Known only from a collection from the Rio Amazonas and from the holotype, whose locality data is unclear (Goyaz, Brazil). The following comment accompanies the specimen label: " Probably somewhere in the Tocantins-Araguaia system. Collected after the conclusion of the Tayer Expedition, at Agassiz's specific request, for comparison with lower Rio Tocantins material. Isbrücker (1973:174) suggests that the locality is "Rio Araguaia drainage, upper course of Rio Vermelho at Goiás (15°57'S 50°07'W), but this has not been positively confirmed" (Ref. 49504).