WHEN MATT TAIBBI, writing in Rolling Stone magazine in 2010, described Goldman Sachs, an American bank, as a “vampire squid”, he traduced an innocent animal. Vampire squid are not vampires. They actually feed on detritus, rather than living prey. They are not squid, either. They are more closely related to octopuses, on the road to which they seem to be an evolutionary staging post.

Real squid belong to a group of cephalopods (as tentacled, swimming molluscs are known) called the Decabrachia (ten-arms). Vampire squid and octopus belong to another, the Vampyropoda (vampire-feet). Unlike octopuses, however, vampire squid (of which only one species, Vampyroteuthis infernalis, survives today) have ten limbs rather than eight—though they do not have the torpedo-shaped bodies of real squid. That, plus evidence from the fossil record, confirms the idea that the groups’ common ancestor was squid-like. But when this common ancestor lived remains a mystery.

Christopher Whalen and Neil Landman of the American Museum of Natural History, in New York, think, however, that they are close to an answer. As they write in Nature Communications, they have found the oldest member of the Vampyropoda yet described. Syllipsimopodi bideni dates from between 323m and 330m years ago, during the Carboniferous period. The previous candidate for the title was Germanoteuthis donai, a Triassic stripling a mere 240m years old.

S. bideni, of which this is the only known specimen, was lying neglected in a drawer in the Royal Ontario Museum, in Canada, until Dr Whalen chanced across it on a visit, while looking for something else. Its elongated gladius (the triangular structure pointing to the right in the picture above) makes it look far more squid-like than V. infernalis. Modern vampire squids have reduced gladii, and octopuses have lost theirs almost completely, giving them their protean ability to squeeze through cracks and escape from aquaria.

S. bideni is thus the closest find so far made to the common ancestor of octopus and squid. And yes, it is indeed named as a compliment to America’s president. Whether he will take it as such is unclear. ■

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