ABSTRACT. Morphometric variation in Bothropoides jararaca (Snakes, Viperidae) in Rio Grande do Sul. Although male and female snakes are born with the same size, growth rates and age of sexual maturation may be different, thus determining sexual dimorphism in the later stages of life. We evaluated the incidence of sexual and ontogenetic morphometric variation in Bothropoides jararaca (Wied, 1824), exploring relationships involving body size and sexual maturity through 14 morphometric variables. We analyzed 142 specimens from the state of Rio Grande do Sul, southern Brazil. Morphometric data -head length, snout-vent length, tail length, total length; head width, ocular width, nasal-loreal width, tail width; nasal-ocular distance, ocular-loreal distance, loreal-nasal distance, ventral-sinfisal distance and rostral-labial distance -and length/ diameter of ovarian follicles, were taken in millimeters by simple rule and analogical caliper, precision 0.05 mm. Sex determination was performed by inspection of the gonads. Age was associated to sexual maturity. For the statistical analysis the analysis of variance (ANOVA) with Tukey's post hoc test was used with, linear regression and canonical discriminant analysis (CDA). Most measures indicated sexual dimorphism (ANOVA, P<0.05) only in adults (Tukey, P<0.05). Regression analysis showed that snout-vent length explains the behavior of other variables (P< 0.001) and in all measures, females grow more than males. The ADC has been successful in separating the genders and age groups, with biological meaning, whereas 79.2% of cases were correctly classified. KEYWORDS.Ontogeny, morphology, dimorphism. RESUMO.Apesar de machos e fêmeas de serpentes nascerem com o mesmo tamanho, as taxas de crescimento e a idade da maturação sexual podem ser diferentes, determinando dimorfismo sexual em estágios posteriores da vida. Avaliamos a ocorrência de variação morfométrica sexual e ontogenética em Bothropoides jararaca (Wied, 1824), explorando as relações entre tamanho corporal e amadurecimento sexual através de 14 variáveis morfométricas. Foram analisados 142 espécimes provenientes do estado do Rio Grande do Sul, sul do Brasil. Os dados morfométricos -comprimento da cabeça, rostro-cloacal, da cauda, comprimento total; largura da cabeça, ocular, nasal, loreal, da cauda; distância ocular-nasal, ocular-loreal, loreal-nasal, ventral-sinfisal e rostral-labial -e comprimento/diâmetro dos folículos ovarianos, foram tomados em milímetros, através de régua simples e paquímetro analógico de precisão 0,05 mm. A determinação sexual foi realizada por inspeção das gônadas. A classificação etária foi associada à maturidade sexual. Para as análises estatísticas foram utilizadas análises de variância (ANOVA) com teste de Tukey post hoc, regressão linear e análise discriminante canônica (ADC). A maioria das medidas indicou dimorfismo sexual (ANOVA, P<0,05) apenas em adultos (Tukey, P<0,05). As análises de regressão mostram que o comprimento rostro-cloacal explica o comportamento das demais variáveis (P<0,001...

ABSTRACT. Studies on the thermal biology of fossorial reptiles that examine the relationship between the body temperature and thermal environment are needed to determine the extent of their thermoregulation abilities. This study assessed the thermal biology of Amphisbaena munoai Klappenbach, 1969 in the rocky fields of the Rio Grande do Sul and in the laboratory.The body temperature of most individuals was between 24 and 30 °C, both in the field (n = 81) and laboratory (n = 19).More individuals were caught in winter (n = 55) and spring (n = 60) than in summer (n = 25) and fall (n = 45), and in spring, individuals showed similar nocturnal and diurnal activities. In the laboratory, we found individuals with body temperatures up to 5 °C higher than the ambient temperature (n = 4), suggesting that some physiological mechanisms participate in the thermoregulation of these animals. Amphisbaena munoai is a thigmothermic species that is capable of actively regulating its temperature by selecting microhabitats such that its various activities occur within an ideal temperature range. This study is the first to evaluate the effect of seasonality and diurnal and nocturnal variations on the thermoregulation of an amphisbaenid.

Habitat fragmentation is one of the sources of the global threat to wildlife populations. During the last four decades, urban development in Brazil’s southern coastline has seen considerable growth, fragmenting the habitat of the sand lizard Liolaemus occipitalis Boulenger, 1885, thus threatening it with extinction. In order to assess the influence of urban development on this species, we used tagging and recapture data to study two populations in Brazil’s southern coastline, one in a conserved area rarely subjected to disturbance and the other in an area undergoing different kinds of anthropogenic disturbance. We explored the consequences of this change in the natural landscape by comparing estimates of survival and abundance with Robust Design Model, and the body condition of individuals in both populations with analysis of covariance and variance. Survival of individuals were lower in the disturbed population than in the conserved population. The abundance of this lizard species was similar between populations. The body condition of females was higher in the disturbed area than in the conserved area, while males were similar among populations, but longer (SVL). This study shows how anthropic impacts can affect a population of lizards and the importance of maintaining protected areas and their interconnection to preserve Liolaemus occipitalis.

Silviculture is among the human activities that contribute most to fragmentation and habitat loss. The comprehension of the effects of such activity on the environment is crucial for conservation. Here, we assessed the effects of silviculture on the local distribution of Contomastix vacariensis, an endemic lizard from southern Brazil. We used a single‐season occupancy model in a Bayesian framework to estimate the occupancy probability of the species in 69 sites with different distances from silviculture areas. Our data showed a low probability of occupancy of C. vacariensis within a distance smaller than 1000 m from silviculture areas, while detection probability was negatively influenced by wind speed. This is the first work to demonstrate a gradual negative effect of exotic silviculture in lizards, which may be more intense inside planted areas and decrease as the distance from the exotic plantation increases. Such results may help delimit the size of conservation areas and management of exotic silviculture species within these areas. Studies with similar methods, considering the distance from the effects of environmental impacts, can be a helpful tool to make predictions based on the projected growth of silviculture in natural areas supporting threatened species.