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Abstract

The Snake-necked Turtle (Hydromedusa tectifera) is mainly distributed in the northeastern provinces of Argentina; however, some isolated populations occur in central Córdoba. This is the first report on some ecological aspects of one of these populations. Population density and annual activity pattern were characterized at Toro Muerto Stream in the Sierras region of the Córdoba province, central Argentina. Turtles were hand-captured and sex and carapace length were determined for each individual. Mark-recapture data were used to estimate population density, variation in monthly capture rates, and sex ratios throughout the sampling months. A total of 96 turtles were captured and density was estimated at 218 individuals ha−1. Individuals were captured all year round, but showed activity peaks in spring and summer. This seasonal pattern has also been observed in other freshwater turtles. During the mating season a higher number of males were captured, which suggested a seasonal difference in activity patterns between sexes.

In: Amphibia-Reptilia

Abstract

Bothrops ammodytoides is a pitviper species endemic to Argentina that inhabits arid and semiarid areas from sea level to more than 3000 m, reaching the southernmost latitude for snakes. According to previous studies, the species is placed in the Bothrops alternatus group. We redescribe Bothrops ammodytoides based on examination of 101 specimens and provide new data on lepidosis, hemipenial morphology, cranial osteology, variation in coloration, and distribution. We compare Bothrops ammodytoides with representative species of the genus and related genera. Morphological comparisons reveal considerable affinities between Bothrops ammodytoides, Bothrops pictus, Bothrops andianus, and Bothrocophias microphthalmus, suggesting that the current taxonomy for Bothrops ammodytoides requires to be reassessed.

In: Amphibia-Reptilia

Abstract

Differences among wetlands can have important consequences on reproductive success of amphibians; therefore habitat selection is expected to be of particular importance for anurans inhabiting heterogeneous environments. To investigate if the red-belly toad (Melanophryniscus stelzneri; Anura: Bufonidae) uses available habitats differentially and to determine the main factors influencing the use of certain water bodies as breeding habitat, we surveyed 30 spawning sites used by red-belly toads, and 30 adjacent unused sites, in an area of the Sierras of Córdoba, Argentina. We evaluated the relative importance of morphological and biotic features of ponds, and the presence of other organisms within the water body on the use of ponds as breeding sites by red-belly toads. Eight habitat variables related to important water body features were recorded and were used to fit a habitat selection model with GLM. Red-belly toads presented a positive selection to mallines, a wetland characteristic of the Sierras of Córdoba. They were associated with small, shallow ephemeral ponds with muddy banks and a high percent of vegetation cover. In general, the ponds used did not host other anuran species or potential predators. Breeding site selection by red-belly toads is largely consistent with records for other species of the genus in other parts of Argentina.

In: Amphibia-Reptilia

Abstract

The diet of Hydromedusa tectifera occurring in two mountain streams in the province of Córdoba is described through a comparative analysis of 154 individuals. Turtles were manually captured between August 2005 and August 2006 from streams at the localities of Tanti and Flor Serrana. Before being released, turtles were stomach-flushed, and sex and carapace length were recorded. The stomach contents were observed under stereomicroscope; prey items were identified and classified according to size and volume. The importance of the different items was quantified using the Index of Relative Importance (IRI). Similarity in the diet between sexes and among size classes and seasons of an annual cycle was evaluated using the simplified Morisita index. Trophic breadth was estimated with the Shannon diversity index. Detrended Correspondence Analysis (DCA) was used to evaluate differences in the diet between categories (sex, size classes). Forty-seven food items belonging to the following taxa were identified: leeches, annelids, gastropods, arachnids, insects, and fishes. According to the IRI value, the most important items in the diet of H. tectifera were larvae of Trichoptera (IRI = 33.5), fishes (IRI = 30), and naiads of Odonata (IRI = 25.2). The relative importance of the items varied with size of turtles but not with sex. Size of prey consumed increased with increasing turtle size. A greater trophic breadth was observed in smaller individuals.

In: Amphibia-Reptilia

Abstract

Species inhabiting broad altitudinal gradients are particularly exposed to the effects of global climate change (GCC). Those species reaching mountain tops are the most negatively affected. Here, using ecological niche models we estimated the climate change exposure of endemic amphibians of the most important extra-Andean mountain system of Argentina: the Sierras Pampeanas Centrales. Our results pinpoint that micro-endemic amphibians of this mountain system are heavily exposed to the effects of GCC, with important constraints of suitable climatic conditions for the six analyzed species. Among the most important findings, our models predict a high probability of a total disappearance of suitable climatic conditions for two of the species, currently restricted to mountain tops. This high exposure, in synergy with their very restricted ranges, and other important human induced threats (as fish invasion and emergent diseases), pose a serious threat to these endemic species, which can enter into the “extinction pathway” in a near future if no concrete conservation actions are taken. Our findings provide additional evidence of the great negative impact of GCC in high-altitude centers of endemism.

In: Amphibia-Reptilia