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Researchers say they've unearthed evidence for what may be the largest invertebrate ever described, an ancient, enormous octopus. Here's science reporter Ari Daniel.
ARI DANIEL, BYLINE: Fossils usually form from bones and other hard materials. Soft parts - not so much. So something like an octopus, which is almost entirely soft, has been harder to come by in the fossil record. Jorg Mutterlose is a paleontologist at Ruhr University Bochum in Germany.
JORG MUTTERLOSE: There are very few, very rare records about the octopus and their evolution.
DANIEL: But more than a decade ago, a Japanese paleontologist approached Mutterlose with an idea - to examine the fossilized contents of big rocks that had formed on the seafloor some a hundred million years ago in what's now northern Japan. The researchers first cut these rocks into thin slices.
MUTTERLOSE: And then taking a picture of the remnants of the animals which have been preserved.
DANIEL: Allowing a 3D reconstruction of any fossils. And there, locked inside were...
MUTTERLOSE: Jaws.
DANIEL: Octopus jaws.
MUTTERLOSE: Which is very similar to the beak of a bird, parrot-like, consisting of a lower jaw, which is like a shovel.
DANIEL: And an upper jaw. Octopus jaws are hard, so they can fossilize. The animals use them like we do, to chomp down on food.
MUTTERLOSE: The opening is much too small to digest a large animal, so they need to tear it apart into pieces with their arms, which are very strong. And then they come up with food to the mouth.
DANIEL: The specimens came from two known extinct species, but these lower jaws were the biggest ones ever found for an octopus. So Mutterlose and his colleagues used their size to estimate the body size of the animals. Their calculations suggested the octopuses were probably gargantuan, each one larger than a school bus, likely the biggest invertebrates ever identified, rivaling other great apex predators of the time. Closer inspection of the specimens revealed numerous chips and scratches.
MUTTERLOSE: So obviously, something happened to the jaws.
DANIEL: That something was likely the consumption of prey with hard shells - things like shrimp, bivalves and lobsters - that would have worn away the jaws as they were crushed, leaving marks behind. These were active carnivores feasting on crunchy creatures, mere crackers for these krakens. In addition, the right side of the jaws tended to be more worn than the left side.
MUTTERLOSE: Single-sided usage might indicate that the brain was already fairly well developed.
DANIEL: Suggesting, says Mutterlose, that these early octopuses may have already displayed the advanced intelligence they're known for today. All this from a handful of old jaws.
MUTTERLOSE: Just a few fossil findings may shed very new light on the evolution of the biosphere.
DANIEL: The results are published in the journal Science. Fernando Fernandez-Alvarez is a zoologist at the Spanish Institute of Oceanography who wasn't involved in this study.
FERNANDO FERNANDEZ-ALVAREZ: I felt amazed. I wasn't expecting any octopus of this magnitude.
DANIEL: He says the findings paint a vivid picture of the ocean ecosystem of the late Cretaceous, one that would have been filled with large and hungry predators.
FERNANDEZ-ALVAREZ: I feel very happy to discover that these animals existed.
DANIEL: It must have been, he says, a very majestic view.
For NPR News, I'm Ari Daniel.
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