A team of paleontologists have discovered fossils of three impressive new ichthyosaurs – ancient marine reptiles – in rocks located 9,000 feet above sea level.
Ichthyosaurs have been found in excavations that took place between 1976 and 1990, but the remains were very fragmentary. Since then, more comparative research on ichthyosaurs has been produced, and now a team of paleontologists have finally been able to assess the Alpine fossils in a greater level of detail.
Among the finds are the superior ribs, the largest tooth attributed to an ichthyosaur (its root width twice as wide as any other aquatic reptile), and the vertebrae larger than a human head. Team research is published Today in the Journal of Vertebrate Paleontology.
Heinz Furer, a paleontologist at the University of Zurich and co-author of the paper, said in an email to Gizmodo. “Combined with a discovery roughly equivalent in time in British Columbia, they were the largest marine reptiles that ever lived on Earth.”
To get fossilized ichthyosaur bones from the mountain, Forer said he and his team had to carry hundreds of pounds of bones on their backs and in a jeep loaned to them from the Swiss Army. They transported the vertebrae across a glacier to a mountain hut, and finally the excavations were lowered down the mountain in a cable car usually used to transport food.
A little over 200 million years ago, the rocks above the Swiss Alps were sediments on the floor of a lake or shallow basin at the edge of Tethys, part of the ocean surrounding the supercontinent Pangea. There ichthyosaurs – aquatic reptiles with bodies resembling whales and dolphins – fed on cephalopods, fish and smaller ichthyosaurs. Most ichthyosaurs were smaller than this giant.
British Columbian ichthyosaur, Shastasaurus sikkanniensis, was about 70 feet tall and toothless; It is believed that it effectively inhaled its prey, according to to National Geographic. Martin Sander, a paleontologist at the University of Bonn in Germany and lead author of the research paper, said that “bigger is always better” and that “life would go there if possible” in press release. Sander noted that the sauropod dinosaurs, modern whales, and Triassic ichthyosaurs were the only animal groups that exceeded 20 metric tons.
The teeth of ichthyosaurs discovered by paleontologists are curved similarly to marine mammals that feed on boneless cephalopods, indicating their preferred food. But Sander said, “It is difficult to determine whether the tooth was from a large, giant-toothed ichthyosaur or from a giant, medium-toothed ichthyosaur.”
In an email to Gizmodo, Sander noted that ichthyosaur teeth had deep grooves along their roots, a pattern similar to that observed in modern monitor lizards. But these two animals are unrelated, so the exact purpose that the tooth grooves serve remains a mystery.
Researchers know that the remains do not belong to any known ichthyosaur. Based on measurements of the various samples—although distorted by tectonic shifts that have undermined the fossils from the sea floor to mountaintops—they suspect the fossils represent three different types, but there are likely to be fewer.
But the team did not assign new species names to the fossils, noting that they were too fragmented to justify such a move; Sometimes animals that were very quickly identified as a new species were later found as part of a previously known species, and Species must be ‘dumped’ in the current fossil record.
The discovery of ichthyosaurs in the Alps greatly expands the geographical footprint of floating reptiles. “The evolution of vertebrates in general is influenced by the realization that giant ichthyosaurs were globally distributed in the late Triassic period,” Sander said.
With such giant planets roaming prehistoric seas around the world, the smaller inhabitants of the Triassic oceans had a lot to worry about, even toothless ichthyosaurs were fearsome predators.
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