Across climates and species, higher vapour pressure deficit is associated with wider vessels for plants of the same height.

While plant height is the main driver of variation in mean vessel diameter at the stem base (VD) across angiosperms, climate, specifically temperature, does play an explanatory role, with vessels being wider with warmer temperature for plants of the same height. Using a comparative approach sampling 537 species of angiosperms across 19 communities, we rejected selection favouring freezing-induced embolism resistance as being able to account for wider vessels for a given height in warmer climates. Instead, we give reason to suspect that higher vapour pressure deficit (VPD) accounts for the positive scaling of height-standardized VD (and potential xylem conductance) with temperature. Selection likely favours conductive systems that are able to meet the higher transpirational demand of warmer climates, which have higher VPD, resulting in wider vessels for a given height. At the same time, wider vessels are likely more vulnerable to dysfunction. With future climates likely to experience ever greater extremes of VPD, future forests could be increasingly vulnerable.

The role of head shape and trophic variation in the diversification of the genus Herichthys in sympatry and allopatry.

In the present study we evaluated the putative cases of sympatric speciation in the genus Herichthys by studying the variation in head shape using principal component analysis, phylomorphospace and reconstructions of the ancestral states of feeding preferences. Herichthys includes both allopatric and sympatric sister species, as well as sympatric unrelated species and thus offers great potential for evolutionary studies of putatively sympatric speciation. Herichthys is the northernmost group of cichlids in America and one of the most ecologically disparate genera within Middle American cichlids. Fifteen anatomical points were recorded on the heads of 293 specimens of the 11 species recognized within the genus. The results show that in spite of having wide variation in consumed diets, most species of Herichthys are close in morphospace. However, morphological variation was great among the two pairs of sympatric sister species in agreement with the suggested sympatric model of speciation.

Exploring the bark thickness-stem diameter relationship: clues from lianas, successive cambia, monocots and gymnosperms.

Bark thickness is ecologically crucial, affecting functions from fire protection to photosynthesis. Bark thickness scales predictably with stem diameter, but there is little consensus on whether this scaling is a passive consequence of growth or an important adaptive phenomenon requiring explanation. With a comparative study across 913 species, we test the expectation that, if bark thickness-stem diameter scaling is adaptive, it should be possible to find ecological situations in which scaling is predictably altered, in this case between species with different types and deployments of phloem. 'Dicots' with successive cambia and monocots, which have phloem-free bark, had predictably thinner inner (mostly living) bark than plants with single cambia. Lianas, which supply large leaf areas with limited stem area, had much thicker inner bark than self-supporting plants. Gymnosperms had thicker outer bark than angiosperms. Inner bark probably scales with plant metabolic demands, for example with leaf area. Outer bark scales with stem diameter less predictably, probably reflecting diverse adaptive factors; for example, it tends to be thicker in fire-prone species and very thin when bark photosynthesis is favored. Predictable bark thickness-stem diameter scaling across plants with different photosynthate translocation demands and modes strongly supports the idea that this relationship is functionally important and adaptively significant.

Unraveling genomic features and phylogenomics through the analysis of three Mexican endemic Myotis genomes.

Background: Genomic resource development for non-model organisms is rapidly progressing, seeking to uncover molecular mechanisms and evolutionary adaptations enabling thriving in diverse environments. Limited genomic data for bat species hinder insights into their evolutionary processes, particularly within the diverse Myotis genus of the Vespertilionidae family. In Mexico, 15 Myotis species exist, with three-M. vivesi, M. findleyi, and M. planiceps-being endemic and of conservation concern. Methods: We obtained samples of Myotis vivesi, M. findleyi, and M. planiceps for genomic analysis. Each of three genomic DNA was extracted, sequenced, and assembled. The scaffolding was carried out utilizing the M. yumanensis genome via a genome-referenced approach within the ntJoin program. GapCloser was employed to fill gaps. Repeat elements were characterized, and gene prediction was done via ab initio and homology methods with MAKER pipeline. Functional annotation involved InterproScan, BLASTp, and KEGG. Non-coding RNAs were annotated with INFERNAL, and tRNAscan-SE. Orthologous genes were clustered using Orthofinder, and a phylogenomic tree was reconstructed using IQ-TREE. Results: We present genome assemblies of these endemic species using Illumina NovaSeq 6000, each exceeding 2.0 Gb, with over 90% representing single-copy genes according to BUSCO analyses. Transposable elements, including LINEs and SINEs, constitute over 30% of each genome. Helitrons, consistent with Vespertilionids, were identified. Values around 20,000 genes from each of the three assemblies were derived from gene annotation and their correlation with specific functions. Comparative analysis of orthologs among eight Myotis species revealed 20,820 groups, with 4,789 being single copy orthogroups. Non-coding RNA elements were annotated. Phylogenomic tree analysis supported evolutionary chiropterans' relationships. These resources contribute significantly to understanding gene evolution, diversification patterns, and aiding conservation efforts for these endangered bat species.

Climatic niche evolution in the viviparous Sceloporus torquatus group (Squamata: Phrynosomatidae).

The cold-climate hypothesis maintains that viviparity arose as a means to prevent increased egg mortality in nests owing to low temperatures, and this hypothesis represents the primary and most strongly supported explanation for the evolution of viviparity in reptiles. In this regard, certain authors have stated that viviparous species will exhibit speciation via climatic niche conservatism, with similar climatic niches being observed in allopatric sister species. However, this prediction remains to be tested with bioclimatic variables relevant to each viviparous group. In the present study, we examined climatic niche evolution in a group of North American viviparous lizards to determine whether their diversification is linked to phylogenetic niche conservatism (PNC). We evaluated the phylogenetic signal and trait evolution of individual bioclimatic variables and principal component (PC) scores of a PC analysis, along with reconstructions of ancestral climate tolerances. The results suggest that diversification of the Sceloporus torquatus group species is associated with both niche differentiation and PNC. Furthermore, we did not observe PNC across nearly all bioclimatic variables and in PC2 and PC3. However, in Precipitation Seasonality (Bio15), in Precipitation of Coldest Quarter (Bio19) and in PC1 (weakly associated with variability of temperature), we did observe PNC. Additionally, variation of the scores along the phylogeny and Pagel's delta (δ) >1 of PC3 suggests a fast, recent evolution to dry conditions in the clade that sustains S. serrifer.

Inferring introgression using RADseq and DFOIL : Power and pitfalls revealed in a case study of spiny lizards (Sceloporus).

Introgression is now commonly reported in studies across the Tree of Life, aided by recent advancements in data collection and analysis. Nevertheless, researchers working with nonmodel species lacking reference genomes may be stymied by a mismatch between available resources and methodological demands. In this study, we demonstrate a fast and simple approach for inferring introgression using RADseq data, and apply it to a case study involving spiny lizards (Sceloporus) from northeastern México. First, we find evidence for recurrent mtDNA introgression between the two focal species based on patterns of mito-nuclear discordance. We then test for nuclear introgression by exhaustively applying the "five-taxon" D-statistic (DFOIL ) to all relevant individuals sampled for RADseq data. In our case, this exhaustive approach (dubbed "ExDFOIL ") entails testing up to ~250,000 unique four-taxon combinations of individuals across species. To facilitate use of this ExDFOIL approach, we provide scripts for many relevant tasks, including the selection of appropriate four-taxon combinations, execution of DFOIL tests in parallel and visualization of introgression results in phylogenetic and geographic space. Using ExDFOIL , we find evidence for ancient introgression between the focal species. Furthermore, we reveal geographic variation in patterns of introgression that is consistent with patterns of mito-nuclear discordance and with recurrent introgression. Overall, our study demonstrates that the combination of DFOIL and RADseq data can effectively detect introgression under a variety of sampling conditions (for individuals, populations and loci). Importantly, we also find evidence that batch-specific error and linkage in RADseq data may mislead inferences of introgression under certain conditions.

Isolation and characterization of microsatellite markers for Sturnira parvidens and cross-species amplification in Sturnira species.

BACKGROUND: Sturnira is one of the most species-rich genera in the Neotropics, and it is found from Mexico and the Lesser Antilles to Argentina. This genus forms a well-supported monophyletic clade with at least twenty-one recognized species, as well as several others under taxonomic review. Sturnira parvidens is a widespread frugivorous bat of the deciduous forests of the Neotropics, is highly abundant, and is a major component in fruit dispersal to regenerate ecosystems. METHODS: We used a technique based on Illumina paired-end sequencing of a library highly enriched for microsatellite repeats to develop loci for S. parvidens. We analyzed millions of resulting reads with specialized software to extract those reads that contained di-, tri-, tetra-, penta-, and hexanucleotide microsatellites. RESULTS: We selected and tested 14 polymorphic (di, tri, and tetra) microsatellites. All markers were genotyped on 26 different individuals from distinct locations of the distributional area of S. parvidens. We observed medium-high genetic variation across most loci, but only 12 were functionally polymorphic. Levels of expected heterozygosity across all markers were high to medium (mean HE  = 0.79, mean HO  = 0.72). We examined ascertainment bias in twelve bats of the genus, obtaining null/monomorphic/polymorphic amplifications. DISCUSSION: The Illumina paired-end sequencing system is capable of identifying massive numbers of microsatellite loci, while expending little time, reducing costs, and providing a large amount of data. The described polymorphic loci for S. parvidens in particular, and for the genus in general, could be suitable for further genetic analysis, including taxonomic inconsistencies, parentage/relatedness analysis, and population genetics assessments.

Erosion of lizard diversity by climate change and altered thermal niches.

It is predicted that climate change will cause species extinctions and distributional shifts in coming decades, but data to validate these predictions are relatively scarce. Here, we compare recent and historical surveys for 48 Mexican lizard species at 200 sites. Since 1975, 12% of local populations have gone extinct. We verified physiological models of extinction risk with observed local extinctions and extended projections worldwide. Since 1975, we estimate that 4% of local populations have gone extinct worldwide, but by 2080 local extinctions are projected to reach 39% worldwide, and species extinctions may reach 20%. Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change.