Researchers have come to that conclusion after examining a ten-armed, 328-million-year-old ancestor of the octopus.

It turns out to be a species unknown to us until recently that the name Syllipsimopodi bidenic – and thus named after US President Joseph Biden. S. bideni belongs to the Octopodiformes, a superorder of squid that includes octopuses and vampire squids. All species that are members of this superorder have eight grasping arms. But S. bideni has ten. “This is the first and only known member of the Octopodiformes to have ten functional arms,” ​​said researcher Christopher Whalen.

About S. bideni
S. bideni was found decades ago in Montana and donated to the Royal Ontario Museum† But in all those years, the remains have never been properly studied. That has now changed. The research not only shows that the squid-like animal deserves its own species and genus name, but also shows that S. bideni with an age of 328 million years is the oldest known member of the Octopidoformes. S. bideni is even a whopping 82 million years older than the oldest member of the Octopodiformes known until recently.

Ten arms

Furthermore, the scientists could clearly see ten arms during the study. These arms also all have suction cups and two of them are a bit longer than the other eight.

Theory

Which S. bideni has ten arms is interesting. For it endorses a theory that was difficult to prove until recently, which suggests that the ancestors of both octopuses and vampire squids had ten arms, two of which have been lost over time, leaving modern octopuses and vampire squids with eight arms today. must do.

As mentioned, S. bideni belongs to the Octopodiformes. A superorder that includes the two orders Octopoda and Vampyromorpha. These orders include octopuses and vampire squids, respectively. All species within this superorder possess eight arms. The vampire squid also have two thin filaments. The superorder Octopodiformes again belongs to the class Cephalopoda (cuttlefish). In addition to the Octopodiformes, this class also includes other orders of molluscs, such as the Sepiida (cuttlefish). These have ten arms (eight short and two longer).

Confirmation

“We have long thought that octopuses obtained their eight arms by eliminating the two filaments that the vampire squid still has, which are suspected to be rudimentary arms,” Whalen explains. “But all previously described fossilized Octopidoformes had only eight arms, so this fossil is the first confirmation of the idea that all squid originally had ten arms.”

With those ten arms must S. bideni have been a formidable hunter. “It’s not inconceivable that they used their sucker-filled arms to pull small ammonites out of their shells or to hunt limopods or clams or other crustaceans closer to shore.”