Primeiro registro de miniaturização em Parodontidae (Actinopteri: Characiformes), com a descrição de quatro novas espécies nas bacias do alto rio Paraná e rio São Francisco.

Abstract

The fish de the genus Apareiodon belonging to the family Parodontidae comprises 14 valid species. They are rheophilic species, usually living in places with running water e rocky bottom. The three genera can be differentiated by the absence e presence de anatomical characters. Miniature fishes are those that have reduced standard length in the adult stage, compared to non-miniature species, relative to non-miniature species, and are often accompanied by pedomorphism. Miniaturization can be separated into two groups: those with identical shape to non-miniature species but reduced size, e those with reduced size with juvenile characteristics. In this paper, the first four miniature species de the genus are described. The new species are: Apareiodon sp. n. 1 known from a marginal pond of the Rio Verde, upper Paraná river basin; Apareiodon sp. n. 2 known from the Rio Mourão, upper Paraná river basin; Apareiodon sp. n. 3 known from Lagoa 45 and Lagoa do Parente from the Rio Turvo, upper Paraná river basin e Apareiodon sp. n. 4 known from a marginal pond of the Rio Boa Vista, São Francisco river basin. The species differ from their congeners by their reduced size, a black spot on the caudal peduncle, more rays on the pectoral fin e fewer cusps on the teeth. The lack of research and data on miniaturization in this genus regarding taxonomic, ecological e natural history aspects is highlighted,and this work is the first record containing data and information on the group. The miniaturization, taxonomic aspects e geographical distribution de the new species are discussed.