Based on examination of the bone fragments, scientists have estimated that the newly identified sea turtle species measured 3.7 meters.
A long time ago, gigantic sea turtles swam Earth's seas.
Until recently, these prehistoric animals, which reached a length of more than 3 meters from head to tail, were believed to only be found in the waters surrounding North America.
Now, scientists have discovered a previously unknown species that is the largest European sea turtle ever identified.
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The species, initially found by a hiker who stumbled upon the remains in 2016 in the Pyrenees mountains of northern Spain, has been given the name Leviathanochelys aenigmatica.
"Leviathan" is the biblical term for a sea monster, alluding to the large size of the creature's body.
"Chelys" translates to turtle and "aenigmática" translates to enigma, referring to the turtle's peculiar characteristics, the authors wrote in a paper published Thursday in the journal
The presence of this unusual animal in this part of the prehistoric world reveals that giant tortoises were more common than previously thought, according to the study.
Before the discovery, the largest European species measured just 1.5 meters in length, similar to today's leatherbacks, which weigh an average of 300 to 500 kilograms and measure between one and two meters, according to the Smithsonian Institution.
A member of the research team at the excavation site in the Pyrenees.
The first turtle remains were discovered in 2016, but the researchers returned in 2021 and found more fragments.
(Credit: Angel Galobart)
However, bone fragments from this newly identified species have led scientists to estimate that Leviathanochelys had a 3.7-meter-long body, almost as big as an average sedan.
"We never thought it was possible to find something like this. After a long study of the bone fragments, we realized that there were some totally different traits, which were not present in any other fossil of a turtle species discovered so far," he said. Albert Sellés, co-author of the study and a postdoctoral researcher at the Miquel Crusafont Catalan Institute of Paleontology at the Autonomous University of Barcelona, in Spain.
Bones full of information
Initially, the researchers believed that the bones belonged to another type of animal, according to Sellés.
"It's quite common to find bone fragments, a lot of them. But most of them provide little information," Sellés said.
"It's quite rare to discover something that really tells you a little about life in the past."
A local museum and the Catalan Ministry of Culture had originally collected the bone specimens, but these went unstudied for nearly five years.
When Sellés and the other researchers began studying the bones in 2021, they realized they were dealing with a completely new species of sea turtle to science, and they quickly returned to the site for further excavation.
There, more fragments of the specimen were discovered, including pieces of the pelvis and shell.
With these findings, the scientists observed more features that they had not previously seen in any living or dead species.
"The main differences of this new fossil are related to the pelvic region. More specifically, with a pair of bony protrusions present in the anterior part of the pelvis, which we suspect are related to some type of muscle that controls the movement of the region. of the turtle," Sellés said.
Fragments of the pelvis and shell of the giant tortoise found in excavations in northern Spain.
(Credit: Angel Galobart)
This trait, or muscle, likely influenced the turtles' respiratory ability, allowing them to hold their breath longer than other species in order to swim deep in the ocean to find food or escape predators, according to Sellés.
Bigger and older than previously known sea turtles
The research team estimated that the animal lived during the Campanian era of the Late Cretaceous, making it at least 72 million years old.
The largest tortoise on record to date, called Archelon, lived about 70 million years ago and was up to 4.5 meters long.
Prior to this recent discovery, all finds of prehistoric giant sea turtles belonged to the same lineage as Archelon.
"We are showing that tortoises could reach really gigantic proportions at different times, and also in different families," Sellés said.
"For the first time, we have found a (giant) tortoise that does not belong to this family."
The researchers hope to return to the fossil site again to search for more bones, as they are not sure that all the fragments of this specimen have been discovered, according to Sellés.