122 research outputs found

    Cytogenetics and sperm ultrastructure of Atelopus spumarius (Anura, Bufonidae) from the Brazilian Amazon

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    The current taxonomy of most Atelopus species is based on morphological and color data only. Recent studies suggest that A. spumarius may represent a species complex assigned under the same name. Karyotypic data and description of sperm ultrastructure for 13 specimens of A. spumarius are presented here for the first time. A chromosomal analysis revealed 2n = 22 chromosomes, with centromeric heterochromatin in all pairs and a nucleolar organizer region (NOR) on the telomere of pair 7. The sperm was of the bufonoid type, presenting a filiform nucleus covered by an acrosomal complex and a mitochondrial collar in the neck region. The tail was composed of an axoneme, an undulating membrane and an axial rod. A karyotype analysis of A. spumarius showed the same chromosome number and similar chromosomal morphology as described for congeneric species, with slight differences probably resulting from pericentric inversions. The NOR location (on pair 7) was the same as that observed for species belonging to the genus Rhinella. The spermatological findings indicate a close relationship between Atelopus and the bufonoid lineage. The present data are useful for reference in future studies to determine whether more than one species are assigned to A. spumarius.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual de Campinas Instituto de Biologia Departamento de Biologia Estrutural e FuncionalUniversidade Estadual do Sudoeste da Bahia Departamento de Ciências BiológicasUniversidade Federal de São Paulo (UNIFESP) Departamento de BiociênciasInstituto Nacional de Pesquisas da Amazônia Coordenadoria de Pesquisa em EcologiaUNIFESP, Depto. de BiociênciasSciEL

    The tadpole of Osteocephalus cabrerai (Anura: Hylidae) from central Amazonia, Brazil

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    Neste estudo, descrevemos o girino de Osteocephalus cabrerai utilizando 37 indivíduos em oito diferentes estágios de desenvolvimento. Também fornecemos informações sobre o sítio e período de reprodução da espécie e comparamos os girinos com outros já descritos do mesmo gênero. O girino de O. cabrerai (Estádio 39) é caracterizado por um corpo ovóide alongado em vista lateral e oval em vista dorsal. O focinho é arredondado, as narinas são ovais e os olhos são laterais. A cauda representa 67% do comprimento total. O girino tem espiráculo único, sinistro e ventrolateral. O tubo anal é destro, curto e aderido à nadadeira ventral. O disco oral é anteroventral, com papilas marginais e submarginais; a fórmula dentária é 2(2)/6(1). Os girinos são encontrados em riachos dentro de floresta de terra firme.Herein we describe the tadpoles of Osteocephalus cabrerai based on 37 individuals of eight different development stages. We provide comments on spawning sites and breeding period, and compare these tadpoles with those of congeners. The tadpole of O. cabrerai (Stage 39) is characterized by an ovoid body, elongated in lateral view and oval in dorsal view. The snout is rounded, the nostrils oval and the eyes lateral. The tail length is 67% of total length. The larva has a single, sinistral spiracle that is ventrolateral in position. The short vent tube is dextral and attached to the ventral fin. The anteroventral oral disc has marginal and submarginal papillae and a labial tooth row formula 2(2)/6(1). Tadpoles inhabit streams in terra firme forest

    Cytogenetic Analysis Of Four Central Amazonian Species Of Colostethus (anura - Dendrobatidae) With A Diploid Complement Of 22 Chromosomes.

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    Colostethus marchesianus from the type locality and three related species had 2n = 22 chromosomes, which differed from most other Colostethus species that have 2n = 24 chromosomes. The species analyzed were morphologically similar and showed a conservative karyotype, although they could be distinguished from each other by their C-banding pattern. Additional NOR sites, heteromorphism in NOR size and heterochromatin, and an additional rDNA site detected by FISH, were observed. These data suggest that chromosomal rearrangements and hetrochromatin-related events may have contributed to the karyotype differentiation of these Colostethus.139189-9

    Evaluation Of The Taxonomic Status Of Populations Assigned To Phyllomedusa Hypochondrialis (anura, Hylidae, Phyllomedusinae) Based On Molecular, Chromosomal, And Morphological Approach.

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    The taxonomic and phylogenetic relationships of the genus Phyllomedusa have been amply discussed. The marked morphological similarities among some species hamper the reliable identification of specimens and may often lead to their incorrect taxonomic classification on the sole basis of morphological traits. Phenotypic variation was observed among populations assigned to either P. azurea or P. hypochondrialis. In order to evaluate whether the variation observed in populations assigned to P. hypochondrialis is related to that in genotypes, a cytogenetic analysis was combined with phylogenetic inferences based on mitochondrial and nuclear sequences. The inter- and intra-population variation in the external morphology observed among the specimens analyzed in the present study do not reflect the phylogenetic relationships among populations. A monophyletic clade was recovered, grouping all the specimens identified as P. hypochondrialis and specimens assigned P. azurea from Minas Gerais state. This clade is characterized by conserved chromosomal morphology and a common C-banding pattern. Extensive variation in the nucleolar organizing region (NOR) was observed among populations, with four distinct NOR positions being recognized in the karyotypes. Intra-population polymorphism of the additional rDNA clusters observed in specimens from Barreiras, Bahia state, also highlights the marked genomic instability of the rDNA in the genome of this group. Based on the topology obtained in the phylogenetic analyses, the re-evaluation of the taxonomic status of the specimens from the southernmost population known in Brazil is recommended. The results of this study support the need for a thorough revision of the phenotypic features used to discriminate P. azurea and P. hypochondrialis. The phylogenetic data presented here also contribute to an extension of the geographic range of P. hypochondrialis, which is known to occur in the Amazon basin and neighboring areas of the Cerrado savanna, where it may be sympatric with P. azurea, within contact zones. The misidentification of specimens may have led to inconsistencies in the original definition of the geographic range of P. azurea. The variability observed in the NOR of P. hypochondrialis reinforces the conclusion that these sites represent hotspots of rearrangement. Intraspecific variation in the location of these sites is the result of constant rearrangements that are not detected by classical cytogenetic methods or are traits of an ancestral, polymorphic karyotype, which would not be phylogenetically informative for this group.147

    Dung Beetles and Long-term Habitat Fragmentation in Alter do Chão, Amazônia, Brazil

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    Made available in DSpace on 2016-02-04T19:48:14Z (GMT). No. of bitstreams: 5 dung.pdf: 445276 bytes, checksum: 84cbf9f9f94fa4a374aa0f82bc416791 (MD5) license_url: 49 bytes, checksum: 4afdbb8c545fd630ea7db775da747b2f (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license.txt: 120 bytes, checksum: c5ec8a89f6203da160ca192812b3f657 (MD5) Previous issue date: 2008

    Comparative cytogenetic analysis of some species of the Dendropsophus microcephalus group (Anura, Hylidae) in the light of phylogenetic inferences

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    Made available in DSpace on 2016-02-04T19:48:03Z (GMT). No. of bitstreams: 5 comparative.pdf: 1738136 bytes, checksum: 90eb23cc0344c7737b0207b774a6360c (MD5) license_url: 49 bytes, checksum: 4afdbb8c545fd630ea7db775da747b2f (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license.txt: 120 bytes, checksum: c5ec8a89f6203da160ca192812b3f657 (MD5) Previous issue date: 20131

    Comparative cytogenetics of nine populations of the Rhinella genus (Anura, Bufonidae) with a highlight on their conservative karyotype

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    The genus Rhinella is one of the most diverse groups of bufonid toads, currently composed by 93 valid species and naturally distributed throughout different Neotropical ecoregions. Here, we analyze nine Brazilian populations of toads representing species of the Rhinella margaritifera and Rhinella marina groups. These new data include the first description of the R. hoogmoedi and R. proboscidae karyotypes, as well as other taxonomically unresolved forms. Chromosomal analysis of the populations revealed pronounced chromosomal uniformity (2n=22), including the diploid number and chromosomal morphology. Three different NOR-bearing chromosomes were identified: in the subterminal region of pair 10q in R. hoogmoedi, Rhinella sp. 1 and Rhinella sp. 2, in subterminal region of 7p in R. proboscidae and Rhinella cf. margaritifera while in R. henseli and R. icterica was detected in interstitial region of 7p. Karyotypic uniformity of the genus permits the inference of interspecific chromosome homologies and evolutionary changes in the NOR-bearing chromosome may represent an informative character in species group level. The review of the cytogenetic data of the Rhinella species together with the new karyotypes reported here contributes to the understanding of the chromosomal evolution of these toads, which karyotypes are highly conserved despite the ample distribution of many forms422445451CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP312286/2015-5sem informação2016/07717-

    Unusual intra-individual karyotypical variation and evidence of cryptic species in Amazonian populations of Pristimantis (Anura, Terrarana)

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    We report a cytogenetic analysis of three Pristimantis fenestratus frog populations of the Amazon region in Brazil. The specimens were sampled in Borba and Manaus, Amazonas State, and in Rio Branco, Acre State. They were analyzed using Giemsa, silver staining, C-banding and FISH with rDNA probes. The karyotypes of the three populations revealed 2n = 34 chromosomes, but they differed in the number and position of Ag-NORs and in the heterochromatin pattern as well. The NOR was located on the pairs 05 and 07 in the Rio Branco specimens, pair 10 in the Manaus specimens, and pair 1 in the Borba specimens. A small C-band was detected on the telomeric region of the pair 05 in the Borba population, while in the Manaus there was a heterochromatic block adjacent to the centromere of pair 9. An unusual intra-individual variation of chromosome number was observed in metaphases of Rio Branco specimens, comprising fundamental numbers of 33, 34 and 35. Additionally, interchromosome thread connections were detected between telomere - telomere, centromere - telomere and centromere - centromere regions, and among chromosomal heterochromatin-rich sites. The NOR sites were also involved in those connections. We hypothesize that this variation is due to chromosome missegregation during mitosis. The inter- and intraindividual variation in chromosome number suggests chromosomal instability in P. fenestratus, which has not been detected in any other anuran group. Since Borba is the type-locality of P. fenestratus, a taxonomic review of the Manaus and Rio Branco populations should be done, as indicated by the cytogenetic evidence that they could be new species of Pristimantis. © 2009 The Authors

    A new pale-ventered nurse frog (Aromobatidae: Allobates) from southwestern Brazilian Amazonia

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    Abstract We use integrative taxonomy to formally describe a candidate species of nurse frog of the genus Allobates from southwestern Brazilian Amazonia. The new species nests within a clade that has been defined historically as A. gasconi, but it has an 8.8–11.0% genetic distance for 16S to samples from the type locality of A. gasconi. The new species differs from congeners mainly by males having a translucent white throat and vocal sac; advertisement calls with a duration of 42–60 ms, two notes separated by an inter-note interval of 8–23 ms, and a dominant frequency of 4,953–6,331 Hz; and exotrophic tadpoles with 2 pyramidal papillae on each end of the upper lip and 10–13 pyramidal and cylindrical papillae surrounding the lower lip. Phylogenetic analyses based on mitochondrial DNA suggest that A. gasconi sensu lato as defined previously represents a complex of as many as seven species, corroborating studies that have shown high levels of cryptic diversity within Allobates
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