Astyanax paranahybae Eigenmann, 1911

type locality Rio Paranahyba, Brazil

distribution Paraná River basin, Brazil

This species was cited by Ringuelet et al. (1967) based on a single examined specimen from Santa Fe city, with no collection number. Their citation was subsequently repeated by several other authors (e.g. Liotta, 2005) but no additional material of A. paranahybae was cited for Argentina. According to Ringuelet et al. (1967), meristic counts of the specimen they examined are similar to A. eigenmanniorum, but it has 3-4 maxillary teeth (instead of 1).

Astyanax paranahybae is known by a single specimen, which was examined by Garutti & Britski (2000). They mentioned that the posterior premaxillary row has 4 teeth in the left premaxilla and 5 in the right one and that it has only 7 branched dorsal-fin rays (vs. 9 in other species of Astyanax). Vari & Castro (2007) discussed the validity of A. paranahybae and suggested that it could be actually a member of Bryconamericus or Piabina, according to these data and the overall form of body.

There are just a few species of Astyanax in Argentina having 3 maxillary teeth, but no one has the combination of characters mentioned by Ringuelet et al. (1967). However, is not clear if the characters mentioned by Ringuelet et al. (1967) were observed by them or if they just copied the diagnosis by Eigenmann (1921). Ringuelet et al. (1967) did not mention how many premaxillary teeth and dorsal-fin rays had the specimen they examined, but the combination of characters provided by them is compatible with the discussion by Vari & Castro (2007) about this species. Therefore, and considering that no other specimen of this species was consequently cited, we consider Astyanax paranahybae, if valid, to be absent in Argentina. Even it is possible that the material examined by Ringuelet et al. (1967) was actually a specimen of Bryconamericus .