A 328 million-year-old fossil vampire squid with 10 arms has rewritten the evolution of the vampyroteuthidae and their descendants, octopuses.

Vampire squids don't have the best public image. The name isn't a winner for a start, and they remind some people of the facehugger from Alien. When the firm Goldman Sachs was described as a “great vampire squid sucking money not blood”, few people took it positively. Nevertheless, palaeontologists claim that in naming the oldest known member of the Vampyropoda, Syllipsimopodi bideni, after US President Joe Biden they are seeking to honor the president, not insult him. At least Biden can take comfort in the scientific importance of the discovery.

Vampyropods, which include octopods as well as vampire squid, don't have bones and teeth, so they fossilize poorly. The new find, described in Nature Communications, is the oldest known specimen by 82 million years, increasing the time these creatures have been occupying the oceans by a third. It's also much better preserved than the previous oldest vampyropod and carries a rather significant difference from modern members of the vampire squid order.

“This is the first and only known vampyropod to possess 10 functional appendages,” said lead author Dr Christopher Whalen of the American Museum of Natural History and Yale in a statement. 

Modern vampire squids have eight arms, and two filaments, but some biologists have maintained that somewhere in their evolutionary history the filaments were arms with suckers attached, a claim this find confirms.

"The arm count is one of the defining characteristics separating the 10-armed squid and cuttlefish line (Decabrachia) from the eight armed Vampyropoda. We have long understood that octopuses achieve the eight arm count through elimination of the two filaments of vampire squid, and that these filaments are vestigial arms,” Whalen said. “However, all previously reported fossil vampyropods preserving the appendages only have eight arms, so this fossil is arguably the first confirmation of the idea that all cephalopods ancestrally possessed ten arms.”

Quite why you'd give up something as useful as two extra arms is a question probably best posed to a vampire squid or octopus, but given the latter's immense success, it's clearly done them no harm.

The specimen was discovered in Montana's Bear Gulch deposit and donated to the Royal Ontario Museum in 1988. Bear Gulch was a shallow bay at the time, with fossils spectacularly well preserved by rapid bursts of mud during the monsoon season, but finding a deeper water species like this was a surprise. Like many other items in museum collections, its significance took decades to be recognized until Whalen and coauthor Neil Landman identified it as something new.

Naming a species after someone is usually a tribute. David Attenborough, for example, has everything from plants to marsupial lions bearing his name. There are exceptions, however. Neopalpa donaldtrumpi, probably wasn't meant the same way, given its description emphasized its blonde wig and small genitals. 

Whalen, however, says he and Landman were honoring Biden who had just been inaugurated when the paper was submitted. “I was encouraged by the plans President Biden put forward to counter anthropogenic climate change, and his general sentiment that politicians should listen to scientists,” he explained.

The genus name means “prehensile foot” in Greek, reflecting the fact this is the oldest of the cephalopods to have suckers, which the authors think may have been used to extract shell creatures similar to modern oysters. Two longer arms may have been particularly well suited to this.

Based on its torpedo-shaped body and large fins, the authors think S. bideni had a lifestyle more similar to modern squids than to its direct descendants.