identify the earliest finned octopuses from sediments dated to about 100 to 72 million years ago. They used the jaw preservation and wear patterns to infer feeding behavior and body size.
What worked and what didn't: The fossil jaws showed extensive wear, which the authors interpret as evidence of dynamic crushing of hard skeletons. Asymmetric wear patterns further suggest lateralized behavior, which the abstract links to advanced intelligence. The study also estimates a total length of roughly 7 to 19 meters.
What to keep in mind: The abstract does not describe experimental limits in detail. The identification, behavioral inference, and size estimate are all based on fossil jaws and their wear as presented in the available summary.

Key points

• The study describes the earliest finned octopuses as invertebrate top predators from the Late Cretaceous.
• The fossils were identified from exceptionally well-preserved jaws and their wear.
• The jaw wear is interpreted as evidence of crushing hard skeletons.
• Asymmetric wear patterns are said to suggest lateralized behavior and advanced intelligence.
• The octopuses are estimated to have reached about 7 to 19 meters in total length.