Car-sized dinosaur-era sea turtle fossils found in Spain
Nov 17 (Reuters) – In the subtropical seas that washed the shores of the archipelago that made up Europe 83 million years ago, one of the largest turtles on record, a reptile the size of a small car – a Mini Cooper to be exact – bravely crossed dangerous waters.
Researchers on Thursday described remains found in northeastern Spain of a turtle called Leviathanochelys aenigmatica that was about 12 feet (3.7 meters) long, weighed just under two tons and lived during the Cretaceous period, the last chapter of the age of dinosaurs. . It is the largest known turtle in Europe.
It is smaller than today’s largest turtle, the leatherback, which can reach 7 feet (2 meters) in length and is known for marathon sea migrations. Leviathanochelys nearly matches the largest turtle on record, Archelon, which lived approximately 70 million years ago and reached about 15 feet (4.6 meters) in length.
“Leviathanochelys was as long as a Mini Cooper, while Archelon was the same size as a Toyota Corolla,” said paleontologist and study co-author Albert Seles of the Institut Català de Paleontologia (ICP), a research center affiliated with the Universitat Autònoma de Barcelona.
It was a good thing it was the size of a car, given the dangerous traffic in the ancient Tethys Sea in which Leviathanohelis swam. Huge marine reptiles with powerful jaws called mosasaurs were the largest predators – some exceeding 50 feet (15 meters) in length. Various sharks and rays, as well as long-necked fish-eating marine reptiles called plesiosaurs, also lurked.
“Attacking an animal the size of Leviathanochelys could probably only have been done by large carnivores in a marine context. At that time, the large marine predators in the European area were mainly sharks and mosasaurs,” said Oscar Castillo, a student in the paleontology master’s program at the Universitat Autònoma de Barcelona and lead author of the study published in the journal Scientific reports.
“During the Cretaceous, there was a tendency for sea turtles to increase their body size. Leviathanochelys and Archelon may represent the pinnacle of this process. Predation pressure has been suggested to be the cause of this increase in body size, but there may be other factors as well,” added Castillo.
Other large turtles from Earth’s past include Protostega and Stupendemys, both of which reached about 13 feet (4 meters) in length. Protostega was a Cretaceous sea turtle that lived about 85 million years ago and, like its later cousin Archelon, inhabited the great inland sea that at the time bisected North America. Stupendemys roamed the lakes and rivers of northern South America about 7-13 million years ago during the Miocene epoch.
Scientists discovered the remains of Leviathanochelys near the village of Coll de Nargó in the Catalan district of Alt Urgell after fossils sticking out of the ground were spotted by a hiker in the Southern Pyrenees mountains. To date, they have found parts of the back of its carapace, or shell, and most of its pelvic girdle, but no skull, tail or limbs.
Fossils show that it possessed a smooth shell similar to leatherback turtles, the shell itself being about 7.7 feet (2.35 meters) long and 7.2 feet (2.2 meters) wide. Leviathanochelys appears to be made for the open ocean, returning to land only rarely – for example to lay eggs.
The presence of several bony prominences on the anterior side of the pelvis differs from any other known sea turtle, indicating that Leviathanochelys represents a newly discovered lineage. This indicates that gigantism in sea turtles evolved independently in separate Cretaceous lineages in North America and Europe.
Leviathanochelys aenigmatica means “enigmatic leviathan turtle” because of its large size and curious pelvic shape, which researchers suspect is related to its respiratory system.
“Some pelagic (open ocean) animals show a modification in their respiratory system to maximize their breathing capacity at great depths,” Sellés said.
Reporting by Will Dunham in Washington Editing by Rosalba O’Brien
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