A new genus and species of vampyropod cephalopod — named Syllipsimopodi bideni after President Joseph Biden — has been identified from an exceptionally well-preserved fossil found in the Bear Gulch Lagerstätte in Montana, the United States.
An artist’s impression of Syllipsimopodi bideni. Image credit: K. Whalen.
Vampyropoda — one of three main groups of internally-shelled cephalopods — combines octopods, vampyromorphs, and their relatives.
These soft-bodied cephalopods are typically characterized by eight arms and an internalized chitinous shell or fin supports.
They are the ancestors of vampire squid and octopus, but their origins are unclear as they rarely fossilize due to their primarily soft tissue composition.
Previously discovered fragmentary remains of vampyropods have been dated to around 240 million years ago, but genetic data indicate that they originated much earlier, between 330 and 250 million years ago.
The newly-identified species lived approximately 328 million years ago during the Carboniferous period, making it the oldest known vampyropod and extending the fossil record of the group by about 82 million years.
Dubbed Syllipsimopodi bideni, it is the only known vampyropod to have 10 functional arms, all with preserved suckers.
“This is the first and only known vampyropod to possess 10 functional appendages,” said Dr. Christopher Whalen, a postdoctoral researcher in the Department of Invertebrate Paleontology at the American Museum of Natural History and the Department of Earth and Planetary Sciences at Yale University.
“The arm count is one of the defining characteristics separating the 10-armed squid and cuttlefish line (Decabrachia) from the eight-armed octopus and vampire squid line (Vampyropoda),” he added.
“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.”
“However, all previously reported fossil vampyropods preserving the appendages only have 8 arms, so this fossil is arguably the first confirmation of the idea that all cephalopods ancestrally possessed 10 arms.”
Syllipsimopodi bideni. Image credit: S. Thurston / AMNH.
Syllipsimopodi bideni was about 12 cm (4.7 inches) long and had a torpedo-shaped body. Its fins were large enough to perhaps function as stabilizers and to help it swim.
One pair of its arms was considerably longer than the other four pairs, similar to the two elongated tentacles of modern squids.
The ancient creature likely used its longer arms to capture prey — smaller, shelled animals, perhaps — and its shorter arms to confine and manipulate prey.
“Our findings suggest that the earliest vampyropods, at least superficially, resembled squids that are living today,” Dr. Whalen said.
“Syllipsimopodi bideni also challenges the predominant arguments for vampyropod origins and offers a new model for the evolution of internally-shelled cephalopods.”
“Syllipsimopodi bideni may have filled a niche more similar to extant squids, a midlevel aquatic predator,” added Dr. Neil Landman, a curator emeritus in the Department of Invertebrate Paleontology at the American Museum of Natural History.
“It is not inconceivable that it might have used its sucker-laden arms to pry small ammonoids out of their shells or ventured more inshore to prey on brachiopods, bivalves, or other shelled marine animals.”
A paper on the findings was published in the journal Nature Communications.
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C.D. Whalen & N.H. Landman. 2022. Fossil coleoid cephalopod from the Mississippian Bear Gulch Lagerstätte sheds light on early vampyropod evolution. Nat Commun 13, 1107; doi: 10.1038/s41467-022-28333-5
Source link: https://www.sci.news/paleontology/syllipsimopodi-bideni-10605.html
