Around 328 million years ago, Fergus County, Montana was no stranger to monsoons. At the time, the region was a marine bay, much like the Bay of Bengal in South Asia. Tropical storms have regularly flushed the bay of fresh water and fine sediment, fueling algal blooms and depleting the water of oxygen in some places. Anything that died in these places could have the rare posthumous chance of being preserved, undisturbed.

When an ancient octopus died in these waters, its soft, spongy body was buried and perfectly fossilized. The fossil was originally donated to the Royal Ontario Museum in Canada in 1988, but it sat in a drawer for decades until Christopher Whalen, a paleontologist from the American Museum of Natural History in New York, pulls him out of a drawer and notices his preserved arms. When he looked under the microscope, he saw small suction cups digging into the rock.

“It’s incredibly rare,” Whalen said.

Thomas Clements, a paleobiologist at the University of Birmingham in England, said: “The likelihood of these tiny little bags of water turning into fossils is just astronomically low.”

Intrigued, Whalen studied the fossil, expecting it to resemble other cephalopods found in Montana limestone. But it turned out to be something quite different. Whalen and his colleagues say the fossil represents the oldest known ancestor of the vampyropods, a group that includes vampire squids and octopuses, pushing back the earliest evidence of the group by 82 million years. Whalen and Neil Landman, curator emeritus at the museum, describe the new species in an article published Tuesday in the journal Nature Communications.

They named him Syllipsimopodi bideni, as in the case of President Joe Biden, to commemorate the start of his presidency and because they “were encouraged by his plans to fight climate change and fund scientific research”, said Whalen said in an email. Biden is not the first president to have a species named after him. A vermiform caecil and a moth with a crown of yellow scales were named after former President Donald Trump. Nine species are named after former President Barack Obama, including several fish and a lichen.

The White House did not respond to a request for comment.

But there is much more to the discovery – including a dispute – than his presidential name.

The new fossil, which has 10 arms, is the oldest known cephalopod to have suction cups on its arms. Modern squids and cuttlefish have 10 arms and octopuses have eight. Vampire squids (which are not squids but close relatives of octopuses) have eight arms and two stringy filaments, thought to be vestigial arms. Thus, the 10-armed S. bideni shows that all cephalopods once had 10 arms, before they were reduced to filaments and eventually lost.

Christian Klug, a paleontologist at the University of Zurich in Switzerland who was not involved in the research, expressed reservations about the new paper. He says the fossil most likely represents a specimen of a known species of ancient cephalopod, Gordoniconus beargulchensis. In 2019, Klug published an article on the anatomy of G. beargulchensis with Landman.

“It’s the exact same size, the exact same age, the exact same locality, the exact same proportions and it’s just preserved a little bit differently,” Klug said.

The new paper relies heavily on visual analysis methods, and those questions could be answered with chemical analyses, said Clements, who was not involved in the research. “With a full suite of techniques, we would definitely have more clues or a lot more answers,” he said, noting that these techniques can be expensive.

When Whalen first examined the fossil, he looked for the phragmocone, a chambered shell characteristic of most fossil cephalopods that helps them control buoyancy. The phragmocone of a nautilus is its coiled shell; a cuttlefish is its cuttlebone. The fossilized chambers of a phragmocone are divided by mineralized sheets, which are very distinctive and generally well preserved, Whalen said.

The G. beargulchensis fossil, which is in the American Museum of Natural History, preserves these distinct leaves, Whalen said. Because this fossil and S. bideni were preserved at the same site and in the same environment, both should have preserved lines, say the authors. But S. bideni had no trace of these lines, suggesting the creature never had an internal chambered shell.

Whalen also expected to see evidence of a primordial rostrum, a mineralized counterweight to ensure early cephalopods could swim horizontally. But the S. bideni fossil had no rostrum, suggesting “it was never there to begin with,” Whalen said.

Instead, the researchers’ analysis revealed that the inner shell of S. bideni is a gladius, a triangular shell-like remnant found in squid and vampire squid. “It’s really not something you would expect to see in such an old animal,” Whalen said. “We knew we were looking at one of the first vampires.”

Klug disputed this conclusion, suggesting that the shell is instead a deformed phragmocone and body chamber of G. beargulchensis, the known cephalopod.

Whalen disagreed. He said the measurements of the new fossil are distinct enough to mark a new species, “even if you disagree with our interpretation that we’re looking at a gladius and not a phragmocone and we’re looking at a vampyropod and not something else. “.

Clements hopes that future chemical analysis can confirm the presence of the suckers, which he says were difficult to discern from the images included in the study.

Suction cups may only be a small part of the S. bideni story, but Whalen is indebted to them. “It had been in a museum since the ’80s, and nobody realized it was important,” he said. “We happen to have this significance because I noticed the arm cupping.”