72 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

    Cytogenetic characterization of Aloysia virgata Ruiz and Pavan (Verbenaceae)

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    Since previous cytogenetic reports of Aloysia have only described the meiotic behavior and chromosomal number of some species, the aim of this work was to provide detailed cytogenetic description of Aloysia virgata that would contribute to the understanding of the taxonomical organization of the Verbenaceae. Aloysia virgata had a karyotype with 2n = 36 metacentric chromosomes, all with similar size. The large amount of heterochromatin seen after Giemsa staining was confirmed by C-banding. Four nucleolar organizer regions (NORs) were detected with an rDNA 45S probe in two homologous pairs and two sites of 5S rDNA located on one chromosomal pair were detected by fluorescence in situ hybridization. The interphase nucleus was classified as semi-reticulate. Meiotic analysis showed a normal chromosomal behavior, with 18 bivalents in some parts of prophase I and in metaphase I. The number of chromosomes, NORs and 5S rDNA segments did not exclude a possible polyploid origin.O gênero Aloysia reúne aproximadamente 30 espécies, porém sua circunscrição tem sido motivo de controvérsia. São poucos os estudos citogenéticos para o gênero, relatando apenas o número e o comportamento cromossômico. O presente trabalho teve como objetivo, identificar os caracteres citogenéticos de Aloysia virgata da flora brasileira que possam ser utilizados para um melhor entendimento e caracterização dos aspectos citogenéticos da família Verbenaceae, que possam contribuir para a organização taxonômica do grupo. Aloysia virgata apresentou cariótipo com 2n = 36 pequenos cromossomos, todos com o mesmo tamanho. Grande quantidade de heterocromatina foi observada com Giemsa e confirmada pela técnica de banda C. Foram detectadas quatro regiões organizadoras de nucléolo (NORs) e dois sítios de rDNA 5S pela técnica de hibridação in situ fluorescente (FISH). O núcleo interfásico foi classificado como semireticulado. Foi realizada a caracterização meiótica, na qual os cromossomos apresentaram comportamento normal, com a presença de 18 bivalentes na prófase I e na metáfase I. O número de cromossomos, de NORs e de segmentos de DNAr 5S não excluem uma possível origem poliplóide.893899Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Sperm Ultrastructure Of Mytella (bivalvia) Populations From Distinct Habitats Along The Northern Coast Of São Paulo State, Brazil.

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    Ultrastructural analyses of bivalve spermatozoa are relevant in studies that aim to identify taxonomic traits for the purposes of discriminating species and conducting phylogenetic studies. In the present work, spermatozoa of mussel specimens of the genus Mytella, collected from two populations living in distinct habitats, were examined by electron microscopy. The objective was to identify sperm ultrastructural taxonomic traits that could be used to differentiate Mytella species. The specimens were from populations that live in intertidal zones on the southeast coast of Brazil, either buried in muddy-sand sediment or anchored to rocky substrates. The acrosomal vesicle was conical and long, the axial rod extended from the nucleus to the acrosome, the nucleus was an oblate spheroid with a condensed chromatin, the intermediate portion contained mitochondria encircling a pair of centrioles, and there was a single flagellum. The sperm was of a primitive type. The spermatozoon ultrastructure did not distinguish the specimens buried in muddy-sand sediment from those anchored to rocky substrates. The data suggest that the specimens analyzed, despite living in distinct habitats, belong to the same species, which conchological analyses identified as M. charruana. The presence of an axial rod in their sperm cells supports the inclusion of M. charruana in the subfamily Mytilinae.34103-1

    Chromosomal analysis of Physalaemus kroyeriAnd Physalaemus cicada(Anura, Leptodactylidae)

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    CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOAll the species of Physalaemus Fitzinger, 1826 karyotyped up until now have been classified as 2n = 22. The species of the P. cuvieri group analyzed by C-banding present a block of heterochromatin in the interstitial region of the short arm of pair 5. Physalaemus cicada Bokermann, 1966 has been considered to be a member of the P. cuvieri species group, although its interspecific phylogenetic relationships remain unknown. The PcP190 satellite DNA has been mapped on the chromosomes of most of the species of the P. cuvieri group. For two species, P. cicada and P. kroyeri (Reinhardt & Lutken, 1862), however, only the chromosome number and morphology are known. Given this, the objective of the present study was to analyze the chromosomes of P. cicada and P. kroyeri, primarily by C-banding and PcP190 mapping. The results indicate that P. kroyeri and P. cicada have similar karyotypes, which were typical of Physalaemus. In both species, the NORs are located on the long arm of pair 8, and the C-banding indicated that, among other features, P. kroyeri has the interstitial band on chromosome 5, which is however absent in P. cicada. Even so, a number of telomeric bands were observed in P. cicada. The mapping of the PcP190 satellite DNA highlighted areas of the centromeric region of the chromosomes of pair 1 in both species, although in P. kroyeri, heteromorphism was also observed in pair 3. The cytogenetic evidence does not support the inclusion of P. cicada in the P. cuvieri group. In the case of P. kroyeri, the interstitial band on pair 5 is consistent with the existence of a cytogenetic synapomorphy in the P. cuvieri species group.All the species ofPhysalaemusFitzinger, 1826 karyotyped up until now have been classified as 2n = 22. The species of theP. cuvierigroup analyzed by C-banding present a block of heterochromatin in the interstitial region of the short arm of pair 5.Physalae102311323CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informação2010/11300-7620163/2008-

    Bivalves of the São Sebastião channel, north coast of the São Paulo State, Brazil

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOThe north coast of the São Paulo State, Brazil, presents great bivalve diversity, but knowledge about these organisms, especially species living subtidally, remains scarce. Based on collections made between 2010 and 2012, the present work provides a species list of bivalves inhabiting the intertidal and subtidal zones of the São Sebastião Channel. Altogether, 388 living specimens were collected, belonging to 52 species of 34 genera, grouped in 18 families. Tellinidae, Veneridae, Semelidae, Ungulinidae, Mactridae, Solecurtidae, Corbulidae, Cardiidae, Lucinidae, Cooperellidae, Nuculidae, Psammobiidae, Donacidae, Solenidae, Periplomatidae, Thraciidae and Arcidae were the most representative families in this collection. Among the identified species, Caryocorbula caribaea, Codakia pectinella and Diplodonta punctata were intertidally abundant, while Macoma uruguayensis and Pitar fulminata were subtidally abundant. © 2014 Check List and Authors.The north coast of the São Paulo State, Brazil, presents great bivalve diversity, but knowledge about these organisms, especially species living subtidally, remains scarce. Based on collections made between 2010 and 2012, the present work provides a speci10197105FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informaçãosem informaçã

    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

    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

    Comparative Cytogenetic Analysis Of Some Species Of The Dendropsophus Microcephalus Group (anura, Hylidae) In The Light Of Phylogenetic Inferences.

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    Dendropsophus is a monophyletic anuran genus with a diploid number of 30 chromosomes as an important synapomorphy. However, the internal phylogenetic relationships of this genus are poorly understood. Interestingly, an intriguing interspecific variation in the telocentric chromosome number has been useful in species identification. To address certain uncertainties related to one of the species groups of Dendropsophus, the D. microcephalus group, we carried out a cytogenetic analysis combined with phylogenetic inferences based on mitochondrial sequences, which aimed to aid in the analysis of chromosomal characters. Populations of Dendropsophus nanus, Dendropsophus walfordi, Dendropsophus sanborni, Dendropsophus jimi and Dendropsophus elianeae, ranging from the extreme south to the north of Brazil, were cytogenetically compared. A mitochondrial region of the ribosomal 12S gene from these populations, as well as from 30 other species of Dendropsophus, was used for the phylogenetic inferences. Phylogenetic relationships were inferred using maximum parsimony and Bayesian analyses. The species D. nanus and D. walfordi exhibited identical karyotypes (2n = 30; FN = 52), with four pairs of telocentric chromosomes and a NOR located on metacentric chromosome pair 13. In all of the phylogenetic hypotheses, the paraphyly of D. nanus and D. walfordi was inferred. D. sanborni from Botucatu-SP and Torres-RS showed the same karyotype as D. jimi, with 5 pairs of telocentric chromosomes (2n = 30; FN = 50) and a terminal NOR in the long arm of the telocentric chromosome pair 12. Despite their karyotypic similarity, these species were not found to compose a monophyletic group. Finally, the phylogenetic and cytogenetic analyses did not cluster the specimens of D. elianeae according to their geographical occurrence or recognized morphotypes. We suggest that a taxonomic revision of the taxa D. nanus and D. walfordi is quite necessary. We also observe that the number of telocentric chromosomes is useful to distinguish among valid species in some cases, although it is unchanged in species that are not necessarily closely related phylogenetically. Therefore, inferences based on this chromosomal character must be made with caution; a proper evolutionary analysis of the karyotypic variation in Dendropsophus depends on further characterization of the telocentric chromosomes found in this group.145

    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-
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