720 resultados para AMPHIBIA: ANURA: BUFONIDAE


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We investigated the morphology of the skin and the biochemistry of the lipids in the skin secretion of Bokermannohyla alvarengai, a montane treefrog that is known to bask regularly, motionless in full sunlight for extended periods of time. Our primary goal was to identify structural and biochemical modifications that might assist this frog species to accommodate the conflicting demands for heat exchange and water balance while basking. The modulation of heat exchange in basking B. alvarengai involves changes in skin coloration. We found that this response was supported by a prominent monolayer of large iridophores, whose light reflectance property is adjusted by the response of intervening melanophores. Mucosubstances and lipid compounds, mainly consisted of saturated fatty acids and presumably secreted from granular glands, were detected on the skin of B. alvarengai. These compounds formed an extra-epidermal layer over the animal's dorsal surface that might assist in the prevention of excessive water loss through evaporation. Additionally, we found well-developed skin folds at the ventral region of the frogs that lead to an increment of surface area. This feature combined with the extensive hypervascularization, also noticed for the skin of B. alvarengai, may play an important role in water reabsorption. The suite of structural and biochemical modifications identified for the integument of B. alvarengai seems to conjugate aspects relevant to both, heat exchange and water balance, allowing for this species to explore basking as an efficient thermoregulatory strategy. J. Morphol. 276:1172-1182, 2015. © 2015 Wiley Periodicals, Inc.

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The possible trade-off between the roles of glucocorticoids as facilitators of energy substrate mobilization and neural inhibitors of sexual behavior during breeding season is under debate. We studied the relationship between calling and territorial behavior with plasma levels of corticosterone (CORT) and plasma levels of testosterone (T) across the breeding season of Hypsiboas faber, a large and territorial Neotropical treefrog. We investigated these relationships through focal observations of males calling naturally, followed by blood sampling for hormonal radioimmunoassay. We additionally used an experimental approach, which consisted of broadcasting recorded advertisement calls for 10 min to simulate an invasion in the territory of the focal subjects, followed by behavioral observation and blood sampling for hormonal radioimmunoassay. Results showed a pattern of co-variation between CORT and T across the breeding season. Furthermore, individual variation in CORT and T was related to different aspects of behavior: individuals with higher CORT showed higher calling rates, and individuals with higher steroid levels, mainly T, showed higher responsivity to social stimulation by other males in the chorus. Experimental simulation of territorial intrusion by using playback of advertisement calls of this species did not elicit consistent changes in agonistic behavior and CORT, but decreased T in focal males. (C) 2012 Elsevier Inc. All rights reserved.

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Fluorescence in situ hybridization (FISH) using telomeric and ribosomal sequences was performed in four species of toad genus Chaunus: C. ictericus, C. jimi, C. rubescens and C. schneideri. Analyses based on conventional, C-banding and Ag-NOR staining were also carried out. The four species present a 2n = 22 karyotype, composed by metacentric and submetacentric chromosomes, which were indistinguishable either after conventional staining or banding techniques. Constitutive heterochromatin was predominantly located at pericentromeric regions, and telomeric sequences (TTAGGG)(n) were restricted to the end of all chromosomes. Silver staining revealed Ag-NORs located at the short arm of pair 7, and heteromorphism in size of NOR signals was also observed. By contrast, FISH with ribosomal probes clearly demonstrated absence of any heteromorphism in size of rDNA sequences, suggesting that the difference observed after Ag-staining should be attributed to differences in chromosomal condensation and/or gene activity rather than to the number of ribosomal cistrons.

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We investigated the relationships of Asian bufonids using partial sequences of mitochondrial DNA genes. Twenty-six samples representing 14 species of Bufo from China and Vietnam and 2 species of Torrentophryne from China were examined. Three samples of Bufo viridis from Armenia and Georgia were also sequenced to make a comparison to its sibling tetraploid species B. danatensis. Bufo americanus, from Canada, was used as the outgroup. Sequences from the 12S ribosomal RNA, 16S ribosomal RNA, cytochrome b, and the control region were analyzed using parsimony. East Asian bufonids were grouped into two major clades. One clade included B. andrewsi, B. bankorensis, B. gargarizans, B. tibetanus, B. tuberculatus, its sister clade B. cryptotympanicus, and the 2 species of Torrentophryne. The second clade consisted of B. galeatus, B. himalayanus, B. melanostictus, and a new species from Vietnam. The placement of three taxa (B. raddei B. viridis, and its sister species, B. danatensis) was problematic. The genus Torrentophryne should be synonymized with Bufo to remove paraphyly. Because B. raddei does not belong to the clade that includes B. viridis and B. danatensis, it was removed from the viridis species group. The species status of B bankorensis from Taiwan is evaluated. (C) 2000 Academic Press.

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The chromosomes of Bufo crucifer, B. ictericus, and B. pamacnemis were studied by conventional staining as well as with C banding and NOR techniques. These species have a diploid number of 2n = 22 and identical karyotypes, composed of metacentric and submetacentric chromosomes. The C banding patterns and NOR data indicate that these species of Bufo are not differentiated by the distribution and amount of constitutive heterochromatin or the position of the nucleolar organizer regions.

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In this paper we provide a cytogenetic analysis of Paratelmatobius cardosoi and Paratelmatobius poecilogaster. The karyotypes of both species showed a diploid number of 24 chromosomes and shared some similarity in the morphology of some pairs. On the other hand, pairs 4 and 6 widely differed between these complements. These karyotypes also differed in their NOR number and location. Size heteromorphism was seen in all NOR-bearing chromosomes of the two karyotypes. In addition, both karyotypes showed small centromeric C-bands and a conspicuous heterochromatic band in the short arm of chromosome 1, although with a different size in each species. The P. cardosoi complement also showed other strongly stained non-centromeric C-bands, with no counterparts in the P. cardosoi karyotype. Chromosome staining with fluorochromes revealed heterogeneity in the base composition of two of the non-centromeric C-bands of P. cardosoi. Comparison of the chromosomal morphology of these Paratelmatobius karyotypes with that of P. lutzii showed that the P. poecilogaster karyotype is more similar to that of P. lutzii than P. cardosoi. These cytogenetic results agree with the proposed species arrangements in the P. cardosoi and P. lutzii groups based on morphological and ecological data.

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Cytogenetic and random amplified polymorphic DNA analyses carried out in the species Leptodactylus podicipinus, L. ocellatus, L. labyrinthicus, and L. fuscus from rural and urban habitats of the northwest region of São Paulo State, Brazil, showed that the karyotypes (2n = 22), constitutive heterochromatin distribution and nucleolus organizer region (NOR) location did not differ between the populations from the two environments. The in situ hybridization with an rDNA probe confirmed the location of the NORs on chromosome 8 revealing an in tandem duplication of that region in one of the chromosomes of L. fuscus. DAPI showed that part of the C-band-positive heterochromatin is rich in AT, including that in the proximity the NORs in L. podicipinus and L. ocellatus. The molecular analyses showed that the two populations (urban and rural) of L. podicipinus and L. fuscus are similar from a genetic point of view. The urban and rural populations of species L. ocellatus and L. labyrinthicus showed differences in genetic structures, probably due to urbanization which interferes with the dispersion of those frogs. The marked differences observed between the two populations of L. ocellatus can be representing the cryptic condition of the species. Unweighted pair-group method of analysis and genetic distance analysis detected the genetic proximity between L. ocellatus and L. fuscus. The results indicate that there was no reduction in the genetic diversity in the populations from the urban environment; however, the survival of these frogs would not be guaranteed in the case of an increase in human impact especially for populations of L. labyrinthicus and L. ocellatus. ©FUNPEC-RP.

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The family Nematotaeniidae, tapeworms commonly found in the small intestines of amphibians and reptiles, includes 27 recognised species distributed among four genera: Bitegmen Jones, Cylindrotaenia Jewell, Distoichometra Dickey and Nematotaenia Lühe. The taxonomy of these cestodes is poorly defined, due in part to the difficulties of observing many anatomical traits. This study presents and describes a new genus and species of nematotaeniid parasite found in cane toads (Rhinella marina) from eastern Brazilian Amazonia. The cestodes were collected during the necropsy of 20 hosts captured in the urban area of Belém, Pará. The specimens were fixed and processed for light microscopy, scanning electron microscopy (SEM) and three-dimensional (3D) reconstruction. Samples were also collected for molecular analyses. The specimens presented a cylindrical body, two testes and paruterine organs. However, they could not be allocated to any of the four existing nematotaeniid genera due to the presence of two each of dorsal compact medullary testes, cirri, cirrus pouches, genital pores, ovaries and vitelline glands per mature segment. Lanfrediella amphicirrus gen. nov. sp. nov. is the first nematotaeniid studied using Historesin analysis, SEM and 3D reconstruction, and it is the second taxon for which molecular data have been deposited in GenBank.

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The nematode parasites of Rhinella marina include species of the genus Rhabdias (Rhabdiasidae: Rhabditoidea). The present study describes Rhabdias paraensis sp. nov., which parasitizes the lungs of R. marina in Brazilian Amazonia. Of the more than 70 known species of this genus, 18 are parasites of bufonids, of which, eight are Neotropical. The new species described here is similar to Rhabdias alabialis in the absence of lips is different by the presence of conspicuous cephalic papillae. We describe details of the four rows of pores, which are distributed equally along the whole of the length of the body and connected with hypodermal cells, using histology and scanning electron microscopy. Other histological aspects of the internal structure of this nematode are also described.

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ABSTRACT: Mesocoelium lanfrediae sp. nov. (Digenea: Mesocoeliidae) inhabits the small intestine of Rhinella marina (Amphibia: Bufonidae) and is described here, with illustrations provided by light, scanning electron microscopy and molecular approachs. M. lanfrediae sp. nov. presents the typical characteristics of the genus, but is morphometrically and morphologically different from the species described previously. The main diagnostic characteristics of M. lanfrediae sp. nov. are (i) seven pairs of regularly-distributed spherical papillae on the oral sucker, (ii) ventral sucker outlined by four pairs of papillae distributed in a uniform pattern and interspersed with numerous spines, which are larger at the posterior margin and (iii) small, rounded tegumentary papillae around the opening of the oral sucker, which are morphologically different from those of the oral sucker itself, some of which are randomly disposed in the ventrolateral tegumentary region of the anterior third of the body. Addionally, based on SSU rDNA, a phylogenetic analysis including Brachycoeliidae and Mesocoeliidae taxa available on GenBank established the close relationship between M. lanfrediae sp. nov. and Mesocoelium sp.

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Este estudo teve como objetivo examinar características da biologia reprodutiva, condição nutricional e hábito alimentar do anuro de serrapilheira por meio de indivíduos coletados na Estação Científica Ferreira Pena, Floresta Nacional de Caxiuanã no período de abril de 1997 a abril de 1998. Uma amostragem de 166 espécimes foi examinada para obtenção de medidas de comprimento rostro-cloaca, massa de corpos de gordura, diâmetro, massa e número de óvulos nas fêmeas, e volume dos testículos em machos. O hábito alimentar da espécie foi determinado através da análise dos conteúdos estomacais. A estrutura da população amostrada indicou um padrão com a predominância de indivíduos adultos, incluindo fêmeas grávidas, nos meses de chuva, e o recrutamento de juvenis no início da estação seca. Igualmente, o diâmetro e a massa de óvulos no ovário, utilizados como indicadores de estágio de desenvolvimento gonadal, foram maiores na estação chuvosa. Entre os machos, os maiores valores de volume dos testículos também apareceram em fevereiro e abril, mas não houve um padrão evidente de correlação com a precipitação. O consumo de alimento não apresentou um padrão claro de variação entre os meses e não foi correlacionado à massa do corpo de gordura. As medidas de corpos de gordura foram positivamente correlacionadas aos estágios de desenvolvimento dos óvulos em fêmeas, indicando que acúmulo de gordura e desenvolvimento gonadal podem ocorrer simultaneamente. A composição da dieta da espécie foi constituída basicamente de formigas, ácaros e cupins, invertebrados abundantes no folhiço na área de estudo.

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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.

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The red-belly toads (Melanophryniscus) of southern South America secrete defensive alkaloids from dermal granular glands. To date, all information on Melanophryniscus alkaloids has been obtained by extraction from either skins or whole organisms; however, in other amphibians, tetrodotoxins, samandarines, and bufadienolides have been detected in both skin and other organs, which raise the possibility that lipophilic alkaloids may occur in non-integumentary tissues in Melanophryniscus as well. To test this hypothesis, we studied the distribution of alkaloids in the skin, skeletal muscle, liver, and mature oocytes of the red-belly toad M. simplex from three localities in southern Brazil. Gas chromatography and mass spectrometry of skin extracts from 11 individuals of M. simplex resulted in the detection of 47 alkaloids (including isomers), 9 unclassified and 38 from 12 known structural classes. Each alkaloid that was present in the skin of an individual was also present in the same relative proportion in that individual's skeletal muscle, liver, and oocytes. The most abundant and widely distributed alkaloids were the pumiliotoxins 251D, 267C, and 323A, 5,8-disubstituted indolizidines 207A and 223D, 5,6,8-trisubstituted indolizidine 231B, 3,5-disubstituted pyrrolizidines cis-223B and cis- and trans-251K, and izidine 211C. We report the first record of piperidines in Melanophryniscus, bringing the total number of alkaloid classes detected in this genus to 16. Alkaloid composition differed significantly among the three study sites. The functional significance of defensive chemicals in non-integumentary tissues is unknown.

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The generic identity of Odontophrynus moratoi is controversial since the original description due to the presence of intermediate morphological features between the genera Odontophrynus and Proceratophrys. Herein we performed molecular analyses of three genes (16S, cyt b and Rag-1) and recovered O. moratoi deeply imbedded inside a clade containing only Proceratophrys species, appearing as the sister group of Proceratophrys concavitympanum. Therefore, this study formally transfers the species O. moratoi to the genus Proceratophrys [Proceratophrys moratoi (Jim & Caramaschi 1980) comb. nov].