Identification key of Pariolius

1 Body color light brown; caudal-fin base with a triangular dark brown spot; very faint or undistinguishable white nuchal collar............................................................................ P. pax sp. nov. (Orinoco)

- Body color dark brown; caudal-fin base with a semilunar dark brown spot; well-defined white nuchal collar.

2 Six branched rays in pectoral fin; subterminal mouth, upper jaw longer than lower jaw; long adipose-fin base, 22.7–25.1 % of SL............................................................... P. maldonadoi sp. nov. (Orinoco/ Amazonas)

- Seven branched rays in pectoral fin; upper mouth, lower jaw longer than upper jaw; short adipose-fin base, 17.1–21.0 % of SL.............................................................................. P. armillatus (Amazonas)