Remarkably well-preserved specimens of the powerful jaws of octopuses show signs of intense wear caused by crushing hard prey.
Giant octopuses measuring 19 meters in length were among the top ocean predators about 100 million years ago, according to new research that uncovered rare fossils hidden within solid rock.
Remarkably well-preserved specimens of the powerful jaws of octopuses show signs of intense wear caused by crushing hard prey, including shells and bones, reports a study published in the journal Science on Thursday.
"This suggests that these giant octopuses may have functioned as top predators in the Cretaceous sea," summarized study co-author Yasuhiro Iba, associate professor of Earth and Planetary Sciences at Hokkaido University in Japan, to CNN.
“We were surprised. The fossil record of octopuses is extremely limited, so finding such large and ecologically important animals in the Cretaceous Ocean exceeded our expectations,” he explains.
The extinct animals, scientifically named Nanaimoteuthis, were about seven to 19 meters long. Researchers estimated their total size by extrapolating from the size of the beaked specimens.
According to the study, these colossal creatures were among the first finned octopuses (possessing paddle-shaped fins on their heads) recorded in scientific history.
Rare fossil evidence of octopuses
Yasuhiro Iba explained that octopuses rarely fossilize because most of their bodies are soft, and it's likely that only a few hard parts, like the jaws, are preserved after death. Scientists conducted a new analysis of 15 enormous jaw fossils previously found in Japan and Vancouver Island, Canada. But the researchers didn't stop there.
The team also unearthed 12 fossilized octopus jaws embedded in sedimentary rock from the Cretaceous Period, dating from 100 million to 72 million years ago. The study authors found the specimens using a 3D imaging technique called milling tomography to create high-resolution datasets and an AI model, according to the study.
Yasuhiro Iba described the method as a "digital fossil mining" approach, which produced 3D models of the jaw fossils.
During the Cretaceous Period, dinosaurs such as Tyrannosaurus rex, Triceratops, and Velociraptor dominated the earth.
Until now, it was thought that vertebrate predators, such as large marine reptiles, sharks, and fish, dominated the seas, says the scientist, but the fossils suggest that octopuses may also have occupied the top of the food chain.
"This indicates that Cretaceous marine ecosystems were more complex and included a wider range of top predators than previously thought," he says.
“Within this ecosystem, Nanaimoteuthis likely used its large body and long arms to capture prey and its powerful jaws to process tough foods,” adds Yasuhiro Iba. “Like modern octopuses, it may have relied on intelligence to find, capture, and consume its prey.”
Yasuhiro Iba now plans to expand digital fossil mining, which he believes can help uncover organisms that were previously undetectable in the fossil record.
"Our goal is to reveal the hidden players in ancient ecosystems and build a much more complete picture of how past ecosystems actually functioned," he says.
Tim Coulson, a professor of zoology at Oxford University in England who did not participate in the study, told CNN that "the work presented in the article is compelling and exciting."
“These animals would have fed on other animals and may have chewed on the bones of large fish and possibly marine reptiles, as well as shells. Their size suggests that they were apex predators, situated at the top of the food chain,” he states.
“The authors argue that the asymmetrical wear patterns on the jaws of octopuses point to evidence of intelligence,” adds Tim Coulson. “While plausible, it’s not possible to say exactly how intelligent these animals were.”
Jakob Vinther, associate professor of macroevolution at the University of Bristol, England, who also did not participate in the study, stated that the research is based on a "rather surprising discovery".
However, he argued that the fossil does not definitively prove that Nanaimoteuthis was a top predator that hunted and fed on some of the large marine reptiles with which it would have shared the ocean.
"The question is whether it would make sense for an animal like this to hunt such large prey," says Jakob Vinther.
Octopuses would have taken a long time to decompose and ingest large animals, and could have met their energy needs by feeding on relatively small prey, he explains.
“But that doesn’t invalidate the fact that these were very likely formidable predators and probably a significant predator for certain larger-bodied prey that existed at that time,” adds Jakob Vinther.
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