A New Species of Piranha (Serrasalmus, Serrasalmidae) from the Upper Madeira River System, Amazon Basin, Bolivia

A new species of piranha, in the genus Serrasalmus (Characiformes, Serrasalmidae), is described from tributaries of the upper Madeira River drainage (Bolivian Amazon Basin). This new species exhibits a similar caudal-fin color like that observed in S. hollandi, and review of the literature suggested that former studies have misidentified these two species. The new species can be diagnosed morphologically from other congeners, but genetic variation of the COI sequence data showed little difference (~1%) from similar, morphologically recognized species. Since Serrasalmus species are widespread and morphologically difficult to identify, a key for identifying Bolivian species of this genus is presented.