Evidências morfológicas sustentam divergência evolutiva por alagamento sazonal de florestas na Amazônia
Spatial variation in morphological traits emerges in response to different selective pressures experienced when geographic range crosses heterogeneous habitats. In seasonally flooded habitats, animal adaptation is conspicuously demonstrated by the ability to swim among tops of hills that form...
| Autor principal: | COELHO, Ana Maria de Sousa |
|---|---|
| Grau: | Dissertação |
| Idioma: | pt_BR |
| Publicado em: |
Universidade Federal do Oeste do Pará
2021
|
| Assuntos: | |
| Acesso em linha: |
https://repositorio.ufopa.edu.br/jspui/handle/123456789/447 |
| Resumo: |
|---|
|
Spatial variation in morphological traits emerges in response to different selective
pressures experienced when geographic range crosses heterogeneous habitats. In
seasonally flooded habitats, animal adaptation is conspicuously demonstrated by the
ability to swim among tops of hills that form islands during flooding, or by the ability to
climb treetops above the water level. We have noticed that a widely distributed
terrestrial snake is forced to climb treetops in flooded várzea forests of eastern
Amazonia. We hypothesized that seasonal flooding of habitats selects morphotypes
by the levels of adaptation to use treetops as foraging and resting sites. We measured
seven morphological variables on 30 Bothrops atrox specimens from floodable várzea
forests, and 25 specimens from non-floodable terra firme forests. Models of
Discriminant Analysis of Principal Components (DAPC) separately by sex showed
morphological differences between these habitat types, which were independent of
geographic distance. We found longer tail and wider head in females and lower head
and slender body in males from the várzea forests sampled. Despite sex-biased
divergences in selected morphological traits, our results converge to natural selection
toward arboreality in seasonally flooded habitats. We ultimately show an intermediary
stage of evolutionary divergence, although speciation is not clear as in island-isolated
populations. |