Biogeography of Mesalina (Reptilia: Lacertidae), with special emphasis on the Mesalina adramitana group from Arabia and the Socotra Archipelago

The lacertid lizards of the genus Mesalina inhabit the arid regions of the Old World, from North Africa to NW India. Of the 19 recognized species within the genus, eleven occur in Arabia. In this study, we explore the genetic variability and phylogeographic patterns of the less studied M. adramitana group from southern Arabia and the Socotra Archipelago within the phylogenetic and biogeographic context of the entire genus. Our unprecedented sampling extends the distribution ranges of most Mesalina species and, for the first time, sequences of M. ayunensis are included in a phylogenetic analysis. We perform analyses of concatenated multilocus datasets and species trees, conduct species delimitation analyses, and estimate divergence times within a biogeographic framework. Additionally, we inferred the environmental suitability and identified dispersal corridors through which gene flow is enabled within M. adramitana. Our results show that the Socotra Archipelago was colonized approximately 7 Mya by a single oversea colonization from mainland Arabia. Then, an intra-archipelago dispersal event that occurred approximately 5 Mya resulted in the speciation between M. balfouri, endemic to Socotra, Samha and Darsa Islands, and M. kuri, endemic to Abd al Kuri Island. Similar to previous studies, we uncovered high levels of genetic diversity within the M. adramitana species-group, with two highly divergent lineages of M. adramitana living in allopatry and adapted to locally specific climatic conditions that necessitate further investigation.All efforts were made to minimize animal suffering. All collecting and export permits were issued by the Nature Conservation Department of the Ministry of Environment and Climate Affairs, Oman (Refs: 08/2005; 16/2008; 38/2010; 12/2011; 13/2013; 21/2013; 37/2014; 31/2016). This work was supported by the Ministerio de Economía y Competitividad, Spain (co-funded by FEDER) under grant numbers CGL2012-36970 and CGL2015-70390-P; Ministry of Environment and Climate Affairs under Grant number 22412027; Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya under grant number 2017-SGR-00991. MSR was funded by an FPI grant from the Ministerio de Economía y Competitividad, Spain (BES-2013-064248). JS was funded by the Czech Science Foundation (GACR, project number 18-15286Y) and the Ministry of Culture of the Czech Republic (DKRVO 2019–2023/6.VII.a, 00023272)