Knodus borari, a new species from the lower Rio Tapajós basin (Characiformes: Characidae)

A new species of Knodus from the Rio Cupari, a right‐bank tributary of the lower Rio Tapajós, is described. Among its congeners, the new species shares exclusively with K. figueiredoi the presence of only uni‐tricuspid teeth in the premaxilla, maxilla and dentary. Knodus borari differs from K. figueiredoi by the colour pattern and morphological characteristics. The new species is the fifth species of the genus described from the Rio Tapajós basin, and the second restricted to the lower portion of the basin. This is additional evidence that the lower Rio Tapajós basin is a region of ichthyofaunal endemism.