We compared the effects of habitat disturbance on the feeding ecology of two local populations of Tropidurus torquatus (Wied, 1820) in restinga habitats on Ilha da Marambaia, Southeastern Brazil. Both populations presented a relatively diverse diet and differ in the number (D Max = 0.22, DF = 2, p = 0.00) and volume of prey consumed (D Max = 0.82, DF = 2, p = 0.00). Ants were the most frequent and numerous preys in both areas, and plant matter and coleopterans were the most important alimentary items in volume. The population from the disturbed area presented a larger niche breadth for number of prey items consumed (Bi num = 3.06) and volume (Bi vol = 2.98), when compared to the other population (Bj num = 2.44, Bj vol = 1.52). Niche overlap was higher for number of items consumed between the populations (Oij num = 0.82) but lower for volume (Oij vol = 0.05). Our data suggest dietary differences between the two lizard populations, and these differences may be associated with environmental modifications. Our main hypothesis to explain the dietary differences is based in the Optimal Foraging Theory. However, the alimentary behavior, and consequently the diet of these lizards, seems to be constrained phylogenetically, with a pattern that may have evolved in the ancestor of all iguanids.

Amphibian antimicrobial peptides have been known for many decades and several of them have already been isolated. However, the number of species investigated is still small. Herein, we report on the skin secretions of Leptodactylus ocellatus, which were extracted by mild electrical stimulation and its semi-preparative reverse-phase chromatography was resolved in more than 30 fractions. Among these fractions, two novel antimicrobial peptides were isolated and their amino acid sequences determined by de novo sequencing. The ocellatins-5 and -6 (21 and 22 amino acid residues, respectively) are amidated at the C-terminus. Ocellatins inhibited the growth of reference strains of both Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) with minimal inhibition concentration values in the range of 32-128 microg/mL. The amino acid sequence of the peptides shows structural similarity with members of the antimicrobial peptides found in the skin secretion of other leptodactylid frogs. This observation is consistent with the hypothesis that many frog skin antimicrobial peptides are related evolutionarily, having arisen from multiple duplications of an ancestral gene that existed before the radiation of the different species.

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The presently known distribution of Leptodactylus natalensis is no longer restricted to the northern and central limits of the Atlantic forest morphoclimatic domain. After Borges-Nojosa encountered it in the Caatinga at the time of this work, during a fi eld expedition in the Parnaíba Delta in December 2007, we identifi ed and collected some individuals of L. natalensis on the Ilha das Canárias, Araioses, located in northern Maranhão state. This new record for Maranhão extends the distribution of L. natalensis to approximately 520km west of the Serra de Baturité, in the state of Ceará.

The Terra Ronca State Park is located in the Cerrado biome. Knowledge on the biology and diversity of Cerrado amphibian assemblages is still incipient. The aim of the present research is to subsidize further studies on anuran composition and conservation of the Brazilian savanna by means of a detailed inventory of anurans from the Terra Ronca State Park. Twenty two species in five families were collected: Bufonidae, Cycloramphidae, Hylidae, Leiuperidae and Leptodactylidae. The most abundant family was Hylidae, with 12 species. Compared to other areas of Cerrado, the region explored in this study showed a high rate in relation to the diversity of amphibians. The goal of this research is to improve the knowledge of the biodiversity of the Brazilian Cerrado in order to better preserve such species.