Salminus franciscanus, a new species from the rio Sao Francisco basin, Brazil (Ostariophysi: Characiformes: Characidae)

Salminus franciscanus, the large-sized dourado from the rio Sao Francisco basin, Brazil, is described. The new species was actually known ichthyologically since at least Valenciennes (in Cuvier & Valenciennes, 1850) but it was never properly identified. Salminus franciscanus can be diagnosed from its congeners by the combination of the presence of an enlarged second tooth in the outer series of the dentary considerably larger than the remaining teeth, the absence of a dark post-orbital stripe, scale counts (68-82 lateral line scales, 11-14 horizontal series of scales between dorsal-fin origin and lateral line, and 68 horizontal series of scales between the lateral line and the pelvic-fin insertion), and a developed extension of the middle rays of the caudal fin. The historical taxonomy of the species is discussed.