A new study found that the Amazonian Peru, now northwestern Peru, was home to at least seven species of crocodiles 13 million years ago.
Researchers at the American Natural Museum of Natural History spent more than 10 years assembling the diversity map of the largest number of crocodile species that coexisted in one place. This place is presumed to be abundant of food sources for these species; prehistoric crocodiles were believed to feed on mollusks like clams and snails.
The team has been exploring the Amazon since 2002 searching for fossils. Some of the significant finds were the fossils of seven species of crocodiles; three were considered new species.
One of the strangest crocodile fossils belongs to the Gnatusuchus pebasensis, a short-faced crocodile with rounded teeth that may have dug through the mud at the bottom of the lakes and swamps to find clams and other mollusks. Dating suggests that the fossil is 13 million years old.
"When we analyzed Gnatusuchus bones and realized that it was probably a head-burrowing and shoveling caiman preying on mollusks living in muddy river and swamp bottoms, we knew it was a milestone for understanding proto-Amazonian wetland feeding dynamics," said Rodolfo Salas-Gismondi, study lead author and a graduate student at the University of Montpellier, in France, according to a news release. He is also a researcher and chief of the paleontology department at the National University of San Marcos' Museum of Natural History in Lima, Peru.
The findings of the study can help scientists have a better understanding of the history and biodiversity of the early Amazon.
"The modern Amazon River basin contains the world's richest biota, but the origins of this extraordinary diversity are really poorly understood," said John Flynn, study co-author and Frick Curator of Fossil Mammals at the American Museum of Natural History.
The study was published in the Feb. 24 issue of the Proceedings of the Royal Society B.
