Habitat use, daily activity periods, and thermal ecology of Ameiva ameiva (Squamata: Teiidae) in a caatinga area of northeastern Brazil.

Estudamos o uso dos recursos espaciais, temporais e térmicos pelo lagarto neotropical Ameiva ameiva durante as estaçõesseca e chuvosa em um ambiente de caatinga do nordeste do Brasil. Os lagartos utilizaram os hábitats e micro-hábitats de vegetação baixa, mas nunca foram observados no hábitat rochoso. Os adultos utilizaram usualmente o hábitat arbóreo-arbustivo, enquanto os juvenis foram observados maisfrequentemente no hábitat arbustivo-herbáceo. Diferenças ontogenéticas no uso do espaço parecem estar relacionadas a diferentes necessidades térmicas entre as classes de idade devido a diferenças de tamanho corporal. As temperaturas corporais dos juvenis foram significativamente maiores que asdos adultos. A maioria das espécies de Teiidae possui temperaturas corporais elevadas, usualmente acima de 37oC, e atividade concentrada nas horas mais quentes do dia, como observado em A. ameiva neste estudo. A sazonalidade influenciou o uso do hábitat e os períodos diários de atividade dos adultos, mas não influenciou as temperaturas corporais. Verificamos flutuações anuais na abundância de indivíduos adultos, com um declínio de lagartos ativos na estação seca; esse fenômeno pode estar relacionado à estivação e/ou ao aumento da taxa de mortalidade durante os meses mais secos.We studied the use of spatial, temporal, and thermal resources by the Neotropical lizard Ameiva ameiva during rainy and dry seasons in a caatinga (xerophilous open forests) environment in northeastern Brazil. Lizards used the vegetation habitats and microhabitats in the ground, but never were seen in the rocky habitat. Adults usually used the arboreal-shrubby habitat, whereas juveniles were sighted more often in the shrubby-herbaceous habitat. Ontogenetic differences in spatial use seem to be linked to different thermal needs between age groups owing to differences in body size. Body temperatures were significantly higher in juveniles than in adults. Most teiid species have elevated body temperatures, usually above 37oC,and are active during the hottest times of day, as was observed for A. ameiva in this study. Seasonality influenced habitat use and daily activity periods of adults, but not body temperatures. We verified annual fluctuations in adult abundance, with a decline of active lizards in the dry season; this phenomenon may be related to aestivation and/or increased mortality rate during the driest months

Geographic distribution model for Mabuya agmosticha (Squamata: Scincidae) in northeastern Brazil

The Neotropical lizard Mabuya agmosticha Rodrigues, 2000 is a habitat-specialist of thorny bromeliads in rocky outcrops of northeastern Brazil. Its distribution in the Caatinga Domain is most likely relictual. In recent years, new surveys conducted in northeastern Brazil have revealed new records of the species in the Caatinga and also in the Atlantic Forest Domain. In this study, we add four new records for M. agmosticha, extending its known geographic range in the states of Rio Grande do Norte and Paraíba. In addition, we investigated the potential geographical distribution of the species using ecological niche modeling (ENM), which combines the available occurrence records with environmental variables. Our model revealed a continuous range of areas with suitable climatic conditions for the species, from the state of Rio Grande do Norte to the northeast portion of the state of Bahia, plus some relictual distribution spots, mainly in the states of Bahia, Pernambuco, Ceará and western Rio Grande do Norte. Based on the model, we suggest that the distribution of M. agmosticha is continuous on a large geographic scale. On a smaller spatial scale, however, it is clear that its distribution is clumped, reflecting its specialist habits associated with rupicolous bromeliads