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Universidade do Porto (2014)

Molecular phylogeny of three Moroccan Chalcides : the C. manueli , C. montanus and C. polylepis clade

Isabel Sofia Fernandes Pinho Tavares

Titre : Molecular phylogeny of three Moroccan Chalcides : the C. manueli , C. montanus and C. polylepis clade

Auteur : Isabel Sofia Fernandes Pinho Tavares

Université de soutenance : Universidade do Porto

Grade : MSc in Biodiversity, Genetics and Evolution 2014

The Mediterranean Basin, in which Morocco is included, is one of the Global Biodiversity Hotspots. Specific characteristics of Morocco, such as the climate and topography, allow high levels of richness and endemism, particularly in herpetofauna. The skink genus Chalcides comprises 28 species, many of them present in Morocco and surrounding areas, and these are characterized by having elongated bodies and reduced limbs. The taxonomy of Chalcides has been revised numerous times, but many species remain difficult to identify in the field, and it seems likely that the current taxonomy still does not fully reflect their evolutionary history. A previous study regarding the phylogeny for the entire genus based on mtDNA identified four major groups. In this work we investigate the molecular phylogenetic relationships of the three taxa within the “Western clade” : C. manueli, C. polylepis and C. montanus. Mitochondrial and nuclear genes of most of the known populations of these three species were analyzed. Our results indicate that current taxonomy does not reflect genetic diversity. None of the three currently recognized species were monophyletic. This was not due to mtDNA introgression, as had been previously hypothesised, as nuclear markers were also discordant with current taxonomy. Levels of genetic diversity were quite high, but not as high as typically seen between three different species. Given that the morphological characters used to distinguish the species, primarily size and colour pattern differences, are known to be prone to homoplasy, we propose that the three species are better refered to as a single, albeit quite variable species, C. polylepis. This has important conservation implications, as C. manueli is currently listed on the IUCN red list as vulnerable. Further studies are still needed to improve knowledge on the genus. A more efficient sampling effort should be taken into account as well as the detailed assessments on the area of possible sympatry between the three morphological forms of Chalcides polylepis. A more thorough study of morphological characters could also turn out to be important in species delimitation in other members of the genus.

Mots clés  : Chalcides, phylogenetic analyses, phylogeography, haplotype networks, mtDNA, MC1R, ACM4


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