Today’s turtles are smaller than humans, but only 9,000 years ago, turtles the size of couches inhabited much of the Brazilian Amazon. The turtle, known scientifically as Peltocephalus maturin, was discovered based on a fossilized jawbone that gold miners dug up in 2007 near the Amazonian city of Porto Velho. This was no ordinary bone, however — this jaw was massive.
“When I saw the material, I was very excited because of its size, so we managed to bring the specimen to our lab,” at the University of São Paulo, says vertebrate paleontologist Gabriel Ferreira, now at the University of Tübingen in Germany.
Ferreira and his colleagues measured the fossil and compared it to both living and extinct turtles, and they were able to determine that the Maturin was a new species to science. Maturin receives its name from Stephen King’s cosmic turtle, which acts as a higher power in many of his novels.
The Peltocephalus maturin’s closest relative living today is the aquatic big-headed Amazon River turtle (P. dumerilianus), which has a shell that is only about 50 centimeters long. In comparison, Maturin’s shell is estimated to be nearly 2 meters long.
Scientists believe that the jawbone of the giant turtle is the largest among any other turtle, making P. maturin one of the largest turtles to ever exist. What makes this turtle so fascinating is not just its size but also when it lived.
Ferreira’s team noted that radiocarbon geochemical analysis estimated the fossil to be between 40,000 and 9,000 years old. Freshwater turtles of a similar size to P. maturin lived much earlier in time. The maturin seems to be the only giant turtle that could have encountered human habitation, as there is evidence of humanity in the Amazon dating back to more than 11,000 years ago.
In 2023, Ferreira and other researchers published a turtle body size evolution analysis, which suggested that freshwater turtles tend to stay a similar size over evolutionary time, with occasional evolution of large species. Previous studies suggested that turtle body size may be influenced by factors such as environmental temperatures, as seen in other vertebrate groups. However, Ferreira noted, “We could not find any evidence of temperature influencing the mean or maximum body size in turtles, so we still do not know what could be driving the evolution of those giants in the past.”
The Peltocephalus maturin is thought to have gone extinct due to human activity in the Amazon. Similar to many other large animals, overkill is considered to be one of the driving factors for extinction across numerous species.
Photo Courtesy of CBS News
