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Le résumé fourni par la source

Atalophlebiinae (Ephemeroptera, Leptophlebiidae) is a mayfly subfamily present in temperate and mountainous areas of South America and Australia. In the first chapter, we tested the hypothesis that both vicariance and dispersal related to the Gondwana breakup contributed to the origin, diversification and shaped the current distribution of this group. The hypothesis was tested using Bayesian phylogenetic trees, fossil based molecular dating and ancestral range estimation to reconstruct the biogeography of the lineages within this group. The results suggested an origin in the late Gondwana supercontinent for Atalophlebiinae after a vicariant event during the Cretaceous period (~108 mya). Subsequently, the lineage diversified into a scenario that refers to a Gondwanic corridor formed by South America, Antarctica and Australia. At the end of the separation of the continents that made up the Gondwanic corridor, speciation occurred within the current distribution areas. The diversity and current distribution of Atalophlebiinae were shaped by complex processes of vicariance, dispersal and speciation within the Gondwanic corridor during the second phase of the supercontinent breakup. In the second chapter, considering the complex landscape dynamic in the South America, we investigated the evolutionary history of Massartella Lestage, 1930 (Ephemeroptera, Leptophlebiidae, Atalophlebiinae). The genus is currently composed of five species endemic to this continent, adapted to cold environments and mountaintops in rainforests regions. Massartella has a disjunct distribution, occurring in mountains along the Atlantic Forest and in the Venezuelan Pantepui region, but being absent between these areas. Here we use Bayesian phylogenetic trees and fossil based molecular dating to reconstruct the evolutionary history of Massartella. Results recovered the genus, and the Pantepui and Atlantic Forest lineages as reciprocally monophyletic and suggest that the last common ancestor of these clades lived ca. 66 mya. The diversification processes started at the same time in both lineages, and the relationships among species of the Pantepui were recovered with high support. On the other hand, many relationships among taxonomic units in the Atlantic Forest mountains remained unclear. The reciprocal monophyly of clades indicates no subsequent connections between these areas, or the extinction of intermediates. Mountain biodiversity has the signature of both ancient and recent geoclimatic events and ecological processes, and climatic oscillations and cycles of marine incursions in the South America may have been responsible for isolating the Pantepui and Atlantic Forest lineages, as well as the speciation processes within these regions.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.