Fabiano Corrêa

Feeding ecology and prey preferences of a piscivorous fish in the Lagoa do Peixe National Park, a Biosphere Reserve in Southern Brazil

We investigated the diet, feeding strategy, size-related dietary shifts and prey preferences of South American Hoplias aff. malabaricus in an internationally recognized but poorly investigated Biosphere Reserve in southern Brazil. Fish were caught between April 2008 and March 2009 using a variety of fishing gear. The analysis of 113 individuals revealed a diet essentially composed of fish (16 species), particularly characid species (9). The diet became more diverse and contained larger fish prey with increasing predator size. Feeding strategy analysis revealed a clear specialization towards the consumption of fish. However, individuals did not prey upon particular prey species, instead opportunistically consuming many different fish species, which could be a strategy to avoid intraspecific competition. Characid species were the most important prey, followed by poecillids. A multi-gear sampling of the ichthyofauna revealed that these prey species were the most abundant (Characidae: 61.3%, Poeciliidae 18.8%) of the 14 fish families occurring at the study site, suggesting that the predator exploits the most abundant fish resources available rather than the rarer fish prey. These findings suggest that potential top-down controls exerted by H. aff. malabaricus in this system follow specific food web pathways that seem to be mediated by the abundance of prey resources.

The activity patterns and microhabitat use of Pseudis minuta Günther, 1858 (Anura, Hylidae) in the Lagoa do Peixe National Park, a biosphere reserve of the brazilian subtropics

Pseudis minuta is abundant in a variety of aquatic environments of the Pampa domain. Therefore, it can be considered a good model for testing hypotheses on environmental heterogeneity and the influence of climate on the activity of anurans. In this study, we examined the spatial distribution pattern of P. minuta in terms of microhabitats and the influence of abiotic factors on seasonal fluctuations in the abundance of this species. Samples were collected monthly from April 2008 to May 2009 in wetlands and coastal dunes in the Lagoa do Peixe National Park. A total of 112 specimens of P. minuta were collected, of which 45 were found in the wetland area and 67 in the dune area. The species showed seasonal fluctuation in abundance, and it was most abundant in months with higher temperatures (spring-summer). Pseudis minuta was mainly associated with aquatic vegetation, an expected pattern in terms of their morphological adaptations to this environment. Among the abiotic parameters analyzed, only the monthly mean temperature showed a significant correlation (p < 0.05; r = 0.67) with the abundance of P. minuta. We concluded that P. minuta is a generalist species with respect to microhabitat use and also that fluctuation in its population abundance is mainly associated with seasonal variation in temperature.

Pisces, Cyprinodontiformes, Rivulidae, Austrolebias minuano (Costa and Cheffe, 2001): new species record at Lagoa do Peixe National Park, state of Rio Grande do Sul, Brazil

Austrolebias minuano (Costa and Cheffe 2001) (Figure 1) is a annual fish belonging to the Rivulidae family that is comprised of approximately 235 species, from which 16 are endemic to Patos Lagoon drainage basin (Costa 2003). They inhabit temporary pools or swamps formed at the rainy season usually during winter months in southern Brazil (Costa 2006, Porciuncula et al. 2006). Adults die when ponds dry out during warmer months, but they leave their eggs buried into the sediment, where they remain in diapause until a new rainy season restores water levels in their habitats (Costa 2006). Austrolebias minuano is one of the species of the A. adloffi species group, which is characterized by a pair of black spots arranged vertically in close proximity, which can coalesce to form an 8-shaped blotch, on posterior portion of caudal peduncle in juveniles and adult females, and sometimes in adult males (Costa 2006). It can be distinguished by a combination of several characters, being among them, a black bar on parietal series of neuromasts, dorsal and anal-fin bases with elongated white spots, anterior flank bars about as wide as interspace and posterior bars wider (Costa op cit.). This species is considered endangered, especially due to expansion of increasingly urbanization and agriculture activities, which drastically alters and/or permanently disrupt their habitats (Fontana et al. 2003; Rosa and Lima 2008).

The ichthyofauna of limnic systems in Quaternary deposits of extreme southern Brazil

Abstract The Quaternary in the state of Rio Grande do Sul (RS), southern Brazil, is geologically represented by the coastal plain and was originated by successive events of Pleistocene-Holocene marine transgressions and the occurrence of alluvial deposits. This paper aimed to characterize the fish assemblage occurring in a swampy Quaternary area adjacent to Lagoa Pequena, a lacustrine system connected to the west margin of the Laguna dos Patos estuary. A checklist is also provided of the ichthyofauna so far recorded in limnic systems of Quaternary deposits in the state of Rio Grande do Sul. A total of 42 species was recorded, distributed in nine orders, 18 families and 31 genera. Characidae and Cichlidae were the most representative families, comprising 15 and 4 species respectively. A bibliographic revision associated to our sample data revealed the occurrence of 156 species in limnic systems inserted in RS Quaternary deposits (114 limnic, 15 marine/estuarine/limnic, ten marine/estuarine, nine estuarine/limnic and eight marine). Characiformes and Siluriformes are the most diverse orders, corroborating the Neotropical pattern. Seven species can be considered endemic to RS Quaternary deposits.

Pisces, Gymnotiformes, Hypopomidae, Brachyhypopomus draco (Giora, Malabarba and Crampton, 2008): new species record at Lagoa do Peixe National Park, state of Rio Grande do Sul, Brazil

The present paper describes a new occurrence of the species Brachyhypopomus draco in a wetland area of the Lagoa do Peixe National Park, state of Rio Grande do Sul, Brazil.

Pisces, Gymnotiformes, Hypopomidae, Brachyhypopomus gauderio Giora and Malabarba, 2009: new species record at Taim Ecological Reserve, south Brazil

The present paper describes a new occurrence of the species Brachyhypopomus gauderio Giora and Malabarba, 2009 in the Taim Ecological Reserve, Rio Grande do Sul state, Brazil.

Mammalia, Chiroptera, Rio Grande, state of Rio Grande do Sul, Brazil

Herein we present a checklist of the bat species recorded in the municipality of Rio Grande, coastal plain of Rio Grande do Sul state. Thirteen species of three families were recorded through field sampling, collection specimen analysis and bibliography compilation. Molossidae and Vespertilionidae, both with five recorded species, were the most representative families, while three species of Phyllostomidae were recorded. Seven species were found in urban areas. In the sampled natural environments, six species were found in riparian systems, being Myotis albescens and Molossus sp. recorded only in these formations. Riparian systems, hence, can represent relevant habitats for chiropteran conservation in coastal areas of southernmost Brazil.

Shape and size variation of Jenynsia lineata (Jenyns 1842) (Cyprinodontiformes: Anablepidae) from different coastal environments

A key question in ecological speciation is to understand the causes and consequences of phenotypic divergence among populations. In this work, we analyzed the body shape and size variation in Jenynsia lineata across different coastal habitats along the Atlantic coast of South America. We hypothesized that J. lineata presents morphological variations to inhabit contrasting environments and that these adaptations are sex specific. We analyzed 13 populations from five coastal habitats, using linear and geometric morphometry, and tested the correlation of body shape variation with environmental variables to understand which environmental factors may influence body shape and size variation. Jenynsia lineata showed differences in body shape and size among populations, and these differences are specific to each sex. While females showed a variation in the caudal peduncle correlated with water current, we did not find such trait variation and correlation in males. Alternatively, individuals from marine rocky pools have a convex body curvature along the dorsal profile and larger body sizes, in both sexes. With these results, we describe the shape and size morphological variation of J. lineata and discuss this uncommon habitat-dependent sexual dimorphism in a Neotropical livebearer fish.