Bus-sized cephalopods harking back to the legendary kraken might have sat on the prime of the meals chain, utilizing their smarts to seek out prey within the oceans of the Late Cretaceous.
Giant vertebrates resembling mosasaurs, plesiosaurs, sharks, and huge fish are thought to have dominated the listing of apex predators within the ocean for over 370 million years, whereas invertebrates like squid and ammonoids had been usually considered as prey.
However researchers now recommend that some big octopuses may have been a part of that higher predatory tier. They described two species of finned octopus, Nanaimoteuthis haggarti and N. jeletzkyi, from the Late Cretaceous period round 100 million to 75 million years in the past, reaching as much as 60 toes (round 19 meters) lengthy. These octopuses might characterize a few of the largest invertebrates to have ever lived.
“Cretaceous ocean might have included not solely massive marine reptiles and sharks, but additionally big octopuses as vital predators,” a paleontologist, Yasuhiro Iba at Hokkaido College, tells Refractor. These big predatory invertebrates had beforehand been neglected, “making historical meals webs extra advanced than we imagined.”
Round 200 million years in the past, within the late Mesozoic period, the explosion of shell-crushing predators initiated a section of predator-driven evolution that additionally formed the modern-type marine ecosystem. Throughout this time, the invertebrates served as small prey. In response to this strain, these soft-bodied animals developed exhausting, mineralized shells for cover.
Some octopuses, nevertheless, adopted a special evolutionary pathway, demineralizing their outer, protecting shells. This resulted within the evolution of the octopuses into soft-bodied creatures with enhanced swimming capacity, improved eyesight, and intelligence.
A number of fossils of those, belonging to the non-tentacled superorder Octobrachia, have already been documented. However their place within the meals chain remained unknown because of the lack of direct evidence, such as stomach contents. Clues from fossils, resembling jaw morphology, do not are typically dependable for evaluating consuming behaviour, at the very least on their very own.
To research the ecological function of the earliest recognized finned octopuses, Iba and his colleagues used a way completely different from conventional fossil evaluation. They examined the bodily put on and tear on the fossilized jaws to reconstruct their carnivorous feeding habits.
A complete of 27 massive fossilized jaws had been analyzed. The researchers appeared for particular harm – resembling chips, deep scratches, and polished surfaces – that happen when fashionable cephalopods (animals like squid, octopus, or nautilus) crack open hard-shelled prey.
Ikegami et al., Science, 2026
The group discovered some intense put on, with as much as 10% of the unique jaw size lacking on account of extreme abrasion. This means that these octopuses possessed a robust chew drive used to crush the exhausting shells and bones of enormous prey.
“The damage on Nanaimoteuthis jaws signifies that they processed prey with exhausting buildings, resembling ammonites, massive bivalves, crustaceans, and fish bones,” says Iba.
Based mostly on the most important fossilized jaw, N. jeletzkyi may need reached a size of two.8 to 7.7 meters; in the meantime, N. haggarti was an estimated whole size of 6.6 to 18.6 meters. “Essentially the most stunning half was the dimensions of the jaws and the physique dimension estimated from them,” he provides.
The paleontologists additionally discovered uneven put on on the jaws, indicating lateralized conduct, that means that the animals might have used one facet extra often throughout feeding. Within the animal kingdom, this behavioral trait is correlated with advanced mind improvement and superior intelligence.
“However we can not immediately measure intelligence from fossils. What we will say is that these octopuses might have already got had a few of the advanced behavioral talents seen in fashionable octopuses,” Iba instructed us.
Based mostly on the fossil deposits from the interval, the researchers recommend that Cretaceous finned octopuses used ecological settings completely different from these of their fashionable kinfolk. Fashionable finned octopuses choose deep-sea environments.
Iba says that this lineage might later have shifted towards the primarily deep-sea, smaller-bodied life we see right this moment.
“Marine ecosystems modified significantly from the top of the Cretaceous into the Cenozoic. Adjustments in predators, prey, and competitors might have made it tough for large octopuses to keep up the identical ecological function,” says Iba. “Future Cenozoic fossil data will likely be wanted to check this concept.”
The research has been printed within the journal Science
Truth-checked by Mike McRae
