In a taxonomic review of Venezuelan Phenacorhamdia, three species were recorded: P. anisura, originally described from the Río San Juan, Golfo de Paria basin; P. provenzanoi, new species, widely distributed in the Orinoco basin and P. taphorni, new species, restricted to upper Apure river basin. Phenacorhamdia anisura is redescribed based on topotypic material and a large number of specimens from sites across the Orinoco basin, expanding both the previously documented morphological variability and distribution of the species. Phenacorhamdia anisura has a broad distribution, sympatric and even syntopic with P. provenzanoi in the Orinoco basin, and is the only species of the genus found in the Golfo de Paria basin. Phenacorhamdia anisura is distinguished from congeners by the combination of maxillary barbel reaching three fourths along pectoral fin, outer mental barbel not reaching the pectoral-fin base, 5–7 gill rakers on the first arch, 41–43 vertebrae, nine pleural ribs, pectoral fin with modally seven branched rays, first basal radial of dorsal fin inserted posterior to vertebrae 11–12, anal fin with 12–15 rays (7–9 branched), caudal-fin lobes pointed, upper caudal-fin lobe with seven branched rays, lower caudal-fin lobe markedly longer than the upper caudal-fin lobe, uniform pigmentation of the body and some proportional measurements. Phenacorhamdia provenzanoi is diagnosed by the high number of vertebrae (47–48), and anal-fin rays (16–18), in combination with the number of gill rakers on the first arch (4–5) and some proportional measurements. Phenacorhamdia taphorni is diagnosed by the possession of multicuspid jaw teeth and fewer vertebrae (39). Morphological evidence supporting a previous hypothesis of phylogenetic affinities of Phenacorhamdia within heptapterids is discussed as well as the relationships of the new species described herein. Apomorphic tooth shape of P. taphorni supports a less inclusive clade within Phenacorhamdia, comprising this species and two undescribed forms of the Mamoré and Paraná basins, respectively.

New taxa: Phenacorhamdia provenzanoi DoNascimiento and Milani, Phenacorhamdia taphorni DoNascimiento and Milani