Giant octopuses measuring up to 62 feet (19 meters) in length were among the top ocean predators around 100 million years ago, according to new research that uncovered rare fossils hidden within solid rock.
Remarkably well-preserved specimens of the octopuses’ powerful jaws show signs of intense wear from crushing hard prey including shells and bones, a study published in the journal Science on Thursday reports.
“This suggests that these giant octopuses may have functioned as apex predators in the Cretaceous sea,” study coauthor Yasuhiro Iba, an associate professor of Earth and planetary sciences at Japan’s Hokkaido University, told CNN.
“We were surprised. The fossil record of octopuses is extremely limited, so finding animals this large and ecologically important in the Cretaceous ocean was beyond our expectations,” he added.
The extinct animals, scientifically named Nanaimoteuthis, were about 23 to 62 feet (7 to 19 meters) in length. The researchers estimated their overall size by extrapolating from the size of the beak specimens.
The colossal creatures were among the earliest finned octopuses, which have paddle-shaped fins on their heads, in the scientific record, according to the study.
Iba explained that octopuses rarely fossilize because most of their bodies are soft, with only a few hard parts like the jaws likely to be preserved after they die. The scientists conducted a fresh analysis of 15 huge jaw fossils previously found in Japan and Canada’s Vancouver Island. But the researchers didn’t stop there.
The team also unearthed 12 fossilized octopus jaws encased in sedimentary rock from the Cretaceous Period, dating back 100 million to 72 million years. The study authors found the specimens by using a 3D-imaging technique called grinding tomography to create high-resolution datasets, and an AI model, according to the study.
Iba described the method as a “digital fossil mining” approach, which produced 3D models of the jaw fossils.
During the Cretaceous Period, dinosaurs including Tyrannosaurus rex, triceratops and velociraptor dominated the land.
And until now, vertebrate predators such as large marine reptiles, sharks and fishes were thought to have commanded the seas, Iba said, but the fossils hint that octopuses may also have occupied the top of the food web.
“This indicates that Cretaceous marine ecosystems were more complex and included a wider range of top predators than previously thought,” he said.
“Within this ecosystem, Nanaimoteuthis likely used its large body and long arms to capture prey, and its powerful jaws to process hard food,” Iba added. “Like modern octopuses, it may have relied on intelligence to find, capture and consume its prey.”
Iba now plans to expand digital fossil mining, which he believes can help to uncover organisms that were previously undetectable in the fossil record.
“Our goal is to reveal the hidden players of ancient ecosystems and build a much more complete picture of how past ecosystems really worked,” he said.
Tim Coulson, professor of zoology at the University of Oxford, England, who was not involved in the study, told CNN that “the work in the paper is compelling and exciting.”
“These animals would have been feeding on other animals, and they could have crunched through bones of large fish and possibly marine reptiles, as well as shells. Their size suggests they were an apex predator, sat at the top of the food chain,” he said.
“The authors argue that asymmetrical patterns of wear on the octopuses’ jaws points to evidence of intelligence,” Coulson added. “Although plausible, it is not possible to say quite how smart these animals were.”
Jakob Vinther, associate professor of macroevolution at the University of Bristol, England, who was also not involved in the study, said the research rests on “a pretty amazing find.”
However, he argued that the fossil does not definitively prove that Nanaimoteuthis was an apex predator that would have hunted and eaten 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 take down such big prey,” Vinther said.
It would have taken the octopuses a long time to break down and ingest large animals, and they could have met their energetic needs by feeding on relatively small prey, he explained.
“But that doesn’t take away from the fact that these were most likely formidable predators and probably a significant predator towards certain larger-bodied prey that existed back then,” Vinther said.
Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
