Current Distribution Patterns Research Articles

Potential Impacts of Climate Change on the Spatial Distribution Pattern of Naked Oats in China

Naked oats, a significant minor cereal crop in China popular for its nutrient richness, have experienced a surge in production in recent years, fueled by the escalating demand for wholesome healthy food. However, the dispersed and disorganized cultivation plan of naked oats poses a significant constraint on its industrial progression. Considering the dual influence of cultivation, management techniques, and global climate change on the production of naked oats, this study explores the potential impacts of climate change on the spatial distribution and yield of this cereal crop. Leveraging CMIP6 climate models (BCC-CSM2-MR, CanESM5, CNRM-ESM2-1) and an optimized MaxEnt model (RM = 0.5, FC = LQ), we simulated potential climate-suitable zones for naked oats from 1990 to 2020 and forecasted alterations under various emission scenarios from 2021 to 2100. The model achieved an average accuracy test with high value (AUC = 0.945) in predicting suitable areas; with precipitation seasonality (Coefficient of Variation) (bio15, 21.70%) and topsoil pH (H2O) (T_PH_H2O, 21.00%) as key factors, both climate and soil properties have a greater influence. Simulation results showed that the climatically suitable area for naked oats increased under all scenarios, with the largest increase in the optimal growing area under ssp126 in the 2030s. The increase was 3.93% with an area of 0.77 × 106 km2. The study also compared the data from the main producing counties of naked oats in Shanxi Province from 2020 to 2022 for statistical purposes, and found that 39 counties were in high climatic suitability zones and 39 counties were in remarkably high climatic suitability zones. The agreement rate between planting areas and climatically suitable areas was as high as 97.44%. Further, the growing area expanded westward, increasing the production intensity. This study reveals the current spatial distribution pattern of naked oats, providing a scientific rationale for addressing climate change through multi-scenario predictions. Our findings have implications for optimizing cultivation layout and identifying optimal zones, supporting sustainable agricultural development strategies in China.

Rethinking Conservation and Restoration Strategies of Endangered and Key Medicinal Clavicarpa Plants in Yunnan-Kweichow Plateau's Karst Areas Under Climate Change.

The Clavicarpa species, valued for their pharmaceutical, ornamental, and economic importance, exhibit notable rarity and endemism in the Karst areas of the Yunnan-Kweichow Plateau in China. These species face significant threats from habitat loss and fragmentation, leading to a decline in biodiversity. To mitigate these threats, the Maxent algorithm was employed to analyze current and future distribution patterns, with a particular focus on the influence of climate variables in predicting potential distribution shifts and assessing extinction risks under the optimistic SSP1-2.6 and the pessimistic SSP5-8.5 socioeconomic scenarios. The EC-Earth3-Veg, MRI-ESM2-0, and MPI-ESM1-2-HR models were utilized for conservation status assessment and project future distributions for four time periods: the present, 2030s, 2050s, and 2070s. The minimum temperature during the coldest month (Bio 6) was identified as the most critical environmental factor, influencing both habitat contraction and expansion. Our modeling indicates that regions such as South, Central, and East China, particularly areas east of the Aihui-Tengchong line and south of the Yangtze River, exhibit the highest suitability for Clavicarpa species within the geographical coordinates of 18° N-45° N and 97° E-120° E. Conversely, climate change projections suggest a habitat expansion for Impatiens claviger, Impatiens tubulosa, Impatiens pritzelii, and Impatiens apalophylla, while Impatiens guizhouensis and Impatiens wilsonii face increased extinction risks. Specifically, I. claviger, I. tubulosa, and I. apalophylla are expected to shift northward, necessitating potential relocation to southern regions, while I. guizhouensis and I. wilsonii are projected to experience habitat losses of over 23.94% and 9.13%, respectively. Our research provides a robust scientific foundation for the conservation and sustainable utilization of these important pharmaceutical species and offers a framework for effective biodiversity management. We recommend using protected areas as a basis for the future conservation, breeding, cultivation, and utilization of Clavicarpa species.

Novelle approach to simulating spinal cord stimulation during tSCS using CT images and FEM

Abstract Transcutaneous spinal cord stimulation (tSCS) offers non-invasive relief for chronic pain and improves motor function in spinal cord injured (SCI) patients. However, its mechanisms are not currently fully understood, and patientspecific factors, such as Body mass index (BMI) and age, complicate treatments. This paper aims to understand tSCS better by developing a novel Finite Element Model (FEM) of the human body using CT scans. Three subjects (sex, male, female, male. Age: 26, 27, 64. BMI: 38.9, 24.1, 28.4) underwent a CT scan, performed on a Cannon Aquilion Prime (Slice thickness [mm]: 0.8, Voxel size [mm3]: 0.564, 0.328, 0.527), which imaged the trunk of the body, from top of the abdomen to the bottom of the pelvis. The images were then used in Materialize Mimics Research 21.0 to create 3D images of individual organs, skin, fat, muscles, skeleton, and spinal cord. After pre-processing in Autodesk Meshmixer, the models were converted into solid CAD objects in Ansys SpaceClaim R2021 and combined into a single abdominal model. Ansys Maxwell R2021 was then used for simulations. Five different two-electrode configurations were tested in the prototype phase with a simplified model setup. The positive electrodes were placed over the (Thoracic) T10, T12, (Lumbar) L2 and L4 vertebrae sequentially, with the negative electrode over (Sacral) S2. The simulations took on average 47.4 hours. A marked decline in electrical current penetration depth was observed as the electrodes were placed closer together which was consistent with known current distribution patterns. A preliminary validation test was also performed using a lamb’s thigh. Two electrodes were placed a known distance apart and a stimulation was given, needle electrodes were then inserted in a grid-like pattern to obtain voltage values. The setup was recreated and simulated in Ansys Maxwell. The resulting average percent difference was 44.93 ± 33.3 % (5Vpp Square wave) and 35.02 ± 23.38 % (5V DC). In both instances, the highest difference was at the edges of the electrodes and the lowest difference in the midpoint between electrodes. Later versions of FEM models incorporated more organs and had improved on previous mesh generation flaws, but encountered new mesh generation errors which could not be rectified before the conclusion of the master’s project. Despite complications, this project has provided a pipeline for creating similar models and shown their usability. Future work will involve overcoming the current mesh generation errors, reducing calculation time, and performing a thorough validation test.

Modeling the ecological niche of rhamnus prinoides L. under climate change scenarios: a MaxEnt modeling approach

ABSTRACT Nowadays, the crucial issue in ecology is how changing climate influences species distributions and existence in a natural ecosystem. Changes in spatiotemporal environmental patterns lead to either expansions, contrasts, or shifts to comparable habitats. The aim of this study was to define the ecological niches, potential distributions and examine trends of changes in Rhamnus prinoides in response to climate change. A bioclimatic, topographic, and soil type dataset were used to analyze the current and future species distribution patterns. The model, with a high accuracy (AUC 0.887, TSS 0.6327), revealed that elevation and soil type are key factors influencing R. prinoides distribution. Under the current climatic conditions, the predicted total suitable habitat of R. prinoides was approximately 15.17% of Tigray. Future climate scenarios predict both expansion and contraction of these areas, particularly in the northwest, central, and southern zones. In addition, areas of new and lost habitat for R. prinoides species were found in all scenarios. Findings of this study concluded that, the distributional range of R. prinoides was found to be primarily associated with altitude and soil type. Moreover, the majority of Tigray’s highlands will continue suitable potential areas for R. prinoides cultivation in the future.

Biogeographical Origins of Caatinga Squamata Fauna

ABSTRACTAimSeveral lines of evidence have noted that open vegetation biomes in the Neotropics are younger than moist forests, leading us to question which historical processes shaped the current species distribution patterns in these new biome formations. Here we investigate the temporal patterns of speciation and colonisation from surrounding biomes (Amazonia, Atlantic Forest and Cerrado) in the Caatinga historical assembly of squamate species, to understand the role of geomorphological events and climate change in driving its diversification.LocationNeotropics.TaxonSquamata (snakes, lizards and amphisbaenians).MethodsWe used a phylogenetic tree and occurrence data for 459 squamate species distributed throughout four different biomes (Amazonia, Atlantic Forest, Cerrado and Caatinga) to reconstruct ancestral geographic ranges using the R package BioGeoBEARS. We used BAMM to estimate the rates of species diversification.ResultsOur results indicate that the current diversity patterns of squamates in the Caatinga were a result of pervasive faunal exchanges from adjacent biomes since the Paleogene, with similar numbers of dispersal events in each source area. The Neogene period was determinant in the diversification process, leading to the current assembly patterns of this group in the Caatinga.Main ConclusionsThe landscape transformation and climate change that increased aridity in northeastern Brazil probably shaped the diversification of dry‐adapted squamates in the Caatinga, like tropidurid lizards. However, the Pleistocene climatic fluctuations associated with the highly heterogeneous gradients of topography, geology, soils, climatic conditions, and different vegetation physiognomies could have facilitated faunal exchange with their neighbouring forested biomes, explaining the current presence of some typical forested lineages inside the Caatinga domain and help us to clarify the current distribution patterns of squamates in this region.

(Invited) Magnetic Field Imaging for Fault Diagnosis of Lithium-Ion Batteries

The popularity of Li-ion batteries for electric vehicles has spotlighted their importance in safety. Nonetheless, they can accidentally fail sometimes due to small, undetectable errors during manufacturing or use. Identifying these flaws and distinguishing between different types of cell failure without physically opening the cell presents a significant challenge. Although minor errors inside the cells can trigger catastrophic failures, tracing them and distinguishing cell failure modes without dissecting the cell remains difficult. Since various defects within the cell could cause abnormal current flow compared to normal cells, visualizing the current inside the battery allows us to pinpoint and track these invisible defects over large-area cells. Focusing on how the current moves inside the battery helps us uncover and address hidden defects, enhancing battery safety and ensuring the reliability of Li-ion batteries.This talk introduces a real-time, non-invasive magnetic field imaging (MFI) tool capable of detecting the magnetic field signal induced by abnormal current flow inside fault-simulated Li-ion pouch cells. MFI offers high-speed scanning (~100 mm/min) and high spatial resolution (0.161 mm) with the benefits of simple instrumentation and the acquisition of directional information. By validating the Biot-Savart law, normal current flow patterns can be identified through cross-validating simulation studies and experimental results using MFI. To demonstrate the efficacy of current flow pattern analysis in battery fault diagnosis, the MFI study was extended to identify detectable defects among various flaws and to determine if the severity of these defects can be quantified by building experimental and simulational fault-simulated cells. Direct visualization of current distribution patterns and understanding pattern changes during operation is believed to expedite the non-destructive, immediate diagnosis of commercial cells and address safety-related challenges.

Magnetically Guided Diagnosis of Current Flow Patterns inside Fault-Simulated Li-Ion Batteries

As the energy industry shifts towards cleaner and more electrified solutions, there's a growing demand for improved batteries, especially for electric vehicles (EVs) and stationary energy storage systems (ESSs). Lithium-ion batteries (LIBs) have been dominant due to their advantages such as high energy/power density, long lifespan, and fast charging capabilities. Despite advancements in cell design making them more efficient and compact, current LIBs face new challenges, particularly in improving reliability and addressing safety concerns. Recent instances of battery recalls due to explosions and fires have underscored the need to address potential failures stemming from internal faults in large-format cell designs and manufacturing, or from "latent" defects arising from misuse or aging under extreme conditions. Therefore, understanding failure scenarios and developing diagnostic tools are crucial for facilitating smoother troubleshooting for battery manufacturers and ensuring the development of safer battery technologies.Advanced imaging methods, both postmortem and in situ, have been developed to reveal the underlying causes of battery failures at the material level. These techniques help identify physical and chemical defects in active materials, degradation of electrolytes, and structural damage in inactive components like separators and current collectors. However, connecting these material-level defects with overall cell failure is difficult due to their random occurrence within complex cell structures. Additionally, many microscale imaging tools designed for customized cells are impractical for commercial cells, making it nearly impossible to detect small errors in large-scale cells during postmortem analysis. Therefore, global imaging techniques are more effective for identifying abnormalities and examining local faults. One powerful tool for this purpose is cell-penetrating X-ray computed tomography, which provides 3D images of the cell's internal structures, although it is time-consuming. However, this method may struggle to detect invisible errors that can lead to abnormal current flow in areas where latent defects exist. Thermal imaging is another useful tool for detecting abnormal heat generation in batteries caused by current flow, but without information on current direction, determining the type and extent of defects and cell degradation may be limited.This research introduces a real-time, noninvasive method for imaging magnetic fields (MFI) generated by current flow within Li-ion pouch cells. This technique provides fast scanning speeds (~100 mm/min), high spatial resolution (0.161 mm2), and a simple setup without the need for magnetic field shielding. Initially, we verified the correlation between magnetic fields and current by conducting MFI studies on 1D straight wires and 2D sheets carrying current. Subsequently, we identified an appropriate pouch cell geometry for analyzing current flow patterns using MFI, cross-referencing with current distribution maps generated by COMSOL simulations. To illustrate the effectiveness of current pattern analysis in identifying failure modes, we analyzed MFI data from fault-simulated batteries (FSBs) deliberately manufactured with faults like lead-tab contact failure, electrode misalignment, and stacking process folds. By using MFI destructive interference with a countercurrent-carrying cell-shaped 2D sheet below, we could selectively enhance areas of failure where abnormal current flows occur. This MFI-guided visualization of current distribution patterns in FSBs provides a nondestructive, immediate diagnostic approach to identify fault types that may not be discernible through electrochemical analysis alone.

Supression of shielding effect of large area field emitter cathode in radio frequency gun environment

Abstract Utilisation of large area field emitters (LAFE) cathodes for rf gun injector hold promise for delivering compact, high power and high brightness electron beam for advanced accelerator technologies. LAFEs subjected to DC electric fields posses significant challenges due to the shielding effect which restricts emission from central emitters and decreases the overall current density. Mitigating the shielding effect of LAFE in rf gun environment is essential for meeting the desired beam quality requirement in an accelerator. The current distribution of LAFE under DC conditions depend on its various geometrical parameters such as emitter height, inter-emitter distance, aspect ratio, number of emitters. Additionally, in rf gunsetup, LAFEs are subjected to variable macroscopic electric field at different emitter position which can potentially alter the current distribution compared to DC fields. In this work, we have systematically studied the shielding effect properties of LAFE in rf gun environment under the influence of various LAFE parameters. A semi-analytical approachhas been adopted to estimate the current distribution which combines the analytically calculated field enhancement factor (γ) and numerically calculated applied rf field values. This new methodology was first validated using COMSOL simulation and then employed for field emission performance estimation of a LAFE cathode integrated in a½ cell S-band (2856 MHz) rf gun. The simulation results reveals that under favourable conditions, a Gaussian spatial distribution of beam can be obtained from LAFE thus countering the shielding effect typical in DC fields. By optimizing the LAFE parameters, the desired current and beam distribution pattern can be achieved. This study highlights the adoption of a promising approach for designing LAFE cathodes suitable for rf gun which can lead to advancement of field emission technologies for accelerator-related applications.

DWINDLING POPULATION OF INDIAN WORKING EQUINES: A WORRYING TREND

The equine species, which includes donkeys, mules, horses, and ponies, have made major contributions to human civilizations all throughout the world. The Indian livestock sector, after an initial decline in period from 2007 - 2012, staged a remarkable comeback during the period from 2012-2019 with an impressive overall growth rate of 4.8%. However, the total population of horses, ponies, mules and donkeys in India is 0.55 million as per the latest livestock census, a decrease by 51.9% over the previous livestock census (2012). The ‘decreasing utility’ due to increasing vehicles and urbanization has been considered as factors for the drastic dip in population. This paper, based on secondary data, aims to provide a concise summary of the current status, growth rate, distribution patterns, and factors leading to the decline in the population of working equines in India. Tabular presentations and graphical representations have been utilized for easy analysis and comparison of population trends across different years.

Patterns of Zoological Diversity in Iran—A Review

Iran is a country characterized by high biodiversity and complex biogeographic patterns. Its diverse landscape and steep climatic gradients have resulted in significant faunal diversity and high level of endemism. To better understand these patterns, we investigated the historical environmental drivers that have shaped Iran’s current geological and climatological conditions, and, consequently, have shaped the current zoological distribution patterns. Furthermore, we provide an overview of the country’s zoological diversity and zoogeography by reviewing published studies on its fauna. We analyzed nearly all available catalogs, updated checklists, and relevant publications, and synthesized them to present a comprehensive overview of Iran’s biodiversity. Our review reports approximately 37,500 animal species for Iran. We also demonstrated that the country serves as a biogeographic transition zone among three zoogeographical realms: the Palearctic, Oriental, and Saharo-Arabian, where distinct faunal elements intersect. This biogeographic complexity has made it challenging to delineate clear zoogeographical zones, leading to varying classifications depending on the taxon. The uplift of mountain ranges, in particular, has played a crucial role in shaping faunal diversity by serving as barriers, corridors, and glacial refugia. These mountains are largely the result of orogeny and plate collisions during the Mesozoic and Cenozoic eras, coupled with the development of the Tethyan Sea and the uplift of several ranges during the Miocene. Despite these insights, our understanding of biodiversity distribution in Iran remains incomplete, even for some well-studied taxa, such as certain vertebrate families and arthropods. We highlight the existing gaps in knowledge regarding zoogeographical patterns and propose approaches to address these gaps, particularly concerning less-studied species and the highly diverse group of insects.

Phylogeography and population genomics of the critically endangered aquatic plant Caldesia grandis in China

Caldesia grandis, a critically endangered aquatic species, is predominantly found in the mid-low mountainous swamps of subtropical China. This study assessed the genetic diversity and population structure of the species using RAD-seq data, explored its phylogeography across the extant nine populations based on five plastid DNA (ptDNA) regions, and conducted niche modeling analysis. We found low genetic diversity (HE = 0.180, Ho = 0.222, and π = 0.197) and genetic differentiation among populations (Fst = 0.089), which was likely due to genetic drift in small populations and frequent inter-population contact during the Quaternary period. Although RAD-seq analysis did not reveal a clear population structure, two distinct clades, comprising western and eastern populations, were identified using five ptDNA haplotypes. Molecular dating and niche modeling suggested that the uplift of the Luoxiao Mts may have contributed to the divergence of the eastern and western clades (ca. 1.51 Ma)during the Pleistocene, which also supports the hypothesis that the Nanling Mts acted as a refugium for C. grandis. Additionally, the repeated glacial periods of the Quaternary, accompanied by contraction and expansion of suitable habitats, likely facilitated gene exchange among populations, influencing the current distribution pattern in subtropical China. Our results suggested that each ptDNA haplotype should be treated as an independent unit for conservation purposes, and ex-situ efforts should be prioritized to conserve C. grandis in China.

Corvisyringophilus, a New Genus in the Family Syringophilidae (Acariformes: Prostigmata) and Its Phylogenetic Position among Primitive Genera.

Syringophilidae is one of the most species-rich families in the superfamily Cheyletoidea, comprising approximately 420 species across 62 genera and two subfamilies. In this paper, we propose a new genus, Corvisyringophilus, and a new species, C. krummi gen. n. et sp. n., found in the wing covert quills of the Common Raven, Corvus corax Linnaeus, in Iceland. Corvisyringophilus is placed among the primitive genera of syringophilid mites, which possess the full complement of idiosomal and leg setae. Phylogenetic analysis based on morphological characters suggests that this genus forms a sister clade to Blaszakia Skoracki & Sikora, 2008, and Charadriphilus Bochkov & Mironov, 1998, which inhabit birds of the orders Musophagiformes and Charadriiformes, respectively. The study proposes that the current distribution patterns of quill mites, based on their morphological characteristics, may result from multiple host switching followed by co-speciation events, highlighting the complex evolutionary dynamics within this family.

Inset-fed quad-port hexagonal-shaped MIMO T-shaped slots on patch with slots on ground plane antenna for IoT and X-band applications

A compact and novel inset-fed hexagonal-shaped multiple input multiple output patch (IHMP) antenna with T-shaped slot is designed for IoT and X-band applications. The IHMP antenna comprises with four identical hexagonal-shaped radiating elements. In order to achieve better diversity performance and low mutual coupling, radiating elements P1, P4 are positioned side by side with ideal distance and P2, P3 are positioned opposite to P1, P4. The proposed hexagonal-shaped MIMO antenna is prototyped on low-cost Fr-4 substrate with the dimensions of 28 × 28 × 1.6 mm3. It achieves dual bandwidths (S11 < −10 dB) of 1.37 GHz (2.12–3.49 GHz) and 1.69 GHz (8.07–9.76 GHz) at 2.5 and 8.7 GHz resonating frequencies. The IHMP antenna having gain of 5.68dBi, and 5.51dBi at 2.5 and 8.7 GHz, respectively. At operating frequencies, surface current distribution and radiation patterns are examined. To calculate the diversity performance of the IHMP antenna, MIMO parameters envelope correlation coefficient < 0.05 within the band, diversity gain > 9.9 within the band, total active reflection coefficient, channel capacity loss < 0.2 bits/sec/Hz, and mean effective gain −3 dB < MEG < −6 dB are also investigated. The simulated and experimentally obtained results are presented and they are in fine agreement.

Simulation of Potential Geographical Distribution and Migration Pattern with Climate Change of Ormosia microphylla Merr. &amp; H. Y. Chen

Conservation and management of endangered species are crucial to reveal the restriction mechanisms of climate change on the distribution change pattern of endangered species. Due to human interference and a limited natural capacity for regeneration, the wild resources of Ormosia microphylla Merr. &amp; H. Y. Chen have progressively dwindled. Therefore, this study reconstructed the historical migration dynamics of the geographical distribution of O. microphylla since the last interglacial period and analyzed its adaptation to climatic conditions, aiming to provide an important reference for the protection of O. microphylla. Using data from 40 distribution resources of O. microphylla and nine climate factors, an optimized MaxEnt model, in conjunction with ArcGIS 10.4.1 software, was used for predicting and visualizing the distribution ranges and the associated changes under historical, current, and future climate scenarios. This analysis was also used to determine the dominant climate factors constraining the distribution of species. The results show that contemporary suitable habitats of O. microphylla are primarily concentrated in the mountainous regions of southern China, including Fujian, Guangdong, Guangxi, and Guizhou. The precipitation of driest quarter (bio17), the temperature seasonality (bio4), the min temperature of coldest month (bio6), and the elevation (elev) were the key limiting factors in the current geographical distribution pattern of O. microphylla. In the SSP126 and SSP585 climate scenarios, the total suitable area of O. microphylla showed a downward trend. The change in the spatial pattern of O. microphylla shows that the increase area is less than the loss area under different climate scenarios in the future. Climate warming may cause fragmentation risk to the suitable area of O. microphylla. Therefore, the corresponding protection suggestions bear significant importance for the conservation and sustainable development of O. microphylla resources.

Prioritizing management actions for invasive non-native plants through expert-based knowledge and species distribution models

Given the high number of non-native plants that are being introduced worldwide and the time required to process formal pest risk analyses, a framework for the prioritization of management actions is urgently required. We therefore propose a framework for a replicable and standardized prioritization for management actions (eradication, control and monitoring) of invasive non-native plants, combining expert knowledge, current and future climatic suitability estimated by species distribution models (SDMs), clustering and ordination techniques. Based on expert consultation and using Italy as case study, invasive non-native plant species were selected and three categories of management actions were identified: eradication, control and containment, and monitoring. Finally, two further classes of priorities were proposed for each of the management actions: “high” and “low” priority. Overall, SDMs highlighted a high and very high suitability for Continental and Mediterranean bioregions for most invasive plants. Cluster analysis revealed three distinct clusters with varying levels of suitability for the Italian bioregions. Cluster 1 exhibited a higher suitability across all Italian bioregions, whereas non-native plants grouped in Cluster 2 predominantly featured high suitability in Mediterranean areas. Finally, Cluster 3 showed the lowest suitability values. Two ordination analysis highlighted the variability in bioclimatic suitability for each non-native plant within each cluster, as well as their current distribution pattern. Lastly, a third ordination, integrating bioclimatic suitability and spatial patterns, has allowed the differentiation of management actions for each non-native plant at both national and bioregional scales. Specifically, seven non-native plants were earmarked for eradication action, six for monitoring action, while the remaining species were deemed suitable for control and containment. Our results and the methodology proposed meet the demand for replicable new early warning tools; that is to predict the location of new outbreaks, to establish priorities for eradication, control and containment, and to monitor invasive non-native species.

Underestimated diversity in Characidium (Characiformes: Crenuchidae) from Neotropical rivers revealed by an integrative approach

Characidium represents the most widely distributed and species-rich fish genus within the family Crenuchidae in the Neotropical region, with numerous species described over the last decade. Despite this taxonomic progress, the understanding of species boundaries and population variation within the genus remains limited. In response, an integrative study was undertaken, utilizing both morphological and molecular data from neotropical freshwater ecoregions with rivers that drain the Brazilian northeastern. The primary objective of this investigation was to elucidate taxonomic delimitations and, where relevant, propose new species hypotheses. Our results propose the existence of 15 operational taxonomic units (OTUs) as species hypotheses. Among these, 10 were identified as valid species, four represented morphotypes that hold the potential of constituting new species, and one OTU was determined as a new species, corroborated by all proposed delimitation methods. Our results demonstrated discrepancies between morphological and molecular data, highlighting the challenges in defining taxonomic boundaries within Characidium. Moreover, our findings provided insights into the intricate diversification history of Characidium species, applied to the species that occur in northeastern Brazilian drainages. We proposed that historical events, such as river connections and barriers, have played a significant role in shaping the current distribution patterns of the genus.

Pleistocene climate oscillations have shaped the expansion and contraction speciation model of the globose Eriosyce sect. Neoporteria cacti in Central Chile.

Pleistocene climatic oscillations, characterized by arid (interglacial) and pluvial (glacial) phases, have profoundly impacted the floras of Mediterranean climates. Our study investigates the hypothesis that these climatic extremes have promoted phases of range expansion and contraction in the Eriosyce sect. Neoporteria, resulting in pronounced genetic structuring and restricted gene flow. Using nuclear microsatellite markers, we genotyped 251 individuals across 18 populations, encompassing all 14 species and one subspecies within the Eriosyce sect. Neoporteria. Additionally, species distribution models were used to reconstruct past (Last Interglacial, Last Glacial Maximum and Mid-Holocene) and current potential distribution patterns, aiming to delineate the climatic influences on species range dynamics. The gene flow analysis disclosed disparate levels of genetic interchange among species, with marked restrictions observed between entities that are geographically or ecologically separated. Notably, Eriosyce subgibbosa from Hualpen emerged as genetically distinct, warranting its exclusion for clearer genetic clustering into north, central and south clusters. The species distribution models corroborated these findings, showing marked range expansions during warmer periods and contractions during colder times, indicating significant shifts in distribution patterns in response to climatic changes. Our findings emphasize the critical role of Pleistocene climatic fluctuations in driving the dynamic patterns of range expansions and contractions that have led to geographical isolation and speciation within the Eriosyce sect. Neoporteria. Even in the face of ongoing gene flow, these climate-driven processes have played a pivotal role in sculpting the genetic architecture and diversity of species. This study elucidates the complex interplay between climatic variability and evolutionary dynamics among mediterranean cacti in central Chile, highlighting the necessity of considering historical climatic millennial oscillations in conservation and evolutionary biology studies.

Evolutionary factors and habitat filtering affect the pattern of Gerbillinae diversity

Abstract How ecological and evolutionary factors affect small mammal diversity in arid regions remains largely unknown. Here, we combined the largest phylogeny and occurrence dataset of Gerbillinae desert rodents to explore the underlying factors shaping present-day distribution patterns. In particular, we analyzed the relative contributions of ecological and evolutionary factors on their species diversity using a variety of models. Additionally, we inferred the ancestral range and possible dispersal scenarios and estimated the diversification rate of Gerbilliane. We found that Gerbillinae likely originated in the Horn of Africa in the Middle Miocene and then dispersed and diversified across arid regions in northern and southern Africa and western and central Asia, forming their current distribution pattern. Multiple ecological and evolutionary factors jointly determine the spatial pattern of Gerbillinae diversity, but evolutionary factors (evolutionary time and speciation rate) and habitat filtering were the most important in explaining the spatial variation in species richness. Our study enhances the understanding of the diversity patterns of small mammals in arid regions and highlights the importance of including evolutionary factors when interpreting the mechanisms underlying large-scale species diversity patterns.

Phylogenetics, character evolution, and historical biogeography of the Neotropical genus Besleria (Gesneriaceae)

Abstract Besleria, a genus of perennial herbs, shrubs, or small trees growing in the understorey of rainforests, is one of the largest genera of neotropical Gesneriaceae, with over 165 species. Despite the ecological importance and ubiquity of Besleria in rainforest ecosystems, taxonomic and evolutionary studies of Besleria are limited. Here, we generated a phylogenetic analysis of Besleria using four nuclear and chloroplast DNA regions (ITS, matK, rps16, and trnL-trnF) covering more than 50% of the recognized species, along with two secondary calibration points to infer divergence times. Our results support the monophyly of Besleria and allowed us to revise the infrageneric classification and biogeographical history of the genus. We identified five major clades that do not correspond to sections or subsections in previous classifications. These clades are well circumscribed geographically but remain difficult to characterize using previously hypothesized morphological characters. Biogeographical reconstructions indicate an origin in the northern Andes during the Middle Miocene (ca. 15 Mya). The current distribution patterns of this plant group have been significantly shaped by geological and climatic events, particularly Andean uplift and the formation of the Panama Isthmus.

Taxonomy, distribution, and conservation status of a rare arboreal lizard, Bronchocela celebensis Gray, 1845 (Reptilia: Agamidae) endemic to Sulawesi, Indonesia.

Bronchocela celebensis Gray, 1845 is one of the rarest species of the genus, known only from less than 20 museum specimens collected from northern Sulawesi. It is often confused with its similar congener, B. cristatella, which occurs widely throughout the Indonesian Archipelago and Peninsular Malaysia, except on the Sulawesi mainland. Here, we examine the morphology of B. celebensis based on 46 museum specimens including freshly collected individuals, and redescribe the species based on the holotype (by monotypy). We studied the characters of B. celebensis with morphometric comparison to its allopatric congener B. cristatella from the adjacent islands of southern Sulawesi in Indonesia. Based on the current distribution pattern and the apparent threats, we update the conservation status of B. celebensis using the IUCN Red List Criteria and propose that it be considered as a Vulnerable (VU) species endemic to Sulawesi.