A vampire squirrel has been weeping in the dark corners of the ocean for 30 million years, a new study of a long-lost fossil find.
Today’s vampire squid (Vampyroteuthis infernalis) can thrive in deep-sea water without oxygen, unlike many other squid species that require thinner habitat on continental shelves.
Very few of the fossil ancestors of the vampire scooter today are left, however, so scientists are not sure when these accessible cephalopods developed the ability to survive with very little oxygen. .
The new fossil analysis is helping to fill a 120-million-year gap in vampire squid evolution, revealing that the ancestors of today’s vampire squirrel lived in the deep oceans during the Oligocene, 23 million to 34 million years ago.
These scooters may have undergone changes to low-oxygen water during the Jurassic, said study co-author Martin Košťák, a paleontologist at Charles University in Prague.
“Living in stable low oxygen levels will bring evolutionary benefits – low predation pressure and less competition,” Košťák wrote in an email to Live Science.
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Rediscovered fossils
Košťák and his colleagues discovered the long-lost fossil in the collections of the Hungarian Museum of Natural History in 2019 while searching for fossils of shellfish ancestors. The fossil was first discovered in 1942 by the Hungarian paleontologist Miklós Kretzoi, who named it as a squid dating back about 30 million years and named it Necroteuthis hungarica. Subsequent researchers, however, argued that it was the ancestor of shellfish.
In 1956, during the Hungarian Revolution, the museum was set on fire, and the fossil was thought to have been destroyed. The rediscovery was a happy surprise.
“It was a real moment,” Košťák said of the rediscovery, “to see something that had previously been suggested for sure.”
The fossil. (Košťák et al., Communication Biology, 2021)
Košťák and his colleagues examined the crown by scanning electron microscopy and performed a geochemical study. They first discovered that Kretzoi ‘s first identification was correct: The fossil is from a squirrel, not a shellfish ancestor.
The inner shell of the animal, or gladius, which is the backbone of its body, was about 6 inches (15 centimeters) long, suggesting that the squid grew to about 13.7 inches (35 cm) of length with arms bent. That’s just a little bigger than today’s vampire squirrel, which reaches about 11 inches (28 cm) of total body length.
The sediments around the crown showed no traces of microfossils often found on the seabed, indicating that the squirrel did not live in shallow waters. The researchers also analyzed levels of changes in carbon in the sediment and found that the sediment apparently came from an anoxic environment, or low oxygen.
These conditions are common in the deep ocean floor. By looking at rock layers above where the fossil was deposited outside what is now Budapest, the researchers were also able to show that the squid may not have been able to have survived in the shallow oceans at the time.
The shallow marine deposits showed very high levels of specific plankton that thrive in low-salt, high-nutrient environments – conditions that today’s vampire squirrel cannot accept.
(Researchers from the Monterey Bay Research Institute found that although they lie in the deep sea, these squirrels do not behave as the night-time predators the name suggests; instead, they wait in their dark environments for clumps of organic matter to flow down in. They then capture these pieces with mucus-covered suckers, MBARI found.)
Deeply changing
The new research, published Thursday (Feb. 18) is in the journal Communication Biology, advising on how vampire squid ancestors learned to live where other squids could not.
Looking deeper into the fossil record, the oldest fossils from this group of squirrels are found in the Jurassic period, between 201 million and 174 million years ago, Košťák said, and are usually found in anoxic sediments.
“The main differences are that these reduced oxygen conditions are off the shelf, [a] shallow water environment, “he said. This means that their ancestors lived in a shallow water environment, but were already adapted to conditions with low oxygen. ”
There is a gap in the fossil record in the Lower Cretaceous, beginning about 145 million years ago. The squirrel may have moved to the deepest ocean by this point, Košťák said, fueled by their experiences with anoxic conditions in the Jurassic. This deep-water lifestyle may explain why the squid survived the crisis that killed the nonavian dinosaurs at the end of the Cretaceous period, he said.
The deep gibberish from 30 million years ago helps connect recent history with the past, Košťák said. He and his colleagues are now trying to make similar connections for shellfish, a group of calm cephalopods that change color and have similar origins.
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This article was originally published by Live Science. Read the original article here.