February 2, 2023

‘Fish lizard’ fossils found in Swiss Alps belonged to some of the largest creatures that ever lived

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Fossils belong to three ichthyosaurs, and according to a new study, they may be some of the largest living animals on Earth. Ancient creatures can reach 80 tons and 65 feet (20 meters) in length, competing with modern sperm whales.

These “fish lizards” first appeared in the ocean about 250 million years ago, resembling long-bodied and short-headed dolphins. They have emerged after the mass extinction. 95% marine species But by 200 million years ago, giant ichthyosaurs were extinct, and only smaller, more dolphin-like people survived until 90 million years ago.

A study detailing the discovery, published Thursday in the Journal of Vertebrate Paleontology.

So how did the remnants of massive sea creatures, including a bowling alley, end up at 9,186 feet (2,800 meters)?

About 200 million years ago, those rock layers were the floor of a vast lake.

“We believe that large ichthyosaurs took fishing schools to the lake. These fossils can also be found in the wanderings that die there,” said study co-author Heinz Ferrer, retired curator of the Paleontological Institute at the University of Zurich and museum. Said in a statement.

But the layers of the Alps, which began 95 million years ago when the African tectonic plate began to push against the European tectonic plate, formed layers of rocks about 30 to 40 million years ago. Fossils were “tectonically degraded” by the movements of the tectonic plate, which pushed them into the shape of a rock on top of a mountain.

“You have to be like a mountain goat to access the relevant beds,” said P. Martin Sander, a professor of vertebrate biology at the University of Bonn in Germany. “They have the disturbing feature of not being below 8,000 feet (2,438.4 meters) above the tree line.”

Although these creatures once ruled the oceans, fossils are rare, which has created a great mystery for biologists. But the remains of these ichthyosaurs have shed new light on these mysterious, extinct creatures.

A big tooth

Fossils were of three different ichthyosaurs. One was about 65 feet (20 m) tall while the other was 49 feet (15 m) long. But the most interesting discovery related to these fossils is by far the largest ichthyosaur tooth.

“This ichthyosaur is huge in terms of standards: its root diameter was 60 mm – the largest specimen in the entire skull to date was 20 mm and came from an ichthyosaur that was about 18 m (59 ft) long. Was, “said Sander.

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Scientists know that small ichthyosours have teeth, but most giant temples were without teeth, and it was assumed that they fed cephalopods, such as scuds, through suction.

The giant ichthyosaurs with teeth may have been similar to the sperm whale and the killer whale today, who use their teeth to catch prey such as giant squid.

But the tooth presents a challenge because it was broken on the crown. Although researchers know that it was an ichthyosaur tooth due to its unique properties, such as the spread of dentin in the root of the tooth, they cannot be sure that the size of the tooth reflects the size of the animal.

This is the thickest ichthyosaur tooth ever found.

“It’s difficult to say whether the tooth is a large ichthyosaur with large teeth or a large ichthyosaur with medium size teeth,” Sander said.

This is because, according to researchers, giants and predators (with teeth) do not align – this is why the blue whale, which weighs 150 tons and is 98 feet (30 meters) long. Any tooth, instead, it filters small organisms out of the water.

Meanwhile, sperm whales, which weigh up to 50 tons and are up to 65 feet (20 meters) long, are predators.

“So seafarers probably can’t be bigger than sperm whales,” Sander said.

Giants in the mountains

Fossils were first discovered during geological mapping of the Alps between 1976 and 1990. Ferrer was part of the original team that recovered the fossils from the rocks, known as the Cossack Formation, and remembers him holding a fossil in his hand as a doctoral student. University of Zurich.

The largest ichthyosour vertebrae was captured in a photograph by study author Heinz Furrer.

In time, the fossils were largely forgotten.

“Recently, though, more remains of giant ichthyosaurs have appeared,” Furrer said. “So it was useful for us to re-examine the Swiss discoveries in more detail.”

Ichthyosaur fossils have been found around the world, but remains of giant species are concentrated in North America. Finding these specimens in modern-day Switzerland increases their range.

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Previous evidence suggests that some of them could reach the size of a blue whale, the world’s largest animal.

“In Nevada, we see the beginning of real giants, and finally in the Alps,” Sander said. Between 145 and 201 million years ago, “only medium-sized dolphins – and orca-like forms survived in the Jurassic (era).”

Sander wonders if there are more “giant sea creatures hidden beneath the glaciers.” But these fossils help fill the gap in knowledge about giant sea lizards.

“It is a great embarrassment to paleontologists that we know very little about these giant ichthyosaurs, despite the unusual size of their fossils,” Sander said. “We hope to meet this challenge and find new and better fossils soon.”

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