Phylogenetic relationships and description of two new species of Diapoma (Characidae: Stevardiinae) from the La Plata River basin

Abstract Herein we describe two new species of Diapoma, one from the Negro River, a tributary Uruguay River in Brazil and Uruguay, Iguaçu Argentina. The basin is distinguished its congeners by following combination characters: black narrow conspicuous line restricted to body horizontal septum, incomplete lateral line, tricuspid teeth inner series premaxilla, lower depth at vertical through dorsal-fin origin (29.3–32.8% SL males 27.7–33.3% females). discontinuous adipose fin hyaline, longer anal-fin base (26.5–32.4% SL), longitudinal stripe along median region caudal-fin rays. Additionally, updated molecular phylogeny genus, including sequences these Diapoma thauma. An identification key for presented, modified previous study.