Three new species of cichlid fishes of the genus Geophagus, part of the Neotropical subfamily Geophaginae, are described from the Orinoco and Casiquiare drainages in Venezuela. Phylogenetic relationships among 16 genera and 30 species of Geophaginae are investigated using 136 morphological characters combined with DNA sequences coding for the mitochondrial gene NADH dehydrogenase subunit 4 (ND4) and the nuclear Recombination Activating Gene 2 (RAG2). Data from previous studies are integrated with the new dataset by incorporating published DNA sequences from the mitochondrial genes cytochrome b and 16S and the microsatellite flanking regions Tmo-M27 and Tmo-4C4. Total-evidence analysis revealed that Geophaginae is monophyletic and includes eighteen genera grouped into two major clades. In the first clade, the tribe Acarichthyini (genera Acarichthys and Guianacara) is sister-group to a clade in which Gymnogeophagus, 'Geophagus' steindachneri, and Geophagus sensu stricto are sister to 'Geophagus' brasiliensis and Mikrogeophagus; all these are in turn sister-group to Biotodoma, Dicrossus and Crenicara. In the second clade, Satanoperca, Apistogramma (including Apistogrammoides), and Taeniacara are sister to Crenicichla and Biotoecus. Monophyly and significantly short branches at the base of the phylogeny indicate that genera within Geophaginae differentiated rapidly within a relatively short period. High morphological, ecological, and behavioral diversity within the subfamily suggest that geophagine divergence may be the result of adaptive radiation.

The Guiana Shield is a sub-region of Amazonia, one of the richest areas on earth in terms of species number. It is also one of the most pristine areas and is still largely unexplored. Species number, distribution, boundaries and their evolutionary histories remain at least unclear but most of the time largely unknown. This is the case for most Anurans, a group which is recognized as threatened globally and is disappearing even from pristine tropical forests. Given the pace of forest destruction and the growing concerns about climate change it is urgently necessary to obtain a better estimate of regional biodiversity in Amazonian frogs as well as a better understanding of the origin and distribution of Anuran diversity. Furthermore, given their sensitivity to climatic conditions, amphibians are a good model to investigate the influence of paleoclimatic events on Neotropical diversification which was supposedly the driving force on biotic evolution during Pleistocene in the Guiana Shield. I first test species boundaries in two species Scinax ruber and Rhinella margaritifera. These species are widely distributed, abundant and largely recognized as species complexes. I used an original species delineation method based on the combined use of mitochondrial and nuclear DNA in phylogenetic and phylogeographic analyses. Phylogenetic analyses demonstrated the polyphyly of Scinax ruber and Rhinella margaritifera. These species consist of multiple lineages that may all merit species status. Conflicting signals of mitochondrial and nuclear markers indicated the possibility of ongoing hybridization processes. Phylogeographic analyses added further information in support of the specific status of these lineages. Our results highlight the utility of combining phylogenetic and phylogeographic methods, as well as the use of both mitochondrial and nuclear markers within one study. This approach helped to better understand the evolutionary history of taxonomically complex groups of species. The assessment of the geographic distribution of genetic diversity in tropical amphibian communities can lead to conclusions that differ strongly from prior analyses based on the occurrence of currently recognized species alone. Such studies, therefore, hold the potential to contribute to a more objective assessment of amphibian conservation priorities in tropical areas. Subsequently, I tested if these first results on cryptic species are generalisable, questioning what would potentially be a minimum estimate of the number of cryptic frog species in Amazonia and the Guiana Shield, using mtDNA with multiple complementary approaches. I also combined isolation by distance, phylogenetic analyses, and comparison of molecular distances to evaluate threshold values for the identification of candidate species among these frogs. In most cases, geographically distant populations belong to genetically highly distinct lineages that could be considered as candidate new species. This was not universal among the taxa studied and thus widespread species of Neotropical frogs really do exist, contra to previous assumptions. Moreover, the many instances of paraphyly and the wide overlap between distributions of inter- and intra-specific distances reinforce the hypothesis that many cryptic species remain to be described. In our data set, pairwise genetic distances below 0.02 are strongly correlated with geographical distances. This correlation remains statistically significant until genetic distance is 0.05, with no such relation thereafter. This suggests that for higher genetic distances allopatric and sympatric cryptic species prevail. Based on our analyses, we propose a more inclusive pairwise genetic distance of 0.03 between taxa to target lineages that could correspond to candidate species. Using this approach, we identify 129 candidate species, two-fold greater than the 60 species included in the current study. This leads to estimates of around 170 to 460 frog taxa unrecognized in Amazonia-Guianas. As a consequence the global amphibian decline detected especially in the Neotropics may be worse than realised. The Rhinella margaritifera complex is characterisized by the presence of many cryptic species throughout its wide distribution, ranging from Panama to Bolivia and almost entire Amazonia. French Guiana has long been thought to harbor two species of this group, though molecular data analysed in previous chapters indicated as many as five lineages. I tested whether morphological measurements are correlated or not with genetic data using discriminant analysis and if diagnostic characteristics among the previously determined lineages can be used to describe these new species. This is a novel integrative method which can lead to a facilitation of the description of cryptic species that have been detected by phylogenetic and/or phylogeographic studies. These analyses, combined with published data of other Rhinella species, indicated that two of these lineages represent previously unnamed species. Two of the remaining are allocable to R. margaritifera while the status of the fifth is still unclear because so far it is morphologically indistinguishable from R. castaneotica. Determining if codistributed species responded to climate change in an independent or concerted manner is a basic objective of comparative phylogeography. Species boundaries, histories, ecologies and their geographical ranges are still to be explored in the Guiana Shield. According to the refugia hypothesis this region was supposed to host a forest refugium during climatic oscillations of the Pleistocene but the causes and timing for this have been criticized. We investigated patterns of genetic structure within 18 frog species in the eastern Guiana Shield to explore species boundaries and their evolutionary history. We used mtDNA and nuclear DNA and complementary methods to compare the genetic diversity spatially and temporally. With one exception all the species studied diversified repeatedly within the eastern Guiana Shield during the last 4 million years. Instead of one Pleistocene forest refugium the Guiana Shield has probably hosted multiple refugia during late Pliocene and Pleistocene. Most of these Pleistocene refugia were probably situated on the coast of French Guiana, Amapà, Suriname and Guyana. This diversification likely resulted from forest fragmentation. Many species deserve taxonomic revisions and their ranges to be reconsidered. The local endemism of the Anuran fauna of the Guiana Shield is likely to be much higher and some areas consequently deserve more conservation efforts. Specifically I questioned whether major intraspecific diversification started before the Pleistocene and occurred within the Guiana Shield or ex situ. According to ecological characteristics of the species involved I will test different diversification hypotheses. The consequences on the diversity and the endemism of the Guiana Shield will be explored. My results demonstrate that we have been grossly underestimating local biological diversity in the Guiana Shield but also in Amazonia in general. The order of magnitude for potential species richness means that the eastern Guiana Shield hosts one of the richest frog fauna on earth. In most of the species studied high levels of mtDNA differentiation between populations call for a reassessment of the taxonomic status of what is being recognised as single species. Most species display deep divergence between eastern Guiana Shield populations and Amazonian ones. This emphasizes that the local endemism in the Guiana Shield of these zones is higher than previously recognized and must be prioritised elements taken into account in conservation planning. Nevertheless, a few other species appear widely distributed showing that widespread species do exist. This underlines the fact that some species have efficient dispersal abilities and that the frog fauna of the eastern Guiana Shield is a mixture of old Guianan endemic lineages that diversified in situ mostly during late Pliocene and Pleistocene and more recently exchanged lineages with the rest of Amazonia. Recognizing this strong historical component is necessary and timely for local conservation as these zones are likely to be irremediably modified in the near future.

The Guiana Shield is a sub-region of Amazonia, one of the richest areas on earth in terms of species number. It is also one of the most pristine areas and is still largely unexplored. Species number, distribution, boundaries and their evolutionary histories remain at least unclear but most of the time largely unknown. This is the case for most Anurans, a group which is recognized as threatened globally and is disappearing even from pristine tropical forests. Given the pace of forest destruction and the growing concerns about climate change it is urgently necessary to obtain a better estimate of regional biodiversity in Amazonian frogs as well as a better understanding of the origin and distribution of Anuran diversity. Furthermore, given their sensitivity to climatic conditions, amphibians are a good model to investigate the influence of paleoclimatic events on Neotropical diversification which was supposedly the driving force on biotic evolution during Pleistocene in the Guiana Shield. I first test species boundaries in two species Scinax ruber and Rhinella margaritifera. These species are widely distributed, abundant and largely recognized as species complexes. I used an original species delineation method based on the combined use of mitochondrial and nuclear DNA in phylogenetic and phylogeographic analyses. Phylogenetic analyses demonstrated the polyphyly of Scinax ruber and Rhinella margaritifera. These species consist of multiple lineages that may all merit species status. Conflicting signals of mitochondrial and nuclear markers indicated the possibility of ongoing hybridization processes. Phylogeographic analyses added further information in support of the specific status of these lineages. Our results highlight the utility of combining phylogenetic and phylogeographic methods, as well as the use of both mitochondrial and nuclear markers within one study. This approach helped to better understand the evolutionary history of taxonomically complex groups of species. The assessment of the geographic distribution of genetic diversity in tropical amphibian communities can lead to conclusions that differ strongly from prior analyses based on the occurrence of currently recognized species alone. Such studies, therefore, hold the potential to contribute to a more objective assessment of amphibian conservation priorities in tropical areas. Subsequently, I tested if these first results on cryptic species are generalisable, questioning what would potentially be a minimum estimate of the number of cryptic frog species in Amazonia and the Guiana Shield, using mtDNA with multiple complementary approaches. I also combined isolation by distance, phylogenetic analyses, and comparison of molecular distances to evaluate threshold values for the identification of candidate species among these frogs. In most cases, geographically distant populations belong to genetically highly distinct lineages that could be considered as candidate new species. This was not universal among the taxa studied and thus widespread species of Neotropical frogs really do exist, contra to previous assumptions. Moreover, the many instances of paraphyly and the wide overlap between distributions of inter- and intra-specific distances reinforce the hypothesis that many cryptic species remain to be described. In our data set, pairwise genetic distances below 0.02 are strongly correlated with geographical distances. This correlation remains statistically significant until genetic distance is 0.05, with no such relation thereafter. This suggests that for higher genetic distances allopatric and sympatric cryptic species prevail. Based on our analyses, we propose a more inclusive pairwise genetic distance of 0.03 between taxa to target lineages that could correspond to candidate species. Using this approach, we identify 129 candidate species, two-fold greater than the 60 species included in the current study. This leads to estimates of around 170 to 460 frog taxa unrecognized in Amazonia-Guianas. As a consequence the global amphibian decline detected especially in the Neotropics may be worse than realised. The Rhinella margaritifera complex is characterisized by the presence of many cryptic species throughout its wide distribution, ranging from Panama to Bolivia and almost entire Amazonia. French Guiana has long been thought to harbor two species of this group, though molecular data analysed in previous chapters indicated as many as five lineages. I tested whether morphological measurements are correlated or not with genetic data using discriminant analysis and if diagnostic characteristics among the previously determined lineages can be used to describe these new species. This is a novel integrative method which can lead to a facilitation of the description of cryptic species that have been detected by phylogenetic and/or phylogeographic studies. These analyses, combined with published data of other Rhinella species, indicated that two of these lineages represent previously unnamed species. Two of the remaining are allocable to R. margaritifera while the status of the fifth is still unclear because so far it is morphologically indistinguishable from R. castaneotica. Determining if codistributed species responded to climate change in an independent or concerted manner is a basic objective of comparative phylogeography. Species boundaries, histories, ecologies and their geographical ranges are still to be explored in the Guiana Shield. According to the refugia hypothesis this region was supposed to host a forest refugium during climatic oscillations of the Pleistocene but the causes and timing for this have been criticized. We investigated patterns of genetic structure within 18 frog species in the eastern Guiana Shield to explore species boundaries and their evolutionary history. We used mtDNA and nuclear DNA and complementary methods to compare the genetic diversity spatially and temporally. With one exception all the species studied diversified repeatedly within the eastern Guiana Shield during the last 4 million years. Instead of one Pleistocene forest refugium the Guiana Shield has probably hosted multiple refugia during late Pliocene and Pleistocene. Most of these Pleistocene refugia were probably situated on the coast of French Guiana, Amapà, Suriname and Guyana. This diversification likely resulted from forest fragmentation. Many species deserve taxonomic revisions and their ranges to be reconsidered. The local endemism of the Anuran fauna of the Guiana Shield is likely to be much higher and some areas consequently deserve more conservation efforts. Specifically I questioned whether major intraspecific diversification started before the Pleistocene and occurred within the Guiana Shield or ex situ. According to ecological characteristics of the species involved I will test different diversification hypotheses. The consequences on the diversity and the endemism of the Guiana Shield will be explored. My results demonstrate that we have been grossly underestimating local biological diversity in the Guiana Shield but also in Amazonia in general. The order of magnitude for potential species richness means that the eastern Guiana Shield hosts one of the richest frog fauna on earth. In most of the species studied high levels of mtDNA differentiation between populations call for a reassessment of the taxonomic status of what is being recognised as single species. Most species display deep divergence between eastern Guiana Shield populations and Amazonian ones. This emphasizes that the local endemism in the Guiana Shield of these zones is higher than previously recognized and must be prioritised elements taken into account in conservation planning. Nevertheless, a few other species appear widely distributed showing that widespread species do exist. This underlines the fact that some species have efficient dispersal abilities and that the frog fauna of the eastern Guiana Shield is a mixture of old Guianan endemic lineages that diversified in situ mostly during late Pliocene and Pleistocene and more recently exchanged lineages with the rest of Amazonia. Recognizing this strong historical component is necessary and timely for local conservation as these zones are likely to be irremediably modified in the near future.

Made available in DSpace on 2015-04-17T14:55:21Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 7359456 bytes, checksum: 16477438042d951ea0467f36a2a1005e (MD5) Previous issue date: 2012-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The taxonomic and trophic structures of termite assemblages were studied in 10 areas of altitudinal forests ( Brejo de Altitude ) in the Caatinga dryland biome and their patterns of species richness and distribution were analyzed. A standardized sampling protocol (30 hours x person) was performed in five 5 x 2 m plots distributed along each of six 65 x 2 m transects; the densities of termite nests were also estimated in each of the 10 forest areas in six 65 m x 20 m plots, and climatic, vegetation, and soil parameters were evaluated. Faunal similarity analyses were made between the 10 altitudinal forest areas and 36 other sites distributed among the major Brazilian morphoclimatic domains. Seventy-one morpho species of termites were identified among 799 specimens encountered. In general, the Apicotermitinae were represented by the largest numbers of species and relative abundance, with the humivorous group being dominant. A total of 13 species constructing conspicuous nests were recorded, with an average of 13.1 to 71.8 active nests/ha. Phosphorus was the best predictor variable of termite richness and abundance in all of the areas, with trunk perimeter being the second best predictor. Grouping analysis of the altitudinal forests formed group I (SOR+RFB+RSN) composed of areas at higher altitudes located in the western region of the Borborema Plateau that showed relatively low richness and abundance, and group II [(SJB+RPF+RMM+PVS)+(PRM+PUB)] composed of areas closest to the coastal Atlantic Forest + areas in Ceará State that showed greater richness and relative abundance; the Triunfo/PE site demonstrated the least faunal similarity with the other areas. These results corroborated the hypothesis that Brejos de Altitude forests do not constitute a distinct biogeographical unit. These Brejos de Altitude forests demonstrate greater faunal similarity with Atlantic Forest and Caatinga areas but less similarity with Amazon and Cerrado sites. These patterns of termite distributions appear to reflect Quaternary period cycles of expansion and retraction of Tropical Rainforests during glacial and interglacial periods as well as current climatic and geomorphological factors. / As estruturas taxonômica e trófica das taxocenoses de cupins foram estudadas em dez áreas de Brejo de Altitude, estabelecidos nos domínios da Caatinga, buscando analisar os padrões de riqueza e distribuição das espécies. Para cada área, foi aplicado um protocolo padronizado de amostragem (30 horas x pessoa), consistindo de cinco parcelas de 5 x 2 m distribuídas ao longo de seis transectos de 65 x 2 m. Para cada área, a densidade de ninhos foi estimada em seis parcelas de 65 m x 20 m, e parâmetros climáticos, da vegetação e do solo foram avaliados. Análises de similaridade faunística foram realizadas entre os Brejos de Altitude e 36 áreas distribuídas entre os maiores Domínios Morfoclimáticos brasileiros. Setenta e uma morfoespécies foram registradas nos Brejos, pertencentes a 36 gêneros e três famílias, com 799 encontros. De forma geral, os Apicotermitinae apresentaram os maiores números de espécies e abundância relativa, e o grupo alimentar dos humívoros foi dominante. Um total de 13 espécies construtoras de ninhos conspícuos foi registrado, e a densidade média variou de 1,3 a 71,8 ninhos ativos/ha. O fósforo foi a melhor variável preditora da riqueza e da abundância de cupins para todas as áreas, sendo o perímetro do tronco a segunda melhor variável preditora. A análise de agrupamento entre as áreas de Brejo formou o grupo I (SOR+RFB+RSN): áreas com riqueza e abundância relativa baixa, maiores altitudes e localizadas a oeste no Planalto da Borborema; e o grupo II [(SJB+RPF+RMM+PVS)+(PRM+PUB)]: áreas com maiores riqueza e abundância relativa, incluindo áreas mais próximas da Floresta Atlântica costeira + áreas no Ceará, enquanto Triunfo/PE apresentou menor similaridade faunística com as demais áreas. Tais resultados corroboram a hipótese de que os Brejos de Altitude não constituem uma unidade biogeográfica. Os Brejos de Altitude apresentaram maior similaridade faunística com a Floresta Atlântica e a Caatinga, respectivamente, e menor similaridade com a Amazônia e o Cerrado. Tais padrões de distribuição podem refletir, além dos fatores climáticos e geomorfológicos atuais, os ciclos de expansão e retração das Florestas Tropicais Úmidas durante os períodos interglaciais e glaciais do Quaternário.

Radiações evolutivas estão entre os eventos mais fascinantes da evolução. Grande parte da diversidade da vida, tanto de espécies como ecológica, surgiu nos breves intervalos temporais de rápida especiação que configuram as radiações. As causas ecológicas e não-ecológicas do surgimento da diversidade em radiações evolutivas, em especial nas radiações adaptativas, são tema de pesquisa há muito tempo, pelo menos desde que Darwin observou a imensa diversidade de um grupo de pássaros nas ilhas Galápagos. Desde então, as ilhas têm sido os ambientes ideais para o estudo desse fenômeno, e foi a partir das observações e experimentos em ilhas que toda a teoria ecológica das radiações evolutivas surgiu. Contudo, as causas ecológicas das radiações explosivas ocorridas em amplas escalas continentais permanecem tema de constante debate. Nesta tese, foram investigados os determinantes ecológicos e não-ecológicos (e.g., geografia, contingências históricas, efeitos filogenéticos) da evolução morfológica dos roedores sigmodontíneos durante sua radiação na região Neotropical, em especial no continente sul-americano. Para isso, foi quantificada a morfologia do crânio e mandíbula de mais de dois mil exemplares do grupo, e foram investigadas variações ecomorfológicas nos níveis interespecífico (I), intraespecífico (II), e entre assembleias de sigmodontíneos (III). Na Parte I da tese, foram investigadas duas predições da teoria da radiação adaptativa, a correlação-fenótipo ambiente (capítulo 1) e a funcionalidade do fenótipo através da força da mordida (capítulo 2), permitindo determinar o papel da divergência ecológica na evolução morfológica das espécies. Na Parte II (capítulo 3), foram investigadas as contribuições relativas de processos determinísticos e neutros sobre a variação morfológica entre populações de uma espécie de roedor sigmodontíneo amplamente distribuída, Akodon cursor. Na Parte III, a influência da variação ambiental e da distribuição espacial das linhagens filogenéticas de sigmodontíneos sobre o tamanho corporal (capítulo 4) e forma do crânio e mandíbula (capítulo 5), foram investigados no contexto biogeográfico da variação no tamanho e forma média entre assembleias de sigmodontíneos. As contribuições originais desta tese foram: (i) mostrar que a radiação evolutiva dos roedores sigmodontíneos foi guiada principalmente por fatores históricos e geográficos ao invés de fatores ecológicos; (ii) sugerir que radiações evolutivas ocorridas em escalas continentais, especialmente de roedores, têm um componente geográfico e histórico mais determinante do que o componente ecológico; (iii) revelar que a força da mordida varia pouco entre roedores sigmodontíneos herbívoros e granívoros, o que provavelmente é resultado do fenótipo generalista desses roedores; (iv) apontar que sigmodontíneos com dieta insetívora têm uma taxa de evolução mais rápida, e parecem estar evoluindo sua forma do crânio/mandíbula e sua força da mordida em uma direção diferente das demais espécies; (v) demonstrar que, dentro de uma espécie de sigmodontíneo (Akodon cursor), fluxo gênico e deriva genética explicam melhor a forma do crânio entre populações, enquanto a variação ambiental explica melhor o tamanho do crânio, indicando que o tamanho é uma característica mais lábil e mais sujeita a pressões ambientais do que a forma do crânio; (vi) mostrar que a variação biogeográfica, tanto do tamanho quanto da forma média do crânio/mandíbula entre assembleias de sigmodontíneos, está sob influência da distribuição diferencial das linhagens filogenéticas ao longo do espaço geográfico, bem como de variáveis ambientais; o que indica conservação filogenética de nicho à nível de metacomunidades. De modo geral, ao investigar as contribuições relativas dos componentes adaptativo e não-adaptativo da evolução morfológica, foram obtidas informações importantes para conhecer as causas da diversificação morfológica em Sigmodontinae, aumentando nosso conhecimento sobre as origens de toda a diversidade biológica. / Evolutionary radiations are among the most fascinating phenomena of evolution. Most of the biological diversity on the planet, both in terms of species and ecological diversity, appeared during these brief intervals of rapid speciation. The ecological and non-ecological causes of the emergence of diversity in evolutionary radiations, especially in adaptive radiations, have long been the subject of research, beginning with Darwin and his notice of the astonishing diversity of bird forms in the Galapagos Islands. Islands have since been ideal environments in which to study evolutionary and adaptive radiations, and indeed it was from observations and experiments on islands that all ecological theory of evolutionary radiations arose. However, the ecological causes of explosive radiations occurring on large continental scales are still a matter of debate. In this dissertation, I investigated the ecological and non-ecological (e.g., geography, historical contingencies, phylogenetic effects) determinants of morphological evolution in sigmodontine rodents during their radiation in the Neotropical region, particularly on the South-American continent. The skull and mandible morphology of more than two thousand specimens was quantified, and ecomorphological variation was investigated on three levels: interspecific (I), intraspecific (II), and among sigmodontine assemblages (III). In part I, two predictions from the ecological theory of adaptive radiation were investigated: the phenotype-environment correlation (chapter 1), and the trait utility through the bite force (chapter 2). This approach enabled determination of the role of ecological divergence in species morphological evolution. In part II (chapter 3), I investigated the relative contributions of deterministic and neutral processes to morphological variation among populations of one widely distributed sigmodontine species, Akodon cursor. In part III, I investigated the influence of environmental variation and spatial distribution of phylogenetic lineages on body size (chapter 4) and on shape of the skull and mandible (chapter 5), in the context of biogeographical variation of mean size and shape in sigmodontine assemblages. The original contributions of this dissertation are as follows: (i) to demonstrate that the evolutionary radiation of sigmodontines was driven mainly by historical and geographical factors instead of ecological factors; (ii) to suggest that evolutionary radiations on continental scales, especially rodent radiations, have a more determinant historical and geographical component than an ecological one; (iii) to show small variation in bite force between sigmodontine herbivores and granivores, which is likely a consequence of the generalist phenotype of these rodents; (iv) to highlight that insectivorous sigmodontines have a faster rate of morphological evolution than other diet groups, and that skull and mandible morphology and bite force are evolving in different directions than in other species; (v) to demonstrate that within a sigmodontine species (Akodon cursor), gene flow and genetic drift better explain variation in skull shape among populations, while environmental variation better explains variation in skull size, which suggests that size is more labile feature than shape and thus more prone to change with environmental pressures; and (vi) to show that biogeographical variation in mean body size, mean skull shape, and mean mandible shape across sigmodontine assemblages is influenced by the different distributions of phylogenetic lineages over geographical space, as well by environmental variables, which indicates phylogenetic niche conservatism at the metacommunity level. These results shed light on some of the factors driving morphological diversification in Sigmodontinae. Further, the analytical approach(es) utilized may be useful for general investigations of the relative contributions of adaptive and non-adaptive components of morphological evolution, thereby potentially increasing our knowledge of the origins of all biological diversity.

Made available in DSpace on 2016-12-23T13:47:35Z (GMT). No. of bitstreams: 1 Dissertacao de Simone Loss de Freitas.pdf: 2778831 bytes, checksum: f273846469d08eec6a2e5aafffe5602f (MD5) Previous issue date: 2007-03-27 / A catita Gracilinanus microtarsus ocorre principalmente ao longo da Mata Atlântica do leste e sul do Brasil. Estudos prévios relevaram altos níveis de divergência genética entre amostras ao longo de sua distribuição. Nesse trabalho nós analisamos a congruência da variação geográfica entre caracteres moleculares e morfológicos para avaliar se populações identificadas como Gracilinanus microtarsus representam mais de uma espécie, como sugerido anteriormente. Nós examinamos 195 espécimes de G. microtarsus, 94 de G. agilis e 12 de Cryptonanus sp., e inferimos a filogenia com base em 25 caracteres morfológicos discretos. Nós comparamos os resultados com uma filogenia baseada em seqüências parciais de citocromo b de 27 espécimes. A monofilia do gênero e das duas espécies G. microtarsus e G. agilis foram corroboradas pelas análises de dados morfológicos e moleculares. A filogenia molecular mostrou três clados e a filogenia com base em dados morfológicos apresentou três linhagens em G. microtarsus, as quais também se segregaram no espaço morfométrico, indicando a possibilidade de existirem três espécies em G. microtarsus. No entanto, as filogenias morfológicas e moleculares não se apresentaram completamente congruentes ao serem comparadas e a análise morfológica resultou como parafilética na filogenia molecular. Portanto, nossos resultados sugerem que G. microtarsus representa apenas uma espécie, diagnosticável por caracteres morfológicos e moleculares, mostrando forte variação morfológica ao longo de sua distribuição / The gracile mouse opossum Gracilinanus microtarsus occurs mainly along the Atlantic forest of eastern and southern Brazil. Earlier studies revealed high levels of genetic divergence among samples across its range. Here, we analyzed the congruence of geographic variation between molecular and morphological characters to evaluate whether the populations that have been segregated by molecular divergence represent more than one species, as previously suggested. We examined 195 specimens of G. microtarsus, 94 of G. agilis, and 12 of Cryptonanus sp., and inferred a phylogeny based on 25 discrete morphological characters. We compared this result with a phylogeny based on partial cytochrome b sequences of 27 specimens. The monophyly of the genus, and of both G. microtarsus and G. agilis were corroborated by morphological and molecular analyses. The molecular phylogeny recovered three clades, and the morphological data indicated three distinct lineages, which also segregated in morphometric space, indicating the possibility of occurrence of three cryptic species within what is currently identified as G. microtarsus. However, morphological and molecular phylogenies were not completely congruent, and the morphological classification of the specimens included in the molecular analysis resulted in a paraphyletic group in the molecular phylogeny. Hence, our results suggest that G. microtarsus represents one species, diagnosable by morphological and molecular characters, showing strong morphological and molecular variation throughout its distributional range

Radiações evolutivas estão entre os eventos mais fascinantes da evolução. Grande parte da diversidade da vida, tanto de espécies como ecológica, surgiu nos breves intervalos temporais de rápida especiação que configuram as radiações. As causas ecológicas e não-ecológicas do surgimento da diversidade em radiações evolutivas, em especial nas radiações adaptativas, são tema de pesquisa há muito tempo, pelo menos desde que Darwin observou a imensa diversidade de um grupo de pássaros nas ilhas Galápagos. Desde então, as ilhas têm sido os ambientes ideais para o estudo desse fenômeno, e foi a partir das observações e experimentos em ilhas que toda a teoria ecológica das radiações evolutivas surgiu. Contudo, as causas ecológicas das radiações explosivas ocorridas em amplas escalas continentais permanecem tema de constante debate. Nesta tese, foram investigados os determinantes ecológicos e não-ecológicos (e.g., geografia, contingências históricas, efeitos filogenéticos) da evolução morfológica dos roedores sigmodontíneos durante sua radiação na região Neotropical, em especial no continente sul-americano. Para isso, foi quantificada a morfologia do crânio e mandíbula de mais de dois mil exemplares do grupo, e foram investigadas variações ecomorfológicas nos níveis interespecífico (I), intraespecífico (II), e entre assembleias de sigmodontíneos (III). Na Parte I da tese, foram investigadas duas predições da teoria da radiação adaptativa, a correlação-fenótipo ambiente (capítulo 1) e a funcionalidade do fenótipo através da força da mordida (capítulo 2), permitindo determinar o papel da divergência ecológica na evolução morfológica das espécies. Na Parte II (capítulo 3), foram investigadas as contribuições relativas de processos determinísticos e neutros sobre a variação morfológica entre populações de uma espécie de roedor sigmodontíneo amplamente distribuída, Akodon cursor. Na Parte III, a influência da variação ambiental e da distribuição espacial das linhagens filogenéticas de sigmodontíneos sobre o tamanho corporal (capítulo 4) e forma do crânio e mandíbula (capítulo 5), foram investigados no contexto biogeográfico da variação no tamanho e forma média entre assembleias de sigmodontíneos. As contribuições originais desta tese foram: (i) mostrar que a radiação evolutiva dos roedores sigmodontíneos foi guiada principalmente por fatores históricos e geográficos ao invés de fatores ecológicos; (ii) sugerir que radiações evolutivas ocorridas em escalas continentais, especialmente de roedores, têm um componente geográfico e histórico mais determinante do que o componente ecológico; (iii) revelar que a força da mordida varia pouco entre roedores sigmodontíneos herbívoros e granívoros, o que provavelmente é resultado do fenótipo generalista desses roedores; (iv) apontar que sigmodontíneos com dieta insetívora têm uma taxa de evolução mais rápida, e parecem estar evoluindo sua forma do crânio/mandíbula e sua força da mordida em uma direção diferente das demais espécies; (v) demonstrar que, dentro de uma espécie de sigmodontíneo (Akodon cursor), fluxo gênico e deriva genética explicam melhor a forma do crânio entre populações, enquanto a variação ambiental explica melhor o tamanho do crânio, indicando que o tamanho é uma característica mais lábil e mais sujeita a pressões ambientais do que a forma do crânio; (vi) mostrar que a variação biogeográfica, tanto do tamanho quanto da forma média do crânio/mandíbula entre assembleias de sigmodontíneos, está sob influência da distribuição diferencial das linhagens filogenéticas ao longo do espaço geográfico, bem como de variáveis ambientais; o que indica conservação filogenética de nicho à nível de metacomunidades. De modo geral, ao investigar as contribuições relativas dos componentes adaptativo e não-adaptativo da evolução morfológica, foram obtidas informações importantes para conhecer as causas da diversificação morfológica em Sigmodontinae, aumentando nosso conhecimento sobre as origens de toda a diversidade biológica. / Evolutionary radiations are among the most fascinating phenomena of evolution. Most of the biological diversity on the planet, both in terms of species and ecological diversity, appeared during these brief intervals of rapid speciation. The ecological and non-ecological causes of the emergence of diversity in evolutionary radiations, especially in adaptive radiations, have long been the subject of research, beginning with Darwin and his notice of the astonishing diversity of bird forms in the Galapagos Islands. Islands have since been ideal environments in which to study evolutionary and adaptive radiations, and indeed it was from observations and experiments on islands that all ecological theory of evolutionary radiations arose. However, the ecological causes of explosive radiations occurring on large continental scales are still a matter of debate. In this dissertation, I investigated the ecological and non-ecological (e.g., geography, historical contingencies, phylogenetic effects) determinants of morphological evolution in sigmodontine rodents during their radiation in the Neotropical region, particularly on the South-American continent. The skull and mandible morphology of more than two thousand specimens was quantified, and ecomorphological variation was investigated on three levels: interspecific (I), intraspecific (II), and among sigmodontine assemblages (III). In part I, two predictions from the ecological theory of adaptive radiation were investigated: the phenotype-environment correlation (chapter 1), and the trait utility through the bite force (chapter 2). This approach enabled determination of the role of ecological divergence in species morphological evolution. In part II (chapter 3), I investigated the relative contributions of deterministic and neutral processes to morphological variation among populations of one widely distributed sigmodontine species, Akodon cursor. In part III, I investigated the influence of environmental variation and spatial distribution of phylogenetic lineages on body size (chapter 4) and on shape of the skull and mandible (chapter 5), in the context of biogeographical variation of mean size and shape in sigmodontine assemblages. The original contributions of this dissertation are as follows: (i) to demonstrate that the evolutionary radiation of sigmodontines was driven mainly by historical and geographical factors instead of ecological factors; (ii) to suggest that evolutionary radiations on continental scales, especially rodent radiations, have a more determinant historical and geographical component than an ecological one; (iii) to show small variation in bite force between sigmodontine herbivores and granivores, which is likely a consequence of the generalist phenotype of these rodents; (iv) to highlight that insectivorous sigmodontines have a faster rate of morphological evolution than other diet groups, and that skull and mandible morphology and bite force are evolving in different directions than in other species; (v) to demonstrate that within a sigmodontine species (Akodon cursor), gene flow and genetic drift better explain variation in skull shape among populations, while environmental variation better explains variation in skull size, which suggests that size is more labile feature than shape and thus more prone to change with environmental pressures; and (vi) to show that biogeographical variation in mean body size, mean skull shape, and mean mandible shape across sigmodontine assemblages is influenced by the different distributions of phylogenetic lineages over geographical space, as well by environmental variables, which indicates phylogenetic niche conservatism at the metacommunity level. These results shed light on some of the factors driving morphological diversification in Sigmodontinae. Further, the analytical approach(es) utilized may be useful for general investigations of the relative contributions of adaptive and non-adaptive components of morphological evolution, thereby potentially increasing our knowledge of the origins of all biological diversity.

Introdução - Culex quinquefasciatus é um mosquito sinantrópico que causa incômodo à população humana e é relacionado com a transmissão de nematóides ou arbovírus em áreas endêmicas, respectivamente, do litoral brasileiro e da América Central ou do Norte. Culex nigripalpus é um mosquito hemi-sinantrópico que possui a capacidade de se dispersar para as áreas antrópicas e transmitir Saint Louis Virus e Equine Encephalitis Virus, respectivamente, na América do Norte e Venezuela. Objetivo - Caracterizar o hábito alimentar de Culex nigripalpus e a densidade, a sobrevivência e o hábito alimentar de Culex quinquefasciatus no Parque Ecológico do Tietê (PET), São Paulo. Métodos - O PET é uma Área de Preservação Ambiental com animais residentes ou migratórios. As amostras de mosquitos adultos foram coletadas, mensalmente, em quatro áreas no PET, durante um ano e por meio de aspirador à bateria. O método de ELISA indireto foi empregado para a identificação do hospedeiro que é fonte alimentar ao mosquito. A densidade da população de Cx. quinquefasciatus foi estimada pelo método de marcação, soltura e recaptura na vegetação da margem de um canal no PET. Amostras de fêmeas de Cx. quinquefasciatus desse local foram dissecadas ou acompanhadas em laboratório para estimativa da taxa de sobrevivência. Resultados – A proporção de repastos sangüíneos de Cx. quinquefasciatus e de Cx. nigripalpus foi, respectivamente, 6,5 e 8,3% em humanos, 18,8 e 27,7% em cães, 7,4 e 2,3% em galinhas, 2,8 e 9,0% em ratos, 3,2 e 8,3% em múltiplos hospedeiros e 67,7 e 60,9% em hospedeiros não identificados. Human Blood Index para Cx. quinquefasciatus e Cx. nigripalpus foi, respectivamente, 0,20 e 0,17. Feeding Index entre os hospedeiros homem/cão, homem/galinha e homem/rato foi, respectivamente, 0,35, 0,63 e 2,65 para Cx. quinquefasciatus e 0,30, 2,56 e 1,05 para Cx. nigripalpus. A distribuição de repastos sangüíneos teve associação significante estatisticamente com as fêmeas de Cx. nigripalpus em estádio de Sella 2 coletadas em todas as áreas do PET. A densidade de Cx. quinquefasciatus para uma área de 2.520 m2 foi 7.262±1.537. A proporção de paridas, a duração do ciclo gonotrófico e a taxa de sobrevivência foram, respectivamente, igual a 0,48, 4,75 (CL 95% = 4,3-5,2) e 0,86, estimados para a população de Cx. quinquefasciatus. Conclusões – Cães e galinhas foram hospedeiros importantes para Cx. quinquefasciatus, enquanto que cães foram hospedeiros importantes para Cx. nigripalpus. O repasto sangüíneo é mais bem detectado pelo ELISA indireto em fêmeas no estádio de Sella 2. A sobrevivência e a densidade de Cx. quinquefasciatus indicam que essa espécie é epidemiologicamente relevante na área do PET como espécies vetora ou peste urbana. Essa espécie deve ser objetivo do programa de controle de vetores no município de São Paulo. / Introduction - Culex quinquefasciatus has high synanthropy, infest human dwellings and is vector of nematoids and arbovirus from endemic areas, respectively, in Brazilian coast and in Central or North America. Culex nigripalpus has average synanthropy and can disperse through the anthropic environment carrying Saint Louis Virus and Equine Encephalitis Virus, respectively, in North America and Venezuela. Objective - To characterize host-feeding habit of Culex nigripalpus and density, survival and host-feeding habit of Culex quinquefasciatus in the Parque Ecológico do Tietê (PET), São Paulo. Methods - The PET is an Area of Environmental Protection with resident or migratory animals. The samples of adult mosquitoes were collected, monthly, in four areas in the PET, during one year and by means of a backpack battery aspirator. An indirect ELISA technique was used for the identification of the host that is an alimentary source for the mosquito species. The density of Cx. quinquefasciatus population was estimated using the Mark, Release and Recapture method on the vegetation of the edge of a canal in the PET. Samples of females of Cx. quinquefasciatus from this place were dissected or followed in laboratory for estimating the survival rate. Results – Cx. quinquefasciatus and Cx. nigripalpus fed on human 6.5 and 8.3%, dog 18.8 and 27.7%, chicken 7.4 and 2.3%, rat 2.8 and 9.0%, multiple hosts 3.2 and 8.2% and unidentified hosts 67.9 and 60.9%, respectively. The unweighted human blood index (HBI) values were 0.20 for Cx. quinquefasciatus and 0.17 for Cx. nigripalpus populations. The feeding index values between the hosts human/dog, human/chicken and human/rat were, respectively, 0.35, 0.63 and 2.65 for Cx. quinquefasciatus and 0.30, 2.56 and 1.05 for Cx. nigripalpus. The distributions of blood-meals had statistically significant association on Sella 2 stage of the Cx. nigripalpus collected in all areas at the PET. The density of Cx. quinquefasciatus for an area of 2,520 m2 was 7,262±1,537. The proportion of parous, gonotrophic cycle length and survival rate were, respectively, equal to 0.48, 4.75 (CL 95% = 4.3-5.2) and 0.86, for Cx. quinquefasciatus population. Conclusions – Dogs and chickens are important hosts for Cx. quinquefasciatus, whereas dog is an important host for Cx. nigripalpus. The host-blood of females in Sella 2 stage increases sensibility of the indirect ELISA assay. The survivorship and the density of Cx. quinquefasciatus indicate that these species are epidemiologically relevant in the PET area as either a pest or vector species. Those species should be a goal of the vector control program of Sao Paulo municipality.

No description available.

No description available.