Guillermo Velo-Antón

Bimodal reproductive species offer an excellent opportunity to study the evolution of reproductive shifts, yet are extremely rare among vertebrates. Salamandra salamandra is one of two bimodal amphibian species, showing two viviparity modes: an aquatic (larviparity) and a terrestrial (pueriparity) mode. Although hybridization between larviparous and pueriparous lineages occurs in natural contact zones, their reproductive output is unknown. We conducted a captive breeding experiment to cross pueriparous insular females and larviparous continental males of S. s. gallaica . We first confirmed the reproductive output of the females and used parentage analysis to confirm the parents of the offspring, which resulted in a single group of aquatic larvae. We report, for the first time, direct evidence of F1 hybrids between parity modes in urodeles and a case of parity mode reversal at the individual level. Our study highlights S. salamandra as a bimodal reproductive species that offers exceptional opportunities to understand the evolution of viviparity.

Aim Hyper‐arid sandy and rocky fields rank among the least biologically diverse habitats of the desert biome, yet knowledge of local biodiversity patterns is also extremely poor. In the Sahara Desert, palaeoclimate oscillations affected the extent of hyper‐arid habitats, but it is unclear how these dynamics determined the evolution and distribution of local specialists. Herein, we assessed cryptic diversity, diversification patterns and spatial connectivity within a Sahara‐widespread group of dryland‐adapted lizards. Location Sahara‐Sahel ecoregions. Taxon Acanthodactylus scutellatus species group. Methods Inter‐ and intraspecific phylogenetic structure, divergence times, spatial genetic patterns and cryptic diversity were assessed using nuclear and mitochondrial loci. The effects of topography and land cover on phylogeographic structure and diversity were tested with generalized linear models. Interspecific hybridization was evaluated using 11 microsatellites across the group's major sympatry zone, predicted based on ecological niche models. Results Species of Acanthodactylus scutellatus group exhibit Late Miocene origins, followed by extensive intraspecific divergence throughout the Pliocene. The northern Sahara worked as a major diversification hotspot, harbouring a patchwork of small‐ranged, divergent lineages. These lineages are parapatric or sympatric and present concordant nuclear and mitochondrial differentiation, suggesting species status. Genetic connectivity increases in southern latitudes, with wide‐ranging lineages spanning from the Red Sea to the Atlantic coast. Within these potential corridors, mountain outskirts and sand fields in the Sahara interior seemingly acted as origins for recent population expansions. Genetic diversity and connectivity are favoured by terrain roughness and soft‐sand cover respectively. Three species inhabit the Atlantic Sahara sympatry zone without evidence of gene flow. Main conclusions Overlooked species‐level diversity within a major specialist group of Sahara drylands exposes the recurrent knowledge shortfalls present in hyper‐arid desert environments. Humidity and sandy habitat shifts triggered potential successions of population isolation and re‐connectivity, which favoured cladogenesis in northern desert regions and population expansions across southern east–west corridors.

Aim The contributions of historical biogeography, morphology and climatic niche evolution in shaping species diversification have been typically examined separately. To fill this gap, we assessed the relative role of geologic history, environment and phenotypic trait evolution in lineage diversification of green lizards in the Mediterranean biodiversity hotspot. Location Eurasia and North Africa. Taxon Green lizards (genera Timon and Lacerta ). Methods For all green lizard lineages, we characterized distributional ranges and external morphological traits across discrete biogeographical areas, occupied macro‐habitats and climatic niches using environmental variables that represent average and extreme climatic conditions. To assess the contribution of geographical factors in shaping diversity patterns, we evaluated the fit of 24 biogeographical models. We used BAMM and estimated phylogenetic signal to assess the rates of lineage diversification and of phenotypic and climatic niche evolution, and to determine whether these processes occurred steadily or at specific time periods as a response to palaeogeological or palaeoclimatic events. Finally, we tested for associations between phenotypic traits and lineage diversification using trait‐dependent diversification analyses (QuaSSE, ES‐sim and STRAPP). Results Biogeographical analyses favoured a dispersal–vicariance model explaining speciation patterns in green lizards, including jump dispersal and constrained dispersal by geographical distance. Lineages accumulated gradually towards the present, with minor divergence in morphological traits and conservatism of climatic niches. In contrast, in the Lacerta agilis lineage, niche evolution may have allowed expansion towards colder environments. Morphological and climatic niche evolution were uncoupled from diversification rates. Main Conclusions Biogeographical processes largely explain the constant lineage diversification of green lizards in the Mediterranean Basin since the Miocene, followed by gradual phenotypic divergence unrelated to cladogenesis. Climatic niche conservatism promoted the accumulation of lineages within the Mediterranean, except for L. agilis , where climatic niche evolution might underpin its range spread towards higher latitudes.