You knew I’d have to read an article titled Earliest octopuses were giant top predators in Cretaceous oceans. How cool is that? And then they’ve illustrated it with some very appealing figures.

Body size estimation of Late Cretaceous octopuses.
The graph shows an allometric relationship between the length of the jaw and mantle in long-bodied species of extant finned octopus . The name of the corresponding species is shown along each growth curve. The sizes of N. jeletzkyi and N. haggarti based on their largest specimen are indicated by black vertical lines. Reconstruction of these two species, the extant giant squid, and gigantic vertebrate predators in the Late Cretaceous are shown with their maximum total length.

Also, the abstract promises much.

Top predators drive changes in ecosystem structure. For the last ~370 million years, large-sized vertebrates have dominated the apex of the marine food chain, while invertebrates have served as smaller prey. Here we describe invertebrate top predators from this “age of vertebrates,” the earliest finned octopuses (Cirrata) from Late Cretaceous sediments (~100 to 72 million years ago), as identified based on huge, exceptionally well-preserved fossil jaws and their wear. This extensive wear suggests dynamic crushing of hard skeletons. Asymmetric wear patterns further indicate lateralized behavior, suggesting advanced intelligence. With a calculated total length of ~7 to 19 meters, these octopuses may represent the largest invertebrates thus described, rivaling contemporaneous giant marine reptiles. Our findings show that powerful jaws, and the loss of superficial skeletons, convergently transformed cephalopods and marine vertebrates into huge, intelligent predators.

But does the paper deliver? Sad to say, it doesn’t. I was disappointed on how far the authors stretched an interesting technique to reach an excessive conclusion.

What they did was collect fossil octopus beaks and subject them to grinding tomography — basically shaving away the rock, photographing each exposed slice, and using an AI to help reconstruct a detailed 3-D image of the beak that allowed them to view the wear and tear on the beak’s surface, presumably seeing the damage acquired as they chewed their way through their Cretaceous prey. The entirety of the data in the paper is an analysis of scratches and wear on these beaks.

Huge lower jaws of fossil octopuses and of an extant giant squid.
(A and B) The largest lower jaws of the Late Cretaceous finned octopus species N. jeletzkyi [(A) NMNS DS00042 3LmvTpM] and N. haggarti [(B) KMNH IvP 902001]. Both specimens show extensive loss of jaw material caused by wear. (C) A lower jaw of the extant giant squid Architeuthis dux (NSMT-Mo 85956), a species having the largest jaw among modern cephalopods. (A) is a digital fossil jaw visualized as a 3D model; (B) is an exceptionally well-preserved nondigital fossil jaw; and (C) is a modern jaw dissected from a carcass of ~10 m total body length. Solid lines indicate the extension of striation on the outer surface of the hood and broken lines show the estimated outline of the rostrum without wear. The hood and lateral walls lost by weathering, shown as shadowed areas, are reconstructed based on the holotype and specimens in fig. S4. (A) and (C) are exhibited in a mirrored position. Scale bar, 20 mm.

That’s good stuff. No data too small — it’s all data. But wait: this paper contains nothing but measurements of beaks, but manages to expand this into a whole set of conclusions about the marine ecosystem.

These wear patterns suggest that Late Cretaceous giant Cirrata were active carnivores that frequently crushed hard shells and bones. The long scratches distributed on wide areas of their jaw reflect the dynamic use of the entire jaw for dismantling prey. Asymmetric loss of the jaw edges suggests lateralized behavior, which has been linked to a highly developed brain and cognition. This, in turn, suggests that the earliest octopuses already possessed advanced intelligence. Laterality is known in modern octopuses, whose high intelligence matches that of vertebrates. The exceptionally large jaws of adult N. jeletzkyi and N. haggarti suggest a strong bite force because cephalopod jaw muscles enlarge as the jaw size increases. The long lateral walls in their jaws revealed by the new digital specimens reported here show that Nanaimoteuthis had large jaw muscles. The chipping on both the rostrum and jaw edge was caused by strong shear stress beyond the yield point of the most robust part of the jaw. The transverse cracks in N. haggarti are probably a trace of larger shear failures. These large fractures thus suggest a powerful bite. In giant Cirrata, the jaws are smaller than those of contemporaneous Cretaceous vertebrate top predators, which measure ~1.7 m in length. Instead of using a large mouth, the long and flexible arms of octopuses serve for catching large prey. The giant Cirrata probably consumed large prey with their long arms and jaws, playing the role of top predators in Cretaceous marine ecosystems.

All we’ve got are scratches on beaks, with extrapolation from beak size to overall size. From that we leap to the conclusion that these giant octopuses were rivals to mosasaurs, plesiosaurs, ichthyosaurs, and sharks. We assume they’re top predators in the absence of actual evidence of predation or their role in the ancient ecosystem.

Convergent evolution among marine top predators in the Paleozoic–Mesozoic.
This model shows the acquisition of jaws and the reduction of superficial skeletons in the evolutionary history of marine vertebrates (top) and cephalopods (bottom) to become top predators. The gray horizontal bars show the chronological range of some selected groups of vertebrates and cephalopods. For cephalopods, stepwise reductions of skeletons are indicated by the blue background.

I’m not even going to touch the idea that asymmetric scratches are good evidence of high intelligence.

I am reminded of the speculations of Mark McMenamin, who thought circular shapes in Triassic sediments were evidence of a gigantic Kraken. He also found a broken piece of rock that he extrapolated to claim it was the tip of a giant kraken beak.

At least McMenamin’s extravagant conclusions weren’t getting published in Science.