Estudo taxon？mico da ictiofauna de água doce da bacia do Rec？ncavo Sul, Bahia, Brasil

the rec？ncavo sul basin is a portion of the coastal river drainages of eastern brazil almost entirely included in the "baixo sul" region of bahia state, and is limited at its northern and northwestern borders by the rio paragua？u basin and at its southern and southwestern borders by the rio de contas basin. in this study a total of 41 strictly freshwater fish species were recorded, belonging to 28 genera, 12 families, and six orders (18 characiformes, 13 siluriformes, five perciformes, two cyprinodontiformes, two gymnotiformes, and one synbranchiformes). ten possibly undescribed, four endemic, and four introduced species were recorded in the area of study. one species occurring in the area is considered threatened with extinction. an identification key to the species known for the rec？ncavo sul is provided, as well as comments about the taxonomy and distribution of some species. due to its comparatively high diversity and relatively pristine condition the rio das almas drainage is suggested as a key area for conservation.