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Universidade do Porto (2012)

Phylogeography of the scorpion genus Buthus in the Maghreb region

Diana de Oliveira Gomes Pedroso

Titre : Phylogeography of the scorpion genus Buthus in the Maghreb region

Auteur : Diana de Oliveira Gomes Pedroso

Université de soutenance : Universidade do Porto

Grade : Mestrado em Biodiversidade, Genética e Evolução 2012

Résumé
The genus Buthus is one of the most widespread scorpion genus in the Maghreb region, and even though several phylogenetic studies were recently performed upon it, the phylogenetic relationships within the genus are still complex and remain partially unsolved. In total, 59 specimens from several Buthus species were used in this work and their phylogenetic relationships investigated with different phylogenetic inference approaches as the Maximum Likelihood (ML) and Bayesian Inference (BI) methods, based on mitochondrial sequence data of three mitochondrial markers. This study was the first to include multiple mitochondrial markers in order to obtain further resolution within the genus The result of the phylogenetic analysis uncovered 5 well supported clades in the Maghreb region : three exclusive to Morocco, one with its distribution core in Morocco but also shared with Algeria and one last clade, unreported until now, from Tunisia. The final trees resulting from the ML and BI analysis do not present basal resolution and still the relationships between the clades lacked support. However, the support for each of the formed clade is high, holding significant levels of genetic diversity within the clade and between clades. The clades with its distribution centre in Morocco present higher genetic distances within each clade, especially the most widespread clade in Morocco (clade 3) in opposition to the single clade present in Tunisia, with the lowest pairwise genetic distance values. There seems to be a positive correlation between genetic distances between clades and geographical distances, which also may point towards a recent expansion of Buthus towards eastern region of the Maghreb, more precisely into Tunisia. This study corroborated the results from previous studies, like Sousa et al. (2012,) and found even more diversity within Buthus, for instance in Tunisia, which had never been studied in such detail before. The genetic distances among the clades also corroborate the theory that the centre of diversity of Buthus is in Morocco, more specifically in the Atlasmountains that can act a reservoir of diversity for Buthus due to its role as a refugia during the glaciations. The mountains can also act as a geographical barrier to gene flow, impeding it, and at the same time, favouring processes of speciation and endemism.

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