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Human‐mediated habitat destruction has had a profound impact on increased species extinction rates and population declines worldwide. The coastal development in the United Arab Emirates (UAE) over the last two decades, serves as an example of how habitat transformation can alter the landscape of a country in just a few years. Here, we study the genomic implications of habitat transformation in the Critically Endangered Emirati Leaf‐toed Gecko (Asaccus caudivolvulus), the only endemic vertebrate of the UAE. We generate a high‐quality reference genome for this gecko, representing the first reference genome for the family Phyllodactylidae, and produce whole‐genome resequencing data for 23 specimens from 10 different species of leaf‐toed geckos. Our results show that A. caudivolvulus has consistently lower genetic diversity than any other Arabian species of Asaccus, suggesting a history of ancient population declines. However, high levels of recent inbreeding are recorded among populations in heavily developed areas, with a more than 50% increase in long runs of homozygosity within a 9‐year period. Moreover, results suggest that this species does not effectively purge deleterious mutations, hence making it more vulnerable to future stochastic threats. Overall, results show that A. caudivolvulus is in urgent need of protection, and habitat preservation must be warranted to ensure the species' survival. [ABSTRACT FROM AUTHOR]

The Montseny brook newt (Calotriton arnoldi), a glacial relict endemic to a small, isolated massif in northeast Spain, is considered the only Critically Endangered urodele in Europe. Its restricted range is divided by a deep valley that acts as an impassable barrier to dispersal, separating two isolated metapopulations (Western and Eastern) that correspond to independent lineages with different evolutionary trajectories, based on genetic and genomic data. Here, we address the ecological differentiation between lineages and discuss its potential effect on the phenotypic distinctness of each lineage. Based on multiple lines of evidence, we formally describe the Western Montseny brook newt as a new subspecies: Calotriton arnoldi laietanusssp. nov. Finally, our study underscores the importance of considering taxonomic progress in the conservation policies of endangered species, ensuring appropriate management and protection of the newly described taxa. [ABSTRACT FROM AUTHOR]

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, particularly 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., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society of Systematic Biologists.)

The Montseny brook newt ( Calotriton arnoldi ), considered the most endangered amphibian in Europe, is a relict salamandrid species endemic to a small massif located in northeastern Spain. Although conservation efforts should always be guided by genomic studies, those are yet scarce among urodeles, hampered by the extreme sizes of their genomes. Here, we present the third available genome assembly for the order Caudata, and the first genomic study of the species and its sister taxon, the Pyrenean brook newt ( Calotriton asper ), combining whole-genome and ddRADseq data. Our results reveal significant demographic oscillations which accurately mirrored Europe's climatic history. Although severe bottlenecks have led to depauperate genomic diversity and long runs of homozygosity along a gigantic genome, inbreeding might have been avoided by assortative mating strategies. Other life history traits, however, seem to have been less advantageous, and the lack of land dispersal has driven to exceptional levels of population fragmentation., Competing Interests: The authors declare no competing interests., (© 2023 The Authors.)

Species living in distinct habitats often experience unique ecological selective pressures, which can drive phenotypic divergence. However, how ecophenotypic patterns are affected by allometric trends and trait integration levels is less well understood. Here we evaluate the role of allometry in shaping body size and body form diversity in Pristurus geckos utilizing differing habitats. We found that patterns of allometry and integration in body form were distinct in species with different habitat preferences, with ground-dwelling Pristurus displaying the most divergent allometric trend and high levels of integration. There was also strong concordance between intraspecific allometry across individuals and evolutionary allometry among species, revealing that differences in body form among individuals were predictive of evolutionary changes across the phylogeny at macroevolutionary scales. This suggested that phenotypic evolution occurred along allometric lines of least resistance, with allometric trajectories imposing a strong influence on the magnitude and direction of size and shape changes across the phylogeny. When viewed in phylomorphospace, the largest rock-dwelling species were most similar to the smallest ground-dwelling species, and vice versa. Thus, in Pristurus, phenotypic evolution along the differing habitat-based allometric trajectories resulted in similar body forms at differing body sizes in distinct ecological habitats., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Society for the Study of Evolution (SSE). All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)