Lizards from the Alto Sertão region of Sergipe state, northeastern Brazil / Lagartos da região do Alto Sertão de Sergipe, nordeste do Brasil

Abstract We present the first detailed inventory of the lizard fauna of Alto Sertão region, west of Sergipe state, based on three field expeditions carried out by the authors and specimens deposited at the Herpetological Collection of Universidade Federal de Sergipe. The three inventories were carried out between 2010 and 2016, in the municipalities of Canindé de São Francisco, Poço Redondo, Monte Alegre de Sergipe, Nossa Senhora da Glória, and Porto da Folha. In total, we sampled 9,485 lizards of 19 species (10 families) of which 10 are new records for the study area. The most abundant species were Ameivula ocellifera, Tropidurus hispidus and T. semitaeniatus. Thirteen species were considered as widely distributed in Caatinga, five presented a relictual distribution and one was exotic. We suggest that future research focus mainly on non-sampled areas and should prioritize the municipalities of Gararu, Nossa Senhora da Glória and Nossa Senhora de Lourdes since they are localities with little or no sampling records.

Resumo Apresentamos o primeiro inventário detalhado da fauna de lagartos da região do Alto Sertão sergipano, nordeste do Brasil, a partir de três expedições de campo realizadas pelos autores e exemplares depositados na Coleção Herpetológica da Universidade Federal de Sergipe. Os três inventários foram realizados entre 2010 e 2016, nos municípios de Canindé de São Francisco, Poço Redondo, Monte Alegre de Sergipe, Nossa Senhora da Glória e Porto da Folha. No total, foram amostrados 9.487 lagartos de 19 espécies (10 famílias), das quais 10 são novos registros para a área de estudo. As espécies mais abundantes foram Ameivula ocellifera, Tropidurus hispidus e T. semitaeniatus. Treze espécies foram consideradas com ampla distribuição na Caatinga, cinco apresentaram distribuição relictual e uma exótica. Sugerimos que futuras pesquisas se concentrem principalmente em áreas não amostradas e priorizem os municípios de Gararu, Nossa Senhora da Glória e Nossa Senhora de Lourdes por se tratarem de localidades com pouca ou nenhuma amostragem.

Ecological release in lizard endoparasites from the Atlantic Forest, northeast of the Neotropical Region.

We compared lizard endoparasite assemblages between the Atlantic Forest and naturally isolated forest enclaves to test the ecological release hypothesis, which predicts that host specificity should be lower (large niche breadth) and parasite abundance should be greater for parasites from isolated forest enclaves (poor assemblages) than for parasites from the coastal Atlantic Forest (rich assemblages). Parasite richness per specimen showed no difference between the isolated and non-isolated areas. Parasite abundance did not differ between the isolated and non-isolated areas but showed a positive relationship with parasite richness considering all areas (isolated and non-isolated). Furthermore, host specificity was positively related to parasite richness. Considering that host specificity is inversely proportional to the host range infected by a parasite, our results indicate that in assemblages with greater parasite richness, parasites tend to infect a smaller range of hosts than do those in simple assemblages. In summary, our study partially supports the ecological release hypothesis: in assemblages with greater parasite richness, lizard parasites from Atlantic Forest are able to increase their parasite abundance (per host), possibly through facilitated infection; however, the amplitude of infected hosts only expands in poor assemblages (lower parasite richness).

Morphological characterization and taxonomic key of tadpoles (Amphibia: Anura) from the northern region of the Atlantic Forest / Caracterização morfológica e chave taxonômica de girinos (Amphibia: Anura) da região norte da Mata Atlântica

Abstract: Although anuran tadpoles are widely distributed and abundant in tropical aquatic habitats, there is a lack of taxonomic keys for the Atlantic Forest. Herein, we developed a dichotomous key for identifying the tadpoles for all species with known larval phase and already recorded in the Atlantic Forest north of the São Francisco River. We analyzed discrete characteristics of 1,042 tadpoles encompassing 63 species of 28 genera from 32 localities. The user-friendly key includes illustration and pictures, and it is a significant step towards improving our knowledge of tadpoles of the Atlantic Forest.

Resumo: Embora os girinos de anuros sejam amplamente distribuídos e abundantes em habitats aquáticos tropicais, não há chaves taxonômicas suficientes para as espécies da Mata Atlântica. Aqui, desenvolvemos uma chave dicotômica para identificar os girinos de todas as espécies com fase larval conhecida e já registradas nesse bioma, ao norte do rio São Francisco. Nós analisamos características discretas de 1.042 girinos pertencentes a 63 espécies (28 gêneros) de 32 localidades. Esta chave de identificação inclui ilustrações e imagens, sendo um passo significativo para um melhor conhecimento dos girinos da Mata Atlântica.

Climatic suitability, isolation by distance and river resistance explain genetic variation in a Brazilian whiptail lizard.

Spatial patterns of genetic variation can help understand how environmental factors either permit or restrict gene flow and create opportunities for regional adaptations. Organisms from harsh environments such as the Brazilian semiarid Caatinga biome may reveal how severe climate conditions may affect patterns of genetic variation. Herein we combine information from mitochondrial DNA with physical and environmental features to study the association between different aspects of the Caatinga landscape and spatial genetic variation in the whiptail lizard Ameivula ocellifera. We investigated which of the climatic, environmental, geographical and/or historical components best predict: (1) the spatial distribution of genetic diversity, and (2) the genetic differentiation among populations. We found that genetic variation in A. ocellifera has been influenced mainly by temperature variability, which modulates connectivity among populations. Past climate conditions were important for shaping current genetic diversity, suggesting a time lag in genetic responses. Population structure in A. ocellifera was best explained by both isolation by distance and isolation by resistance (main rivers). Our findings indicate that both physical and climatic features are important for explaining the observed patterns of genetic variation across the xeric Caatinga biome.

The role of local versus biogeographical processes in influencing diversity and body-size variation in mammal assemblages.

Our objective was to estimate and analyze the body-size distribution parameters of terrestrial mammal assemblages at different spatial scales, and to determine whether these parameters are controlled by local ecological processes or by larger-scale ones. Based on 93 local assemblages, plus the complete mammal assemblage from three continents (Africa, North, and South America), we estimated three key distribution parameters (diversity/size slope, skewness, and modal size) and compared the values to those expected if size distributions are mainly controlled by local interactions. Mammal diversity decreased much faster as body size increased than predicted by fractal niche theory, both at continental and at local scales, with continental distributions showing steeper slopes than the localities within them. South America showed a steeper slope (after controlling for species diversity), compared to Africa and North America, at local and continental scales. We also found that skewness and modal body size can show strikingly different correlations with predictor variables, such as species richness and median size, depending on the use of untransformed versus log-transformed data, due to changes in the distribution density generated by log-transformation. The main differences in slope, skewness, and modal size between local and continental scales appear to arise from the same biogeographical process, where small-sized species increase in diversity much faster (due to higher spatial turnover rates) than large-sized species. This process, which can operate even in the absence of competitive saturation at local scales, generates continental assemblages with steeper slopes, smaller modal sizes, and higher right skewness (toward small-sized species) compared to local communities. In addition, historical factors can also affect the size distribution slopes, which are significantly steeper, in South American mammal assemblages (probably due to stronger megafauna extinction events in South America) than those in North America and Africa.

Ecological release in lizard assemblages of neotropical savannas.

We compare lizard assemblages of Cerrado and Amazonian savannas to test the ecological release hypothesis, which predicts that niche dimensions and abundance should be greater in species inhabiting isolated habitat patches with low species richness (Amazonian savannas and isolated Cerrado patches) when compared with nonisolated areas in central Cerrado with greater species richness. We calculated microhabitat and diet niche breadths with data from 14 isolated Cerrado patches and Amazon savanna areas and six central Cerrado populations. Morphological data were compared using average Euclidean distances, and lizard abundance was estimated using the number of lizards captured in pitfall traps over an extended time period. We found no evidence of ecological release with respect to microhabitat use, suggesting that historical factors are better microhabitat predictors than ecological factors. However, data from individual stomachs indicate that ecological release occurs in these areas for one species (Tropidurus) but not others (Ameiva ameiva, Anolis, Cnemidophorus, and Micrablepharus), suggesting that evolutionary lineages respond differently to environmental pressures, with tropidurids being more affected by ecological factors than polychrotids, teiids, and gymnophthalmids. We found no evidence that ecological release occurs in these areas using morphological data. Based on abundance data, our results indicate that the ecological release (density compensation) hypothesis is not supported: lizard species are not more abundant in isolated areas than in nonisolated areas. The ecology of species is highly conservative, varying little from assemblage to assemblage. Nevertheless, increases in niche breadth for some species indicate that ecological release occurs as well.