Today’s representatives reach out with eight arms – the primeval ancestors of the octopuses, however, once had ten tentacles. This is now documented by the oldest known fossil of a representative from the family tree of the eight-armed squid (Vampyropoda). The researchers named the approximately 328-million-year-old cephalopod Syllipsimopodi bideni in honor of President Joe Biden’s commitment to bringing science back to life.
Supple, “fingered” and highly intelligent: The octopus, also known as the octopus, is one of the most bizarre and prominent inhabitants of the sea. They have produced numerous species that inhabit many different habitats. Their success is based on the feature that also characterizes their name – octopus means “eight-footed”. With their flexible and suction-proof appendages, they can tap into many food sources. Together with the vampire squid-like (Vampyromorpha), they form the superordinate group of the so-called Vampyropoda – the eight-armed squid. The number of tentacles distinguishes them from the second large group of cephalopods: the Cephalopoda – the ten-armed squid. Among them are the cuttlefish and squid, with their more torpedo-shaped bodies.
Insight into evolutionary history
Relatively little is known about the evolutionary history of the eight-armed squid, as little has been preserved of their soft body structures. The oldest fragmentary remains discovered so far have been dated to be around 240 million years old. However, the process of the so-called molecular clock suggested a more far-reaching evolutionary history: traces in the genome of today’s representatives of the Vampyropoda suggested an age of over 300 million years for this developmental line of cephalopods.
The current discovery by Christopher Whalen and Neil Landman from the American Museum of Natural History in New York fits in with this result. They report an exceptionally well-preserved fossil of an ancient eight-armed squid from the Royal Ontario Museum’s collections. It was actually discovered in 1988 in a fossil deposit in Montana. Only now, however, did the detailed examination by the two paleontologists show the importance of the fossil.
According to the dating, the creature, which is about twelve centimeters long, lived around 328 million years ago. As the investigations of its body structures showed, the cephalopod showed characteristics that clearly identify it as a representative of the Vampyropoda. The researchers point out that Syllipsimopodi bideni is now shifting the fossil record of its group back in time by around 82 million years. Probably the most interesting aspect, however, is the number of its arms: “This is the first and only known representative of the eight-armed squid that has ten functional appendages,” says Whalen.
Originally there were ten
As he and his colleague explain, this finding confirms the assumption that the original ancestor of the eight-armed squid had ten arms. So far, this has been based on hints that Kraken get their eight arms by eliminating two units. Interestingly, in the case of the vampire squid, they are still preserved as filaments – rudimentary remnants of arms. “This fossil now provides the first concrete confirmation that these cephalopods originally had ten arms,” says Whalen.
As can be seen from the analyses, two of the arms in Syllipsimopodi bideni were elongated in relation to the other eight arms – similar to modern-day representatives of the ten-armed squid. Another similarity to these cephalopods was the torpedo-shaped body. “Our results suggest that the earliest vampyropods resembled, at least superficially, cuttlefish and squid living today,” says Whalen. His colleague Landman adds: “Syllipsimopodi may also have filled a niche like that of cuttlefish and squid today, namely that of a medium-sized aquatic predator.” Specifically, the researchers suspect that the animal used its longer arms to catch prey and its shorter arms to hold and manipulate victims.
Finally, the question remains why the primeval squid was named after Joe Biden of all people. Apparently, this had a political motivation with a more fundamental connection to science: “The plans that the new president has put forward to combat anthropogenic climate change and his general opinion that politicians should listen to the scientists inspired me for this naming”. , says Whalen.
Source: American Museum of Natural History, Yale University, Article: Nature Communications, doi: 10.1038/s41467-022-28333-5