RESUMEN
The genetic variation of Brazilian populations of the mouse opossum Gracilinanus agilis was analyzed on the basis of the mitochondrial Cytochrome b gene (mt-Cytb) and the exon 28 of the nuclear Von Willenbrand factor (e28-vWF). The radiation of Gracilinanus was dated at 4.80 Ma, with the appearance of G. agilis around 1.93 Ma. Gracilinanus aceramarcae appeared as the first offshoot of the genus, followed by Gracilinanus emiliae and Gracilinanus microtarsus, which composed a sister clade of G. agilis. Phylogeographic analyses and genetic distance estimates indicate G. agilis as a single species, with haplotypes grouping in three well-supported clades, one from midwestern Brazil, a second one from northeastern Brazil, and a third one from eastern Brazil. Phylogeographic patterns in G. agilis were interpreted in search for congruence between genetic breaks and historic geomorphologic events documented for the region stretching northeastern to central-western of the Brazilian shield. The Rio São Francisco and the Serra Geral de Goiás were found to represent relevant geographic barriers to gene flow for G. agilis populations as well as for populations of several other widespread taxa.
Asunto(s)
Citocromos b/genética , Zarigüeyas/genética , Análisis de Secuencia de ADN/veterinaria , Factor de von Willebrand/genética , Animales , Secuencia de Bases , Brasil , Variación Genética , Mitocondrias/genética , Zarigüeyas/clasificación , FilogeografíaRESUMEN
Abstract: The Amazonian rainforest harbors one of the most diverse mammal faunas found anywhere in the world, although this fauna is still poorly known. Inventories are essential for the understanding of the biology and ecology of species, and provide basic data for conservation. Over 15 years of sampling in the Saracá-Taquera National Forest, we recorded 72 species of small (nonvolant), medium, and large mammals belonging to 30 families in 10 orders. These taxa included 29 species endemic to the Amazon biome, and 14 classified as threatened with extinction. Overall, the mammalian species richness recorded in the present study was equal to or greater than that recorded in other Amazonian studies, reflecting high levels of diversity on a biogeographic scale. This reinforces the importance of this national forest for the maintenance of the region's mammalian fauna. Some of the species were recorded in the region for the first time, thus extending their known geographic distribution.
Resumo: A floresta amazônica abriga uma das maiores riquezas de mamíferos do mundo. Entretanto, existe pouco conhecimento sobre a fauna local. Estudos de levantamentos podem contribuir para o incremento no conhecimento sobre a biologia e a ecologia das espécies e são a base para a conservação. Ao longo de 15 anos de amostragem, nós registramos 72 espécies de pequenos, médios e grandes mamíferos pertencentes a 10 ordens e 30 famílias, das quais 29 espécies são endêmicas da Amazônia e 14 são também consideradas ameaçadas de extinção. No geral, a riqueza de mamíferos foi igual ou superior ao de outros estudos conduzidos no bioma, indicando uma alta diversidade em escala biogeográfica. Os resultados mostram a importância desses ambientes para a manutenção das espécies. Algumas tiveram seu primeiro registro para a área e outras a ampliação da sua área de distribuição.