Caimans are alligatorid crocodilians within Caimaninae. The group is one of two primary lineages within Alligatoridae, the other being alligators. Caimans inhabit Central and South America. They are relatively small crocodilians, with the smallest being Cuvier's dwarf caiman (Paleosuchus palpebrosus), which grows to 1 m (3 ft) long, and the largest being the black caiman (Melanosuchus niger), which can grow to 4 m (13 ft) or more. Several extinct forms are known, including Purussaurus, a giant Miocene genus that grew to 12 m (39 ft) and the equally large Mourasuchus, which had a wide duck-like snout.