discovery of the largest tooth of a giant prehistoric reptile

Weighing up to 80 tons and measuring more than 20 meters, ichthyosaurs, which had an elongated body and a small head, are considered one of the largest animals to have ever existed.


The tooth.

ROSI ROTH/AFP

“A Great Mystery”

Appearing about 250 million years ago, some smaller, dolphin-like ichthyosaur representatives survived until 90 million years ago. But most died out 200 million years ago, especially those that evolved to become gigantic.

These would have rivaled our current large sperm whales, while remaining smaller than the largest living animal on Earth today, the blue whale (up to 30 meters long).

Few fossils of this prehistoric giant have been discovered so far, which constitutes “a great mystery”, according to Professor Martin Sander, lead author of this work published in the Journal of Vertebrate Paleontology.

Found at an altitude of 2,800 meters

The specimens in question were unearthed between 1976 and 1990, in the canton of Grisons in Switzerland, but have only recently been studied in detail.

Funny fact: they were found at an altitude of 2,800 meters. The seabed of the time, which surrounded the only existing super-continent (Pangea), was gradually found, due to plate tectonics, at the top of these mountains. From an early ichthyosaur were found a series of ten rib fragments, accompanied by a vertebra, suggesting an animal about 20 meters long. Or more or less the equivalent of the largest specimen ever discovered (21 meters), named Shonisaurus sikanniensis and found in Canada.

Martin Sander posing with a reptile bone.

Martin Sander posing with a reptile bone.

LAURENT GARBAY/AFP

The second animal measured about 15 meters, according to the seven vertebrae examined.

A root 60 millimeters in diameter

But the highlight of the show is this tooth “enormous, even for an ichthyosaur: its root is 60 millimeters in diameter”, detailed in a press release Martin Sander, from the University of Bonn. The specimen found in Canada apparently had no teeth. Ichthyosaurs with and without teeth would have cohabited, according to the study.

The largest tooth discovered so far (and the only other for a giant ichthyosaur) measured 20 millimeters in diameter, from an animal almost 18 meters long.

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