30 research outputs found

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

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    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

    Comparative phylogeography in the Atlantic forest and Brazilian savannas: pleistocene fluctuations and dispersal shape spatial patterns in two bumblebees

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    Background: Bombus morio and B. pauloensis are sympatric widespread bumblebee species that occupy two major Brazilian biomes, the Atlantic forest and the savannas of the Cerrado. Differences in dispersion capacity, which is greater in B. morio, likely influence their phylogeographic patterns. This study asks which processes best explain the patterns of genetic variation observed in B. morio and B. pauloensis, shedding light on the phenomena that shaped the range of local populations and the spatial distribution of intra-specific lineages. Results: Results suggest that Pleistocene climatic oscillations directly influenced the population structure of both species. Correlative species distribution models predict that the warmer conditions of the Last Interglacial contributed to population contraction, while demographic expansion happened during the Last Glacial Maximum. These results are consistent with physiological data suggesting that bumblebees are well adapted to colder conditions. Intra-specific mitochondrial genealogies are not congruent between the two species, which may be explained by their documented differences in dispersal ability. Conclusions: While populations of the high-dispersal B. morio are morphologically and genetically homogeneous across the species range, B. pauloensis encompasses multiple (three) mitochondrial lineages, and show clear genetic, geographic, and morphological differences. Because the lineages of B. pauloensis are currently exposed to distinct climatic conditions (and elevations), parapatric diversification may occur within this taxon. The eastern portion of the state of São Paulo, the most urbanized area in Brazil, represents the center of genetic diversity for B. pauloensis

    Recent evolutionary history of Chrysoperla externa (Hagen 1861) (Neuroptera: Chrysopidae) in Brazil

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    This work aimed to elucidate the distribution of Chrysoperla externa haplotypes and investigate whether it exhibits structure based on genetic composition as opposed to geographic location. The genetic diversity of C. externa, analyzed by AMOVA using the COI and 16S rRNA genes as mitochondrial markers, showed significant haplotype structure arising from genetic differences that was not associated with sampling location. This was reflected in the network grouping. Bayesian inference showed that haplotype distribution may have its origins in C. externa divergence into two distinct clades, which dispersed to various locations, and their subsequent diversification. The evolutionary history of C. externa may include multiple ancestral haplotypes differentiating within the same geographic area to generate the current broad genetic diversity, so that the earlier geographical history has been erased, and now we have highlighted its more recent genetic history

    Data from: Insights into the origin and distribution of biodiversity in the Brazilian Atlantic forest hotspot: a statistical phylogeographic study using a low-dispersal organism

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    The relative importance of the processes that generate and maintain biodiversity is a major and controversial topic in evolutionary biology with large implications for conservation management. The Atlantic Forest of Brazil, one of the world's richest biodiversity hotspots, is severely damaged by human activities. To carry out an efficient conservation policy, a good understanding of spatial and temporal biodiversity patterns and their underlying evolutionary mechanisms is required. With this aim, we performed a comprehensive phylogeographic study using a low-dispersal organism, the land planarian species Cephaloflexa bergi (Platyhelminthes, Tricladida). Applying a multi-locus DNA sequence variation approach under the ABC framework we evaluated two scenarios proposed to explain the diversity of SAF region. We found that most sampled localities harbour high levels of genetic diversity, with lineages sharing old common ancestors that predate the Pleistocene. Remarkably, we detected the molecular hallmark of the isolation-by-distance effect and little evidence of a recent colonization of SAF localities; some populations nevertheless might result from very recent secondary contacts. We conclude that extant SAF biodiversity originated and has been shaped by complex interactions between ancient geological events and more recent evolutionary processes, while Pleistocene climate changes would have a minor influence in generating present day diversity. We also demonstrate that land planarians are an advantageous biological model for making phylogeographic and, particularly, fine-scale evolutionary inferences, and propose appropiate conservation policies

    Molecular ecology of the southern gray brocket deer (Mazama gouazoubira fischer, 1814)

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    The gray brocket deer (Mazama gouazoubira Fisher 1814) hasawide distribution range throughout South America, inhabiting dense and continuous forests and open savannahs such as the Brazilian Cerrado, from the south of the Amazon River basin up to northern Argentina and throughout all of the forested areas in Uruguay. The gray brocket is a small to medium sized deer with a wide range of individual pelage colouration from dark gray to reddish brown. Due to its widespread distribution and the wide range of morphological variation, this species is an excellent model to examine the patterns of genetic variation and to explore if patterns of population genetic differentiation are correlated with historical distribution and ecology. The aim of this chapter is to provide an overview of the current state of knowledge of the gray brocket deer population dynamics, evolutionary patterns and demographic history obtained with morphologic, molecular, and ecological data. This Neotropical deer has retained high levels of genetic and morphological variation that could be correlated to an episode of demographic and geographic expansion in South America that likely occurred during the middle Pleistocene. Genetic analyses using mtDNA markers suggests that geographically separated subpopulations within the wide range of distribution of this species are acting as a metapopulation that has helped maintain remarkably high levels of genetic diversity. In spite of this high genetic diversity, the species could be endangered in the near future if habitat alteration and poaching continues. The signatures observed may only reflect the past demographic expansion and the genetic diversity with mtDNA markers reflecting only a shadow of the past overabundance of this species. Finally, we provide perspectives on how the application of novel next generation sequencing and niche modelling methodologies will magnify the power to contribute to the understanding of the potential extinction risks of cervid species and we propose future guidelines to design management and conservation strategies to better assess the conservation status of gray brocket deer populations in the Neotropics.Genética de La Conservación Departamento Biodiversidad y Genética Instituto de Investigaciones Biológicas Clemente Estable Ministerio de Educación y Cultura, Av. Italia 3318Núcleo de Pesquisa E Conservação de Cervídeos (NUPECCE) Departamento de Zootecnia Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Via de Acesso Paulo Donato Castellane, S/NNúcleo de Pesquisa E Conservação de Cervídeos (NUPECCE) Departamento de Zootecnia Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Via de Acesso Paulo Donato Castellane, S/

    Data from: Vicariance and marine migration in continental island populations of a frog endemic to the Atlantic Coastal forest

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    The theory of island biogeography is most often studied in the context of oceanic islands where all island inhabitants are descendants from founding events involving migration from mainland source populations. Far fewer studies have considered predictions of island biogeography in the case of continental islands, where island formation typically splits continuous populations and thus vicariance also contributes to the diversity of island populations. We examined one such case on continental islands in southeastern Brazil, to determine how classic island biogeography predictions and past vicariance explain the population genetic diversity of Thoropa taophora, a frog endemic to the Atlantic Coastal Forest. We used nuclear microsatellite markers to examine the genetic diversity of coastal and island populations of this species. We found that island isolation has a role in shaping the genetic diversity of continental island species, with island populations being significantly less diverse than coastal populations. However, area of the island and distance from coast had no significant effect on genetic diversity. We also found no significant differences between migration among coastal populations and migration to and from islands. We discuss how vicariance and the effects of continued migration between coastal and island populations interact to shape evolutionary patterns on continental islands
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