Giant Turtle Revealed in 'Remarkable' 57-Million-Year-Old Fossils

Paleontologists have uncovered fossils of a giant turtle species with some striking features, such as its shape, that lived tens of millions of years ago in South America.

The research team found the turtle remains in the Andes mountain range across at least four different sites within the Socha region of Boyacá department, northeastern Colombia.

The fossils consist of several turtle shells, including some complete specimens, as well as a number of isolated bones, a study published in the journal of the Argentine Paleontological Association reported. The authors said they had identified at least 21 individuals at various stages of life, including hatchlings, juveniles, and adults.

According to the study, the fossils represent a now-extinct turtle species known as Puentemys mushaisaensis, which lived in the northernmost part of South America around 57 million years ago.

This creature was huge for a turtle, reaching a total body length of around 5 feet. It also had a particularly distinctive feature: an extremely circular carapace (the upper domed part of the shell)—something that no living turtle possesses.

"The most remarkable feature was its almost circular carapace outline and large size combined," the study's lead author, Edwin-Alberto Cadena with the Faculty of Natural Sciences at the Universidad del Rosario in Bogotá, Colombia, told Newsweek.

The discovery of P. mushaisaensis in Socha is significant because the only other record of the species comes from a site (the Cerrejón coal mine) located around 310 miles to the north near Colombia's Caribbean coast. Thus, the latest results significantly expands its known range.

This finding has helped to shed light on what the environments of northern South America were like around the time that this turtle lived, when the Andes region was lower in elevation.

Based on the type of rocks that the fossils were found in, as well as the shape of the shells and limb bones, the researchers determined that the turtle lived in lakes or moderately large rivers.

Taking this into account, as well as the new location where the fossils were found, the researchers concluded that there was likely significant connectivity between the aquatic ecosystems (i.e. rivers and lakes) of northern South America. An aquatic "corridor" like this may have enabled P. mushaisaensis to spread out over a relatively large area.

"The shell and limb bones found, as well as their internal bone tissue, indicate that it was a species of turtle well-adapted for freshwater ecosystems and an excellent swimmer," Cadena said. "This likely facilitated its wide distribution in the northernmost part of South America."

In addition, the newly uncovered fossils are better preserved than any of the previous records for this species, enabling the research team to confirm that it belonged to an extinct group of turtles known as Bothremydidae.

Despite this, there are still several unknowns regarding the life and behavior of the species, according to the researchers.

"In terms of its diet, we still lack data as we do not have skull or mandible fossils," Cadena said. "However, we would expect it to have been a mollusk and plant-eating turtle, similar to some of its closer relatives—bothremydid turtles found in North America and Africa."

Based on the fossil-rich sites where the turtle remains were found, which also include the bones of large crocodiles and snakes, it also likely that P. mushaisaensis was preyed upon by other creatures, particularly the hatchlings and juveniles.

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