Diversity patterns and evolutionary history of Arabian squamates

Abstract

Aim: Deserts are generally perceived as areas of low diversity, and hence receive little attention from researchers and conservationists. Squamates are the dominant group of vertebrates in arid regions, and as such represent an ideal model to study biodiversity patterns in these areas. We examine spatial patterns of diversity, evolutionary history and endemism of terrestrial squamates of the Arabian Peninsula and test hypotheses on the role of topography and history of isolation so as to identify possible environmental drivers of diversification. Location:The Arabian Peninsula.Taxon: Squamate reptiles (Squamata; lizards and snakes). Methods:We generated distribution maps for all Arabian squamate species (including yet undescribed) and reconstructed their phylogenetic relationships using existing and newly produced genetic data for nearly all the species. We assessed patterns of the distribution of species richness, phylogenetic diversity and phylogenetic endemism across the peninsula to identify areas that could be considered evolutionary or endemicity hotspots for squamates. We evaluated community turnover across the peninsula and assessed the possible environmental drivers affecting the diversity of Arabian squamates in a regression framework. Results:The main hotspots of Arabian squamate diversity are mostly along the mountains that rim the peninsula while the most arid, central regions support a low diversity of species. The distribution of the phylogenetic diversity mirrors that of the species richness. Phylogenetic endemism is also highest in the mountains, especially when only endemic species are analysed. The deserts of northern Arabia are poor in terms of species richness and they show low connectivity to the peninsular communities.Topographic heterogeneity is the strongest predictor for Arabian squamates, followed by elevation. There is no correlation between richness and temperature. Main conclusions: The mountains of Arabia support rich and unique squamate communities that are dominated by local radiations of closely related and narrow-ranging species. In particular, the Asir Mountains of SW Arabia, Dhofar Province of Oman and

The role of Sahara highlands in the diversification and desert colonization of the Bosc's fringe‐toed lizard

“…The positive correlation of genetic diversity with climatic stability and altitude highlights the expected role of mountains as both diversification hotspots and climatic refugia (Table 1; Figure S3.8; Rahbek et al, 2019). Our results revealed absolute altitude as the main topographic factor related to the diversification of A. boskianus , contrary with other squamates where genetic diversity is driven by topographic heterogeneity (Šmíd et al, 2021). Historical range fragmentation (Figures S3.7) and the presence of endemic lineages/sub‐lineages (Figures 2a and 3a) to Hoggar, Tassili n’Ajjer and Fezzan suggest a “sky‐island” pattern around Central Sahara highlands (e.g., Gonçalves, Pereira, et al, 2018; Metallinou et al, 2015).…”

“…A similar phylogeographic scenario was found around the Arabian mountains, where intense Miocene tectonic activity may have also played an important role in generating diversity (Machado et al, 2020). Our genetic output provides new evidence for the Yemen, Dhofar and Al Hajar mountain diversification centres (Šmíd et al, 2021; Figures 2 and 3). The genetic distinctiveness of Levant populations (Table S2.4) also matches with previous studies (e.g., Metallinou et al, 2015).…”

Overlooked species diversity in the hyper‐arid Sahara Desert unveiled by dryland‐adapted lizards

“…Biased by this poor diversity, we tend to perceive desert biomes as vast and homogeneous environments devoid of life, which consequently attract less research and conservation interest (Durant et al, 2012) despite providing key global ecosystems services (e.g., climate regulation [Barkley et al, 2022]). However, many deserts experienced a dynamic geological past (Pepper & Keogh, 2021) that generated high levels of endemism (Šmíd et al, 2021) and unique biodiversity adaptations to aridity (Ward, 2016). The Sahara Desert, together with the neighbouring Sahel (Figure 1), is the largest warm desert on Earth, exhibiting a wide variety of climate and topography (Brito et al, 2014).…”

Molecular Phylogeny of <i>Walterinnesia aegyptia</i> (Reptilia, Elapidae) Isolated from Ha’il Province, Saudi Arabia

“…Our molecular data showed that W. morgani from Riyadh, Saudi Arabia, is nearly genetically identical (D = 0) to W. aegyptia from Ha'il and Ryiadh, Saudi Arabia, and Sinai, Egypt. As a result, it is certain that the samples identified as W. morgani from Riyadh, Saudi Arabia [16] are conspecific with W. aegyptia.…”

“…W. aegyptia envenomation causes respiratory failure and muscle paralysis in mice and humans, followed by rapid death when lethal doses of the venom are injected [12] [13] [14]. To the best of our knowledge, only two previous studies on phylogenetic analysis (using venom and/or 16S and 12S rRNA mitochondrial genes) of Walterinnesia and Naja snake species samples collected from across Saudi Arabia [15] [16]. Therefore, the present study aimed to determine the phylogenetic relationships in Walterinnesia and Naja species in Saudi Arabia using the mitochondrial 16S and 12S rRNA gene sequences.…”