Car-sized dinosaur-era sea turtle fossils have been discovered
Nov 17 (Reuters) – Roaming the subtropical seas that washed the shores of the archipelago that formed Europe 83 million years ago was one of the largest turtles on record, a reptile the size of a car small – a Mini Cooper to be precise -. which faced dangerous waters.
Researchers on Thursday described the remains discovered 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 the dinosaurs. It is the most well-known turtle in Europe.
It eclipsed today’s largest turtle, the leatherback, which can grow to 7 feet (2 meters) long and is known for marathon sea migrations. Leviathanochelys nearly matched the largest turtle on record: Archelon, which lived about 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 Sellés of the Catalan Institute of Paleontology (ICP), a center for research attached to the Autonomous University of Barcelona.
It was good to be the size of a car, considering the dangerous traffic in the ancient Tethys Sea in which Leviathanochelys swam. Huge sea reptiles with powerful jaws called mosasaurs were the largest predators, some more than 50 feet (15 meters) long. Also lurking were various sharks and rays, as well as long-necked fish-eating marine reptiles called plesiosaurs.
“Attacking an animal the size of Leviathanochelys could possibly only have been done by large predators in the marine context. At that time, large marine predators in the European area were mainly sharks and mosasaurs,” said Oscar Castillo, a student of a course master’s degree in paleontology at the Autonomous University of Barcelona and lead author of the study published in the journal Scientific reports.
[1/2] An illustrated reconstruction of the large Cretaceous sea turtle Leviathanochelys aenigmatica, which lived about 83 million years ago and whose fossils were found in the Alt Urgell region, northeast of Spain, seen in this undated image. ICRA_Arts/Conca Della Museum – Catalan Institute of Paleontology Miquel Crusafont/Handout via REUTERS
“During the Cretaceous, there was a tendency for sea turtles to increase their body size. Leviathanochelys and Archelon may represent the apex of this process. It has been hypothesized that the reason for this increase in body size they are predatory pressures, but there could be other factors,” added Castillo.
Other large turtles from Earth’s past include Protostega and Stupendemys, both reaching 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 then split North America in two. Stupendemys roamed the lakes and rivers of northern South America about 7-13 million years ago during the Miocene epoch.
Scientists unearthed the remains of Leviathanochelys near the town of Coll de Nargó, in the Alt Urgell region, after a hiker spotted fossils sticking out of the ground in the Southern Pyrenees mountains. So far, 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 indicated that it possessed a smooth shell similar to leatherback turtles, with the shell itself about 2.35 meters long and 2.2 meters wide. Leviathanochelys seems built for the open ocean, returning to land only rarely, for example to lay eggs.
The presence of a pair of bony prominences on the front of the pelvis differs from any other known sea turtle, indicating that Leviathanochelys represents a newly discovered lineage. It shows that sea turtle gigantism developed independently in separate Cretaceous lineages in North America and Europe.
Leviathanochelys aenigmatica means “enigmatic leviathan turtle” because of its large size and the curious shape of its pelvis that researchers suspect was related to its respiratory system.
“Some pelagic animals (that live in the open ocean) show a modification in their respiratory system to maximize their breathing capacity at great depths,” said Sellés.
Reporting by Will Dunham in Washington, Editing by Rosalba O’Brien
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