Huge turtle measuring up to 12 FEET long roamed Spain 83 million years ago, fossil analysis reveals 

The fossilised remains of a humongous species of marine turtle have been discovered in Spain dating back 83 million years. 

The remains belong to an entirely new species, which may have been one of the largest marine turtles to have ever lived.  

The species, which researchers from Universitat Autònoma de Barcelona have named Leviathanochelys aenigmatica, had an estimated body length of up to 12.27 feet (3.74 metres). 

That’s more than twice the size of the average human! 

An illustrated reconstruction of Leviathanochelys aenigmatica, one of the largest turtles ever 

The excavation site in the Cal Torrades locality in Spain where the remains were found 

In the study, published in Scientific Reports, the researchers explained the turtle’s name was derived from the ‘Leviathan, in reference to the Biblical marine beast, in allusion to the body size of the new species’, and chelys, which is latinised version of the ancient greek word for female turtle. 

Aside from being one of the largest marine turtles found anywhere in the world, Leviathanochelys represents the largest to have been discovered in Europe. 

This prehistoric reptile towers over any other of its extinct or living relatives in Europe, with the largest reaching about 4.9 feet (1.5 metres) in length.

However, the Leviathanochelys is significantly smaller than the ancient extinct genus Archelon, which is the largest known marine turtle. 

Archelon lived in the seas surrounding the North American continent and grew to a staggering 15.1 feet long (4.6 metres).

It roamed during the late Cretaceous period, which was between 100.5 and 66 million years ago, and could weigh up to 3.2 tonnes.

In their new paper, Àngel H. Luján, Albert Sellés, and colleagues described the remains of the new marine turtle specimen, which were excavated between 2016 and 2021 from the Cal Torrades locality in Northeastern Spain.

The remains of the turtle were excavated between 2016 and 2021 from the Cal Torrades locality in Northeastern Spain

The turtle has a distinctive protruding bone that is different from other species (illustration)

The fossils they found consisted of a fragmented, but nearly complete pelvis, along with parts of its carapace, or upper shell.

The creature from the Testudine family dated back to the Campanian Age, between 83.6 to 72.1 million years ago, meaning that it existed around the same time as the Archelon. 

However, one distinctive feature that set the Leviathanochelys apart was a bone protruding forwards from the front of the pelvis, which the researchers believe may have been related to the respiratory system.

The presence of this bone suggests that the creature could represent a new taxon of ancient marine turtles. 

Based on the size of the pelvis, the authors estimated that the turtle may have reached a body length of 12.27 feet.

They also judged that it had a maximum pelvis width of 2.9 feet (88.9 centimetres), which is actually slightly larger than the biggest estimates for Archelon’s best known specimen at 2.66 feet wide (81 cm).

In the study, the authors noted that this discovery ‘sheds a light on the diversity of marine turtles and on how the phenomenon of gigantism in these groups was also occurring in Europe.’

‘Despite the scarcity and fragmentary nature of the individual, the new evidence not only increases the taxonomic diversity of the Late Cretaceous marine turtle biota in Europe, but also opens a new line of exploration and raises new questions,’ they concluded. 

WHAT ARE LEATHERBACK TURTLES AND WHAT DO WE KNOW ABOUT THEM?

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.

They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. 

Leatherbacks weigh between 600 and 1,500 lbs (270 to 700 kg) on average and are normally between 55 to 63 inches (140 to 160 cm) in length.  

Leatherback turtles (pictured) are named for their shell, which is leather-like rather than hard, like other turtles. They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans (stock)

Pacific leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall. 

Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch. 

Globally, leatherback status according to the International Union for Conservation of Nature, leatherbacks are listed as Vulnerable

Many subpopulations – such as in the Pacific and Southwest Atlantic – are Critically Endangered.