A new analysis of long-lost fossils found that the vampire squid has been lurking in the dark corners of the ocean for 30 million years.
modern Vampire squid (Hell vampire) Can reproduce in hypoxic deep waters, which is different from many other squids that require shallow habitats on the continental shelf. However, the fossil ancestors of the vampire squid rarely survive today, so scientists are not sure when these elusive cephalopods will evolve to survive almost without oxygen.
The new fossil analysis helps fill the 120 million-year gap in the evolution of the vampire squid, revealing that the ancestors of the modern vampire squid had lived in the deep ocean during the Oligocene period 23 to 34 million years ago. The co-author of the study, paleontologist Martin Košťák of Charles University in Prague, said that these squids may have evolved adaptability to hypoxic water during the Jurassic period.
related: Photo of hell vampire squid
Košťák wrote in an email to Live Science: “Life at a stable low oxygen level brings evolutionary advantages-low predation pressure and less competition.”
When Košťák and his colleagues were looking for fossils of cuttlefish ancestors, they found the long-lost fossil in the collection of the Hungarian Museum of Natural History in 2019. The fossil was originally discovered in 1942 by Miklós Kretzoi, a Hungarian paleontologist who identified it as a squid about 30 million years ago and named it squid. Hungarian dead bacteria. However, later researchers believe that this is the ancestor of the squid. In 1956, during the Hungarian Revolution, the museum was burned down and the fossils were believed to have been destroyed. Rediscovery is a surprise.
Speaking of rediscovery, Košťák said: “This is a great moment, seeing some things suggested before will definitely be lost.
Košťák and his colleagues studied the fossils with scanning electron microscopes and performed geochemical analyses. They first discovered that Kretzoi’s original identity was correct: the fossil came from squid, not the ancestor of cuttlefish. The animal’s inner shell, which forms the backbone of its body, is about 6 inches (15 cm) long, which indicates that the squid grows to about 13.7 inches (35 cm) (including arms). This is only slightly larger than the modern vampire squid, which is about 11 inches (28 cm) in length.
The sediments around the fossils did not show traces of the microfossils often found on the seafloor, indicating that the squid did not live in shallow water.The researchers also analyzed carbon Found in sediments, sediments may come from anoxic or hypoxic environment.
These conditions are characteristic of the deep seabed. By observing fossils deposited in layers of rock outside of Budapest today, the researchers were also able to prove that squid might not be able to survive in the shallow seas at that time. The shallow sea sediments show high levels of specific plankton, which bloom in a low-salt, high-nutrient environment-conditions that modern vampire squid cannot tolerate.
(Researchers at the Monterey Bay Institute found that when these squids lurked in the deep sea, they did not behave like nightmare predators as their name implies; instead, they waited in a dark habitat for organic debris to be extinguished. Then , They captured these fragments with suction cups covered with mucus, MBARI discovered.)
The new research was published in the journal on Thursday (February 18) Communication biology, Suggesting how the ancestors of the vampire squid learned to live where other squids could not.Looking down in the fossil record, the oldest fossil in this group of squids was found in JurassicKosak said that between 201 million and 174 million years ago, they usually existed in hypoxic sediments.
“The main difference is that these hypoxic conditions are determined on the shelf. [a] He said, “This means that the ancestors were residents of shallow water environments, but they have adapted to low oxygen environments.”
Since about 145 million years ago, there have been gaps in the fossil record of the Lower Cretaceous. Košťák said that by this point, the squid may have moved to deeper oceans, mainly due to their experience in the Jurassic hypoxic conditions. He added that this deep-water lifestyle may explain why the squid survived the crisis of killing non-avian dinosaurs at the end of the Cretaceous.
Košťák said that the deep squid 30 million years ago helped to connect modern history to the abyss. He and his colleagues are now trying to establish a similar connection for cuttlefish, a group of cute, discolored cephalopods whose origins are also dim.
Originally published in “Life Science”.