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Reptiles de Uruguay
... DINAC (0-5)-Distribución Nacional. Datos obtenidos de Achaval (2001) y Carreira et al. (2005). También fueron utilizados datos de campo de los autores. ...
... No se encuentra categorizada en la lista roja de IUCN (2008). La tasa de encuentros es baja y existen pocos ejemplares en colecciones nacionales (Carreira et al. 2005). Algunos estudios relativamente recientes, indican la presencia de al menos una población que se reproduce en un área restricta del territorio (Magnone et al., 2005). ...
Conservation status of the turtles and terrapins (Reptilia, Testudines) of Uruguay. Based on the index proposed by Reca et al. (1994), the conservation status of Uruguayan turtles was evaluated. The categories Endangered, Vulnerable, and Low Concern were applied. Nine species were analyzed, of which Dermochelys coriacea, Lepidochelys olivacea, Phrynops williamsi and Caretta caretta have conservation problems. On the other hand Acanthochelys spixii was considered as vulnerable. The main limitation of this index is the lack of basic information about some species, and thus the low confidence in the values of the variables. For this reason the species should constantly be reevaluated.
... However, the similarity with other Coastal environments suggest a stronger abiotic influence in the structure of Biota Neotrop., vol. 12, no. 3 communities, which is supported by the similarity observed between the study area and the Coastal environment of Uruguay ( Carreira et al. 2005). In both areas, the climatic conditions and the marine influence are similar. ...
Abstract: This study examined species composition differences among snake and lizard assemblages from coastal dunes and restinga habitats in southernmost Brazil. Animals were collected between April 2009 and March 2010 using pitfall traps, artificial shelters, and time-constrained searches in grasslands areas susceptible to flooding. Species richness was higher in the restinga, but lower than the observed in other Brazilian biomes, possibly associated with more unstable microclimate conditions and low habitat complexity (vertical and horizontal
distribution of the vegetation) in this habitat. This hypothesis is supported by the fact that the most abundant species of both snakes and lizards have fossorial habits. The assemblage of snakes is apparently mainly determined by abiotic characteristics of the habitat, while the assemblage of lizards, by vegetation cover.
Genotoxicity studies have revealed that pesticides bind to genetic material in non-target vertebrates, thereby impairing the genetic integrity of these animals. The main objective of this study was to determine the genotoxic damage in erythrocytes of two native South American amphibian Physalaemus cuvieri and Physalaemus gracilis, both species exposed to a glyphosate-based herbicide. We evaluated the presence of micronuclei (MN) and erythrocyte nuclear abnormalities (ENA) as biomarkers for potential genotoxic compounds. Tadpoles were exposed to doses permitted by Brazilian legislation and concentrations found naturally in Brazilian and Argentinian waters (500, 700 and 1000 μg/L). Glyphosate-based herbicide caused micronuclei formation and several types of erythrocyte nuclear abnormalities in both Physalaemus species. The total frequency of MN and ENA demonstrated the occurrence of cell damage at all tested concentrations. Glyphosate herbicide can be considered a genotoxic that may impact the genetic integrity of native populations of P. cuvieri and P. gracilis.
The genus Scinax currently includes more than 120 species, recovered in two major clades, the S. catharinae and the S. ruber clades. The latter comprises 75 species, most of which remain unassigned to any species groups, while 12 are included in the S. rostratus and S. uruguayus groups. In this paper we present a taxonomic review of the two species currently included in the S. uruguayus group, discussing some putative phenotypic synapomorphies of this group. Although S. pinima and S. uruguayus have been considered as distinct species, this has been based on scant evidence, and several authors doubted of their distinctiveness. Our study of available specimens of S. pinima and S. uruguayus corroborates that both are valid and diagnosable species based on phenotypic evidence. Furthermore, our results show that S. pinima previously known only from its type locality, has a much widespread distribution than previously thought (including the Brazilian states of Paraná, Santa Catarina, and Rio Grande do Sul), which, added to the biological information presented here allows to suggest the removal of this species from the “Data Deficient” IUCN Red List category to “Least Concern”. Also, we describe a new species formerly reported as S. aff. pinima and S. uruguayus from NE Argentina and some localities from the Brazilian State of Rio Grande do Sul. All species are diagnosed and characterized using adult and larval morphology, osteology, vocalizations, cytogenetics, and natural history.
Background:
Most tropical regions have a climate characterized by marked seasonal rainfall patterns, and these seasonal patterns of rainfall directly affect anuran activity. However, in regions with temperate climates, the main aspect of climate related to anuran activity is the thermal regime. Thus, transitional climate regions represent good opportunities to study the effect of abiotic factors on anuran activity. In this study, we present new data on the activity pattern and calling season of Neotropical anurans in a subtemperate climate. Anuran activity was assessed based on the rate of capture of specimens in pitfall traps and calling surveys. The field study was conducted between May 2010 and April 2011 in wetlands in southernmost Brazil.
Results:
An analysis based on directional (circular) statistics showed that general activity in the studied anurans was significantly seasonal. In addition, the general activity pattern of most species was regulated by temperature, not by rainfall, and approached that observed in regions with a temperate climate. However, we did not record a well-defined peak in the number of species displaying calling activity. This parameter did not exhibit any influence of temperature variations or rainfall.
Conclusions:
The observed general activity pattern is different from that expected for the majority of anurans inhabiting eastern South America. The present study showed that the general activity patterns of most anurans in the wetland region in southernmost Brazil are regulated by temperature and not rainfall, similar to the pattern of anuran assemblies from temperate climates. However, the nonexistence of a significant relationship between calling activity and any of the environmental variables tested suggests the presence of a different environmental factor (e.g., photoperiod or the length of the hydroperiod of the relevant water bodies) as a trigger for the levels of general calling activity.
The Pampas is a biologically rich South American biome, but is poorly represented in phylogeographic studies. While the Pleistocene glacial cycles may have affected the evolutionary history of species distributed in forested biomes, little is known about their effects on the habitats that remained stable through glacial cycles. The South American Pampas have been covered by grasslands during both glacial and interglacial periods and therefore represent an interesting system to test whether the genetic structure in such environments is less pronounced. In this study, we sampled Pampean populations of Homonota uruguayensis from Southern Brazil and Uruguay to assess the tempo and mode of population divergence, using both morphological measurements and molecular markers. Our results indicate that, in spite of its narrow geographic distribution, populations of H. uruguayensis show high levels of genetic structure. We found four major well-supported mtDNA clades with strong geographic associations. Estimates of their divergence times fell between 3.16 and 1.82 million years before the present. Populations from the central portion of the species distribution, on the border between Uruguay and Brazil, have high genetic diversity and may have undergone a population expansion approximately 250,000 years before the present. The high degree of genetic structure is reflected in the analyses of morphological characters, and most individuals could be correctly assigned to their parental population based on morphology alone. Finally, we discuss the biogeographic and conservation implications of these findings.
The presence of Tomodon ocellatus in Paraguay is confirmed and we record the first voucher specimen of Micrurus silviae for the country. Reference materials are deposited in the Colección Zoológica de la Facultad de Cien-cias Exactas y Naturales (CZ-CEN). Las serpientes del género Tomodon están res-tringidas a Sudamérica y se conocen tres es-pecies, Tomodon dorsatus Duméril, Bibron & Duméril, 1854, Tomodon ocellatus Duméril, Bibron & Duméril, 1854, y Tomodon orestes Harvey & Muñoz, 2004 (Cei, 1993; Giraudo & Scrocchi, 2002; Harvey & Muñoz, 2004). Estas se distribuyen desde las altas elevacio-nes en Bolivia, el centro y sur de Brasil, norte de Argentina, sur-este de Paraguay y Uruguay (Peters & Orejas Miranda, 1970; Giraudo & Scrocchi, 2002; Harvey & Muñoz, 2004). En Paraguay está registrada Tomodon dor-satus (Cacciali, 2009; Motte et al., 2009), y ade-más fue citada Tomodon ocellatus Giraudo & Scrocchi, 2002) aunque esta última sin material de refe-rencia. En esta nota confirmamos la presencia de esta especie en Paraguay, proporcionando material de referencia. El ejemplar se encuen-tra depositado en la Colección Zoológica de la Facultad de Ciencias Exactas y Naturales (CZ-CEN), San Lorenzo, con número de catálogo CZ 0805. Durante una revisión de los reptiles de la Colección Zoológica de la Facultad de Cien-cias Exactas y Naturales (CZ-CEN), en un lote de ejemplares donado por el Centro Multidisci-plinario de Investigaciones Tecnológicas (CE-MIT), identificamos un ejemplar de Tomodon ocellatus; el mismo fue colectado en Paraguay pero carece de localidad específica, sin em-bargo muchas de las colectas realizadas por el CEMIT fueron hechas en las cercanías de Pira-pó, Departamento de Itapúa (Frederick Bauer com. pers.), el espécimen es una hembra, largo hocico-cloaca= 334 mm, largo cola= 43 mm, 1 pre-Ocular, 2 post-oculares, temporales 2+2, 7 supralabiales, 3 y 4 en contacto con la órbita, 9 infralabiales, 1-5 en contacto con el par de geniales, escamas dorsales 19-19-17, 146 esca-mas ventrales y 29 subcaudales, anal dividida. (Fig. 1). Tomodon ocellatus es una serpiente terres-tre asociada a pastizales en Argentina, Brasil y Uruguay (Cei, 1993; Carreira et al., 2005), difiere de otras especies del género por tener 19 hileras de escamas dorsales en la mitad del cuerpo y el patrón de coloración de manchas semicirculares oscuras opuestas o alternadas
Snakes of the pseudoboine genera Clelia, which is probably polyphyletic, and Boiruna are distributed from southern Argentina, southern Brazil, and Uruguay northwards into central México. Six members occur in Paraguay and Argentina: B.maculata, Clelia bicolor, C.clelia, C.plumbea, C.quimi, and C.rustica. Historically, there has been taxonomic confusion among the larger species (B.maculata, C.clelia, C.plumbea, and C.rustica) and between the small species (C.bicolor and C.quimi). All of the species except C.rustica have distinct ontogenetic color changes. Species can be distinguished on the bases of size, color, hemipenial spines, and loreal, supralabial, and ventral scale counts. Much of the morphological evolutionary differentiation in Boiruna and Clelia seems to have taken place in the snout region, as evidenced by the differing proportions of the scales of the loreal region. Boiruna maculata has the widest ecological amplitude. It is broadly distributed in most vegetation types north of the 38th parallel in central Argentina, being absent only from the deltaic sediments of Buenos Aires Province, Argentina and the broad valleys and rolling hills of eastern Paraguay. Clelia bicolor is most common in the Paraguay and Paraná river valleys, with a few records from the Andean foothills in northern Argentina. Clelia clelia is distributed along the Río Paraguay and the lower Paraná, and is also found throughout much of eastern Paraguay. Clelia plumbea is apparently parapatric with C.clelia along the Río Paraná in southeastern Paraguay and Misiones Province, Argentina. The ranges of C.quimi to the east and C.bicolor in the west about in this same region without apparent overlap. There are no vouchered records of Clelia rustica from Paraguay. In Argentina, it is a species of temperate climates; north of the 30th parallel, it occurs in the Andean foothills and the wet forests of Misiones Province. Southwards, it is widely distributed to beyond the 40th parallel.
In Uruguay, there was no information about the variations degree in Bothrops pubescens venoms until the present work, in which we investigated intraspecific venom variation using polyacrylamide gel electrophoresis (SDS-PAGE). We found some differences in the venom protein profile; however, they were not related to the parameters studied (geographic distribution, weight, sex, and captivity time). Moreover, we distinguished two different groups in relation to band densities at 49 and 57 kDa. Specimens with predominant density in the 49kDa band tend to be predominantly females. Weight distribution in this group extended for all the range (150-1500 g) with an average weight of 720 g. The other group (57kDa predominant band) showed restricted weight range (150-400 g) with an average weight of 280 g. Cluster analysis was also performed. The variability observed in the venom profile probably corresponds to genetic variations.
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