Abstract:Pleurodema guayapae is a species that inhabits saline environments and semidesert zones from central Argentina. To date, the knowledge about the reproductive biology of this species is very poor, and our aim is to contribute to its knowledge with the description of some important reproductive aspects. For this, field work was undertaken in an area near to Patquía, La Rioja province. Sampling was undertaken during three summer periods (2006-2007; 2007-2008; 2008-2009) in Chamical-Patquía area, where we could find reproductively active populations. We observed and described breeding sites, type of clutch, process of foam nest construction, clutch and egg number and sizes, and hatching time and stage. Behaviour observations were performed from the time that males began to call until the pairs ended up the foam nests building, and layed the eggs. Additionally, one amplected pair was observed and filmed in the process of foam nest construction, and four amplectant pairs were collected and separatelly placed in plastic containers, for nests observations in the laboratory. Hatching time was based on three different foam nests of known age. We found that P. guayapae populations were acoustically active only after a rainfall. Its breeding sites were represented by ephemeral ponds of fresh water, product of rains. The males emitted their calls inside or outside these ponds. A detailed description of the foam nest construction process by both females and males was made. The clutches were in dome-shaped foam nest type of 6-9cm in diameter and 1-3cm in height, some of which were in communal nests. The nests had an average of 1 137 pigmented eggs. This species showed a short hatching time. Our results allow us to conclude that this species should be considered an extreme explosive breeder. Our results are discussed with others obtained for related species. Rev. Biol. Trop. 62 (1): 173-181. Epub 2014 March 01.Key words: communal nest, ephemeral environment, explosive breeder, foam nest construction.The reproductive mode in amphibians was defined by Salthe & Duellman (1973) as "a combination of traits that includes oviposition site, ovum and clutch characteristics, rate and duration of development, stage and size of hatchling, and type of parental care, if any". Thirty-nine reproductive modes have been recorded for anurans around the world (Haddad & Prado, 2005). Altig & McDiarmind (2007) provide a generalized framework for diversity of amphibian eggs and ovipositional modes and introduce a standardized terminology for clutch structures.The genus Pleurodema Tschudi (Leptodactylidae: Leiuperinae) is distributed from Panama throughout South America to Southern Chile and Argentina, and currently is represented by 15 species (Cei, 1980;Valetti, Salas & Martino, 2009; Maciel & Nunez, 2010;Kolenc et al., 2011;Faivovich et al., 2012). This genus has very variable ovipositional modes. The eggclutch structure in the Southern Chilean populations of P. thaul and P. bufoninum is strings in water (Weigandt, Úbeda & Díaz, 2004). ...

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We aimed at determining sizes and shape of erythrocytes and evaluating the differences among larva, juvenile and adult Hypsiboas cordobae. Length and width of 40 randomly chosen erythrocytes and their respective nuclei from individuals of different ages collected in the experimental field "Las Guindas" (Córdoba, Argentina) were measured. Erythrocyte and nuclear areas were estimated assuming an ellipsoidal shape, and the aspect ratio, which reflects the shape of the cell, was calculated. The erythrocytes were oval, and their nuclei were also oval and centrally located. Erythrocyte size increased with age, whereas nuclei were larger in tadpoles than in juveniles. The cell and nucleus shapes also changed with age from the spherical shape in larvae to the more ellipsoidal one in adults. Discriminant analysis confirmed the existence of highly significant (P < 0.0001) differences in erythrocyte and nuclear areas among larvae, juveniles and adults, with a classification rate of 93.33%.

In this study karyotypic features of the five species of the family Bufonidae from the central area of Argentina are described. The species are Rhinella achalensis, Rhinella arenarum, Rhinella fernandezae, Rhinella schneideri and Melanophryniscus stelzneri. The metaphases were obtained from intestinal and testis cells, using conventional techniques. Twenty metaphasic figures per individual were analyzed and the total length of each chromosome and the length of the four arms were measured. The obtained measurements were processed using Excel 2000 to obtain the average length of the arms p and q, the arm ratio, the centromeric index, the relative chromosome length and the relative arm length. All species showed karyotype 2n = 22, and karyotype formula of 6 : 5. Pairs one to six were large, with a relative chromosome length between 18.64-7.59%; pairs seven to eleven were small, with a relative chromosome length between 7.18-2.42%. In all species the chromosome morphology was metacentric or submetacentric. Karyotype and ideograms were made for all species, based on morphometric parameters of the chromosome complement. Finally, discriminant analysis was used to separate the five species analyzed, with a highly significant classification rate of 80% and P < 0.0001. These results agree, in general, with those presented by other authors, however, in M. stelzneri detailed karyological studied have not been made so far, thus this work represents a significant contribution to the karyotypic decryption features of this species and the Rhinellla species from central area of Argentina.