The outstanding biodiversity of the Guiana Shield has raised many questions about its origins and evolution. Frogs of the genera Adelastes, Otophryne and Synapturanus form an ancient lineage distributed mostly across this region. These genera display strikingly disparate morphologies and life-history traits. Notably, Synapturanus is conspicuously adapted to fossoriality and is the only genus within this group to have dispersed further into Amazonia. Moreover, morphological differences among Synapturanus species suggest different degrees of fossoriality that might be linked to their biogeographical history. Through integrative analysis of genetic, morphometric and acoustic data, we delimited 25 species in this clade, representing a fourfold increase. We found that the entire clade started to diversify ~55 Mya and Synapturanus ~30 Mya. Members of this genus probably dispersed three times out of the Guiana Shield both before and after the Pebas system, a wetland ecosystem occupying most of Western Amazonia during the Miocene. Using a three-dimensional osteological dataset, we characterized a high morphological disparity across the three genera. Within Synapturanus, we further characterized distinct phenotypes that emerged concomitantly with dispersals during the Miocene and possibly represent adaptations to different habitats, such as soils with different physical properties.

Summary Specimens of 4 marine fish species 3 from genus Trachinotus, T. carolinus, T. falcatus, T. goodei, and 1 from genus Selene, S. vomer belonging to the family Carangidae (Perciformes) were analyzed. All the specimens analyzed inhabit the South/Southeast coast of Brazil, and were sampled from the locality São Sebastião, SP. The 4 species presented 2nϭ48 chromosomes, being the chromosome formula for Selene vomer 46Aϩ2ST, T. carolinus 8MSMϩ40A, T. falcatus 38Aϩ10MSM and T. goodei 4MSMϩ44A chromosomes. The 4 species presented 1 pair of NORs. Small blocks of heterochromatin were found in these 4 species. The karyotypic characteristics of these species were discussed in comparison with other species and populations of Perciformes already analysed. The cytogenetic analysis of fish species is well advanced for the freshwater fish that inhabit Brazilian rivers, and a growing number of species is being analyzed, so that an expressive amount of information is currently available for this group. This fact results in a great amount of data about the evolutionary relationship of species and genera of freshwater species. In some cases, the cytogenetic information associated with molecular markers was used in the description of new species (Albert et al. 1999). When compared with the amount of data available for freshwater fish species from the Neotropical region, the cytogenetic information about marine fishes from the Brazilian coast is still incipient. Key wordsIn a preliminary analysis of Trachinotus carried out by Zeinad and Almeida-Toledo (1994) the chromosome number and morphology for T. carolinus and T. falcatus were established. Pauls et al. (1998) and Netto et al. (1998) described respectively the karyotype of T. goodei and the chromosome number and formula of Selene volmer. All these analysis were performed using conventional Giemsa staining. However, no data about the C-banding pattern of heterochromatin or nucleolus or-

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is caused by a respiratory virus with a wide range of manifestations, varying from asymptomatic to fatal cases, with a generally short outcome. However, some individuals present long-term viral shedding. We monitored 38 individuals who were mildly affected by the SARS-CoV-2 infection. Out of the total studied population, three (7.9%) showed atypical events regarding the duration of positivity for viral RNA detection. In one of these atypical cases, a previously HIV-positive male patient presented a SARS-CoV-2 RNA shedding and subgenomic RNA (sgRNA) detected from the upper respiratory tract, respectively, for 232 and 224 days after the onset of the symptoms. The SARS-CoV-2 B.1.1.28 lineage, one of the most prevalent in Brazil in 2020, was identified in this patient in three serial samples. Interestingly, the genomic analyses performed throughout the infectious process showed an increase in the genetic diversity of the B.1.1.28 lineage within the host itself, with viral clearance occurring naturally, without any intervention measures to control the infection. Contrasting widely spread current knowledge, our results indicate that potentially infectious SARS-CoV-2 virus might be shed by much longer periods by some infected patients. This data call attention to better adapted non-pharmacological measures and clinical discharge of patients aiming at preventing the spread of SARS-CoV-2 to the population.

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