Importantes estudos voltados para a análise das secreções de anfíbios fundamentam-se na grande quantidade de componentes biologicamente ativos presentes nas mesmas, tais como aminas biogênicas, esteróides, aminopolissacarídeos, glicosídeos, inibidores de proteases e diversos outros compostos, responsáveis pela complexa sintomatologia observada no envenenamento. O gênero Bufo apresenta diversas moléculas em suas excreções que podem ser divididas em categorias como aminas biogênicas, bufadienolídeos (bufogeninas), esteróides (bufotoxinas), alcalóides, peptídeos e proteínas. Marongio (2006) verificou que o veneno do sapo Bufo paracnemis, hoje classificado como Rhinella schneideri, apresenta componente ativo sobre a via clássica do sistema complemento (SC), necessitando de melhores estudos e caracterização. Os objetivos deste trabalho foram, portanto, o isolamento e caracterização química do componente do veneno de Rhinella schneideri responsável pelos efeitos observados sobre o sistema complemento. Para a purificação, o veneno foi inicialmente submetido a uma cromatografia catiônica (CM-Celulose-52), obtendo-se 7 frações denominadas C1, C2, C3, C4, C5, C6 e C7. A fração C1 foi cromatografada em resina aniônica (DEAE-SepharoseTM), resultando em 4 subfrações denominadas D1, D2, D3, e D4. A subfração D3 apresentou atividade sobre o sistema complemento e foi submetida a uma Gel Filtração (SephacrylTMS-200), fornecendo 5 subfrações denominadas S1, S2, S3, S4, e S5. As subfrações S2 e S5 induziram redução da atividade hemolítica das vias clássica/lectinas. Ambas apresentaram resultados positivos nos ensaios de migração de neutrófilos e imunoeletroforese bidimensional. No ensaio de capacidade geradora de SC5b-9, a subfração S2 apresentou maior significância frente as demais subfrações utilizadas. Visando esclarecer o mecanismo de ação das subfrações ativas sobre o sistema complemento, testes de determinação da atividade proteolítica ou inibitória de proteases (tripsina, quimotripsina e elastase) foram realizados. No entanto, nas concentrações utilizadas, as amostras não mostraram atividade proteolítica ou inibitória de protease. Os compostos isolados foram também submetidos ao sequenciamento amino-terminal inicial. Foi possível a identificação dos primeiros 15 aminoácidos da banda protéica majoritária do gel de poliacrilamida e 10 e 5 aminoácidos das subfrações S2 e S5, respectivamente. No entanto, os resultados de sequenciamento N-terminal apresentaram baixa confiabilidade, devido à baixa quantidade de material utilizada. Neste trabalho foram isolados e caracterizados dois compostos capazes de induzir a ativação do sistema complemento. Esta ação foi evidenciada, após exposição do soro humano normal às subfrações, por induzirem à formação do complexo SC5b-9 e aumentarem a migração de neutrófilos, provavelmente por induzirem a formação de fatores quimiotáticos. Este estudo permitiu avaliar melhor alguns componentes presentes na complexa mistura que é o veneno de Rhinella schneideri, que, no futuro, poderão se tornar ferramentas farmacológicas importantes para o estudo de diversas patologias relacionadas ao sistema complemento. / Important studies focused on amphibians secretions analysis are based on large amount of biologically active components present in them, such as biogenic amines, steroids, polysaccharide amine, glycosides, protease inhibitors and several other compounds, responsible for complex symptomatology observed in the envenomation by Bufo paracnemis. The genus Bufo presents several molecules in their excretions that can be divided into categories such as biogenic amines, bufadienolides (Bufogenin), steroids (Bufotoxins), alkaloids, peptides and proteins. Marongio (2006) found in one of his studies the toad poison of Bufo paracnemis, now classified as Rhinella schneideri, has an active component of the classical pathway of the complement system (SC), which needs further studies and characterization. The purification process of this study was accomplished through cation chromatography (CM-Cellulose-52), and seven fractions were obtained, called C1, C2, C3, C4, C5, C6 e C7. The fraction C1 was chromatographed on anion-exchange resin (DEAE- SepharoseTM) resulting in 4 subfractions referred to as D1, D2, D3, and D4. The subfraction D3 showed activity on complement system and was subjected to gel filtration (SephacrylTMS-200) giving 5 subfractions termed S1, S2, S3, S4, and S5. The subfractions S2 and S5 induced reduction of the hemolytic activity of the classical/lectin pathway. Both showed positive results in the assays of migration of neutrophils and bidimensional immunoelectrophoresis. In the assay of generating capacity of SC5b-9, the subfraction S2 presented greater significance when compared to the other used subfractions. Aiming to clarify the action mechanism of the active subfractions on the complement system, tests of determination of the proteolytic or inhibitory activity of proteases (trypsin, chymotrypsin and elastase) had been done. However, in the used concentrations, the samples had not shown proteolytic or inhibitory activity of protease. The isolated compounds also had been submitted to the initial amino-terminal sequence. The identification of the first 15 aminoacids of the major proteinic band of the polyacrylamide gel and 10 and 5 aminoacids of the subfractions S2 and S5 was possible, respectively. However, the sequence of N-terminal results had presented low trustworthiness, due to the low amount of used material. In this work, were isolated and characterized two capable compounds to induce the activation of the complement system. This action was evidenced, after exposition of the normal human serum to the subfractions, for inducing to the formation of the SC5b-9 complex and will increase the migration of neutrophils, probably because they can induce the formation of chemotactic factors. This study allowed a better evaluation of some components present in the complex mixture which is the poison of Rhinella schneideri, that, in the future, important pharmacological tools for the study of diverse pathologies related the complement system.

Toxinas animais são moléculas aplicáveis na geração de agentes terapêuticos e/ou de ferramentas experimentais para a pesquisa básica e aplicada, justificando sua purificação e análise funcional. Considerando que estudos de venenos de sapos são relevantes, por serem estes considerados uma boa fonte de toxinas que atuam sobre diferentes sistemas biológicos, os objetivos deste trabalho foram isolar toxinas presentes no veneno de Rinella schneideri e avaliar suas ações sobre a atividade da enzima Na+K+-ATPase e os sistemas nervosos central e periférico. O veneno de Rhinella schneideri foi inicialmente submetido a diferentes extrações resultando em quatro amostras. A AMOSTRA A, que apresenta apenas componentes de baixa massa molecular, foi a mais efetiva na redução da atividade da Na+K+-ATPase e foi, portanto, liofilizada e submetida a uma cromatografia de fase reversa em sistema CLAE em coluna C2C18. Das 5 frações majoritárias obtidas nesta cromatografia apenas as Rs3, Rs4 e Rs5 induziram uma redução concentração-dependente da atividade da Na+K+-ATPase, mostrando IC50% de 33,6 g, 47,7 g e 98,92 g, respectivamente. Estes resultados indicam que o veneno de R. schneideri apresenta pelo menos três substâncias capazes de inibir a Na+K+-ATPase. As frações Rs3, Rs4 e Rs5, foram submetidas à espectrometria de massa e revelaram massas moleculares de 403, 401 e 387 Da, provavelmente correspondentes à Telocinobufagina, Desacetilcinobufagina e Bufalina, respectivamente. Estes compostos mostraram também neuroproteção central muito relevante sobre crises convulsivas induzidas por PTZ (Pentilenotetrazol) e NMDA (n-metil-d-aspartato), sendo que a Rs5 foi a que causou maior neuroproteção. No entanto, estas mesmas frações apresentaram ação neurotóxica periférica, induzindo bloqueio da junção neuromuscular de pintainhos. Manifestações como alucinações, dormência, confusão mental também são observadas em envenenamentos por sapos, que podem ser induzidos por alcalóides presentes no veneno, o que justifica os estudos para a identificação dos mesmos. Neste trabalho confirmou-se a presença de ii alcalóides no veneno. No entanto, foram priorizados os estudos com as toxinas isoladas Rs3, Rs4 e Rs5, por apresentarem ações biológicas importantes. Concluindo, neste trabalho foram isolados 3 compostos de baixa massa molecular, denominados Rs3, Rs4 e Rs5, que são capazes de inibir a atividade da Na+K+- ATPase, bloquear a transmissão do impulso nervoso na junção neuromuscular de pintainhos e, principalmente a Rs5, proteger crises convulsivas induzidas por PTZ e NMDA. Estudos adicionais serão necessários para estabelecer a correlação entre estes efeitos e determinar o mecanismo de ação destas toxinas. / Animal toxins are molecules applicable in the generation of therapeutic agents and / or experimental tools for basic and applied research, justifying its purification and functional analysis. Whereas studies of poison toads are relevant, since these are considered a good source of toxins that act on different biological systems, the objectives of this work were to isolate toxins in the venom of Rinella schneideri and evaluate their actions on the Na+K+-ATPase activity and the central and peripheral nervous systems. The venom Rhinella schneideri was initially submitted to different extractions resulting in four samples. The SAMPLE A, with only low molecular mass components, was the most effective in reducing the activity of Na+K+-ATPase and was lyophilized and subjected to reverse phase chromatography in the HPLC system in C2C18 column. Five majority fractions were obtained from this chromatography and only Rs3, Rs4 and Rs5 induced a concentration-dependent reduction in activity of Na+K+-ATPase, showing IC50% 33.6 g, 47.7 g and 98.92 g, respectively. These results indicate that R. schneideri venom presents at least three substances that can inhibit the Na+K+-ATPase. Fractions Rs3, Rs4 and Rs5 were submitted to mass spectrometry assay showing molecular masses of 403, 401and 387 Da, probably corresponding to Telocinobufagin, Desacetylcinobufagin and Bufalin, respectively. These compounds also showed a very relevant central neuroprotection on seizures induced by PTZ (Pentylenetetrazole) and NMDA (N-methyl-d-aspartate), and the Rs5 caused the highest neuroprotection. However, these same fractions showed neurotoxicity on peripheral nervous system, inducing blockade of the neuromuscular junction of chicks. Manifestations such as hallucinations, numbness, mental confusion are also seen in poisoning by toads, which can be induced by alkaloids present in the venom, which justifies the studies for their identification. This work confirmed the presence of alkaloids in the venom. However, have been prioritized the studies with isolated toxins Rs3, Rs4 and Rs5, because they have important biological actions. In conclusion, in this study were isolated three compounds with iv low molecular mass, known as Rs3, Rs4 and Rs5, which are capable of inhibiting the activity of Na+K+-ATPase, blocking the nerve impulse transmission at the neuromuscular junction of chickens, and especially the Rs5 by protecting seizures induced by PTZ and NMDA. Additional studies are necessary to establish the correlation between these effects and determine the mechanism of action of these toxins.

Orientador: Luciano Alves dos Anjos / Resumo: O presente estudo analisou a fauna parasitária de três espécies de anuros desde a fase larval até a adulta, Hypsiboas cinerascens, Hypsiboas geographicus e Rhinella marina da Reserva Florestal Ducke, Amazônia Central. A fauna de parasitas de anuros da região é pouco conhecida, sendo a fase larval a menos estudada. Os dados analisados durante os dois anos de coleta demonstraram que espécies parasitas diferem nas duas fases de vida dos anfíbios anuros. Foram analisados um total de 224 girinos, e 38 indivíduos adultos, em três áreas de amostragem diferentes: poças temporárias, poça permanente, e uma lagoa da reserva. Um total de 827 parasitas foi encontradonosgirinos, e 3.534 nos adultos. Nas fases larvais foram encontrados nematoidespertencentes à espécie Gyrinicola chabaudi, metacercárias de trematódeos de Diplostomídeos e protozoários do gênero Nyctotherus. Nos adultos, a riqueza parasitária foi maior: nestes foram encontrados nematoides, trematódeos, acantocéfalos, carrapatos e larvas de Diptera. As fases larvais das espécies de anuros aqui estudados, representam novos registros de hospedeiros para o nematoide Gyrinicola chabaudi, ampliando o conhecimento de sua distribuição geográfica. Com os dados obtidos, podemos compreender que a riqueza entre as duas fases de desenvolvimento dos anuros são bem distintas. Durante o processo de metamorfose até a fase adulta o animal transporta grupos de parasitas, conectando-os entre o ambiente aquático e o ambiente terrestre. Este traba... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Submitted by FRANCIELE CRISTINA DE SOUZA null (francielexingu@gmail.com) on 2017-04-24T18:57:03Z No. of bitstreams: 1 Dissertacao_FRANCIELE_FINAL Unesp.pdf: 3022787 bytes, checksum: 6f9282ebb7236dffb5792ca794b069dd (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-26T13:57:06Z (GMT) No. of bitstreams: 1 souza_fc_me_bot.pdf: 3022787 bytes, checksum: 6f9282ebb7236dffb5792ca794b069dd (MD5) / Made available in DSpace on 2017-04-26T13:57:06Z (GMT). No. of bitstreams: 1 souza_fc_me_bot.pdf: 3022787 bytes, checksum: 6f9282ebb7236dffb5792ca794b069dd (MD5) Previous issue date: 2017-03-02 / Fundação de Amparo à Pesquisa do Estado do Amazonas (FAPEAM) / O presente estudo analisou a fauna parasitária de três espécies de anuros desde a fase larval até a adulta, Hypsiboas cinerascens, Hypsiboas geographicus e Rhinella marina da Reserva Florestal Ducke, Amazônia Central. A fauna de parasitas de anuros da região é pouco conhecida, sendo a fase larval a menos estudada. Os dados analisados durante os dois anos de coleta demonstraram que espécies parasitas diferem nas duas fases de vida dos anfíbios anuros. Foram analisados um total de 224 girinos, e 38 indivíduos adultos, em três áreas de amostragem diferentes: poças temporárias, poça permanente, e uma lagoa da reserva. Um total de 827 parasitas foi encontradonosgirinos, e 3.534 nos adultos. Nas fases larvais foram encontrados nematoidespertencentes à espécie Gyrinicola chabaudi, metacercárias de trematódeos de Diplostomídeos e protozoários do gênero Nyctotherus. Nos adultos, a riqueza parasitária foi maior: nestes foram encontrados nematoides, trematódeos, acantocéfalos, carrapatos e larvas de Diptera. As fases larvais das espécies de anuros aqui estudados, representam novos registros de hospedeiros para o nematoide Gyrinicola chabaudi, ampliando o conhecimento de sua distribuição geográfica. Com os dados obtidos, podemos compreender que a riqueza entre as duas fases de desenvolvimento dos anuros são bem distintas. Durante o processo de metamorfose até a fase adulta o animal transporta grupos de parasitas, conectando-os entre o ambiente aquático e o ambiente terrestre. Este trabalho é o primeiro, até o momento, que descreve este tipo de interação na região, contribuindo assim com o aumento de registro de novas informações sobre estudos parasitológicos na Amazônia. / The present study analyzed the parasitic fauna of three species of anurans from the larval to adult phase, Hypsiboas cinerascens, Hypsiboas geographicus, and Rhinella marina of the Ducke Forest Reserve, Central Amazonia. The anurans parasitic’ fauna of the region is little known, being the larval stage less studied. The data analyzed during two years of collection showed that parasite species differ in two life stages of anuran amphibians.A total of 224 tadpoles, and 38 adult individuals, were analyzed in three different sampling areas, temporary pools, permanent pond, and one reserve pond. A total of 827 parasites were found in tadpoles, and 3,534 in adults. In the larval stages nematodes belonging to the species Gyrinicola chabaudi, metacercariae of trematodes of the family Diplostomidae, and protozoa of the genus Nyctotherus sp. In adults, parasite diversity was higher: in these were found nematodes, trematodes, acantocephalus, ticks, and larvae of Diptera. Larval phases of the anuran species studied here represent new host register for the Gyrinicola chabaudi nematode, increasing the knowledge of its geographical distribution.With obtained data we can understand that diversity and richness between the two stages of anuran development are very different. During the process of metamorphosis to adulthood the animal carries groups of parasites, connecting them between the aquatic environment and terrestrial environment. This work is the first, to date, which describes this type of interaction in the region, thus contributing to the increase in the registration of new information on parasitological studies in the Amazon.

Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2014-02-07T15:00:20Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_AnaliseTaxonomicaMolecular.pdf: 13154268 bytes, checksum: 998f972766bb7eefd7573313e2fe0e58 (MD5) / Made available in DSpace on 2014-02-07T15:00:20Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_AnaliseTaxonomicaMolecular.pdf: 13154268 bytes, checksum: 998f972766bb7eefd7573313e2fe0e58 (MD5) Previous issue date: 2010 / PROCAD - Programa Nacional de Cooperação Acadêmica / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os anfíbios da espécie Rhinella marina também conhecidos como Sapo-Cururu e possuem distribuição mundial. Possuem hábitos noturnos, e devido a sua alimentação bem diversificada vivem em diferentes habitats. Assim podem estar parasitados com uma variedade de helmintos. Dentre os helmintos, os cestodas são o objeto de estudo deste trabalho. Os membros da Família Nematotaennidae são comumente encontrados parasitando o intestino delgado de anfíbios e répteis. O presente trabalho tem como objetivo identificar e caracterizar morfologicamente e molecularmente um cestoda parasito de R. marina da cidade de Belém-PA. Para isso vinte hospedeiros foram capturados em domicílios da região metropolitana de Belém-PA e, após necropsia, os cestoda foram retirados do intestino delgado, alguns exemplares foram fixados em A.F.A, alguns fixados em Glutaraldeído a 2% em tampão cacodilato, e outros em álcool absoluto para serem processados para diferentes técnicas. Parte da amostra foi desidratada em uma série etanólica, corados com Carmin®, clarificados com Salicilato de Metila®. Alguns exemplares foram desidratados e incluídos em parafina para realização de cortes transversais e longitudinais. Os exemplares fixados em glutaraldeído foram desidratados e incluídos em Historesina®. Os cestoda também foram processados para microscopia Eletrônica de Varredura. A identificação foi realizada por meio de desenhos realizados no microscópio Olympus BX 41 com câmara clara, fotografias feitas em microscópio MEDILUX, com sistema de captura de imagem e MEV. Os Cortes histológicos longitudinais foram fotografados e com o Software RECONSTRUCTTM foi realizada a reconstrução tridimensional do corpo do parasito. Helmintos fixados em álcool absoluto foram submetidos a extração de DNA, amplificação gênica pela técnica de PCR e seqüenciamento de nucleotídeos. Os cestoda possuem um corpo cilíndrico, filiforme e indistintamente segmentado, exceto na porção posterior. Escólice com quatro ventosas sem rostéolo ou órgão apical, os proglotes grávidos apresentam duas cápsulas piriformes, que se fundem na base, contendo os ovos. A partir das observações por microscopia eletrônica e luz dos cestoda encontrados no intestino delgado de R. marina, observou-se que estes cestoda pertencem à Família Nematotaeniidae, no entanto os outros caracteres morfológicos e moleculares por nós encontrados não encaixam este cestóide em nenhum gênero desta Família. / The amphibians of the species Rhinella marina known also as Giant Toad and have cosmopolitan distribution. Posses nocturnes habits, due of variety of feeding they can live in different habitats. Then, they can have many kinds of helminthes parasites. Among the helminthes, the cestodas are the target of study of this work. The members of Nematotaeniidae Family are commonly found in small intestine of repitilian and amphibians. The frequent auto-infestation would justify the high taxes of parasitism in one host. The present study has the objective to identify and to characterize the Cestoda of Rhinella marina from Belém-PA. Twenty hosts were captured in homes of the metropolitan area of Belém-PA and, after necropsy the Cestoda were isolated of intestine, and some specimens were fixed in A.F.A (Glacial Acid Acetic 2%, Formaldehyde 3% and 95 % of Etanol 70º GL), and some worms fixed in 2% Glutaraldehyde in Cacodilate buffer 0,1m P.h 7,4, to process in different techniques. One part of the samples was dehydrated in Etanol Series, and stained with Carmim®, and clarified with Metil Salicilate®. Some specimens were dehydrated and included in Paraffin for acomplishement of longitudinal and tranverse cuts. The worms fixed in Glutaraldehyde were dehydrated and included in Historesin®. Some Cestoda were processed for Scanning Electron Microscopy (SEM). An indentification was accomplished throught drawings in Olympus BX 41 microscope equipped with camera lucida, pictures were taken in a MEDILUX microscope, with image captures system and in MEV JEOL 5310. Histological sections were photographed and 3D reconstruction was made in RECONSTRUCTTM software. The cestoid possess a cylindrical body, filiform and with difficult segmentation, except in the final portion of the strobila. Escolex with four suckers without hooks or apical organ, the pregnant proglotis presents two piriform capsules, funded in the basis and containing one or more eggs. The observations in SEM and light microscopy of the cestoda founded in small intestine of R.marina from Belém-PA, we observed that these Cestoda belong to Nematotaeniidae Family, meanwhile the other morphologic characters observed did not permit us to classify this helminth in any Gender of this Family.

The amphibian decline phenomenon now involves in excess of a third of the roughly 6000 species of amphibians on the planet. The problems that drive the declines are diverse with no end in sight. The Amphibian Conservation Action Plan (ACAP) aims to stem amphibian decline through four recommended actions by researchers and conservation biologists: (1) Expand scientific understanding of amphibian declines and extinctions; (2) continue to document amphibian diversity and ecology and how they are changing; (3) develop and implement long-term conservation programs; (4) prepare emergency response actions for eminent crises. This Dissertation focused on two of those recommendations: expanding scientific understanding of amphibian declines and extinctions and continuing to document amphibian diversity and ecology and how they are changing. The first chapter is a review of the amphibian decline phenomenon. The second, third, and fourth chapters focus on expanding scientific understanding of amphibian diversity and ecology with the description of a formerly unknown species (chapter 2), and ecological papers on two poorly known species (chapters 3 and 4). Chapter five focuses on the first ACAP recommendation in improving scientific understanding of the causes behind amphibian decline. The chapter is an experimental examination of two related species and their developmental reactions to common heavy metal contaminants. The goal of this Dissertation is to contribute toward the general amphibian knowledge base relative to the recommendations of ACAP.

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.