No abstract

Brachyhypopomus bombilla, B. draco and B. gauderio are recorded for the first time in freshwaters of Argentina. These species were collected in the Río Paraná basin at the Iberá Wetlands and Pre-Delta National Park. Brachyhypopomus bombilla, B. draco and B. gauderio can be sympatric and syntopic in Pre-Delta National Park, whereas B. bombilla and B. gauderio occupy the same environments in the Iberá Wetlands. Some records of B. brevirostris for Argentina are misidentifications of B. gauderio, whereas others could correspond to one of these three species.

Astyanax erythropterus (Holmberg, 1891) originally described on the basis of one juvenile, is redescribed herein based on juveniles and adults from the type-localiy. The species differs from its congeners by the combination of 11-13 transverse rows scales above lateral line and 8-10 rows below lateral line; 49-54 perforated scales in the lateral series; iii-v,38-42 anal-fin rays, and dorsal, anal and caudal fins vermilion red in juveniles. The vermilion red coloration of unpaired fins in juveniles of Astyanax is only known in A. correntinus.

Killifishes (Cyprinodontiformes) are a group of fish that include a high proportion of small-bodied species living in seasonal aquatic habitats, with narrow geographical distributions and high human impact. They are among the most vulnerable vertebrates in the Neotropical region, with nearly half of the species in threat categories. Herein, we propose a new phylogenetic hypothesis of the Rivulidae genus Austrolebias, based on 10 genes (six nuclear and four mitochondrial) and 191 morphological characters, including 90% of the total valid species of this genus. An updated definition and diagnosis of the existing subgenera of Austrolebias is provided, and these are erected to genera. Also, four new genera are erected to accommodate the taxonomy of the group to the current phylogenetic hypothesis. Additionally, we describe Argolebias guarani sp. nov., from a seasonal pond in the Middle Paraná River basin, which is diagnosed by a unique colour pattern. This addition reinforces this area as a biodiversity hotspot of endemicity and highlights the importance of this region for conservation. Data on the ontogenetic changes in colour pattern, chorion ornamentation of the egg and ecology of this species are also provided.

El objetivo general del presente trabajo fue identificar las especies de peces que capturan los pescadores y el uso que le dan a las mismas en la cuenca inferior del río Luján. Para tal fin, se realizaron entrevistas semiestructuradas durante la primavera de 2015, el verano y el otoño 2016, las cuales permitieron obtener información sobre el uso que les dan los pescadores a los peces capturados. Se analizaron a lo largo de este período dos escenarios: los días de semana y los fines de semana. En la cuenca inferior del río Luján coexiste una diversidad de contextos sociales manifestados a través de sus actores: los pobladores locales y los pobladores de partidos vecinos que visitan el área. Las especies más mencionadas a lo largo de todo el estudio fueron: Pimelodus maculatus, Pimelodus albicans, Astyanax sp., Megaleporinus obtusidens y Rhamdia quelen. Los resultados obtenidos permiten plantear la importancia que tiene este territorio en la ribera del río Luján para los pobladores de la zona y de las regiones cercanas dado que los días de semana es un sitio que ofrece un espacio para realizar pesca de subsistencia mientras que los fines de semana constituye un espacio para el esparcimiento familiar.