High Levels of Diversity Uncovered in a Widespread Nominal Taxon: Continental Phylogeography of the Neotropical Tree Frog

Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally distributed in South America, that may represent a complex of multiple species, each with a more limited distribution. To understand the spatial pattern of molecular diversity throughout the range of this species complex, we obtained DNA sequence data from two mitochondrial genes, cytochrome oxidase I (COI) and the 16S rhibosomal gene (16S) for 407 samples of D. minutus and closely related species distributed across eleven countries, effectively comprising the entire range of the group. We performed phylogenetic and spatially explicit phylogeographic analyses to assess the genetic structure of lineages and infer ancestral areas. We found 43 statistically supported, deep mitochondrial lineages, several of which may represent currently unrecognized distinct species. One major clade, containing 25 divergent lineages, includes samples from the type locality of D. minutus. We defined that clade as the D. minutus complex. The remaining lineages together with the D. minutus complex constitute the D. minutus species group. Historical analyses support an Amazonian origin for the D. minutus species group with a subsequent dispersal to eastern Brazil where the D. minutus complex originated. According to our dataset, a total of eight mtDNA lineages have ranges >100,000 km2. One of them occupies an area of almost one million km2 encompassing multiple biomes. Our results, at a spatial scale and resolution unprecedented for a Neotropical vertebrate, confirm that widespread amphibian species occur in lowland South America, yet at the same time a large proportion of cryptic diversity still remains to be discovered

Início da vida sexual na adolescência e relações de gênero: um estudo transversal em São Paulo, Brasil, 2002 Sexual debut in adolescence and gender relations: a cross-sectional study in São Paulo, Brazil, 2002

Trata-se de estudo transversal com o objetivo de identificar os diferenciais de gênero presentes no início da vida sexual de adolescentes. Foram entrevistados 406 adolescentes de 15 a 19 anos de idade inscritos em uma unidade de saúde da família da zona leste do Município de São Paulo, Brasil, entre maio e dezembro de 2002. Quase a metade dos adolescentes já havia iniciado sua vida sexual, em média aos 15 anos de idade, fossem homens ou mulheres. O início da vida sexual ocorreu, em grande parte, de forma não planejada (72,7%) e dentro de casa (86,1%). O uso de um método contraceptivo na primeira relação sexual foi similar entre homens e mulheres (61,0%), entretanto, foi observado um aumento maior na proporção de uso de algum anticonceptivo entre os homens na última relação sexual. Pelo fato de terem iniciado sua vida sexual em relacionamentos estáveis com vínculos afetivo-amorosos, as mulheres mostraram-se mais vulneráveis às DST/AIDS, pois substituíram o preservativo masculino por outros métodos na última relação sexual, enquanto os homens permaneceram utilizando largamente o condom, provavelmente por estarem inseridos em relacionamentos não estáveis.<br>This cross-sectional study aimed to assess gender differences in adolescents in relation to onset of sexual activity. A total of 406 15-19-year-old adolescents from a family health unit in the city of São Paulo, Brazil, were interviewed from May to December 2002. Nearly half had already had their first sexual intercourse, at a mean age of 15, independently of gender. Sexual debut was usually unplanned (72.7%) and inside the home (86.1%). An equal proportion (61.0%) of males and females used some contraceptive method in their first sexual intercourse; however, more males had used a contraceptive method in their most recent intercourse. Having initiated their sexual activity in stable, affective relationships, females proved to be more vulnerable to STD/ AIDS, since they switched from condoms to the pill in their subsequent sexual activity. Male adolescents continued to use mostly condoms, probably because they were involved mainly in non-stable relationships