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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Espécies do gênero Physalaemus no Estado do Rio de Janeiro (Amphibia, Anura, Leptodactylidae)

Weber , Luiz Norberto 11 March 1998 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-05-24T20:39:02Z No. of bitstreams: 1 278465.pdf: 13267990 bytes, checksum: 89cdf568e9d07d32cd7551478285b385 (MD5) / Made available in DSpace on 2018-05-24T20:39:02Z (GMT). No. of bitstreams: 1 278465.pdf: 13267990 bytes, checksum: 89cdf568e9d07d32cd7551478285b385 (MD5) Previous issue date: 1998-03-11 / Este trabalho aborda aspectos da morfologia, reprodução, vocalização, hábitos e distribuição de sete espécies do gênero Physalaemus Fitzinger, 1826, do Estado do Rio de Janeiro. São descritas a morfologia externa de adultos e de algunas larvas, bem como características relacionadas com o comportamento reprodutivo, envolvendo: sítios de postura; local de desenvolvimento larvar; sítios de vocalização; período reprodutivo. As análises de som de algumas vocalizações são apresentadas. Comentários taxonômicos e biogeográficos das espécies são discutidos e comparados com os encontrados na literatura. / This work is about the morphology, reproduction, mating calls, natural history and distribution of seven species of the genus Physalaemus Fitzinger, 1826, from the State of Rio de Janeiro. The morphology of adults and tadpoles are described, as well as characteristics related with the reproductive behavior, including breeding sites; larval development; calling sites; breeding seasons. Some vocalizations are described. Taxonomic and biogeographic notes of the species are discussed and compared with the literature.
42

Estudo do balanço hídrico em uma comunidade de Anuros do Litoral Norte da Bahia, Brasil

Gomes, Lucianne Dabés Haddad January 2009 (has links)
Submitted by Mendes Eduardo (dasilva@ufba.br) on 2013-08-05T17:10:17Z No. of bitstreams: 1 DISSER LUCIANNE.pdf: 2055483 bytes, checksum: 145fc49106e3aecf38c1ab6025536bd0 (MD5) / Approved for entry into archive by Ana Valéria de Jesus Moura (anavaleria_131@hotmail.com) on 2016-06-21T17:33:44Z (GMT) No. of bitstreams: 1 DISSER LUCIANNE.pdf: 2055483 bytes, checksum: 145fc49106e3aecf38c1ab6025536bd0 (MD5) / Made available in DSpace on 2016-06-21T17:33:44Z (GMT). No. of bitstreams: 1 DISSER LUCIANNE.pdf: 2055483 bytes, checksum: 145fc49106e3aecf38c1ab6025536bd0 (MD5) / Fapesb / Tradicionalmente, considera-se que nos “anfíbios típicos” (p. ex., sapos e rãs) a perda evaporativa de água através da pele é similar à perda evaporativa de água de uma superfície de água livre, como a de um lago. Todavia, nos últimos 50 anos, estudos têm mostrado que nem todas as espécies seguem este padrão (Young et al. 2005; Hillman et al. 2009). Estudos mostraram que a umidade está entre os principais fatores que afetam a distribuição ecológica dos anfíbios, influenciando a composição das comunidades de anuros (Duellman e Trueb 1986; Toft 1982; Shoemaker et al. 1992; Giaretta et al. 1997; Bastazini et al. 2007). Assim, muitos anuros desenvolveram adaptações para manter a homeostasia hídrica, reduzindo a perda evaporativa de água ou aumentando a capacidade de absorção de água do meio. Diversas são as maneiras pelas quais algumas espécies de anfíbios reduzem a perda evaporativa de água do seu corpo (Wells 2007; Hillman et al. 2009). Os mecanismos de conservação de água nos anfíbios podem envolver a diminuição da perda de água através da pele, modificação dos produtos nitrogenados excretados pelos rins e o acúmulo de água em vesículas e tecidos (p.ex., bexiga e sacos linfáticos). Estes mecanismos, por sua vez, estão associados a adaptações comportamentais (Stille 1958), morfológicas (Winokur e Hillyard 1992) e/ou fisiológicas (Duellman e Trueb 1986). Como adaptações comportamentais em anuros destacam-se a redução da superfície corpórea através da posição de conservação e o padrão de atividade noturna (Gillis 1979). A postura corpórea de um anuro ainda pode estar associada diretamente à reidratação, postura conhecida como water absorption response, onde a superfície ventral é pressionada contra o substrato úmido (Stille 1958; Brekke et al. 1991). Uma área na região ventral conhecida como pelvic patch ou seat patch é responsável por 70% a 90% da absorção de água (McClanahan e Baldwin 1969; Christensen 1974), sendo constituída por uma elaborada rede de capilares (Roth 1973; Christensen 1974). Ainda como adaptações morfológicas à desidratação e/ou reidratação, destacam-se: presença de glândulas secretoras de lipídeos na pele, tornando-a impermeável; cobertura de sacos linfáticos; espessura, forma e presença de verrugas hidrofílicas (protrusões que aumentam a área de superfície e caracterizam o tegumento ventral de muitos anuros, aumentando a absorção de água) (Winokur e Hillyard 1992); e aumento da capilaridade no ventre (Toledo e Jared 1993). Além disso, a região ventral da epiderme de alguns anuros possui propriedades quimiosensoriais e pode detectar sais, ajudando os indivíduos a evitar águas hiperosmóticas (Koyama et al. 2001). Anuros neotropicais de ambientes hidricamente estressantes parecem possuir adaptações para reduzirem a perda de água ou aumentar a captação de água do meio. Hillman et al. (2009) categorizaram a utilização do habitat por anfíbios anuros usando características morfológicas. Todavia, não há estudos que tenham investigado a desidratação ou reidratação em anuros como variáveis explicativas dos padrões de distribuição espacial das espécies de comunidades de ambientes hidricamente estressantes, como os de Caatinga ou de Restinga (ver Rizzini 1979 para caracterização de Caatinga e Restinga). O presente estudo almeja preencher parte desta lacuna de conhecimento e tem por objetivo principal testar se variáveis fisiológicas relacionadas à economia de água (taxas de desidratação e de reidratação) são capazes de explicar a distribuição espacial de uma comunidade de anuros, estudada por Bastazini et al. (2007), em ambiente de Restinga no Litoral Norte do Estado da Bahia, partindo do pressuposto de que não há diferença entre taxa de desidratação 1ºdia vs. 2ºdia, que há diferença entre taxa de reidratação a partir da água e de um substrato neutro e, já que foram coletadas apenas 11 espécies das 30 originais, que essas 11 espécies podem representar o padrão de distribuição das 30 espécies encontradas por Bastazini et al. (2007). Como objetivo secundário foi testada a hipótese nula que não há diferença entre taxa de desidratação em um meio onde o animal possa adotar uma postura de conservação de água (desidratação no vidro) e onde não possa (desidratação na grade). / Salvador, Bahia
43

Girinos de espécies do gênero Ololygon pertencentes ao grupo "Catharinae" no Estado do Rio de Janeiro (Amphibia, Anura, Hylidae)

Carvalho-e-Silva, Sergio Potsch de January 1986 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-10-18T20:43:03Z No. of bitstreams: 1 200885.pdf: 5771245 bytes, checksum: 78ce10d3d1c6cfa5d881b3a033ed2847 (MD5) / Made available in DSpace on 2017-10-18T20:43:03Z (GMT). No. of bitstreams: 1 200885.pdf: 5771245 bytes, checksum: 78ce10d3d1c6cfa5d881b3a033ed2847 (MD5) Previous issue date: 1986 / O estudo da morfologia e dos hábitos das larvas e do comportamento reprodutivo de seis espécies do gênero Ololygon pertencentes ao grupo “catharinae” no Estado do Rio de Janeiro, como sejam albicans, argyneornata, flavoguttata, humilis, obtriangulata e trapicheiroi, demonstrou que elas constituem espécies plenas. Quatro subgrupos podem ser reconhecidos: “argyreornata” incluindo argyneornata e humilis, “trapicheiroi” incluindo albicans trapicheiroi, “flavoguttata” incluindo apenas flavoguttata, e “obtriangulata” com apenas obtriangulata. Aspectos da morfologia, como sejam o tamanho das narinas e do espiráculo, assim como a quantidade de papilas na margem da boca, são confrontados com as características das coleções de água em que vivem as larvas, respectivamente. As larvas de todas as espécies envolvidas vivem no fundo de águas límpidas e frias nas matas ou em seu bordo. / The study of morphology and habits of tadpoles and of the reprodutive behaviour of six species of the “catharinae” group of the genus Ololygon in the State of Rio de Janeiro, viz: albicans, argyneornata, flavoguttata, humilis, obtriangulata and trapicheiroi demonstrated that they are all full species. Four subgroups are identified: “argyreornata”, including argyneornata and humilis, “trapicheiroi” including albicans trapicheiroi, “flavoguttata” including only flavoguttata, and “obtriangulata”. Some aspects of morphology, such as the size of the nostrils and of the spiracle opening as well as the number of labial papilae are confronted with the features of the water in which the tadpoles live, respectively. All the tadpoles studied here live in the bottom of clear and cool water, inside the forests or in their border.
44

Microbiota cutânea e secreções dérmicas de Proceratophrys boiei (Amphibia, Anura) em fragmentos de Floresta Atlântica / Cutaneous Microbiota and Skin Secretions on Proceratophrys boiei (Amphibia, Anura) in Atlantic Forest Fragments

Assis, Ananda Brito de 01 December 2015 (has links)
A pele dos anfíbios atua como primeira barreira de proteção contra microorganismos invasores. Além dos componentes mecânicos, essa proteção deve incluir mecanismos bioquímicos e biológicos derivados tanto da comunidade microbiana ali residente quanto da secreção de moléculas bioativas a partir de glândulas dérmicas. Os objetivos gerais deste estudo foram: caracterizar a comunidade microbiana hospedada pela espécie Proceratophrys boiei e analisar a sua relação com comunidades microbianas ambientais; avaliar se nessa espécie a microbiota e a secreção cutâneas podem ser entendidas como um componente de proteção; avaliar a estabilidade de tais componentes a partir de diferentes populações em fragmentos florestais. Especificamente, as seguintes hipóteses foram testadas: 1. A composição da microbiota ambiental varia entre os fragmentos e micro-hábitats de Floresta Atlântica amostrados e tem relação com alguns parâmetros ambientais analisados; 2. A diversidade da microbiota cutânea de P. boiei é relacionada à diversidade da microbiota nos ambientes que ocupa. Ademais, em termos de composição, a microbiota cutânea é um subconjunto da microbiota ambiental que ocorre nos seus micro-hábitats; 3. A riqueza e abundância de bactérias da microbiota cutânea de P. boiei varia entre os diferentes remanescentes de Floresta Atlântica; 4. A riqueza e a abundância de bactérias presente na pele de P. boiei com atividade antimicrobiana varia entre populações ou locais de amostragem; 5. Existe efeito antimicrobiano das secreções sobre alguns patógenos e os perfis das secreções cutâneas diferem entre populações de P. boiei. Os resultados mostraram que a microbiota cutânea de P. boiei apresenta variações entre indivíduos e populações. Além disso, a qualidade do hábitat pode ser importante para a composição de bactérias hospedadas. Existe um compartilhamento de bactérias entre a microbiota cutânea de P. boiei e os micro-hábitats solo e água, ocupados por essa espécie, porém as comunidades dérmicas compõem-se principalmente por bactérias não detectadas nas amostras ambientais analisadas. Foi observada certa estabilidade na estrutura da microbiota cutânea de P. boiei quando analisadas populações distintas, mas variações na distribuição de morfotipos bacterianos em uma mesma localidade ocorre. Microbiota cutânea e secreções dérmicas de P. boiei podem prevenir infecções na pele, dada a atividade antimicrobiana demonstrada nesta pesquisa. Contudo, variações nos espectros de ação foram observadas em ambos os componentes, assim como, diferenças populacionais nas abundâncias e percentuais de bactérias produtoras de antimicrobianos. O estudo também demonstrou que certas características independem do contexto ambiental ocupado pelas populações, uma evidência de que o microambiente da pele dessa espécie oferece condições e certa estabilidade para a colonização de comunidades bacterianas específicas. A sustentabilidade de populações dessa espécie pode estar relacionada às interações entre hospedeiro, microrganismos e ambiente. / The skin of amphibians acts as first barrier of protection against invading microorganisms. Besides the mechanical components, this protection probably include biochemical and biological mechanisms derived from both the resident microbial community and the secretion of bioactive molecules from dermal glands. The aims of this study were to characterize the microbial community hosted by Proceratophrys boiei and analyse its relationship with environmental microbial communities; evaluate whether microbiota and skin secretion of this species can be understood as a protection component; evaluate the stability of these components through different populations in forest fragments. Specifically, the following hypotheses have guided this research: 1. The composition of environmental microbiota varies among microhabitats and fragments of Atlantic Forest and relates to some environmental parameters; 2. The diversity of skin microbiota of P. boiei relates to the diversity of microbes in the environment it occupies. Furthermore, in terms of composition, the skin microbiota is a subset of environmental microbes that occurs in its microhabitat; 3. The richness and abundance of bacteria from the skin microbiota of P. boiei varies between different remnants of Atlantic Forest; 4. The richness and abundance of bacteria present on the skin P. boiei with antimicrobial activity varies between populations or sampling sites; 5. There is antimicrobial activity of the skin secretions against some pathogens and its profiles differ between populations of P. boiei. The results showed variations on the microbial skin of P. boiei between individuals and populations and the quality of habitats could be important for the composition of hosted community. There is a sharing of bacteria between the skin microbiota of P. boiei and the microbial communities of microhabitats soil and water. However, mainly bacteria not detected in environmental samples composes the dermal communities. We observed some stability in the structure of the skin microbiota when analysed different populations, but variations in the distribution of bacterial morphotypes occurs in all sites. Skin microbiota and dermal secretions of P. boiei can prevent infection through the skin, according to the antimicrobial activity demonstrated in this study. There were variations in the action spectrum for both components, but population differences were mainly in abundance and percentage of bacteria producing antibiotics. This research showed the importance of the microbiota and skin secretion of P. boiei as components of protection and the importance of the environment for the composition of these associated communities. At the same time, we have shown that certain characteristics are independent of the environmental context occupied by the population, evidence that the microenvironment of the skin provides a certain stability for the colonization of specific bacterial communities. The sustainability of populations of this species may relates to interactions between host organisms and the environment.
45

Species Limits, and Evolutionary History of Glassfrogs

Castroviejo-Fisher, Santiago January 2009 (has links)
Recognizing the mechanisms of speciation and the limits of species is essential to understand the origin of biodiversity and how to conserve it. The general aims of my investigations during my doctoral studies were two-fold: to study evolutionary patterns and processes, and to provide specific and superspecific taxonomic classifications that try to reflect evolutionary history. I have focused my research on anurans in their biodiversity hotspot, the American Tropics. I have used morphological, behavioral (mating calls), and genetic (DNA sequences) characters to study species boundaries between frogs of the genus Pristimantis and the family Centrolenidae (glassfrogs). The results show that the exclusive use of single lines of evidence or the application of arbitrary thresholds impair and bias our ability to recognize new species and limit the possibility to understand evolutionary processes. Only an integrative approach combining every source of evidence provides the necessary feedback to discover all species and test their identity by comparing independent sets of data. This approach further allows identifying those species that probably represent stable comparative units (well supported species hypotheses) and to flag taxa that require further assessment. Phylogenetic reconstructions based on seven nuclear and mitochondrial genes for about 100 species of glassfrogs revealed that previous hypotheses of relationships were mislead by rampant convergent evolution at the phenotypic level. None of the previously suggested classifications fit with the reconstructed evolutionary history. Consequently, we proposed a new classification consistent with this phylogeny. I also studied the tempo and mode of diversification among glassfrogs. Based on sequences from ten genes in 87 species, I estimated species divergence times, age-range correlation between sister species, and reconstructed ancestral areas and dispersal/vicariance events. The results revealed a complex model of diversification where geographical isolation seems to be the dominant scenario for speciation and only clades of altitudinal generalists have been able to spread across the Neotropical rainforests.
46

Microbiota cutânea e secreções dérmicas de Proceratophrys boiei (Amphibia, Anura) em fragmentos de Floresta Atlântica / Cutaneous Microbiota and Skin Secretions on Proceratophrys boiei (Amphibia, Anura) in Atlantic Forest Fragments

Ananda Brito de Assis 01 December 2015 (has links)
A pele dos anfíbios atua como primeira barreira de proteção contra microorganismos invasores. Além dos componentes mecânicos, essa proteção deve incluir mecanismos bioquímicos e biológicos derivados tanto da comunidade microbiana ali residente quanto da secreção de moléculas bioativas a partir de glândulas dérmicas. Os objetivos gerais deste estudo foram: caracterizar a comunidade microbiana hospedada pela espécie Proceratophrys boiei e analisar a sua relação com comunidades microbianas ambientais; avaliar se nessa espécie a microbiota e a secreção cutâneas podem ser entendidas como um componente de proteção; avaliar a estabilidade de tais componentes a partir de diferentes populações em fragmentos florestais. Especificamente, as seguintes hipóteses foram testadas: 1. A composição da microbiota ambiental varia entre os fragmentos e micro-hábitats de Floresta Atlântica amostrados e tem relação com alguns parâmetros ambientais analisados; 2. A diversidade da microbiota cutânea de P. boiei é relacionada à diversidade da microbiota nos ambientes que ocupa. Ademais, em termos de composição, a microbiota cutânea é um subconjunto da microbiota ambiental que ocorre nos seus micro-hábitats; 3. A riqueza e abundância de bactérias da microbiota cutânea de P. boiei varia entre os diferentes remanescentes de Floresta Atlântica; 4. A riqueza e a abundância de bactérias presente na pele de P. boiei com atividade antimicrobiana varia entre populações ou locais de amostragem; 5. Existe efeito antimicrobiano das secreções sobre alguns patógenos e os perfis das secreções cutâneas diferem entre populações de P. boiei. Os resultados mostraram que a microbiota cutânea de P. boiei apresenta variações entre indivíduos e populações. Além disso, a qualidade do hábitat pode ser importante para a composição de bactérias hospedadas. Existe um compartilhamento de bactérias entre a microbiota cutânea de P. boiei e os micro-hábitats solo e água, ocupados por essa espécie, porém as comunidades dérmicas compõem-se principalmente por bactérias não detectadas nas amostras ambientais analisadas. Foi observada certa estabilidade na estrutura da microbiota cutânea de P. boiei quando analisadas populações distintas, mas variações na distribuição de morfotipos bacterianos em uma mesma localidade ocorre. Microbiota cutânea e secreções dérmicas de P. boiei podem prevenir infecções na pele, dada a atividade antimicrobiana demonstrada nesta pesquisa. Contudo, variações nos espectros de ação foram observadas em ambos os componentes, assim como, diferenças populacionais nas abundâncias e percentuais de bactérias produtoras de antimicrobianos. O estudo também demonstrou que certas características independem do contexto ambiental ocupado pelas populações, uma evidência de que o microambiente da pele dessa espécie oferece condições e certa estabilidade para a colonização de comunidades bacterianas específicas. A sustentabilidade de populações dessa espécie pode estar relacionada às interações entre hospedeiro, microrganismos e ambiente. / The skin of amphibians acts as first barrier of protection against invading microorganisms. Besides the mechanical components, this protection probably include biochemical and biological mechanisms derived from both the resident microbial community and the secretion of bioactive molecules from dermal glands. The aims of this study were to characterize the microbial community hosted by Proceratophrys boiei and analyse its relationship with environmental microbial communities; evaluate whether microbiota and skin secretion of this species can be understood as a protection component; evaluate the stability of these components through different populations in forest fragments. Specifically, the following hypotheses have guided this research: 1. The composition of environmental microbiota varies among microhabitats and fragments of Atlantic Forest and relates to some environmental parameters; 2. The diversity of skin microbiota of P. boiei relates to the diversity of microbes in the environment it occupies. Furthermore, in terms of composition, the skin microbiota is a subset of environmental microbes that occurs in its microhabitat; 3. The richness and abundance of bacteria from the skin microbiota of P. boiei varies between different remnants of Atlantic Forest; 4. The richness and abundance of bacteria present on the skin P. boiei with antimicrobial activity varies between populations or sampling sites; 5. There is antimicrobial activity of the skin secretions against some pathogens and its profiles differ between populations of P. boiei. The results showed variations on the microbial skin of P. boiei between individuals and populations and the quality of habitats could be important for the composition of hosted community. There is a sharing of bacteria between the skin microbiota of P. boiei and the microbial communities of microhabitats soil and water. However, mainly bacteria not detected in environmental samples composes the dermal communities. We observed some stability in the structure of the skin microbiota when analysed different populations, but variations in the distribution of bacterial morphotypes occurs in all sites. Skin microbiota and dermal secretions of P. boiei can prevent infection through the skin, according to the antimicrobial activity demonstrated in this study. There were variations in the action spectrum for both components, but population differences were mainly in abundance and percentage of bacteria producing antibiotics. This research showed the importance of the microbiota and skin secretion of P. boiei as components of protection and the importance of the environment for the composition of these associated communities. At the same time, we have shown that certain characteristics are independent of the environmental context occupied by the population, evidence that the microenvironment of the skin provides a certain stability for the colonization of specific bacterial communities. The sustainability of populations of this species may relates to interactions between host organisms and the environment.
47

Diversity and phylogeography of eastern Guiana Shield frogs

Fouquet, Antoine January 2008 (has links)
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.
48

Diversity and phylogeography of eastern Guiana Shield frogs

Fouquet, Antoine January 2008 (has links)
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.
49

Dinâmica dos girinos e caracterização da larva do anuro endêmico Hylodes fredi (ANURA: HYLODIDAE) na Mata Atlântica da Ilha Grande, Rio de Janeiro

Rafael Camilo Laia 26 February 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Hylodes fredi é um anfíbio anuro endêmico da Mata Atlântica da Ilha Grande, estado do Rio de Janeiro. Os girinos desta rã são encontrados nos remansos dos córregos de floresta de águas límpidas, substrato rochoso e em áreas de água rasa, onde os machos adultos podem ser visualizados em atividade de canto. Buscando aumentar a compreensão da dinâmica populacional das larvas de H. fredi, comparamos suas ocorrência, densidade e condição energética em quatro córregos na porção sul da Ilha Grande em um período de doze meses, relacionando inclusive com parâmetros físico-químicos da água. A condição energética foi calculada como o resíduo da relação entre o logaritmo natural da massa e o logaritmo natural do comprimento do corpo de todas as larvas amostradas desta espécie. A densidade e a condição energética dos girinos de H. fredi variaram entre os córregos. Todas as variáveis da água medidas (oxigênio dissolvido, condutividade, temperatura e profundidade), com exceção do pH, influenciaram na diferenciação entre os córregos. A ocorrência de girinos de diferentes tamanhos e massas ao longo de todos os meses, sem uma clara tendência de crescimento sazonal, sugere que H. fredi possui um extenso período reprodutivo durante todo o ano. Tanto os fatores ambientais da água quanto as densidades dos girinos de H. fredi diferenciaram entre as mesmas áreas. Entretanto não houve diferenciação coincidente na condição energética das larvas de H. fredi e nos fatores abióticos entre os mesmos córregos. As diferen as nas densidades e nas condições energéticas médias dos girinos de H. fredi entre as estações seca e chuvosa sugerem que as condições do ambiente são mais apropriadas na estação chuvosa, com uma maior disponibilidade de recursos. As larvas de H. fredi vivendo em córregos com maiores densidades de girinos da família Hylodidae (H. fredi e Crossodactylus gaudichaudii) possuem, em média, condição energética mais reduzida. Isso provavelmente pode ser explicado pelo compartilhamento de recursos, uma vez que, quando limitados, estes seriam mais escassos para cada indivíduo. A densidade de girinos de H. fredi foi mais influenciada por fatores físico-químicos do ambiente enquanto a condição energética dessas larvas foi mais influenciada por fatores biológicos do ambiente. Assim, os girinos de H. fredi variam na densidade e na condição energética como resultado de um balanço entre os parâmetros bióticos e abióticos dos córregos em que as larvas ocorrem. Neste trabalho, nós também descrevemos o girino de H. fredi. / Hylodes fredi is an endemic frog from Ilha Grande, an Atlantic Forest island, located in Rio de Janeiro state, southeast Brazil. The tadpoles of this species are found in clear stream backwaters in the forest, rocky substrate, in shallow waters where calling male frogs can be found. In order to improve the population dynamic knowledge of H. fredi larval stage, we compared their occurrence, density and energetic condition in four streams from the south portion of Ilha Grande in twelve months, relating them to the physicochemical parameters of the water. Energetic condition was calculated as residual of the relationship between the natural logarithm of mass and the natural logarithm of body length of all the H. fredi tadpoles sampled. Density and condition of the H. fredi larvaes varied between the streams. All variables of water measured (dissolved oxygen, conductivity, temperature and depth), except for pH, influenced the discrimination between the streams. The occurrence of tadpoles with different sizes and masses in all the months, without a clear seasonal variation, suggests that H. fredi has an extensive reproductive period along the year. Both environmental factors of the water and H. fredi tadpoles densities were different between the same streams. However, the energetic condition of the larvaes and the abiotic factors did not differentiated between the same streams. The differences found in density and energetic condition of H. fredi tadpoles between dry and wet seasons indicate that environmental conditions are more appropriate in the wet season, with greater availability of resources. Hylodes fredi larvaes living in streams with higher densities of Hylodidae tadpoles (H. fredi and Crossodactylus gaudichaudii) have smaller energetic condition values. This result seems to be probably due to the sharing of the limited resources, once these would be scarcer for each individual. Density of H. fredi tadpoles was more influenced by the physicochemical factors of the environment, while energetic condition of these tadpoles was more influenced by the biological factors of the environment. Then, density and energetic condition of H. fredi tadpoles vary in result of a balance between the abiotic and biotic parameters of the streams in which the larvaes occur. In this study, we also describe the tadpole of H. fredi.
50

Dinâmica dos girinos e caracterização da larva do anuro endêmico Hylodes fredi (ANURA: HYLODIDAE) na Mata Atlântica da Ilha Grande, Rio de Janeiro

Rafael Camilo Laia 26 February 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Hylodes fredi é um anfíbio anuro endêmico da Mata Atlântica da Ilha Grande, estado do Rio de Janeiro. Os girinos desta rã são encontrados nos remansos dos córregos de floresta de águas límpidas, substrato rochoso e em áreas de água rasa, onde os machos adultos podem ser visualizados em atividade de canto. Buscando aumentar a compreensão da dinâmica populacional das larvas de H. fredi, comparamos suas ocorrência, densidade e condição energética em quatro córregos na porção sul da Ilha Grande em um período de doze meses, relacionando inclusive com parâmetros físico-químicos da água. A condição energética foi calculada como o resíduo da relação entre o logaritmo natural da massa e o logaritmo natural do comprimento do corpo de todas as larvas amostradas desta espécie. A densidade e a condição energética dos girinos de H. fredi variaram entre os córregos. Todas as variáveis da água medidas (oxigênio dissolvido, condutividade, temperatura e profundidade), com exceção do pH, influenciaram na diferenciação entre os córregos. A ocorrência de girinos de diferentes tamanhos e massas ao longo de todos os meses, sem uma clara tendência de crescimento sazonal, sugere que H. fredi possui um extenso período reprodutivo durante todo o ano. Tanto os fatores ambientais da água quanto as densidades dos girinos de H. fredi diferenciaram entre as mesmas áreas. Entretanto não houve diferenciação coincidente na condição energética das larvas de H. fredi e nos fatores abióticos entre os mesmos córregos. As diferen as nas densidades e nas condições energéticas médias dos girinos de H. fredi entre as estações seca e chuvosa sugerem que as condições do ambiente são mais apropriadas na estação chuvosa, com uma maior disponibilidade de recursos. As larvas de H. fredi vivendo em córregos com maiores densidades de girinos da família Hylodidae (H. fredi e Crossodactylus gaudichaudii) possuem, em média, condição energética mais reduzida. Isso provavelmente pode ser explicado pelo compartilhamento de recursos, uma vez que, quando limitados, estes seriam mais escassos para cada indivíduo. A densidade de girinos de H. fredi foi mais influenciada por fatores físico-químicos do ambiente enquanto a condição energética dessas larvas foi mais influenciada por fatores biológicos do ambiente. Assim, os girinos de H. fredi variam na densidade e na condição energética como resultado de um balanço entre os parâmetros bióticos e abióticos dos córregos em que as larvas ocorrem. Neste trabalho, nós também descrevemos o girino de H. fredi. / Hylodes fredi is an endemic frog from Ilha Grande, an Atlantic Forest island, located in Rio de Janeiro state, southeast Brazil. The tadpoles of this species are found in clear stream backwaters in the forest, rocky substrate, in shallow waters where calling male frogs can be found. In order to improve the population dynamic knowledge of H. fredi larval stage, we compared their occurrence, density and energetic condition in four streams from the south portion of Ilha Grande in twelve months, relating them to the physicochemical parameters of the water. Energetic condition was calculated as residual of the relationship between the natural logarithm of mass and the natural logarithm of body length of all the H. fredi tadpoles sampled. Density and condition of the H. fredi larvaes varied between the streams. All variables of water measured (dissolved oxygen, conductivity, temperature and depth), except for pH, influenced the discrimination between the streams. The occurrence of tadpoles with different sizes and masses in all the months, without a clear seasonal variation, suggests that H. fredi has an extensive reproductive period along the year. Both environmental factors of the water and H. fredi tadpoles densities were different between the same streams. However, the energetic condition of the larvaes and the abiotic factors did not differentiated between the same streams. The differences found in density and energetic condition of H. fredi tadpoles between dry and wet seasons indicate that environmental conditions are more appropriate in the wet season, with greater availability of resources. Hylodes fredi larvaes living in streams with higher densities of Hylodidae tadpoles (H. fredi and Crossodactylus gaudichaudii) have smaller energetic condition values. This result seems to be probably due to the sharing of the limited resources, once these would be scarcer for each individual. Density of H. fredi tadpoles was more influenced by the physicochemical factors of the environment, while energetic condition of these tadpoles was more influenced by the biological factors of the environment. Then, density and energetic condition of H. fredi tadpoles vary in result of a balance between the abiotic and biotic parameters of the streams in which the larvaes occur. In this study, we also describe the tadpole of H. fredi.

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