Name: Lopes S

Biodeserts supervisor: Brito JC Velo-Antón G

Title: Phylogenetics and hybridization assessment of Acanthodactylus scutellatus species group in North Africa

Institution: University of Porto

Status: Completed



Geological and paleoclimatic events are two main forces driving evolutionary processes in nature. These are poorly studied phenomena in North Africa, despite its great diversity of habitats, heterogeneous landscapes, and complex climatic and geological histories. Modern biodiversity patterns of the Sahara and the adjacent arid Sahel likely resulted from strong oscillations in climate and land-cover. Acanthodactylus scutellatus species group comprises important elements of the herpetofauna of arid ecosystems in North Africa, and well adapted to xeric conditions. Despite their remarkable diversity, the taxonomy within the complex is controversial, and with the exception of morphological data, little is known about these organisms. Observations of morphologically intermediate individuals in sympatry areas suggested hybridization between taxa. The present study aims to infer: 1) phylogenetic relationships within this group and identify major lineages; and 2) contemporary gene flow in a contact zone in Mauritania. Phylogenetic analyses were based on 466 specimens that were sequenced for both 12S and Cyt-b mitochondrial genes (756 total bp), and for the C-mos nuclear gene (513 total bp). A total of 208 individuals of the contact zone were genotyped for 15 microsatellites. Our results show that recovered major lineages do not match with current systematics, suggesting that taxonomy and systematics need revision. Genotyping analyses confirmed the historical lineages found in the studied contact zone and show absence of gene flow between them, with no hybrids detected despite the large sampling and broad geographic coverage. Lack of observed gene flow raises questions about the putative role of reproductive barriers and habitat selection in preventing admixture. Finally, the molecular tools applied allowed for insights on the species boundaries, relationships, history and diversity of this group, in addition to contributing to the knowledge about gene flow in the Sahara-Sahel.