Scinax

Abstract: Patterns and levels of allozyme variation among populations of Amazonian frogs were used to test the riverine barrier hypothesis of species differentiation. Two frog species were sampled from each of the two main forest habitats on both banks of the Jurua' River in the southwestern Brazilian Amazon Basin at various points along its course to contrast different barrier strengths. Scarthyla ostinodactyla and Scinax rubra were sampled from flooded forest (varzea), and Physalaemus petersi and Epipedobates femoralis from non-flooded forest (terra firme). All species showed high levels of within-population genetic variation. Average Nei's (1978) and Rogers' (1972) genetic distances between sampled sites for all species were high indicating substantial among-population differentiation. The observation of low gene flow between sampled sites within species was further substantiated with Slatkin's (1993) A([ analyses. Randomization tests suggested that there was some population structure at a few assayed polymorphic loci that was consistent with the riverine barrier hypothesis. However, it was apparent from the raw allozyme frequency data that these results were largely driven by substantial differentiation at one or a few collecting localities rather than by basin-wide patterns of riverine differentiation. Phenograms using genetic distance matrices supported this interpretation. Patterns of geographic variation are probably more consistent with the idea of this region being a zone of secondary contact.

Abstract: The comprehension of structure and functioning of communities are fundamental for the execution of conservation efforts in forested areas. In the present study we evaluated a community of anurans in a State Forest in Southeast Brazil, emphasizing the reproductive biology of the species. It has been found 21 species, of four families: Bufonidae, Hylidae, Leptodactylidae, and Microhylidae. The species of the family Bufonidae reproduced during the dry and cold season, while other species reproduced only during the wet and warm season of the year. Besides temporal segregation, some species divided the physical environment during reproductive season. Strong temporal and spatial overlap was observed among phylogenetically close species (of the same genus), such as Hyla nana and H. sanborni, Scinax fuscovarius and Scinax sp. (aff. similis), and Leptodactylus fuscus, L. mystacinus, and Leptodactylus sp. (gr. fuscus). In these cases, acoustic differences may be the main factor responsible for the reproductive segregation. Lack of reproductive segregation was observed among species of the genus Bufo, which were found in interespecific amplexus, even with acoustic differences in their advertisement calls.

Abstract: In this article, we describe a new species of Scinax from the state of Parana, southern Brazil, based on the external morphology of adults and their advertisement calls. The new species is diagnosed by the size of its males (SVL 27.8–31.6 mm); the snout subovoid in the dorsal view and slightly acuminate in profile; the vocal sac subgular and ventrally not reaching the pectoral region; and the advertisement call composed of a single pulsed note with 7–13 pulses, and a duration of 0.16–0.25s. This new species occurs in natural highland grassland formations, in the threatened ecosystem of the Atlantic Forest in the state of Parana, southern Brazil.