A new species of Hemiodus is described from the Rio Xingu basin, Pará, Brazil. It is distinguished from congeners by the combination of presence of a dark longitudinal stripe extending from head to tip of lower caudal-fin lobe, an oblique blotch on dorsal-fin, 9-11 scale rows above lateral line, 58-66 perforated lateral line scales, and 17-20 circumpeduncular scales. Comments on the conservation status of the new species, as well as its relationships among Hemiodus species, are made.
Keywords: Pisces, Hemidus ternetzi, Hemiodus thayeria, Hemiodus tocantinensis, South America, taxonomy.