The fossils belong to three ichthyosaurs and are perhaps one of the largest animals to ever live on Earth, according to a new study. Ancient creatures could reach 80 tons and 65 feet (20 meters) in length, rivaling modern sperm whales.
These “fish lizards” first appeared in the ocean about 250 million years ago, somewhat resembling dolphins with elongated bodies and small heads. They emerged after the mass extinction in Perm destroyed more than 95% of marine species. But 200 million years ago, giant ichthyosaurs became extinct, and only smaller, dolphin-like ones lived until 90 million years ago.
A study describing the discovery, published Thursday in the Journal of Vertebrate Paleontology.
So how did the remains of massive sea creatures, including one longer than a bowling alley, end up at an altitude of 9,186 feet (2,800 meters)?
About 200 million years ago, these rock layers were the floor of a wide lagoon.
“We believe that large ichthyosaurs followed fish in the lagoon. Fossils may also have originated from homeless people who died there,” said study co-author Heinz Führer, a retired curator at the Paleontological Institute and Museum of the University of Zurich.
But the folding of the Alps, which began 95 million years ago when the African tectonic plate began to push against the European tectonic plate, created piles of rock layers about 30 to 40 million years ago. The fossils were “tectonically deformed”, crushed by the movements of the tectonic plates, which pushed them to a rock formation at the top of the mountain.
“You have to be something like a mountain goat to have access to the appropriate beds,” said study lead author P. Martin Sander, a professor of vertebrate paleontology at the University of Bonn in Germany, in a statement. “They have the unpleasant property of not being found below about 8,000 feet (2,438.4 meters), well above the tree line.
Although these creatures once ruled the seas, fossils are rare, which is a great mystery to paleontologists. But the remains of these ichthyosaurs shed new light on these mysterious, extinct creatures.
One huge tooth
The fossils belong to three different ichthyosaurs. One was about 65 feet (20 meters) long, while the other was 49 feet (15 meters) long. But the most exciting find associated with these fossils is the largest ichthyosaur tooth ever discovered.
“This is huge by ichthyosaur standards: its root is 60 millimeters in diameter – the largest specimen still in a full skull to date is 20 millimeters and comes from an ichthyosaur that is nearly 18 meters (59 feet) long. Said Sander.
Scientists know that the smaller ichthyosaurs had teeth, but most of the giant ones were toothless and are thought to feed on cephalopods, such as squid, by sucking.
Giant ichthyosaurs with teeth were probably similar to sperm whales and killer whales today, using their teeth to catch prey such as giant squid.
But the tooth is a challenge because it is broken in the crown. Although researchers know that this is an ichthyosaur tooth due to unique characteristics, such as the folding of dentin at the root of the tooth, they cannot be sure that the size of the tooth reflects the size of the animal.
“It’s hard to tell if a tooth is a large ichthyosaur with giant teeth or a giant ichthyosaur with medium teeth,” Sander said.
This is because, according to researchers, being a giant and a predator (with teeth) do not align – that’s why the blue whale, which weighs 150 tons and can reach 98 feet (30 meters) in length, does not have any teeth. Instead, it filters small creatures out of the water.
Meanwhile, sperm whales, which weigh 50 tons and reach 65 feet (20 meters) in length, are hunters.
“Therefore, marine predators probably can’t get much bigger than a sperm whale,” Sander said.
Giants in the mountains
The fossils were first discovered during geological mapping of the Alps between 1976 and 1990. Führer was part of the original team that extracted the fossils from the rocks known as the Koesen Formation, and remembers holding the fossils in his hand as a doctoral student in University of Zurich.
Over time, the fossils were largely forgotten.
“Recently, however, more giant ichthyosaur remains have emerged,” Furer said. “So we thought it was worth analyzing the Swiss finds in more detail as well.”
Ichthyosaur fossils have been found around the world, but the remains of giant species are concentrated in North America. Finding these specimens in modern Switzerland expands their scope.
Previous evidence suggests that some of them may reach the size of blue whales, the world’s largest animal.
“In Nevada we see the beginning of real giants, and in the Alps the end,” Sander said. “Only medium to large dolphins – and killer whale-like forms survived the Jurassic period (period)” between 145 and 201 million years.
Sander wonders if there are any more “giant sea creatures hidden under the glaciers.” But these fossils help fill the knowledge gap about giant sea lizards.
“This is a major embarrassment for paleontology that we know so little about these giant ichthyosaurs, despite the sheer size of their fossils,” Sander said. “We hope to meet this challenge and find new and better fossils soon.”
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