Geophagus pyrineusi, new species, is described from the rio Teles Pires drainage, rio Tapajós basin, Brazil. The new species can be diagnosed from the majority of the congeners by presenting a complete infraorbital bar. Additionally, it differs from all other congeners by several coloration-related character states: flank bars 5 and 6–7 as dark as the infraorbital bar, and almost as dark as the midlateral spot; retention of dorsal melanophoric patch 6 as a distinct mark (not connected to any lateral melanophoric patch), and almost as dark as the midlateral spot in adults; retention of lateral melanophoric patch 1p and almost complete absence of dorsal- and caudal-fin color patterns in adults, among other characters.