Researchers have discovered two new crocodile species - dating back 5 million years - in fossil records, one of which grew up to well over four meters long.
While studying the wealth of fossil crocodiles from the Miocene in the Urumaco River in Venezuela, the scientists discovered two new crocodile species: the Globidentosuchus brachyrostris, which belonged to the caiman family and had spherical teeth, and Crocodylus falconensis, a crocodile that the researchers assume grew up to well over four meters long.
Fourteen species of crocodile lived in South America around 5 million years ago, at least seven of which populated the coastal areas of the Urumaco region at the same time.
Paleontologists from the University of Zurich have found evidence of an abundance of closely related crocodiles that remains unparallelled to this day.
As they were highly specialised, the crocodiles occupied different eco-niches. When the watercourses changed due to the Andean uplift, however, all the crocodile species became extinct.
Nowadays, the most diverse species of crocodile are found in northern South America and Southeast Asia: As many as six species of alligator and four true crocodiles exist, although no more than two or three ever live alongside one another at the same time.
It was a different story nine to about five million years ago, however, when a total of 14 different crocodile species existed and at least seven of them occupied the same area at the same time, international team headed by paleontologists Marcelo Sanchez and Torsten Scheyer from the University of Zurich have found.
The deltas of the Amazonas and the Urumaco, a river on the Gulf of Venezuela that no longer exists, boasted an abundance of extremely diverse, highly specialised species of crocodile that has remained unparallelled ever since.
As Sanchez and his team reveal, Venezuela's fossils include all the families of crocodile species that still exist all over the world today.
They include the Crocodylidae, the so-called true crocodiles, the Alligatoridae, which, besides the true alligators, also include caimans and the Gavialidae, which are characterised by their extremely long, thin snouts and are only found in Southeast Asia nowadays.
On account of the species' extremely different jaw shapes, the researchers are convinced that the different crocodilians were highly specialised feeders: With their pointed, slender snouts, the fossil gharials must have preyed on fish.
With its spherical teeth, however, Globidentosuchus brachyrostris most likely specialised in shellfish, snails or crabs. And giant crocodiles, which grew up to 12 meters long, fed on turtles, giant rodents and smaller crocodiles.
"There were no predators back then in South America that could have hunted the three-meter-long turtles or giant rodents. Giant crocodiles occupied this very niche," said Scheyer.
