A recent field inventory focusing on catfishes of the trichomycterine genus Cambeva detected the occurrence of two morphotypes, C. barbosae and C. cubataonis, in the Guaratuba-Babitonga-Itapocu area (GBIA) of southern Brazil, reporting some discordance with results of coalescent-based approaches for species delimitation that indicated different estimates of species number. Contrastingly, based on examination of characters taken from the external morphology and osteology, we here recognised six species of Cambeva in GBIA: C. cf. botuvera, a polymorphic and geographically widespread species; C. cubataonis, endemic to the Rio Cubatão do Norte; and four new species, two endemic to the Rio Itapocu basin, one endemic to the Baía de Babitonga system and one endemic to the Baía de Guaratuba system. We performed a molecular phylogenetic analysis indicating that Cambeva comprises three major clades, the alpha-, beta- and gama-clades, with C. cf. botuvera and a clade comprising C. cubataonis and three new species belonging to the beta-clade and another new species belonging to the gama-clade. We concluded that species here recognised are not in fact incongruent with results of that recent study when taxa are correctly identified by a representative sample of morphological characters, highlighting the importance of osteological characters for delimiting trichomycterine species.

The complete mitogenome of four Scleromystax barbatus populations distributed along the species natural range was reconstructed, comprising the first study with this genus and the second with Corydoradinae specimens sampled from their natural environment and deposited in permanent collections. The mitogenome of S. barbatus is a circular molecule of 16,694 base pairs (bp) comprising 37 genes, 22 of which are tRNA, two are rRNA, 13 are protein-coding genes and one control region (D-loop). An 18-nucleotide insertion sequence was found between the ATPase subunit 6 and COIII genes. Most genes are encoded on the heavy strand, while the ND6 and eight tRNAs are found on the light strand. Phylogenetic analyses using other available Callichthyidae mitogenomes confirmed the monophyly of Callichthyinae and Corydoradinae and indicate that S. barbatus populations form a separate and more closely related branch of Corydoras nattereri + Corydoras paleatus.

This study assessed the lapillus otolith shapes of males and females of Scleromystax barbatus from southern and southeastern regions in the Atlantic Rainforest biome employing Fourier and Wavelet descriptors. The utricular otoliths of S. barbatus are ovoid, with the gibbus maculae occupying almost all the ventral portion, similar to most Callichthyidae species. Otoliths of males and females of S. barbatus from the southeastern studied region are more elongated in the anterior-posterior direction and present larger sulcus and gibbus maculae, with heterogeneous borders. We found no sexual-based dimorphism in otolith shape within regions, however regional differences were registered and attributed to variations in fish life history mediated by differences in environmental factors (e.g., climatic conditions) between the southern and southeastern regions in the Atlantic Rainforest biome. Additional studies are suggested to investigate the influence of genetic effects and their environmental interactions to better understand how these factors are related with otolith shape and influence the discrimination among S. barbatus populations.

To investigate reproductive characteristics in a small population of Psalidodon aff. fasciatus living in isolation in an environment with a unique geological configuration, a doline-shaped depression (known as Furna 2), with a mean diameter of 80 m and water depth of 50 m, a natural heritage of the Vila Velha State Park (VVSP).

Aspidoras fuscoguttatus Nijssen & Isbrücker, 1976 is a small, relatively common armored catfish considered endemic to the upper Paraná river basin. Here, based on recent collections, as well as morphological and molecular evidence, the known geographic distribution of this species is extended to the basin of the São Francisco River. Specimens were collected during biological surveys in two unnamed tributaries of the Paraopeba River, in the headwaters of the São Francisco River. The new records may be a consequence of headwater stream-captures between São Francisco and upper Paraná drainages. Continued surveys are needed to assess and mitigate natural and human impacts, including biological exchanges between basins.