| Amazon river dolphin, Tucuxi, Guiana dolphin, La Plata dolphin, Araguaian river dolphin|
Boto is a Portuguese name given to several types of dolphins and river dolphins native to the Amazon and the Orinoco River tributaries. A few botos exist exclusively in fresh water, and these are often considered primitive dolphins.
The botos are a paraphyletic group, defined largely by their evolutionary convergences.
The genus Sotalia is divided into two species. The costero (S. guianensis) is distributed in the Atlantic, from Florianópolis in Santa Catarina, Brazil, and northwards. The tucuxi (S. fluviatilis) lives in the rivers of the Amazon.
Burmeister's porpoise is marine and lives from Santa Catarina to the south.
The Amazon river dolphin (Inia geoffrensis) thrives in fresh water, is endemic to the Amazon basin, and is placed in the Data Deficient category of the IUCN.
The Araguaian river dolphin (I. araguaiaensis) is a newly identified species native to the Araguaia-Tocantins basin of Brazil.
The La Plata dolphin (Pontoporia blainvillei), another vulnerable Brazilian denizen, is a marine river dolphin that ranges from Espírito Santo, Brazil, to the south.Suborder Odontoceti
Species Sotalia fluviatilis, tucuxi
Species Sotalia guianensis, costero
Species Phocoena spinipinnis, Burmeister's porpoise
Species Inia araguaiaensis
Species Inia geoffrensis
Subspecies Inia geoffrensis geoffrensis, Amazon river dolphin
Subspecies Inia geoffrensis boliviensis, Bolivian river dolphin
Subspecies Inia geoffrensis humboldtiana, Humboldt's river dolphin
Species Pontoporia blainvillei, la Plata dolphin