My previous account on the Nannostomidi (1951, The Amsterdam Naturalist, 1 (1): 11—27) dealt with the synonymy of the recognized species. Diagnoses were given of the three genera, Nannostomus, Poecilobrycon and Nannobrycon (new genus). The account was based on but little material, largely on descriptions in literature, yet it could readily be proved that the species described before belong to 5 species only and to 3 well defined genera. I have since had the opportunity to study rather large series from Surinam and some other localities. An entirely new species was found among this material, which is so interesting in many respects that it induced me to reconsider the matter of the phylogeny of the tribe.