William L. Fink and Antonio Machado-Allison

A new species of piranha in the genus Serrasalmus is described from the Rio Negro and the Rio Japur , of Brazil, and a tributary of the R¡o Casiquiare of Venezuela. Serrasalmus gouldingi is a serrsalmin unique in having the following combination of features: proximal black band on caudal fin, vertically elongated stripes on the lateral body, and no prominent vertical humeral blotch. Two new species of Pristobrycon are described from black water areas of southern Venezuela, P. maculipinnis from the R¡o Pamoni and P. careospinus from the R¡o Atacavi. Pristobrycon maculipinnis is a serrasalmin presenting a unique combination of features including dark spots on the vertical fins and scattered irregularly over the body and head, lack of a pre-anal spine, and lack of fine 'pepper-like' spots. Pristobrycon careospinus is a serrasalmin with the unique combination of large dark ovate spots on the body side and no preanal spine. Morphometric and pigmentation features are discussed, and comparisons made with appropriate species.