Gnatusuchus is an extinct genus of caiman represented by the type species Gnatusuchus pebasensis from the Middle Miocene of Peru. Gnatusuchus lived about 13 million years ago (Ma) in a large wetland system called the Pebas mega-wetlands that covered over one million square kilometers of what is now the Amazon Basin (the modern basin had not yet developed at that time and instead of draining east-to-west across Amazonia and into the Atlantic Ocean, river systems drained northward through the wetlands and into the Caribbean Sea). Gnatusuchus likely fed on bivalves in oxygen-poor marsh and swamp environments, using blunt teeth to crush their thick shells. Gnatusuchus has a short, rounded snout and shovel-shaped lower jaw, which may have been adaptations for feeding on these bivalves. The teet