. There were seven species of crocodiles living in pre-Amazonian northeastern Peru 13 million years back. Researchers at the American Museum of Natural History claim that in no other time on Earth have so many species of crocodiles coexisted in one location. After more than 10 years of research in Amazon zone beds, it was discovered that there is an abundance of food, particularly mollusks such as snails and shells. Crocodiles eat a very small portion of these animals. The researchers published their results in the journal Proceedings of the Royal Society. (citation below) Scientists will have an improved understanding of the Amazon’s rich biodiversity. A life reconstruction of the head of the mollusk-crunching Gnatusuchus pebasensis, a 13-million-year-old, short-faced crocodile. Aldo Benites – Palomino was the co-author. Professor John Flynn is the Frick Curator of Fossil Mammals, American Museum of Natural History. He said that the modern Amazon River basin has the richest biodiversity in the world, though the causes of such a rich diversity are not well understood. It’s an enormous rain forest, so our exposure to rocks and therefore to fossils that may be preserved is extremely limited. “So whenever you have a window such as these fossilized mega-wetland deposits with so many unique species, it can give new insights into ancient ecosystems. What we found was not what you might expect. The Amazon basin’s rivers formed 10.5 millions years ago. It was a vast wetland area that contained swamps, lakes and embayments. These were remnants of coastlines which formed bays. Rivers flowed toward the Caribbean from northward. The river flows eastward towards the Atlantic Ocean today. It is essential to understand what types of life were present at the time to fully comprehend Amazonian history and its origins. There is plenty fossil evidence for invertebrates such as crustaceans, mollusks and other invertebrates in this region. However, only a few vertebrates are found. Professor Flynn and colleagues have been leading prospecting and excavating expeditions at the fossil outcrops in the Pebas Formation, north east Peru. The fossils found in these outcrops date back to the Miocene (from 23.). 03 up to 5. 332 millions years ago. The proto-Amazonian mega-wetland swamps 13 were home to crocodiles. Image: American Museum of Natural History. Three new species of crocodiles have been discovered. Gnatusuchus Pebasensis, a caiman that has a small snout with globular teeth and had a short face was what the researchers found fascinating. This species is thought to have “shovelled” mud bottoms while searching for other mollusks. According to the study, Gnatusuchus (and other shell-crunching Crocodiles) rose with an increase in mollusk diversity and numbers. This was before the huge wetlands became the Amazon River drainage system. Rodolfo Sals-Gismondi is a French graduate student. He said that the study was led by Rodolfo Salas–Gismondi. “When we analysed Gnatusuchus bone and discovered it was likely a head-burrowing caiman preying upon mollusks in muddy rivers and swamp bottoms we realized it was an important milestone in understanding proto-Amazonian food web dynamics.” Rodolfo also works as a paleontology museum of Natural History, Lima. The first Paleosuchus fossil was also found by the team. This paleontological specimen, which is a long-snouted caiman with a longer nose, could catch a wide range of prey including fish. According to Mr. Salas Gismondi, “We found a special time in history when the mega-wetland ecosystem was at its highest size and complexity just before it descended into the Amazon River system.” He also said that the team discovered the first fossil representative of Paleosuchus, an ancient caiman with a longer and more complex snout that could catch a wider variety of prey, including fish, and that the caimans with broad palates diversified into the generalist feeders they are today’s. Six species of caimans are found in the Amazon basin. Only three species of caimans ever live in the same habitat. Rarely do they share the same habitats. Seven species shared the same habitat millions of years ago. Citation: A Miocene hyperdiverse crocodylian group reveals peculiar trophic dynamics within proto-Amazonian megawetlands,” Rodolfo Sals-Gismondi, John J. Flynn, Patrice Bab, Julia V. Tejada -Lara & Frank P. Wesselingh & Pierre -Olivier Antoine. Proceedings of the Royal Society B.February 2015. DOI: 10.1098/rspb.2014. 2490.
