Anurans of the genus Brachycephalus are among the smallest vertebrates in the world, due to an extreme process of miniaturization. As an example of this process, Brachycephalus species show loss of fingers, loss of the eardrum and middle ear, bone fusions, and the presence of paravertebral plates and parotic plaque. However, no studies addressing the consequences of miniaturization on internal organs, such as the lungs and heart, are currently available.
View Article and Find Full Text PDFSynchrotron radiation phase-contrast microtomography is sensitive to low attenuating tissues, giving an alternative visualisation of the sample and being useful for investigating microstructure inside biological specimens without staining them with a contrast medium. The phase-contrast technique has been widely used in the scientific community, as it is a technique associated with radiography and microscopy and able to enhance contrast in soft tissues, specifically at the edges, showing details that could not be seen by the absorption technique. This work aims to show the ability of synchrotron-based phase-contrast microtomography for the visualisation of soft tissues and hard internal structures of millimetre-sized biological organisms.
View Article and Find Full Text PDFThe Amazonia and the Atlantic Forest, separated by the diagonal of open formations, are two ecoregions that comprise the most diverse tropical forests in the world. The Sphaenorhynchini tribe is among the few tribes of anurans that occur in both rainforests, and their historical biogeographic have never been proposed. In this study, we infer a dated phylogeny for the species of the Sphaenorhynchini and we reconstructed the biogeographic history describing the diversification chronology, and possible patterns of dispersion and vicariance, providing information about how orogeny, forest dynamics and allopatric speciation affected their evolution in South America.
View Article and Find Full Text PDFThe aim of this work is to present the thesis "On the Ontogenetic Evolution of the Human Embryo in its Relations with Phylogenesis," by Affonso Regulo de Oliveira Fausto (1866-1930), published in Brazil in 1890. To our knowledge, it was one of the first Brazilian academic works focused specifically on evolution. It was also the first doctoral thesis that addressed the topic of recapitulation in order to analyze what was then called the progressive evolution of the human species in tandem with the embryological development of the individuals that would constitute the Brazilian "type.
View Article and Find Full Text PDFBased on concordant differences in male advertisement call, tadpole morphology, and absence of haplotype sharing in the barcoding 16S mitochondrial DNA, we describe here a new species of spotted leaf frog of the genus from Atlantic Forest, State of Rio de Janeiro, Southeast Brazil. The new species is most similar to (type locality) and (type locality). It differs from these species by the size of the calcar, moderate-sized body (snout-vent length 30.
View Article and Find Full Text PDFIsland Rule postulated that individuals on islands tend to dwarfism when individuals from mainland populations are large and to gigantism when mainland populations present small individuals. There has been much discussion about this rule, but only few studies were carried out aiming to reveal this pattern for anurans. Our study focused on measuring the size of individuals on islands and to find a possible pattern of size modification for insular anurans.
View Article and Find Full Text PDFThe literature regarding the type series of Scinax perpusillus (Lutz & Lutz, 1939) presents two distinct numbers for the holotype. In 1973, thirty-four years after the description, Bertha Lutz associated numbers to the type series. This numbering has been followed by subsequent reviewers of Scinax ever since, with exception of Peixoto (1987) who assigned another number to the holotype.
View Article and Find Full Text PDFSince Scinax arduous description, many other populations belonging to the Scinax perpusillus group have been recorded for the States of Espírito Santo and Minas Gerais, Southeastern Brazil. Both in collections and publications most of these new specimens are identified as S. arduous, Scinax cf.
View Article and Find Full Text PDFThe largest anuran diversity belongs to the Neobatrachia, which harbor more than five thousand extant species. Here, we propose a new hypothesis for the historical aspects of the neobatrachian evolution with a formal biogeographical analysis. We selected 12 genes for 144 neobatrachian genera and four archaeobatrachian outgroups and performed a phylogenetic analysis using a maximum likelihood algorithm with the rapid bootstrap test.
View Article and Find Full Text PDFThe hylid frog Scinax perpusillus species group comprises 13 species that share, in addition to a few morphological features, reproduction that occurs exclusively associated with bromeliads. Among the species in the group, Scinax v-signatus (Lutz, 1968) is one of the few with a relatively large geographic distribution, occurring in association with bromeliads growing on granitic outcrops above 800 m along the Serra dos Órgãos (a local designation of Serra do Mar) in the Atlantic forest, State of Rio de Janeiro. Here we demonstrate that previous assessment of the distribution of this species was overestimated, and reevaluate the available data on its occurrence.
View Article and Find Full Text PDFThe life cycle and behavior of Amblyomma rotundatum were evaluated under laboratory conditions. The experiment started with four engorged females collected from toads (Rhinella schneideri) naturally infested at the Pirapitinga Ecological Station in the state of Minas Gerais, Brazil. Developmental periods of free-living stages were assessed in an incubator at 27 ± 1 °C, >80 % RH and darkness.
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