Conquering the Sahara and Arabian deserts: systematics and biogeography of Stenodactylus geckos (Reptilia: Gekkonidae)

Abstract

BackgroundThe evolutionary history of the biota of North Africa and Arabia is inextricably tied to the complex geological and climatic evolution that gave rise to the prevalent deserts of these areas. Reptiles constitute an exemplary group in the study of the arid environments with numerous well-adapted members, while recent studies using reptiles as models have unveiled interesting biogeographical and diversification patterns. In this study, we include 207 specimens belonging to all 12 recognized species of the genus Stenodactylus. Molecular phylogenies inferred using two mitochondrial (12S rRNA and 16S rRNA) and two nuclear (c-mos and RAG-2) markers are employed to obtain a robust time-calibrated phylogeny, as the base to investigate the inter- and intraspecific relationships and to elucidate the biogeographical history of Stenodactylus, a genus with a large distribution range including the arid and hyper-arid areas of North Africa and Arabia.ResultsThe phylogenetic analyses of molecular data reveal the existence of three major clades within the genus Stenodactylus, which is supported by previous studies based on morphology. Estimated divergence times between clades and sub-clades are shown to correlate with major geological events of the region, the most important of which is the opening of the Red Sea, while climatic instability in the Miocene is hypothesized to have triggered diversification. High genetic variability is observed in some species, suggesting the existence of some undescribed species. The S. petrii - S. stenurus species complex is in need of a thorough taxonomic revision. New data is presented on the distribution of the sister species S. sthenodactylus and S. mauritanicus.ConclusionsThe phylogenetic hypothesis for the genus Stenodactylus presented in this work permits the reconstruction of the biogeographical history of these common desert dwellers and confirms the importance of the opening of the Red Sea and the climatic oscillations of the Miocene as major factors in the diversification of the biota of North Africa and Arabia. Moreover, this study traces the evolution of this widely distributed and highly specialized group, investigates the patterns of its high intraspecific diversity and elucidates its systematics.

Out of Arabia: A Complex Biogeographic History of Multiple Vicariance and Dispersal Events in the Gecko Genus Hemidactylus (Reptilia: Gekkonidae)

“…2, S5). This date matches very well the geological estimates of the break-up of the Afro-Arabian continent and the consequent formation of the Red Sea and the Gulf of Aden [28], [29] and is supported by the same vicariant split from other studies [35], [36]. Therefore, the break-up of the African and Arabian tectonic plates seems to be responsible for the vicariant separation of the ancestors of these endemic African species from the rest of the Arid clade.…”

“…Since the closest relatives of H. persicus are found in northern Oman, the dispersal occurred most probably via the Gomphotherium land bridge [61] connecting the Arabian and Anatolian plates 18 Ma. After a temporary period of disconnection the bridge was continuously present since the mid-Miocene about 15 Ma ago and allowed faunal exchanges between Eurasia and Afro-Arabia [35], [36], [61], [62]. Alternatively, the colonization of Iran could take place across the Proto-Arabian Gulf after the Gomphotherium bridge disappeared.…”

“…The long-term connectivity between Africa and Arabia and the subsequent geological events have had a crucial impact on the regional biogeography and explain the close biogeographic affinities between NE African and SW Arabian faunas [33], [34]. It has been suggested that the diversity and distribution of current Afro-Arabian herpetofauna was influenced mainly by the three following factors: 1) the formation of the Red Sea in the Oligocene (27–24 Ma), which resulted in a vicariance event separating African and Arabian fauna [35], [36]; 2) temporary reconnection of Africa and Arabia 10–5.3 Ma [29] and the geographic proximity of these landmasses, particularly in the narrowest point (Bab-el-Mandeb strait), which was only 5 km wide during the driest periods within the last 0.5 million years [37] and may have facilitated faunal exchange by means of dispersal [32], [34]; and 3) the penetration of some Afrotropical and Mediterranean elements to SW Arabia from the north along the Hijaz and Asir mountain ranges, which provide suitable conditions for more temperate species than the otherwise arid desert environment of the Arabian Peninsula [35], [38], [39]. All these factors may have affected speciation and current distribution of Hemidactylus geckos.…”

An integrative systematic revision and biogeography ofRhynchocalamussnakes (Reptilia, Colubridae) with a description of a new species from Israel

“…The Middle Miocene global climate change resulted in an aridification process of the mid-latitude continental regions, triggering the expansion of sand areas in Arabia and North Africa (Flower & Kennett, 1994; Le Houérou, 1997; Edgell, 2006). The formation and progression of sandy habitats probably promoted vicariance and/or isolation of hard-substrate specific taxa, such as Rhynchocalamus , restricting the snakes to their current distribution, similar to what has been suggested for other reptiles, such as the geckos of the genus Stenodactylus (Metallinou et al, 2012), the Arid clade of Hemidactylus (Carranza & Arnold, 2012; Šmíd et al, 2013), the Ptyodactylus hasselquistii species complex (Metallinou et al, 2015), the lacertid genus Acanthodactylus (Tamar et al, 2016a) and the agamid genus Pseudotrapelus (Tamar et al, 2016b). The sands of the north-west Negev in Israel, extending westwards in the northern Sinai Peninsula, restrict the distribution of R. melanocephalus and R. dayanae sp.…”

Differentiation of North African foxes and population genetic dynamics in the desert—insights into the evolutionary history of two sister taxa, Vulpes rueppellii and Vulpes vulpes

“…However, most studies have focused on smallsized, non-volant vertebrates with relatively low dispersal capacity (Boratyński et al 2012;Dobigny et al 2013;Guiller et al 2001;Metallinou et al 2012;Sousa et al 2011), while still very little is known about larger and more vagile species, for which barrier effects may be less pronounced. Of the few existing studies on large and medium size mammals, some show very little to no genetic structure (Bärmann et al 2013;Gaubert et al 2012;Lerp et al 2011), while others exhibit distinct mitochondrial lineages that co-occur throughout North Africa (Gaubert et al 2009(Gaubert et al , 2011Godinho et al 2012;Trucchi and Sbordoni 2009).…”