Stupendemys is a prehistoric genus of freshwater turtles. Its fossils have been found in northern South America, in rocks dating from the Middle Miocene to the beginning of the Pliocene, about 13 to 5 million years ago.
Stupendemys geographicus is the largest known turtle species. Based on a fossil of a turtle shell up to 3.3 meters long, it is estimated that its total body length could have reached 5 meters (because of its very long neck) and weighed about 5 tons. The discovery of a new fossil gives scientists another opportunity to learn more about this super-giant turtle!
A close relative of today’s land turtles is the Podocnemis expansa species that lives in South America. Their body length is about 75 cm to 1 meter and their average weight is 90 kg.
A fossil specimen of a terrestrial turtle shell (Stupendemys geographicus).
Podocnemis expansa is a species of turtle in the family Podocnemididae. It was first scientifically described by Schweigger in 1812. It is found in the Amazon River basin. Adults typically reach a length of 1 meter. Females have a flat, broad shell and are larger and more numerous than males.
Marcelo Sánchez, director of the Insтιтute of Paleontology at the University of Zurich in Switzerland, has studied new fossil specimens found in Colombia and Venezuela in recent years. “There are many fossil specimens with shells that are more than 3 meters long with an estimated weight of 1,145 kg, more than 100 times that of Podocnemis expansa,” said the new study.
Over time, the weight of the land turtle has decreased significantly, but it is still the largest turtle that has ever existed on Earth, according to new research.
Venezuelan paleontologist Rodolfo Sánchez and a giant land turtle fossil discovered in Urumac, Venezuela, dating back about 8 million years.
Comparison of the size of the giant tortoise with adults and the modern Podocnemis expansa.
Recently, paleontologists discovered a nearly complete fossil specimen of a giant tortoise. This fossil specimen exhibits some previously undiscovered features, namely a pair of long horns.
Not all giant tortoises have these long horns, in fact, they only exist in males. These horns do not grow on the head but they grow on the front of the body and on both sides of the neck and are considered a prominent feature of male tortoises.
The pair of horns on the shell of a male turtle.
Through analysis and speculation, paleontologists believe that the pair of horns on the shell of a land turtle has a defensive function. Although they are huge and have extremely hard shells, in the era in which they lived, this turtle species still had natural enemies, the Purussaurus crocodile.
According to the bite marks discovered through fossil specimens of giant land turtles, it is clear that they were attacked by Purussaurus crocodiles, and the bite force from this giant crocodile’s bites can completely break the “solid” shell of the Stupendemys geographicus turtle.
This is similar to the way the Amazonian black Caiman crocodile kills Podocnemis expansa turtles today.
Purussaurus is an extinct genus of giant caiman that lived in South America during the Miocene epoch, from Colhuehuapian to Montehermosan in the SALMA taxonomy.
Comparing the size of a Purussaurus crocodile to a human.
In addition to the discovery of the fossilized turtle shell, archaeologists also found other bone samples that had never been discovered before. Based on the analysis and anatomy of the new fossil samples, paleontologists also determined and proved that this giant turtle species is related to many species of turtles living in the Amazon today.
Skull and jaw fossil of a giant land turtle.
Taxonomic position of the giant land turtle.
The fossils in this analysis come from Brazil, Colombia, Venezuela and other countries. It is found that this area covers almost the entire northern part of South America. The now deserted areas where the giant land turtle fossils were found were once wetlands and tropical rainforests.
Diagram of the location where the land turtle fossil was found.
Paleontologist Professor Edwin Cardina and a fossil of a giant tortoise.
The giant tortoise lived in central and northern South America from 13 to 5 million years ago. Judging from the geological layers where the fossils were found, this giant tortoise usually lived in ponds and lakes in the rainforest or in slow-moving rivers. It spent most of its time in water and ate mainly plants.
The first fossil of this species was found in the 1970s and named in 1976, until now it is considered the largest turtle species ever discovered by humans.
