Name: Drienne Messa Faria
Type: PhD thesis
Publication date: 09/07/2018
Advisor:
Name |
Role |
|---|---|
| Ana Paula Cazerta Farro | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Ana Lucia Cypriano de Souza | External Examiner * |
| Ana Paula Cazerta Farro | Advisor * |
| Andreia Barcelos Passos Lima Gontijo | External Alternate * |
| Flávio José de Lima Silva | External Examiner * |
| Haydée Andrade Cunha | External Examiner * |
| Maurício Hostim Silva | Internal Alternate * |
| Sarah Maria Vargas | Internal Examiner * |
Summary: ABSTRACT
Stenella is a genus of the Delphindae family composed of five species of cricumtropical distribution, with the exception of S. clymene and S. frontalis, endemic to the Atlantic Ocean. This genus is paraphyletic, whose taxonomic classification and phylogenetic are considered confusing and possibly reflect the recent divergence (about three million years) between their species and hybridization events. The aim of this thesis was to test the hypothesis of hybridization among species of the genus Stenella and to evaluate the genetic diversity and differentiation of one species, Stenella longirostris. Using mitochondrial molecular markers, strong evidence of hybridization between S. clymene and S. coeruleoalba species has been demonstrated, which reinforces that this process may be one of those responsible for the complex taxonomy of the group. No signs of mixing were found between S. longirostris and other species, and monophyly clades were observed for this species. It was shown that individuals of S. longirostris from the Fernando de Noronha Archipelago (islands-associated) compose a population with low genetic diversity and high genetic isolation from other populations of the world. Besides this population, the presence of another population formed by individuals sampled along the Brazilian coast (non-associated-islands) was displayed. Genetic structuring in three populations of S. longirostris was demsontrated throughout the world, one composed of the individuals from the Pacific Ocean and another by the Atlantic Ocean + Indian Ocean dolphins, which shows that there is a genetic mixture between populations that are geographically distant from different ocean basins.
Key-words: Delphinidae, Delphinidae, introgression, genetic structuring, genetic variability, Stenella longirostris.
