Desvendando o desconhecido: diversidade, distribuição e diversificação de anuros no interflúvio Purus-Madeira
The Purus-Madeira Interfluve (PMI) represents one of the less known areas of Brazilian Amazonia. Despite it is extremely threatened by anthropic actions, the knowledge about the taxonomic identity of anurans inhabiting the PMI and the processes driving their distribution and diversification are p...
| Autor principal: | Silva Junior , Miquéias Ferrão da |
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| Grau: | Tese |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/12271 http://lattes.cnpq.br/5370319983922485 |
| Resumo: |
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The Purus-Madeira Interfluve (PMI) represents one of the less known areas of Brazilian
Amazonia. Despite it is extremely threatened by anthropic actions, the knowledge about
the taxonomic identity of anurans inhabiting the PMI and the processes driving their
distribution and diversification are poorly known. The main goals of this thesis were to
investigate the hidden diversity in anurans, provide bases to ecological and conservation
studies through the description of new taxa, and illuminating the role of environment on
species distribution and diversification along the PMI. In the first chapter, we integrated
morphology, bioacoustics, and genetics to explore if there was hidden diversity in anurans
of the genus Scinax along 1000 km of landscapes in the PMI. Integrative analyses
revealed that approximately 82% of the regional richness in Scinax was unknown to
science. Results highlighted how much the PMI faunal diversity is poorly known and its
need for conservation actions. In the second chapter, we formally described the most
widely distributed new species of Scinax in the PMI and tested if its geographic
distribution and abundance were driven by environmental variables. Scinax ruberoculatus
is easily distinguished from its congeners through morphological (adults and tadpoles)
and bioacoustical characters. Differing from the predicted for aquatic breeding anurans,
its distribution and abundance along the PMI is positively driven by silt content and not
by forest structure (tree density). It is suggested that this habitat-association is driven by
the species’ reproductive needs once reproductive sites in silty soils may be less
ephemeral, favouring the survival of tadpoles of the new species. In the third chapter,
we described a new species of Scinax with distribution apparently restricted to the central
portion of PMI. Despite it is close related to species of the Scinax wandae clade, the new
species is distinguished from all other Amazonian Scinax through morphology and
colouration, as well as by the advertisement call. The species’ habitat is deeply threatened
by the anthropic pressure due to property speculation as result of the reconstruction of the
BR-319 highway. In the fourth chapter, Scinax onca was described based in specimens
from two distinct populations in the PMI, one living in dense forests and the other in open
forests. Phylogenetic analyses of the first chapter recovered these populations as
reciprocally monophyletic. Differences in colour pattern, as well as its evolutionary
relationship, led us to hypothesize that environmental gradients of the PMI may be
responsible by observed differentiation in these populations. However, data collected
along its distribution are necessary to elucidate if the observed differentiation is really influenced by environmental gradients. In the fifth chapter, we used a diminutive
terrestrial anuran (Phyzelaphryne miriamae) and widely distributed in the PMI as a model
to test if the gene flow along the landscape can be explained by the ecological gradient
hypothesis. For the first time in Amazonia, genomic landscape analyses and thousands of
single nucleotide polymorphisms (SNPs) were used to test this hypothesis. Genetic
structure analyses estimated five ancestral populations in P. miriamae. Results indicated
that the effect of environmental gradients on gene flow of the target species was
pronounced. After accounting the effect of geographic distance, the explanation of
environmental variables ranges from 24.7 % (silt content) to 30.2% (temperature
seasonality). On the other hand, geographic distance explained just 2.3–3.7% of the gene
flow. Although there is an effect of geographic distance on gene flow in P. miriamae, it
is restricted to short and long distances, being null in moderated distances. |