The Tucuxi dolphin (pronounced 'too-koo-shee') (Sotalia fluviatilis), is "the world's only exclusively freshwater delphinid" (IUCN) - a freshwater member of the family of Oceanic Dolphins within the order of cetaceans. It is closely related to the Costero (Guiana Dolphin - Sotalia guianensis). Tucuxi is the form of Sotalia in the Amazon region and Costero occurs in the marine and estuarine waters of eastern South and Central America and the Caribbean. Threats to the Tucuxi include water pollution, hydroeclectric facilities, noise pollution and habitat destruction.