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Invasive predators are one of the causes of population declines of anurans around the world. The American Bullfrog (Lithobates catesbeianus) stands out among these predators. Based on field observations and stomach content analysis, predation on native anurans by invasive Bullfrogs was investigated in two localities of Southeastern Brazil. The spatial variation in predation and similarity in microhabitat use by native species and Bullfrogs were also determined. Anurans of the families Bufonidae, Hylidae, Leiuperidae and Microhylidae were found among Bullfrog prey. The species preyed upon had medium to high similarity with Bullfrogs regarding microhabitat use. Anurans had high relative importance in the diet of adult Bullfrogs from the site where natural vegetation is preserved. Thus, the possible negative impact of predation by Bullfrogs can be more significant on anuran species which use microhabitats similar to those used by the invasive frogs. This impact may also be higher in preserved sites, increasing the necessity of monitoring and controlling the spread of this invasive species to natural areas. However, as factors other than predation are known to contribute toward negative impacts, further studies are required to clarify the status of invasive Bullfrogs in Brazil.
Here we present data on the morphology and habits of male and female individuals of Chelonoidis carbonaria and on their diet based on scat analysis (n = 21) at Fazenda Rio Negro, Brazilian Pantanal, subregion of Nhecolândia, from January 2004 to April 2007. The tortoises in the Pantanal had an average larger weight than the ones sampled in the Amazon, which could be a result of low local hunting pressure over the species and/or abundant resource availability. For both males and females, fruits represented the highest portion of items consumed, reflecting the importance of fruits in their diet. Because 90% of the seeds found in scat samples were found intact, and considering both the retention time of seeds in the digestive tract and distance traveled while retaining the seeds, tortoises can be considered important seed dispersers in the Pantanal. For instance, we found out that tortoises can be extremely important in the dispersal and recruitment of Syagrus flexuosa, an uncommon palm species in the study area, the seeds of which are not usually found in other frugivores' scats. Also, the tortoise's ability to ingest large-sized seeds that are usually consumed by a limited range of dispersers make tortoises even more important especially in areas where mammals exist in low density or are already extinct.
Phyllomedusa sauvagii lays its eggs surrounded by peculiar vesicles in nests made with tree leaves and, until now, the function of these vesicles was thought to be for maintaining moisture. The histomorphological and histochemical analysis of the oviduct of individuals in ovulatory period, and the study of the vesicles in the oviduct, ovisac and in the nest, showed unexpected results. Vesicles originate from glycoconjugates, proteins and lipids secreted in the PCP and PC and organized in the oviductal lumen and, according to their content, it is possible to recognize at last four types. Furthermore, both in the ovisac and in the nest, vesicles show peculiar relationships with oocites/eggs/embryos through specific communication channels, showing the existence of more complex interactions than previously thought.
Seasonal distribution, size classes, density, biomass, population structure, and sex ratio of Trachemys dorbigni were investigated in Delta do Jacui State Park, Rio Grande do Sul — Brazil, between 2003 and 2006 using mark-recapture methods. A total of 137 Trachemys dorbigni individuals were captured: 93 females, 30 males, and 14 undetermined. Recapture rate was 5.1%, with a total of 7 recaptures (one animal was recaptured twice and 5 other animals were recaptured once). Individuals in these populations were active between August and April, and no turtles were captured in February. Sexual dimorphism index (i.e., females' carapace length divided by males' carapace length) was 1.13, and females were bigger than males in all analyzed variables, except tail base to the cloaca opening length. Density was 7.61 turtles/ha, and biomass was 8.71 kg/ha. The distribution of body size classes revealed that the samples were composed mainly of adults (89.78%). Sex ratio was different from 1:1 (3:1; χ2 = 32,27; df = 1; p < 0.001).
Roads that cross natural areas may exert negative effects on the local fauna. Among them, the most obvious negative effect is vehicular run over. For snakes, the risk of roadkill seems to be higher in habitat generalists, locally abundant or highly mobile species. High snake mortality by roadkill occurs mainly when animals cross roads during terrestrial movements to breeding, wintering, foraging or summering habitats. We here describe snake road mortality at Núcleo Picinguaba, Parque Estadual da Serra do Mar, a protected rainforest area located on the northern coast of the State of São Paulo, Brazil. We sampled a 16 km tract of a paved road from October, 2001 to December, 2002, totalling 5,173 km. We found 60 roadkilled snakes, belonging to 15 species, representing around 58% of the species recorded for the region. More mobile species seemed to be more vulnerable to road mortality than sedentary species. Snake species encountered dead on the road tended to have great mobility, to be active foragers, and to show plasticity in microhabitat use. Road mortality seemed to coincide with age and sex specific seasonal activities. The higher number of juveniles found in May could reflect juvenile recruitment, mainly for more active species and for those with greater dispersion ability. The increased road mortality in October may be a consequence of males searching females during the mating period. Although the density of roadkilled species in the area is poorly known, the relative low rate of snake mortality we found at Núcleo Picinguaba, associated with the small length of the highway inside the park and the relatively low traffic volume, indicate that the actual negative effect of the BR-101 highway on local snake populations is negligible for the most common and abundant species. However, given that the Serra do Mar State Park is a type II park in the IUCN Protected Area Management Categories, measures which result in decrease of snake mortality should be implemented by the park managers.
The activity of many species of anurans is affected by variables such as rainfall, air temperature, photoperiod, and food resources. In this study we investigated the activity period of the toad Melanophryniscus moreirae and tested the influence of photoperiod and air temperature on the number of toads seen active. The study was carried out between March 2004 and December 2005 on the elevated area of Parque Nacional do Itatiaia (PNI) southeast Brazil, at elevations varying from 2300 to 2400 m. Twenty 10 × 10 m plots were established as sampling units. To evaluate hourly activity, the plots were visited between 05:00 and 24:00 h, one plot at each hourly interval. Hourly activity was estimated based on the total number of toads seen at hourly intervals, across the study period. Annual and reproductive activities were estimated based on the total number of individuals and number of amplectant pairs, respectively, found within a month. Melanophryniscus moreirae is a strictly diurnal species with two peaks of activity, one in the morning and another in the afternoon. Along the study, toads were only seen from September to April. Photoperiod had a significant effect on monthly activity. The reproductive activity is restricted to the period from September to December.
New fossil turtle material from the Early Cretaceous of (Valanginian) of Colombia is described here. The material consists of carapace bones discovered in shallow marine sequences of the Rosablanca Formation, Eastern Cordillera, Zapatoca, Department of Santander. These fossils represent the oldest record of eucryptodiran turtles for the northernmost part of South America. Although detailed taxonomic resolution cannot be defined within Eucryptodira, the material resembles marine turtles in morphology and histology particularly to Protostegidae clade. Eucryptodires are the new element in the reptilian fauna of the Rosablanca Formation, which also has panpleurodires turtles, undescribed fish, plesiosaurs, and ichthyosaurs.
The advertisement call is responsible for attracting females and helps the calling male to keep the acoustic territory by warning other males of its position. This call is species-specific and, because of this, it is frequently used in studies of taxonomy and phylogeny. In this study, we describe the advertisement call of Scinax similis recorded in Magé, State of Rio de Janeiro, Brazil, and compare it with the call presented by Haddad et al. in audio form. The advertisement call of Scinax similis is short and composed of one multipulsed note with two bands of frequency of similar intensity. The dominant frequency was found in the second band. The difference in the advertisement call of S. similis from the Municipality of Magé and the call presented by Haddad et al. can be interpreted as variation between populations and/or social context consequences. Between Brazilian species of the Scinax ruber clade, the call of S. similis is similar to that of S. auratus and S. juncae.
Union Island, St. Vincent and the Grenadines (8.4 km2) has an unusually diverse reptilian fauna for such a small area, but lacks native or well-established introduced amphibians. In June 2010, we conducted a rapid assessment of 10 sites (coastal or with some variation of dry forest habitats) chosen on the basis of vegetative complexity, height and extent of canopy, and degree of human disturbance. We encountered 10 of the 15 species recorded from Union, missing only a few secretive litter-dwelling or fossorial forms and a recently introduced species for which the current status is unknown. Shannon-Weiner indices of diversity were negatively correlated with vegetative complexity, but the density of Anolis aeneus, the most frequently encountered species, was positively correlated with complexity. We supplemented the rapid assessment with visual surveys for Corallus grenadensis, an arboreal boid, smaller individuals of which feed largely on anoles. Encounter rates for C. grenadensis were not correlated with anoline densities, which we attribute to the relative paucity of both snakes and their prey on a small, dry island.
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