Giant extinct turtle found in the Amazon

Fossilised remains of a giant freshwater turtle which lived between 40,000 and 9,000 years ago have been found in the Brazilian Amazon.

It’s shell, or carapace, measured about 1.8 m, making it one of the largest freshwater turtles in the world.

Peltochephalus maturin lived during the late Pleistocene period (2.58 million to 11,700 years ago) which ended at the same time as the last Ice Age. It is described in a paper published in Biology Letters.

It is bigger than today’s largest freshwater turtles: the Asian narrow-headed softshell turtle (Chitra chitra) which has a maximum shell length of 140 cm, and the South American river turtle (Podocnemis expansa) with a shell measuring 110 cm.

“In the past, we only know of a few turtles living in fresh waters that had a shell length of more than 150 cm,” explains first author Dr Gabriel S. Ferreira from the University of Tübingen, Germany. “Such large animals are most recently known primarily from the Miocene, the period around 23 to 5 million years ago.”

Sea turtles can get much bigger. Today, the leatherback sea turtle can reach 2.7 m in length and weigh 500 kg, making it the largest non-crocodilian reptile alive.

And, as is so often the case, we can find even larger animals in the fossil record. The largest turtle ever was the Archelon. This beast lived during the end of the days of dinosaurs and measured 4.6 m from head to tail and could weigh more than 3 tonnes.

Ferreira’s team described the new species based on its massive fossilised jaw which was found by gold miners at the “Taquaras” quarry in Porto Velho in the western Brazilian state of Rondônia near the Bolivian border – 2,700 km northwest of Rio de Janeiro.

Characteristics of the jaw suggest an omnivorous diet and a close relationship to the modern big-headed Amazon turtle (Peltocephalus dumerilianus).

Palaeontologists analyse fossil turtle lower jaw on table
First author Dr. Gabriel S. Ferreira (right) taking samples for the geochemical analyses. Credit: University of Tübingen.

The armoured reptile was named after author Stephen King’s fictional character Maturin.

“We named the new species after the giant turtle ‘Maturin’, an overarching protagonist in the Stephen King multiverse. Maturin is responsible for the creation of the universe in King’s novels and films,” Ferreira says.

The authors note that overkilling of “megafauna” is believed to be a factor in the extinction of many large species in South America and Australia. But, they add, there is little discussion about the impact of hunting on large aquatic reptiles.

Peltochephalus maturin is the youngest known giant freshwater turtle in the fossil record. It could have lived alongside the early human inhabitants of the Amazon.

“People settled in the Amazon region around 12,600 years ago. We also know that large tortoises have been on the diet of hominins since the Paleolithic. Whether freshwater turtles, which are much more difficult to catch due to their agility, were also eaten by early humans and whether Peltocephalus maturin – together with the South American megafauna – fell victim to human expansion is still unclear.

“Here we need more data from the Late Pleistocene and Early Holocene deposits of the Amazon Basin,” says Ferreira.

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