Advances in genomics have greatly enhanced our understanding of mountain biodiversity, providing new insights into the complex and dynamic mechanisms that drive the formation of mountain biotas. These span from broad biogeographic patterns to population dynamics and adaptations to these environments. However, significant challenges remain in integrating large-scale and fine-scale findings to develop a comprehensive understanding of mountain biodiversity. One significant challenge is the lack of genomic data, especially in historically understudied arid regions where reptiles are a particularly diverse vertebrate group. In the present study, we assembled a de novo genome-wide SNP dataset for the complete endemic reptile fauna of a mountain range (19 described species with more than 600 specimens sequenced), and integrated state-of-the-art biogeographic analyses at the population, species, and community level. Thus, we provide a holistic integration of how a whole endemic reptile community has originated, diversified and dispersed through a mountain system. Our results show that reptiles independently colonized the Hajar Mountains of southeastern Arabia 11 times. After colonization, species delimitation methods suggest high levels of within-mountain diversification, supporting up to 49 deep lineages. This diversity is strongly structured following local topography, with the highest peaks acting as a broad barrier to gene flow among the entire community. Interestingly, orogenic events do not seem key drivers of the biogeographic history of reptiles in this system. Instead, past climatic events seem to have had a major role in this community assemblage. We observe an increase of vicariant events from Late Pliocene onwards, coinciding with an unstable climatic period of rapid shifts between hyper-arid and semiarid conditions that led to the ongoing desertification of Arabia. We conclude that paleoclimate, and particularly extreme aridification, acted as a main driver of diversification in arid mountain systems which is tangled with the generation of highly adapted endemicity. Overall, our study does not only provide a valuable contribution to understanding the evolution of mountain biodiversity, but also offers a flexible and scalable approach that can be reproduced into any taxonomic group and at any discrete environment.

• Keywords
• Arabia, Hajar Mountains, arid environments, biogeography, ddRADseq, desertification, genomics, mountain building, reptiles,
• MeSH
• Biodiversity MeSH
• Phylogeography MeSH
• Genomics * MeSH
• Reptiles * genetics   classification   MeSH
• Biota * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

In the arid landscapes of the Arabian Peninsula, high levels of cryptic diversity among reptiles, and especially in geckos, have recently been revealed. Mountain ranges within the peninsula were shown to contain the highest richness of reptile endemicity, serving as refugia to species less adapted to the hyper-arid conditions of the lowlands. With up to 19 endemic reptile species, the Hajar Mountains of southeastern Arabia are a clear example of this pattern. Owing to its old geological history, complex topography and geographic isolation from the rest of the peninsula, this mountain range rises as a hotspot of reptile biodiversity and endemicity in Arabia, and provides the perfect scenario to study the processes of evolution and diversification of reptiles in arid mountain ranges. In the present study we investigate the systematics of the Pristurus rupestris species complex, a group of geckos exhibiting cryptic morphological traits along with a remarkably deep evolutionary history. Initially considered a single species distributed throughout coastal Arabia, and with some scattered populations at the Horn of Africa, several recent studies have shown that Pristurus rupestris actually comprises a species complex restricted to the Hajar Mountains of southeastern Arabia. Here, we utilize an integrative approach assembling several morphological, genetic, genomic, and ecological datasets to resolve this long-standing systematic challenge. Results support the existence of four new cryptic Pristurus species in the Hajar Mountains with three new Oman endemics. While no unique diagnostic morphological characters were identified, some slight morphological differences occur between species, especially among high-elevation species relative to the rest. Despite the lack of clear morphological differentiation, extreme levels of genetic variation were found between species with genetic distances of up to 24% in the 12S mitochondrial marker, resulting from deep divergence times of up to 10 mya. Moreover, all species have been found in sympatry with at least another representative of the species complex and without any signs of apparent and ongoing gene flow among them. These findings yield profound implications for conservation efforts, as one of these newly described species presents an extremely restricted distribution (only known from a single locality and three individuals), requiring immediate attention for protection. Overall, this study sheds light on the hidden diversity within the P. rupestris species complex, emphasizing the importance of preserving biodiversity in the face of ongoing environmental changes, while highlighting, once again, the Hajar Mountains of southeastern Arabia as a cradle of reptile biodiversity.

• MeSH
• Biodiversity MeSH
• Phylogeny MeSH
• Genomics MeSH
• Lizards * genetics   classification   anatomy & histology   MeSH
• Genetic Speciation * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Arabia MeSH

Geckos of the genus Trigonodactylus are widely distributed in the sand deserts of the Arabian Peninsula. Three species of this genus are currently recognized, with a fourth one, Stenodactylus pulcher, which placement within Trigonodactylus has been tentatively suggested, but not yet confirmed. We present a phylogenetic analysis of the genus Trigonodactylus with new specimens collected in central Saudi Arabia and southern Jordan. New genetic data has been generated from three mitochondrial markers to investigate the phylogenetic relationships of all species of the genus and to assess the putative generic assignment of S. pulcher. Our results confirm that S. pulcher indeed belongs within Trigonodactylus, branching as a sister lineage to all other species of the genus. The new samples cluster within Trigonodactylus arabicus, thus confirming the genetic homogeneity of the species across its large and seemingly inhospitable range. The new specimen collected in southern Jordan represents the first record for the country and a considerable range extension to the northwest from all previously reported localities. Our findings and discovery of a new species for Jordan highlight the need of more field surveys to be carried out in the underexplored parts of Jordan and northern Saudi Arabia, as these places still hold a potential for new discoveries and are crucial for understating the biogeography of the Arabian herpetofauna.

• Keywords
• Middle East, Mitochondrial DNA, Palearctic naked-toed geckos, Range extension, Stenodactylus,
• Publication type
• Journal Article MeSH