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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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.

Polyploidization plays an important role in speciation and evolution in anurans. However, a few stable triploid populations and some isolated triploid individuals have been reported. Here, we report the discovery of naturally occurring triploids in contact zones between diploidOdontophrynus cordobaeand tetraploidO. americanusfrom Central Argentina, and propose values of erythrocyte area for the distinction of ploidy levels. A total of 101 individuals from three contact zones were studied and ploidy of each specimen was identified by mean chromosome count and erythrocyte size. Twenty three adult triploid specimens (males: ; females: ) from two contact sites were identified (percentage of individuals per ploidy level: site S2, %, %, %; site S3: %, %, %). The limit values of erythrocyte nuclear area used to distinguish between different ploidy levels were 23.62 μm2(probability to be assigned to a respective ploidy level = 94.78%) for separating diploids and triploids and 27.67 μm2(98.62%) for triploids and tetraploids. The high number of adult triploids occurring in more than one contact site betweenO. cordobaeandO. americanusindicates that is not an isolated event. However, further studies are necessary to provide a hypothesis on the origin and evaluate the possible maintenance of triploids in syntopy withO. cordobaeandO. americanus.

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%.

We in situ assessed the influence of natural fluoride concentrations in lotic freshwater ecosystems on diet and morphology of Boana cordobae tadpoles. Two streams were sampled in Argentina: Los Vallecitos stream (LF-LV) and Los Cerros Negros stream (HF-CN) with low and high fluoride levels, respectively. We captured tadpoles of B. cordobae in each stream using nets. Body weight (BW), total length (TL) and body condition (BC) of tadpoles was registered. Food items were identified to genus level and assigned to functional traits. Tadpoles showed significant differences in TL between streams, with smaller individuals in HF-CN, while did not show differences in BW and BC. The diet of tadpoles consisted mostly of microalgae. In tadpoles from HF-CN stream the proportion of cyanobacteria was lower than tadpoles from LF-LV. In relation to functional traits, small algae, high profile and colonial algae were more abundant in HF-CN. Algae attached by pads showed a higher proportion in HF-CN diets and stalked algae were more abundant in LF-LV. The differences in TL and diet of tadpoles can be attributed to differences in algal community composition, with genera that are affected by high concentrations of natural fluoride; for example cyanobacteria. The low algal richness registered in HF-CN stream does not affect the physiological state of the tadpoles, possibly because of a higher algal density in HF-CN diets. However, in further studies it would be important to evaluate the population status of B. cordobae from the HF-CN, because a small body length of tadpoles could have consequences at the population level.

Las diferencias fenotípicas intraespecíficas entre poblaciones separadasgeográficamente es común entre los anfibios anuros. En el presentetrabajo se realiza una caracterización morfométrica de Hypsiboascordobae, con el objetivo de estudiar la variación geográfica a lo largode la distribución de la especie. Se midieron 15 variables un totalde 86 individuos, pertenecientes a seis localidades de las provinciasde Córdoba y San Luís. Se observó dimorfismo sexual en diez de lasvariables. El análisis comparativo mostró diferencias significativasentre poblaciones, y el análisis discriminante mostró altos porcentajesde clasificación (87,50%). Ocho variables morfométricas mostraronrelación significativa y positiva con la latitud; mientras que diez variablesmostraron relación significativa y positica con la altitud. Sin embargo, enambos casos las correlaciones entre las distancias morfométricas y laslatitudinales/altitudinales no resultaron significativas (Test de Mantel).Esta variación geográfica en la morfometría de la especie puede debersea diferencias ambientales, o podrían deberse también a la edad de losindividuos. Por lo tanto, estos datos podían ser complementados conestudios relacionados directamente a las condiciones ambientales decada localidad, como así también estudios de esqueletocronología quepermitan determinar la edad de los individuos.ABSTRACTMorphometric differentiation and geographic variation amongpopulations of Hypsiboas cordobae (Anura: Hylidae). Intraspecificphenotypic differentiation among geographically separatedpopulations is common in anurans. We performed morphometricanalyses of the endemic frog Hypsiboas cordobae in order to assess thegeographic variation of morphometric variables along of distribution ofthe species. We measured 15 morphometric variables on 86 individualsfrom six localities of Córdoba and San Luís provinces. We foundsexual dimorphism in ten variables. The comparative analysis showedsignificant differences between populations and discriminant analysesshowed high percentages of classification (87,50%). Eight morphometricvariables showed positive correlation with latitude; and ten variablesshowed positive correlation with altitude. However, the correlationsbetween morphometric distances and latitudinal/altitudinal were notsignificant. This geographic variation in the morphometry of the speciesmay be due to environmental differences, or may be due to the age ofindividuals. Therefore, these data could be supplemented by studiesdirectly related to the environmental conditions of each locality, as wellas skeleton-chronological study to determine individual age.

Four populations of Rhinella arenarum from aquatic environments with different degrees of disturbance in central Argentina were compared to assess the ability of cytomorphology and cytomorphometry of blood cells as a hematological biomarker. A total of 93 specimens of R. arenarum (adults sexually mature) were captured during the spring. From the analysis of cell, no variations were found in terms of morphology, whereas in nuclear and cell areas and Price-Jones curves, we observed a smaller size in erythrocytes of individuals inhabiting the site most altered, "Villa Dalcar," as well as for leukocytes, lymphocytes, neutrophils, and eosinophils for the same site. This could be caused by presence of different pollutants in the lake. Furthermore, this was confirmed by the high levels of environmental variables (conductivity, total dissolved solids, and salinity) show that Villa Dalcar is the site most affected by human activities.