Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Phylogeography and species delimitation of the saharo-arabian genus mesalina (sauria : lacertidae) based on genetic markers

Φυλογεωγραφία και οριοθέτηση ειδών του σαχαρο-αραβικού γένους mesalina (sauria : lacertidae) με χρήση γενετικών δεικτών

Auteur : Kapli, Paschalia

Université de soutenance : University of Crete (UOC)

Grade : Doctor of Philosophy (PhD) 2014

Résumé

The area of the Middle East and North Africa constitute the “Saharo-Sindian” zoogeographical region that is characterized by the widest system of warm deserts globally. The periphery of the desert zone has been recognized at sites (e.g. African and Middle-eastern Mediterranean zone) as high biodiversity zone. However, our knowledge on the biodiversity of the main Saharo-Arabian region and of the historical processes that have shaped it, remains limited. The lack of knowledge could be primarily attributed to the practical difficulties in the access of the area as well as the methodological difficulty in reconstructing the historical biogeography in such dynamically changing areas. Understanding the biodiversity patterns in the widest desert system would eventually enhance both our understanding and the approaching methods in historical biogeography. Furthermore, such studies could provide important knowledge in the context of confronting and preventing desertification events. The main goal of the present study was to contribute to the understanding of historical processes that have shaped the fauna of the Saharo-Arabian region. Within that frame we conducted the systematic study of the lizard genus Mesalina Gray 1838, also known as the “desert runner” that is widely distributed in the study area. To achieve that, we retrieved both mitochondrial and nuclear DNA sequences, which were analysed with up to date phylogenetic and phylogeographic methods. For the de novo approach of the number of Mesalina species, we propose a new methodology that extends the application of the “Poisson Tree Process” and “Generalized Mixed Yule Coalescent” so that multiple genetic markers can be taken under account in the species estimation. According to the results, Mesalina originated in early Miocene (21-23 million years ago). The major splitting events of the genus are driven by the coupling effect of the dynamic tectonic movement of the Arabian Peninsula and the climatic oscillations that have occurred since the Miocene. The same historical processes seem to have been the driving force of other taxonomic groups while analogous patterns have been observed in the study of other desert systems, as in the case of Australia. Regarding the number of species of the genus, our results suggest that the number that was assumed according to morphology (14 species) is significantly smaller and statistically inferior compared to the number suggested by the newly proposed methodology (49 species). Thus, the results of the current studycorroborates the emerging hypothesis that the Saharo-Arabian region is characterised by many and geographically restricted species rather than few and widely distributed species, which is the current perception. Concluding, the findings of the present study contribute to our understanding of the main forces that have shaped the fauna of the Saharo-Arabian region and highlight Mesalina as a suitable organism for the systematic study of desert habitats.

Mots Clés : Historical biogeography ; Middle east ; North Africa ; Saharo-Arabian region ; Desert habitat ; Mesalina ; Lacertidae ; Phylogeny ; Species delimitation ; Multile genetic loci

Présentation de la thèse (National Archive of PhD)