Jupiaba Zanata, 1997 is a genus with small species within Characidae, identified by a pair of modified bones in the form of spines just anteriorly to pelvic-fin base. The genus is mostly distributed throughout the Amazon drainage, except J. acanthogaster (Eigenmann, 1911), which also occurs in the Paraguay river basin. In this work, we recorded for the first time J. acanthogaster in the Sucuriú River drainage, upper Paraná river basin, Brazil. Its occurrence may be a consequence of the historical hydrological interaction between the Paraná and Paraguay river basins.
The aim of this study was to investigate the diet composition and feeding strategies of Triportheus nematurus at the Miranda-Abobral floodplain region and evaluate if the temporal phenomenon of the flood pulse has influenced in the diet composition of the species. The fishes were sampled quarterlybetween August/2014 and July/2016-in the marginal ponds located in the Estrada Parque (MS 184). The feeding habits of T. nematurus was characterized as omnivorous and its opportunistic feeding behaviour, since its diet is composed of different resources along of the year. Insects and organic matter were the most important items during the drought period; plant material (leaves and roots) and Euglenophyceae algae were more expressive during the inundation period; insects and fruits were also abundant during the flood period. Through statistical analysis, it was possible to verify significant variation in the diet composition of the species. This variation in the components of the diet may be related to the availability of resources in the ponds throughout the year and reflect an already known pattern in Neotropical fish populations, which present high alimentary plasticity.
The presently reported study provides the length-weight relations (LWR) for 23 species from headwater streams of the Bodoquena Plateau, which is located on the southern border of the Brazilian Pantanal. The following species were studied Steindachnerina brevipinna
During focal observations carried out in the Olho d’Água River, upper Paraguay River basin, Brazil, we registered the defensive behaviour of one pair of Crenicichla lepidota attempting to protect their offspring from conspecific and non-specific predators. Adults exhibited substrate-guarding behaviour and displayed primary and secondary anti-predation mechanisms. The primary mechanisms (e.g., fin flicking and flaring, gill extending) were ineffective against conspecific predators or against other species. Secondary mechanisms included charging would-be predators of the offspring, and this tactic was successful against non-specifics. This record confirms, in the wild, agonistic behaviour as an effective secondary defence mechanism used in parental care in Crenicichla lepidota.
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