Redescrição de Bryconamericus iheringii (Boulenger, 1887) (Characiformes: Characidae).

Abstract

Bryconamericus iheringii (Boulenger, 1887) was described from the laguna dos Patos basin, where it is widely distributed. Together with other species that occur exclusively in the south of Neotropical region, B. iheringii forms a clade characterized by the subterminal mouth, always at level of ventral margin of the orbit; 5–6 rows of scales above lateral line; teeth of the outer row of premaxilla aligned; and dentary with teeth gradually decreasing in an anteroposterior direction. The lack of taxonomic studies regarding B. iheringii makes it difficult to identify it in relation to other congeners, as well as to determine its area of occurrence. The objective of this work was to restrict Bryconamericus iheringii to populations that are phenotypically closer to the lectotype of the species. For this, 225 specimens from the laguna dos Patos and rio Uruguai basins were analyzed. Of these, 131 specimens were identified as B. iheringii and supported the redescription proposed here. Furthermore, we present a new diagnostic proposal for B. ikaa and B. ytu. Bryconamericus iheringii is diagnosed from B. ikaa by color and B. ytu by the number of gill-rakers. Bryconamericus pliodus and B. boops are maintained as junior synonyms of B. iheringii. Finally, we suggest carrying out analyzes in populations distributed in other basins (upper and lower Paraná basins) to determine whether or not these populations belong to B. iheringii.