Evolutionary Patterns Research Articles

Investor behavior in crisis: a comparative study of fear-driven downtrends and confidence-led recoveries

PurposeThe purpose of this research is to investigate the differences between financial crises of fear and confidence and the differential behavior between downtrends and recovery.Design/methodology/approachFive national stock markets have been analyzed – the USA (SP500), China (Hang Seng), Spain (IBEX 35), Japan (Nikkei) and Germany (DAX) – through the evolution of three world economic crises: the mortgage bubble crisis of 2007 in the first place, with special attention to the bankruptcy of Lehman Brothers, which will be treated as an independent crisis process, and the crisis caused by COVID-19. The behavioral finance theory, with the support of the complexity theory in the field of risk management, will establish the different behavioral biases that explain the differences between the two types of crises, fear and confidence, when confronted with risk.FindingsEconomic crises resulting from a shocking event, addressed as crises of fear in this research, such as Lehman Brothers or COVID-19, are fast-moving; all the economies analyzed show a common pattern of evolution. The difference is found in the recovery periods in which the previous parallelism does not continue. Crisis events that arise from a social context, addressed as crises of trust in this research, follow similar patterns in their evolution; nonetheless, the start date presents higher variations than those originated by a shock. These crises also lack parallelism between fall and recovery.Practical implicationsUnderstanding crisis process patterns may help to prevent them and alleviate their effects when they occur.Originality/valueUnderstanding crisis process patterns may help to prevent them and alleviate their effects when they occur. This constitutes an original field of research.

TS-MAE: A masked autoencoder for time series representation learning

Self-supervised learning (SSL) has been widely researched in recent years. In Particular, generative self-supervised learning methods have achieved remarkable success in many AI domains, such as MAE in computer vision, well-known BERT, GPT in natural language processing, and GraphMAE in graph learning. However, in the context of time series analysis, not only is the work that follows this line limited but also the performance has not reached the potential as promised in other fields. To fill this gap, we propose a simple and elegant masked autoencoder for time series representation learning. Firstly, unlike most existing work which uses the Transformer as the backbone, we build our model based on neural ordinary differential equation which possesses excellent mathematical properties. Compared with the position encoding in Transformer, modeling the evolution patterns continuously could better extract the temporal dependency. Secondly, a timestamp-wise mask strategy is provided to cooperate with the autoencoder to avoid bias, and it also could reduce the cross-imputation between variables to learn more robust representations. Lastly, extensive experiments conducted on two classical tasks demonstrate the superiority of our model over the state-of-the-art ones.

A transcriptomic hourglass in brown algae.

Complex multicellularity has emerged independently across a few eukaryotic lineages and is often associated with the rise of elaborate, tightly coordinated developmental processes1,2. How multicellularity and development are interconnected in evolution is a major question in biology. The hourglass model of embryonic evolution depicts how developmental processes are conserved during evolution, and predicts morphological and molecular divergence in early and late embryogenesis, bridged by a conserved mid-embryonic (phylotypic) period linked to the formation of the basic body plan3,4. Initially found in animal embryos5-8, molecular hourglass patterns have recently been proposed for land plants and fungi9,10. However, whether the hourglass pattern is an intrinsic feature of all complex multicellular eukaryotes remains unknown. Here we tested the presence of a molecular hourglass in the brown algae, a eukaryotic lineage that has evolved multicellularity independently from animals, fungi and plants1,11,12. By exploring transcriptome evolution patterns of brown algae with distinct morphological complexities, we uncovered an hourglass pattern during embryogenesis in morphologically complex species. Filamentous algae without canonical embryogenesis display transcriptome conservation in multicellular stages of the life cycle, whereas unicellular stages are more rapidly evolving. Our findings suggest that transcriptome conservation in brown algae is associated with cell differentiation stages, but is not necessarily linked to embryogenesis. Together with previous work in animals, plants and fungi, we provide further evidence for the generality of a developmental hourglass pattern across complex multicellular eukaryotes.

Characteristics of Inherited Metabolic Disorders Following Kidney Transplantation: A 13-Year Observational Study

Background and Objectives: Inherited metabolic disorders (IMDs), primarily cystinosis, Fabry disease, and methylmalonic acidemia (MMA), are genetic conditions that typically result in multi-organ disease manifestations. Kidney function progressively deteriorates in many cases, with patients eventually reaching end-stage kidney disease (ESKD) and requiring renal replacement therapy. Kidney transplantation has been deemed the optimal renal replacement therapy option to achieve long-term survival in patients with IMD. Whilst improved long-term survival is expected, the patterns of clinical evolution for IMD after transplantation remain largely unknown. Methods: Our group conducted a retrospective observational study that included 37 adult patients with IMD (11 with cystinosis, 20 with Fabry disease, and 6 with MMA). The study evaluated the clinical status and progression of these patients following kidney transplantation between January 2010 and December 2023. Results: This generally resulted in good graft outcomes for patients with IMD. Standard immunosuppression regimes included tacrolimus, mycophenolate mofetil, and prednisolone. The mean graft survival duration was noted to be 12 years in patients with cystinosis, 11 years in patients with Fabry disease, and 7 years in patients with MMA. Suboptimal outcomes were noted with grafts of cadaveric origin and poor adherence to the prescribed post-transplant immunosuppression regime. A greater extra-renal morbidity burden was associated with a reduced duration of graft function and increased mortality in patients with IMD. Conclusions: Our findings emphasise the need for a multi-disciplinary approach in the care of IMD patients following kidney transplantation.

Regularities of decomposition of metastable phases in titanium pseudo-β-alloys

The results of a study of metastable phase decomposition in a titanium pseudo-β-alloy are presented. The paper considers main patterns of evolution of the structure and phase composition of a high-alloy titanium grades with a thermally unstable β-phase depending on the heat treatment mode. The influence of the isothermal holding temperature on the morphology and degree of recrystallization of the precipitating phase is shown. The results of the study indicate that low-temperature decomposition of the metastable β-phase in the alloy leads to its embrittlement.

Identification and Spatiotemporal Evolution Analysis of the Urban–Rural Fringe in Polycentric Cities Based on K-Means Clustering and Multi-Source Data: A Case Study of Chengdu City

Urban fringe areas, serving as transitional zones between urban and rural landscapes, are characterized by their transitional nature, high dynamics, and spatial heterogeneity. Identifying the extent of an urban–rural fringe (URF) and analyzing its evolutionary characteristics are crucial for urban planning and development. However, limited research exists regarding the identification of a URF and the analysis of its spatiotemporal evolution in polycentric cities. Using Chengdu as a case study, this research employed the K-means clustering method to identify the spatial extent and evolution patterns of the URF in Chengdu from 2010 to 2020 based on the spatiotemporal characteristics of multi-source data. The results indicate that (1) the K-means clustering method can reasonably and efficiently identify URF in polycentric cities; (2) Chengdu exhibited a polycentric urban structure with a “main center-subcenter” pattern, where the URF was adjacent to the main and subcenters, assuming an overall annular wedge shape; (3) there was a significant expansion of the URF in the northeast–southwest direction from 2010 to 2020, accompanied by substantial land use changes. The evolution of the URF was driven by the dual mechanisms of urban suburbanization and rural urbanization, exhibiting characteristics such as singular urban functions, dispersed and chaotic land use, fragmented landscapes, and increasing complexity. This study extended the research on URFs, aiding in the understanding of urban spatial growth patterns and providing decision support for the integrated development of urban and rural areas.

Impact of Digital Inclusive Finance and Environmental Regulation on Eco‐Efficiency of Farmland Utilization in China

ABSTRACTThe farmland pollution has threatened the lifeblood of people's livelihoods through the soil‐to‐crop system, and the resulting food safety risks are becoming more and more pronounced. Digital inclusive finance (DIF) can provide convenient financial services for the eco‐transformation of farmland utilization. This study analyzed the spatial evolution pattern of eco‐efficiency of farmland utilization (EEFU) and DIF, empirically tested the impact of DIF on EEFU, and discussed the impact of DIF on EEFU with changes in the level of environmental regulatory intensity based on panel data from 2011 to 2022 in China. The results found that the development of EEFU and DIF is increasing, and the polarization phenomenon is constantly easing, but the absolute differences between different provinces in China have an expanding trend. DIF can improve the EEFU, and this promotion effect is more pronounced in eastern and central China, non‐grain‐producing areas, and areas with low levels of financial development. DIF will not be able to improve EEFU until environmental regulation has reached a certain level. China should fully leverage the positive role of DIF and environmental regulations in promoting the EEFU, provide more differentiated financial products, financial tools, and financial models for the eco‐transformation of farmland utilization, and explore a path for eco‐transformation of farmland utilization that complements environmental regulations and development of market‐inclusive finance.

Genome-wide analysis and expression profile of the bZIP gene family in Neopyropia yezoensis.

The basic leucine zipper (bZIP) family consists of conserved transcription factors which are widely present in eukaryotes and play important regulatory roles in plant growth, development, and stress responses. Neopyropia yezoensis is a red marine macroalga of significant economic importance; however, their bZIP family members and functions have not been systematically identified and analyzed. In the present study, the bZIP gene family in Ny. yezoensis was characterized by investigating gene structures, conserved motifs, phylogenetic relationships, chromosomal localizations, gene duplication events, cis-regulatory elements, and expression profiles. Twenty-three Ny. yezoensis bZIP (NyybZIP) genes were identified and sorted into 13 out of 30 groups, which were classified based on the bZIPs of Ny. yezoensis and 15 other red algae species. Phylogenetic analysis revealed that bZIP genes may have a complex evolutionary pattern in red algae. Cross-species collinearity analysis indicated that the bZIP genes in Ny. yezoensis, Neoporphyra haitanensis, and Porphyra umbilicalis are highly evolutionarily conserved. In addition, we identified four main categories of cis-elements, including development-related, light-responsive, phytohormone-responsive and stress-responsive promoter sequences in NyybZIP genes. Finally, RNA sequencing data and quantitative real-time PCR (qRT-PCR) showed that NyybZIP genes exhibited different expression patterns depending on the life stage. NyybZIP genes were also found to be involved in the nitrogen stress response. We thought that bZIP genes may be involved in Ny. yezoensis growth and development, and play a significant role in nitrogen deficiency response. Taken together, our findings provide new insights into the roles of the bZIP gene family and provide a basis for additional research into its evolutionary history and biological functions.

The spatial-temporal evolution patterns of landslide-oriented resilience in mountainous city: A case study of Chongqing, China

Cities, as complex systems with multi-interconnected subsystems, face significant challenges from both rapid urbanization and climate change. Ensuring high resilience in urban areas is essential for managing these dynamic risks effectively. This study introduces an innovative, data-driven approach to quantitatively analyze the spatial-temporal evolution patterns of urban resilience, validated through a case study of Chongqing, a representative mountainous city in China. Based on historical landslide data from Chongqing (2010–2020), which includes 4464 events, along with indicator data from the Chongqing Statistical Yearbook, we developed a comprehensive assessment framework. This framework incorporates 33 variables, covering indicators of physical-environmental resilience (PER) and socio-economic resilience (SER). The model integrates the Random Forest (RF) algorithm, Analytic Hierarchy Process (AHP), and Coupling Coordination Degree (CCD) model. Key findings include: (1) Social development in mountainous cities like Chongqing follows a point-to-area pattern. Although there is an overall increase in SER, the CCD in more developed areas (Chongqing urban circle) was generally higher than in less developed areas (northeastern and southeastern Chongqing) (2) The PER model demonstrated exceptional performance (AUC values consistently above 0.95). Spatiotemporal evolution models reveal that Chongqing maintains a high overall PER. Notably, from 2019 to 2020, the proportion of administrative units classified as highly resilient peaked at 24.5%, marking a historical high. (3) Multi-year average rainfall primarily impacts PER (ranked first), while Gross Domestic Product (GDP) significantly affect SER. The development of multi-dimensional recovery indicators provides a robust framework for assessing resilience against landslides in mountainous cities. The CCD model illustrates the importance of regional dynamic coordinated development in resilience trajectories. This study provides a detailed blueprint for the scientific development of resilient mountainous cities, emphasizing the need for a spatial-temporal perspective on resilience and the benefits of coordinated regional development.

Assessing Watershed Flood Resilience Based on a Grid-Scale System Performance Curve That Considers Double Thresholds

Enhancing flood resilience has become crucial for watershed flood prevention. However, current methods for quantifying resilience often exhibit coarse spatiotemporal granularity, leading to insufficient precision in watershed resilience assessments and hindering the accurate implementation of resilience enhancement measures. This study proposes a watershed flood resilience assessment method based on a system performance curve that considers thresholds of inundation depth and duration. A nested one- and two-dimensional coupled hydrodynamic model, spanning two spatial scales, was utilized to simulate flood processes in plain river network areas with detailed and complex hydraulic connections. The proposed framework was applied to the Hangjiahu area (Taihu Basin, China). The results indicated that the overall trend of resilience curves across different underlying surfaces initially decreased and then increase, with a significant decline observed within 20–50 h. The resilience of paddy fields and forests was the highest, while that of drylands and grasslands was the lowest, but the former had less recovery ability than the latter. The resilience of urban systems sharply declined within the first 40 h and showed no signs of recovery, with the curve remaining at a low level. In some regions, the flood tolerance depth and duration for all land use types exceeded the upper threshold. The resilience of the western part of the Hangjiahu area was higher than that of other regions, whereas the resilience of the southern region was lower compared to the northern region. The terrain and tolerance thresholds of inundation depth were the main factors affecting watershed flood resilience. The findings of this study provide a basis for a deeper understanding of the spatiotemporal evolution patterns of flood resilience and for precisely guiding the implementation and management of flood resilience enhancement projects in the watershed.

The Effect of Dam Break Speed on Flood Evolution in a Downstream Reservoir of a Cascade Reservoir System

The dam break flood is one of the potential causes of catastrophic events in cascade hydropower hub groups. Investigating the movement patterns of dam break flooding among reservoir groups under different dam break speeds is crucial for flood prevention and emergency response. In this study, the evolution characteristics of dam break floods were investigated in a cascading reservoir system, focusing on different break speeds of the upstream dam. The results indicate that the dam break speed determines the concavity or convexity of the water level curve changes in the upstream reservoir. Accordingly, dam breaks are classified into three modes: instant dam break, fast dam break, and slow dam break. An approximate critical speed has been identified to differentiate between the fast dam break and slow dam break. Further investigation into the evolution patterns of dam break floods in downstream reservoirs under different break modes was conducted. Correspondingly, the flood peak discharge and peak arrival time of the dam break floods vary differently with break speed under different break modes. Finally, a theoretical analysis for the flood peak discharge at the dam site during gradual dam break at a certain speed was established, which is able to predict the over-dam flood peak discharge in fast and slow dam break modes. This study is based on a combination of laboratory flume experiments and three-dimensional numerical simulations. This study has theoretical significance for the reinforcement of public infrastructure safety and the prevention of natural disasters.

WRKY Transcription Factors (TFs) as Key Regulators of Plant Resilience to Environmental Stresses: Current Perspective

Plants encounter various stresses in their natural environments and can effectively respond to only one stress at a time. Through a complex gene network, transcription factors (TFs) such as WRKY TFs regulate a diverse array of stress responses. The clarification of the structural characteristics of WRKY proteins, along with recent advancements in molecular dynamics simulations, has shed light on the formation, stability, and interactions of DNA–protein complexes. This has provided a novel viewpoint regarding the control of WRKY TFs. The investigation of superfamilies, encompassing their historical development, diversity, and evolutionary patterns, has become feasible due to the transcriptome approach’s capacity to provide extensive and comprehensive transcripts. The significance of WRKY TFs lies in their pivotal role within several signaling cascades and regulatory networks that influence plant defense responses. The present review summarizes the functional aspects of the high-volume sequence data of WRKY TFs from different species studied to date. Moreover, a comparative analysis approach was utilized to determine the functions of the identified WRKY TFs in response to both abiotic and biotic stresses, as revealed through numerous studies on different plant species. The results of this review will be pivotal in understanding evolutionary events and the significance of WRKY TFs in the context of climate change, incorporating new scientific evidence to propose an innovative viewpoint.

Understanding scientific knowledge evolution patterns based on egocentric network perspective

Understanding scientific knowledge evolution patterns based on egocentric network perspective

Dynamic evolution of high-speed railway driver fatigue across scheduling shifts – a simulator study in China

ABSTRACT Scheduling significantly contributes to fatigue among high-speed rail (HSR) drivers, impacting both driving performance and safety. This study aims to analyse distinctiveness and evolutionary patterns of driver fatigue across different scheduling shifts, leveraging an HSR simulator and wearable devices. Through an extensive statistical examination, differences in most heart rate variability features were identified across shifts. The evolution of self-reported fatigue and physiological fatigue was investigated using a Markov chain and a hidden Markov model (HMM) that is extended using softmax regression, respectively. Results indicated a similarity in the initial fatigue state distribution and evolution trends across shifts, albeit with varying degrees of fluctuation. Morning shifts exhibited a higher likelihood of fatigue accumulation. The study revealed that even adequate pre-rest did not entirely counterbalance the impact of circadian rhythms. These findings may contribute to comprehending the temporal dynamics of driver fatigue evolution and offer insights for optimizing driver scheduling practices.

Evolution and simulation optimization of rural settlements in urban-rural integration areas from a multi-gradient perspective: A case study of the Lan-Bai urban agglomeration in China

With the rapid growth of global urbanization, rural land has been continuously occupied, which has brought about profound changes in human-land relationship. As a rural regional system in the frontier area of urbanization, the rural settlements in the urban-rural integration area (URIA) are in a profound transformation due to multiple disturbances such as internal natural factors and social and economic factors brought about by external urbanization. Based on the internal and external system factors of rural settlements, this paper constructs an analytical framework to explore the spatial and temporal evolution pattern of URIA rural settlements from 2000 to 2020, and then summarizes its evolution model, and predicts the situation of rural settlements in different scenarios in 2030. Finally, the optimal control strategy is proposed. The results show that: (1) From 2000 to 2020, affected by the gradient of natural environment, the scale of rural settlements in URIA shows a trend of decreasing in low-altitude areas near rivers and increasing in high-altitude areas far from rivers. Under the socio-economic gradient, there is a phenomenon that the scale of rural settlements in the inner edge of URIA with better socio-economic environment decreases and the scale of settlements in the outer area of URIA with poor socio-economic environment increases. (2) Based on different environmental factors, in the internal natural environment, it shows the evolution mode of “terrain containment” and “water source guidance”, while in the socio-economic environment, it shows the evolution mode of “urban sprawl encroaches rural”, “population decrease and land increase”. (3) The simulation results of rural settlements in 2030 show that the scale of rural settlements in the periphery of URIA continues to increase under the natural development (ND) scenario, while the scale of rural settlements in the inner edge decreases and the distribution is scattered. Under the urban-rural integration development (URD) scenario, rural settlements are mainly concentrated in the core area of URIA, and the area of rural settlements turning into urban land has dropped significantly. (4) Based on different gradients, the settlements are divided into three types: centralized development type, restricted development type and migration remediation type. Patch reconstruction is carried out by gravity model, which can theoretically save land and vacate 327 hm2 of construction land index. Compared with the extensive development model of the ND scenario, the URD scenario has important theoretical significance in limiting the blind expansion of the city and realizing the integration of urban and rural development in Lanbai.

Spatial and temporal evolution patterns and driving mechanisms of rural settlements: a case study of Xunwu County, Jiangxi Province, China

Urbanization and industrialization have driven rapid socio-economic development, leading to a significant population shift from rural areas to cities. This demographic transition has resulted in substantial changes in rural settlements, presenting considerable challenges for rural revitalization. Given the spatial differentiation, it is crucial to analyze the spatiotemporal evolution patterns and driving mechanisms of rural settlements under various development scenarios and at multiple scales within a county. Such analysis is essential for rational planning and sustainable development. This study analyzes the spatial and temporal evolution patterns and driving mechanisms of rural settlements in Xunwu County, Jiangxi Province, China, using land use dynamics, hot and cold spot analysis, and center of gravity migration models. The Multiscale Geographically Weighted Regression Model (MGWR) is employed to explore their transformation driving mechanisms. The results show that during 2010–2020 in the study area, the total change rate of rural settlements was 39.82%, with a dynamic degree of 2.87%. The average centroid of the settlements is located in Wenfeng Township, gradually migrating southeastward by 3.7 km. Cold spots are shrinking northward, while hotspots are gathering in Chengjiang Town. Socio-economic conditions dominate the evolution of rural clusters in this region, showing obvious spatial heterogeneity. This is followed by locational conditions that are weakening in influence, while the impact of natural geographical conditions exists in the northeast region. The research findings offer a scientifically rigorous and well-founded analysis of the evolution and driving mechanisms of rural settlements. This analysis provides a solid theoretical basis for policy planning in urban-rural integrated development and supports the sustainable growth of rural communities.

Quantitative simulation and validation of energy carbon emission efficiency changes in Chinese urban agglomerations

In the context of the global energy dilemma, enhancing energy efficiency has inevitably become a pivotal strategy for mitigating energy waste and promoting sustainable development. Urban agglomerations, as growth poles leading high-quality regional economic development, play a significant role in this process. Within these urban agglomerations, the aggregation of various factors and the substitution of energy resources substantially influence the energy carbon emission efficiency (ECEE) of surrounding cities during their development and maturation phases. This study initially employs a three-stage Data Envelopment Analysis (DEA) to quantitatively analyze the ECEE values of 19 urban agglomerations from 2006 to 2020. It then establishes a methodology for calculating the joint intensity (JI) and joint threshold (JT) of ECEE within these urban agglomerations. Finally, a validation process is executed using MATLAB simulation and verification methodology to fit and authenticate the evolutionary patterns of ECEE in Chinese urban agglomerations. The primary objective of this research is to model the evolution of ECEE, thereby exploring the sustainable development pathways for urban agglomerations in China. The research findings indicate that: (1) The results from the three-stage DEA demonstrate that, after removing the influences of external environmental factors and random errors, the comprehensive technical efficiency (TE) of energy carbon emissions for the 19 urban agglomerations in China experienced a wave-like increase, rising from 0.410 to 0.506 between 2006 and 2020. (2) The calculation results of the constructed JI model indicate that the JT values of ECEE for national-level, regional-level, and local-level urban agglomerations are 1006.92, 226.60, and 160.14, respectively. The national-level urban agglomerations have significantly higher JT values and JI than the other two levels of urban agglomerations. (3) The results of the Matlab simulation verification show that 16 urban agglomerations fit well with the wave-like ascending evolutionary pattern. However, four urban agglomerations exhibit an opposite fitting effect due to the influence of their pillar industries or the small number of cities within these accumulations, making them unrepresentative. Consequently, the evolutionary curve of ECEE in Chinese urban agglomerations generally exhibits a wave-like upward trend over time.

Genomic analyses of the southern and eastern yellowjacket wasps (Hymenoptera: Vespidae) reveal evolutionary signatures of social life

Abstract Insects have evolved remarkably complex social systems. Social wasps are particularly noteworthy because they display gradations in social behaviors. Here, we sequence the genomes of two highly diverged Vespula wasps, V. squamosa and V. maculifrons Buysson (Hymenoptera: Vespidae), to gain greater insight into the evolution of sociality. Both V. squamosa and V. maculifrons are social wasps that live in large colonies characterized by distinct queen and worker castes. However, V. squamosa is a facultative social parasite, and V. maculifrons is its frequent host. We found that the genomes of both species were ~200 Mbp in size, similar to the genome sizes of congeneric species. Analyses of gene expression from members of different castes and developmental stages revealed similarities in expression patterns among immature life stages. We also found evidence of DNA methylation within the genome of both species by directly analyzing DNA sequence reads. Moreover, genes that were highly and uniformly expressed were also relatively highly methylated. We further uncovered evidence of differences in patterns of molecular evolution in the two taxa, consistent with V. squamosa exhibiting alterations in evolutionary pressures associated with its facultatively parasitic or polygyne life history. Finally, rates of gene evolution were correlated with variation in gene expression between castes and developmental stages, as expected if more highly expressed genes were subject to stronger levels of selection. Overall, this study expands our understanding of how social behavior relates to genome evolution in insects.

Sequence comparison of the mitochondrial genomes of five caridean shrimps of the infraorder Caridea: phylogenetic implications and divergence time estimation

BackgroundThe Caridea, affiliated with Malacostraca, Decapoda, and Pleocyemata, constitute one of the most significant shrimp groups. They are widely distributed across diverse aquatic habitats worldwide, enriching their evolutionary history. In recent years, considerable attention has been focused on the classification and systematic evolution of Caridea, yet controversies still exist regarding the phylogenetic relationships among families.MethodsHere, the complete mitochondrial genome (mitogenome) sequences of five caridean species, namely Heterocarpus sibogae, Procletes levicarina, Macrobrachium sp., Latreutes anoplonyx, and Atya gabonensis, were determined using second-generation high-throughput sequencing technology. The basic structural characteristics, nucleotide composition, amino acid content, and codon usage bias of their mitogenomes were analyzed. Selection pressure values of protein-coding genes (PCGs) in species within the families Pandalidae, Palaemonidae, and Atyidae were also computed. Phylogenetic trees based on the nucleotide and amino acid sequences of 13 PCGs from 103 caridean species were constructed, and divergence times for various families within Caridea were estimated.ResultsThe mitogenome of these five caridean species vary in length from 15,782 to 16,420 base pairs, encoding a total of 37 or 38 genes, including 13 PCGs, 2 rRNA genes, and 22 or 23 tRNA genes. Specifically, L. anoplonyx encodes an additional tRNA gene, bringing its total gene count to 38. The base composition of the mitogenomes of these five species exhibited a higher proportion of adenine-thymine (AT) bases. Six start codons and four stop codons were identified across the five species. Analysis of amino acid content and codon usage revealed variations among the five species. Analysis of selective pressure in Pandalidae, Palaemonidae, and Atyidae showed that the Ka/Ks values of PCGs in all three families were less than 1, indicating that purifying selection is influencing on their evolution. Phylogenetic analysis revealed that each family within Caridea is monophyletic. The results of gene rearrangement and phylogenetic analysis demonstrated correlations between these two aspects. Divergence time estimation, supported by fossil records, indicated that the divergence of Caridea species occurred in the Triassic period of the Mesozoic era, with subsequent differentiation into two major lineages during the Jurassic period.ConclusionsThis study explored the fundamental characteristics and phylogenetic relationships of mitogenomes within the infraorder Caridea, providing valuable insights into their classification, interspecific evolutionary patterns, and the evolutionary status of various Caridea families. The findings provide essential references for identifying shrimp species and detecting significant gene rearrangements within the Caridea infraorder.

A New Pattern of Phytomelanin Deposition in Cypselae of Bahieae (Asteraceae, Heliantheae Alliance)

ABSTRACTPhytomelanin is the dark and highly inert substance found in the fruit walls of the Heliantheae alliance clade within Asteroideae (Asteraceae). Phytomelanin deposition pattern in the cypselar wall was studied in two taxa of the Bahieae—Bahia pedata A. Gray and Palafoxia arida B. L. Turner. The pericarp anatomy studies have revealed that the phytomelanin deposits in the schizogenous space between the hypodermis and fiber layer. Our findings reveal that phytomelanin deposition is associated with fiber and has also brought out a new pattern of phytomelanin deposition between inner (fibrous zone) and outer sclerified layers (hypodermal) in the schizogenous space. The study recorded a first‐time report of a second layer of phytomelanin outer to the sclerified hypodermal cells at maturity. Our observations point to phytomelanin precursors being synthesized as pliable fluid substances associated with fiber cells and solidifies later in the intercellular space. The study also recorded the first report for the occurrence of tracheoidal cells in the pericarp wall of the Bahieae within the Heliantheae alliance. Our study has provided insights to decipher evolutionary patterns and the significance of phytomelanin in the phytomelanic fruit clade (PFC), and it could help to resolve long‐standing debates on deposition patterns and the site of synthesis of phytomelanin.