Biology subjects

Tejero-Cicuendez, H.

Publications and source records attributed to Tejero-Cicuendez, H..

11 recordsLinked to original sources

bioRxiv2025

Aridity Drives Climatic Specialization and Phylogenetic Clustering in Terrestrial Vertebrates

Arid environments constitute one of the main terrestrial biomes on Earth and are predicted to expand under ongoing climate change. Studying the effect of arid conditions on biodiversity patterns and ecological dynamics is therefore critical to understand the evolutionary fate of desert-adapted faunas. Here we provide a global assessment of how aridity influences climatic niche breadth and phylogenetic structure across terrestrial vertebrates. Using distributional data for over 34,000 species of amphibians, squamates, birds, and mammals, combined with environmental data and nearly complete phylogenies of these clades, we quantified species positions along aridity gradients and their climatic niche breadth, and evaluated phylogenetic clustering at multiple spatial scales. Across all groups, species occupying more arid environments exhibited significantly narrower climatic niches than those from non-arid habitats, supporting the hypothesis that ecological filtering in deserts promotes climatic specialization. Further, analyses of system-wide community phylogenetic structure revealed significant phylogenetic clustering in most arid systems for all clades except birds, underscoring that deserts broadly act as ecological filters at large scale, but this effect is subjected to clade-specific traits. However, finer-scale analyses showed significant phylogenetic overdispersion in several cases, suggesting that competition and micro-niche dynamics might be stronger determinants of phylogenetic structure at the local-to-regional level. Together, our results demonstrate that drylands act as ecological filters shaping both functional and evolutionary dimensions of biodiversity, with implications for predicting biotic responses to desertification and climate change.

evolutionary biology↗

bioRxiv2025

Lizards on a sky archipelago: Genomic approaches to the evolution of the mountain genus Iberolacerta

The mountain-dwelling lizards of the genus Iberolacerta inhabit several isolated massifs across central and southwestern Europe. Their restricted and fragmented ranges, coupled with high altitude specialization in most species, entail a significant threat in the context of climate change for this group of lizards that has attracted interest from different fields. On the one hand, the alpine confinement of these relict species precedes the Pleistocene glacial cycles, and a few hypotheses have been proposed to explain it: from competitive exclusion by the wall lizards of the genus Podarcis, to adaptations to either cold or hypoxia, that would prevent them from expanding into lowlands. On the other hand, extensive research on chromosome evolution has shown Iberolacerta karyotypes to fairly differ from other lacertid lizards, exhibiting reductions in chromosome numbers and multiple sex chromosome determination systems. Here we present a chromosome-level genome assembly for Iberolacerta aurelioi, an Endangered rock lizard endemic to the Pyrenees. This genome has shed light on a genome architecture shaped by chromosome fusions, whose adaptive potential we discuss, as well as on expression shifts towards a hemoglobin isoform of enhanced oxygen affinity, as an adaptation to altitudinal hypoxia. In addition, medium coverage whole-genome sequencing data from 12 representatives encompassing all species and subspecies within the genus allowed us to address phylogenomic relationships, unveiling introgression events, gathering evidence in support of the competitive exclusion hypothesis through past demographic inference, and providing insights into homozygosity burdens, which offer valuable information for conservation efforts.

genomics↗

bioRxiv2023

Geographic patterns of living tetrapod diversity reveal the signature of global diversification dynamics

AimBiodiversity is distributed unevenly among lineages and regions, and understanding the processes generating these global patterns is a central goal in evolutionary research, particularly in light of the current biodiversity crisis. Here, we integrate phylogenetic relatedness with species diversity patterns in four major clades of living tetrapods (amphibians, squamates, birds, and mammals) to approach this challenge. LocationGlobal. Time period300 million years ago - Present. Major taxa studiedTetrapods. MethodsWe studied geographic patterns of richness-corrected phylogenetic diversity (residual PD), identifying regions where species are phylogenetically more closely or distantly related than expected by richness. We explored the effect of different factors in residual PD: recent speciation rates, temporal trends of lineage accumulation, and environmental variables. Specifically, we searched for evolutionary and ecological differences between regions of high and low residual PD. ResultsOur results show heterogeneous spatial patterns of diversity dynamics across tetrapods. They reveal an overall negative relationship between recent speciation rates and residual PD, underscoring the role of recent speciation events in structuring current biogeographic patterns. Furthermore, we found differences between endothermic and ectothermic tetrapods in response to temperature and precipitation, highlighting the pivotal role of thermal physiology in shaping diversity dynamics. Main conclusionsGeographic patterns of diversity dynamics are heterogeneous across tetrapod clades and help us disentangle the evolutionary and ecological processes underlying them. By illuminating the multifaceted factors underpinning global diversity patterns, our study represents a significant advancement towards better understanding of how the present-day diversity of tetrapods was formed and how speciation rates influenced their species and phylogenetic diversity across clades and regions.

evolutionary biology↗

bioRxiv2023

Hidden in the sand: phylogenomics unravel an unexpected evolutionary history on the desert-adapted vipers of the genus Cerastes

The desert vipers of the genus Cerastes are a small clade of medically important venomous snakes within the family Viperidae. According to published morphological and molecular studies, the group is comprised by four species: two morphologically similar and phylogenetically sister taxa, the African horned viper (Cerastes cerastes) and the Arabian horned viper (Cerastes gasperettii); a more distantly related species, the Saharan sand viper (Cerastes vipera), and the enigmatic Bohmes sand viper (Cerastes boehmei), only known from a single specimen in captivity allegedly captured in Central Tunisia. In this study, we analyzed one mitochondrial marker (COI) as well as genome-wide data (ddRAD sequencing) from 28 and 41 samples, respectively, covering the entire distribution range of the genus to explore the population genomics, phylogenomic relationships and introgression patterns within the genus Cerastes. Additionally, and to provide insights into the mode of diversification of the group, we carried out niche overlap analyses considering climatic and habitat variables. Both nuclear phylogenomic reconstructions and population structure analyses have unveiled an unexpected evolutionary history for the genus Cerastes, which sharply contradicts the morphological similarities and previously published mitochondrial approaches. Cerastes cerastes and C. vipera are recovered as sister taxa whilst C. gasperettii is a sister taxon to the clade formed by these two species. We found a relatively high niche overlap (OI > 0.7) in both climatic and habitat variables between C. cerastes and C. vipera, contradicting a potential scenario of sympatric speciation. These results are in line with the introgression found between the northwestern African populations of C. cerastes and C. vipera. Finally, our genomic data confirms the existence of a lineage of C. cerastes in Arabia. All these results highlight the importance of genome-wide data over few genetic markers to study the evolutionary history of species.

genomics↗

bioRxiv2023

The origin of a mountain biota: hyper-aridity shaped reptile diversity in an Arabian biodiversity hotspot

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 include from broad biogeographic patterns, to population dynamics and adaptations to these environments. However, significant challenges remain in integrating these 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. We generated de novo genome-wide SNP data for more than 600 specimens and integrated state-of-the-art biogeographic analyses at the community, species and population level. We, thus, provide for the first time, a holistic integration of how a whole endemic reptile community has originated, diversified and dispersed through a mountain range. Our results show that reptiles independently colonized the Hajar Mountains of eastern Arabia 11 times. After colonization, species delimitation methods suggest high levels of within-mountain diversification, supporting up to 49 putative species. This diversity is strongly structured following local topography, with the highest peaks acting as a broad barrier to gene flow among the entire community. Surprisingly, orogenic events do not seem to rise as key drivers of the biogeographic history of reptiles in this system. However, paleoclimate seems 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 to 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. Our study provides a valuable contribution to understanding the evolution of mountain biodiversity and the role of environmental factors in shaping the distribution and diversity of reptiles in arid regions.

evolutionary biology↗

bioRxiv2022

Species boundaries to the limit: validating species delimitation methods is critical to avoid taxonomic inflation in the genomic era

With the advent of molecular phylogenetics, the number of taxonomic studies unveiling and describing cryptic diversity has greatly increased. However, speciation between cryptic lineages is often defined without evaluating population structure or gene flow, which can lead to false claims of species status and, subsequently, taxonomic inflation. In the present study we focus on the intriguing case of the Arabian gecko Trachydactylus hajarensis (Squamata: Gekkonidae), a species for which cryptic diversity has been previously reported. We generated mitochondrial data (12S rDNA) and genome-wide SNP data (ddRADseq) for 52 specimens to determine phylogenomic relationships, population structure and gene flow within this species. Then, we applied species delimitation methods (SDMs) to evaluate several competing species hypotheses through the Multispecies Coalescent model. Results show that T. hajarensis is comprised by three well-defined lineages, two of them in the Hajar Mountains of eastern Arabia, and one in Masirah Island, in the southeastern coast of Oman. Even though high levels of past introgression and strong mitonuclear discordances were found, current gene flow is scarce with clear boundaries between populations and shallow levels of admixture in the contact zone between lineages. Surprisingly, species tree topology differed between methods and when different individuals were used in downsampled datasets. Conventional SDMs supported up to three putative new species within the group. However, after species validation with the genealogical divergence index (gdi), none of the putative species held. Overall, this study highlights the importance of sample choice, integrative analyses, and validation methods to not incur into taxonomic inflation, providing a set of already available tools to assess and validate population structure, gene flow, and SDMs before describing new species.

evolutionary biology↗

bioRxiv2022

Evolution along allometric lines of least resistance: Morphological differentiation in Pristurus geckos

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 shape diversity in Pristurus geckos utilizing differing habitats. We found that patterns of body shape allometry and integration were distinct in species with different habitat preferences, with ground-dwelling Pristurus displaying the most divergent allometric trend and the strongest integration. There was also strong concordance between static allometry across individuals and evolutionary allometry among species, revealing that body shape differences 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 in body shape 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 shapes at differing body sizes in distinct ecological habitats.

evolutionary biology↗

bioRxiv2022

Genomics reveals introgression and purging of deleterious mutations in the Arabian leopard (Panthera pardus nimr)

Low genetic variation and high levels of inbreeding are usually a consequence of recent population declines in endangered species. From a conservation point of view, it is essential to genetically screen endangered populations to help assess their vulnerability to extinction and to properly create informed management actions towards their conservation efforts. The leopard, Panthera pardus, is a highly generalist predator with currently eight different subspecies inhabiting a wide range of habitats. Yet, genomic data is still lacking for the Critically Endangered Arabian leopard (P. p. nimr). Here, we sequenced the whole genome of two specimens of Arabian leopard and assembled the most complete genomic dataset for leopards to date, including genomic data for all current subspecies. Our phylogenomic analyses show that leopards are divided into two deeply divergent clades, one including the only African subspecies and a second one including all seven subspecies of Asian leopards. Interestingly, the Arabian leopard represents a well-differentiated lineage sister to the rest of Asian subspecies. The demographic history, genomic diversity, Runs of Homozygosity (RoHs), and mutational load in the Arabian leopard indicate a prolonged population decline, which has led to an increase in inbreeding and RoHs, with consequent purging of deleterious mutations. Our study represents the first attempt to genetically inform captive breeding programs for this Critically Endangered subspecies. Still, more genomes, particularly from wild individuals, are needed to fully characterise the genetic makeup of this singular and iconic subspecies.

genomics↗

bioRxiv2021

Ecological specialization, rather than the island rule, explains morphological diversification in an ancient radiation of geckos

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this "island effect". Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialisation is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonisation. Namely, only one of the three colonisation events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialisation explains better the body size and shape evolution in Pristurus. Particularly, the colonisation of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent-island systems.

evolutionary biology↗

bioRxiv2021

Desert lizard diversity worldwide: effects of environment, time, and evolutionary rate

AimBiodiversity is not uniformly distributed across the Earths surface, even among physiographically comparable biomes in different biogeographic regions. For lizards, the worlds large desert regions are characterized by extreme heterogeneity in species richness, spanning some of the most species-rich (arid Australia) and species-poor (central Asia) biomes overall. Regional differences in species diversity may arise as a consequence of the interplay of several factors (e.g., evolutionary time, diversification rate, environment), but their relative importance for biogeographic patterns remains poorly known. Here we use distributional and phylogenetic data to assess the evolutionary and ecological drivers of large-scale variation in desert lizard diversity. LocationDeserts worldwide. Major taxa studiedLizards (non-snake squamates). MethodsWe specifically test whether diversity patterns are best explained by differences in the ages of arid-adapted lineages (evolutionary time hypothesis), by regional variation in speciation rate, by geographic area of the arid systems, and by spatial variation related to environment (climate, topography, and productivity). ResultsWe found no effect of recent speciation rate and geographic area on differences in desert lizard diversity. We demonstrate that the extreme species richness of the Australian deserts cannot be explained by greater evolutionary time, because species began accumulating more recently there than in more species-poor arid regions. We found limited support for relationships between regional lizard richness and environmental variables, but these effects were inconsistent across deserts, showing a differential role of the environment in shaping the lizard diversity in different arid regions. Main conclusionsOur results provide evidence against several classic hypotheses for interregional variation in species richness, but also highlight the complexity of processes underlying vertebrate community richness in the worlds great arid systems.

evolutionary biology↗

bioRxiv2020

Reconstructing Squamate Biogeography in Afro-Arabia Reveals the Influence of a Complex and Dynamic Geologic Past

The geographic distribution of biodiversity is central to understanding evolutionary biology. Paleogeographic and paleoclimatic histories often help to explain how biogeographic patterns unfold through time. However, such patterns are also influenced by a variety of other factors, such as lineage diversification, that may affect the probability of certain types of biogeographic events. The complex and well-known geologic and climatic history of Afro-Arabia, together with the extensive research on reptile systematics in the region, makes Afro-Arabian squamate communities an ideal system to investigate biogeographic patterns and their drivers. Here we reconstruct the phylogenetic relationships and the ancestral geographic distributions of several Afro-Arabian reptile clades (totaling 430 species) to estimate the number of dispersal, vicariance and range contraction events. We then compare the observed biogeographic history to a distribution of simulated biogeographic events based on the empirical phylogeny and the best-fit model. This allows us to identify periods in the past where the observed biogeographic history was likely shaped by forces beyond the ones included in the model. We find an increase in vicariance following the Oligocene, most likely caused by the fragmentation of the Afro-Arabian plate. In contrast, we did not find differences between observed and expected dispersal and range contraction levels. This is consistent with diversification enhanced by environmental processes and with the establishment of a dispersal corridor connecting Africa, Arabia and Eurasia since the middle Miocene. Finally, here we show that our novel approach is useful to pinpoint events in the evolutionary history of lineages that might reflect external forces not predicted by the underlying biogeographic model.

evolutionary biology↗