Diversity Dynamics Research Articles

Spatio-temporal dynamics of net primary productivity and the economic value of Spartina alterniflora in the coastal regions of China

This study employs an improved Carnegie–Ames–Stanford Approach (CASA) model to calculate the Net Primary Productivity (NPP) of Spartina alterniflora (SA) and various other land use/land cover types (LULC) across coastal China over multiple years. The research aims to provide significant theoretical and practical insights into carbon sink research in coastal zones, sustainable development, and resource management. Key findings include identifying the first εmax value of 2.219 g C/MJ for SA, addressing a critical data gap in CASA modeling research on invasive plants. SA's NPP exhibited higher values in Shanghai and Zhejiang due to factors such as genetic diversity, invasion duration, and tidal dynamics. In contrast, other LULC exhibited higher NPP values in southern and inland regions, characterized by greater vegetation cover and favorable growing conditions. In 2020, SA and other LULC sequestered 16.352 kt C and 0.821*106 kt C, respectively. From 2000 to 2020, the average annual NPP and total carbon storage of SA and other LULC increased significantly, primarily driven by Shanghai and deciduous needleleaf forests, respectively. Seasonal NPP trends followed summer> spring> autumn> winter, influenced by climate conditions and plant life activities. Economic assessments in 2020 estimated SA's carbon storage value at RMB0.409 billion (Market Value method) or RMB5.562 billion (Carbon Tax method), with RMB2.054 billion attributed to oxygen release values, underscoring its economic and ecological potential. Among other LULC, evergreen broadleaf forests showed the highest carbon storage value (RMB183.463 billion). The study emphasizes the critical role of all LULC in carbon storage and oxygen release, advocating for targeted conservation and land management strategies. It suggests that managing SA should balance stringent control in high-risk areas, lenient measures in low-risk areas, eradication of scattered populations, and maximizing ecological benefits in retention areas, with continuous monitoring and adaptive management strategies to balance conservation and development efforts.

Responses of soil fungal community composition and function to wetland degradation in the Songnen Plain, northeastern China.

Wetlands are ecosystems that have a significant impact on ecological services and are essential for the environment. With the impacts of rapid population growth, wetland reclamation, urbanization, and land use change, wetlands have undergo severe degradation or loss. However, the response of soil fungal communities to wetland degradation remains unknown. It is crucial to comprehend how the diversity and population dynamics of soil fungi respond to varying levels of degradation and ecological progression in the wetlands of the Songnen Plain. In this study, high- throughput sequencing technology to analyze the variety and abundance of soil fungi in the undegraded (UD), light degraded (LD), moderate degraded (MD), and severe degraded (SD) conditions in the Halahai Nature Reserve of Songnen Plain. This study also explored how these fungi are related to the soil's physicochemical properties in wetlands at various degradation levels. The findings indicated that Basidiomycota and Ascomycota were the primary phyla in the Songnen Plain, with Ascomycota increasing and Basidiomycota decreasing as wetland degradation progressed. Significant differences were observed in soil organic carbon (SOC), total nitrogen (TN),and soil total potassium (TK) among the succession degradation stages. With the deterioration of the wetland, there was a pattern of the Shannon and Chao1 indices increasing and then decreasing. Non-metric Multidimensional Scaling (NMDS) analysis indicated that the fungal community structures of UD and LD were quite similar, whereas MD and SD exhibited more distinct differences in their fungal community compositions. Redundancy analysis (RDA) results indicated that Soil Water content (SWC) and total nitrogen (TN) were the primary environmental factors influencing the dominant fungal phylum. According to the FUNGuild prediction, Ectomycorrhizal and plant pathogens gradually declining with wetland degradation. In general, our findings can offer theoretical support develop effective solutions for the preservation and rehabilitation of damaged wetlands.

Generic diversity and septal complexity in Cretaceous ammonoids. Effects of oceanic anoxic events on the ammonoid evolutionary dynamic

AbstractThis paper analyzes the relationship between the number of genera of Cretaceous planiespiral ammonoids and their sutural complexity estimated by their fractal dimension. It is confirmed that the dynamics of generic diversity is associated with the appearance/disappearance of simple suture genera, which are not ascribed to a particular family. The maximum oscillations of generic diversity occur in the Aptian and Albian which are associated with large variations in the number of genera with simple sutures. From the Middle Campanian there is a continued loss of diversity until the end of the Maastrichtian linked to a net reduction of single suture genera. The direct relationship between the number of genera and the range of septal complexity in each substage indicates that different degrees of septal complexity are different ecomorphological strategies of adaptation to different niches. This result confirms that the specialist forms are those with simple sutures while the genera with complex septa are either generalist forms or are adapted to environments that do not undergo major fluctuations over geological time. The ammonoid generic diversity recorded dynamics is different from that of other marine invertebrates, reflecting paleobiological and/or taphonomic differences. The symmetrical distribution of septal complexity values points to the relative fidelity of the fossil record of Cretaceous ammonoids. The effect of seven oceanic anoxic events of the Cretaceous on the number of genera and septal complexity is analyzed, obtaining no statistically distinguishable effects of the oscillations of these variables with respect to those occurring in other intervals where such events are not recorded.

Reassessing the Early Devonian flora from Consthum Quarry (Luxembourg)

The Early Devonian plant fossil record provides evidence of large vegetation turnover events in addition to rapid morphological and anatomical changes among vascular plants. The Ardenno-Rhenish Massif has historically yielded a vast number of these plant fossils allowing us to obtain a nearly unparalleled snapshot of Early Devonian vegetation. Nonetheless, the interest for describing or redescribing fossil floras from this region has waned in recent years despite their inherent value to understand Early Devonian plant diversity dynamics. Here, we describe a newly collected macrofossil flora from the middle Emsian Schuttbourg Formation at Consthum Quarry (Luxembourg). Six different plant macrofossil taxa were identified, including Drepanophycus spinaeformis and Psilophyton cf. princeps, in addition to putative macroalgal and fungal remains. The flora also includes other equivocal specimens resembling Sawdonia, Huvenia and Zosterophyllum. The composition of the assemblage is extremely similar, at generic level, to older Pragian–early Emsian and coeval floras from nearby localities, which indicates that there was no major floral turnover until the latter part of the Emsian in this region. Taxonomic descriptions also highlight many of the underlying issues in identifying Early Devonian sterile specimens. Inconsistencies in plant fossil identifications from this region call for a thorough revision of Belgian and German floras that together could provide a high-resolution picture of plant diversity changes in the Early Devonian.

Exploring microbial diversity in the rhizosphere: a comprehensive review of metagenomic approaches and their applications.

The rhizosphere, the soil region influenced by plant roots, represents a dynamic microenvironment where intricate interactions between plants and microorganisms shape soil health, nutrient cycling, and plant growth. Soil microorganisms are integral players in the transformation of materials, the dynamics of energy flows, and the intricate cycles of biogeochemistry. Considerable research has been dedicated to investigating the abundance, diversity, and intricacies of interactions among different microbes, as well as the relationships between plants and microbes present in the rhizosphere. Metagenomics, a powerful suite of techniques, has emerged as a transformative tool for dissecting the genetic repertoire of complex microbial communities inhabiting the rhizosphere. The review systematically navigates through various metagenomic approaches, ranging from shotgun metagenomics, enabling unbiased analysis of entire microbial genomes, to targeted sequencing of the 16S rRNA gene for taxonomic profiling. Each approach's strengths and limitations are critically evaluated, providing researchers with a nuanced understanding of their applicability in different research contexts. A central focus of the review lies in the practical applications of rhizosphere metagenomics in various fields including agriculture. By decoding the genomic content of rhizospheric microbes, researchers gain insights into their functional roles in nutrient acquisition, disease suppression, and overall plant health. The review also addresses the broader implications of metagenomic studies in advancing our understanding of microbial diversity and community dynamics in the rhizosphere. It serves as a comprehensive guide for researchers, agronomists, and policymakers, offering a roadmap for harnessing metagenomic approaches to unlock the full potential of the rhizosphere microbiome in promoting sustainable agriculture.

Diversity trends among faculty in STEM and non-STEM fields at selective public universities in the U.S. from 2016 to 2023

During the 2015–2016 academic year, racial protests swept across college campuses in the U.S. These protests were followed by large university investments in initiatives to promote diversity, which combined with existing diversity dynamics, have helped to shape recent faculty diversity trends. We document diversity trends among faculty in STEM and non-STEM fields since the protests in 2015–2016. We find that recent diversity trends are narrowing the gender gap among faculty in STEM and non-STEM fields, but widening racial-ethnic gaps, especially among Black faculty. A large body of prior research suggests these trends will affect students’ college experiences and how they choose majors.

Predefined-time convergence strategies for multi-cluster games in hybrid heterogeneous systems

This paper explores the problem of (generalized) Nash equilibrium search in multi-cluster games with heterogeneous dynamics and multiple constraints. Within this research framework, each agent acquires information solely through local interactions with its neighbors and forms clusters based on similarity of interests. These clusters manifest dual relationships of cooperation and competition: agents within the same cluster enhance decision-making capabilities through cooperation, while different clusters compete to maximize their respective benefits. To delve into these complex interactions among clusters and the learning and evolution processes among agents, four distributed control algorithms suitable for various scenario requirements are designed and implemented. These algorithms ensure that each agent converges to a Nash equilibrium (NE) or generalized Nash equilibrium (GNE) of the multi-cluster system within predefined time points. Finally, we apply these algorithms to the connectivity control problem of unmanned aerial vehicle swarms with diverse dynamics, validating the theoretical results through comprehensive simulations.

Neuron configuration enhances the synchronization dynamics in ring networks with heterogeneous firing patterns

Neuron synchronization is fundamental for brain dynamics. While several efforts have been made to understand neuron coupling between tonic and bursting neurons, the position of neurons in a neural network and its relationship with synchronization is not fully understood. This work investigates the impact of neuronal heterogeneity on firing pattern transitions and synchronization in networks comprising tonic and bursting neurons. Using the Huber-Braun model, we explore two configurations: one with neurons grouped closely and another with maximal separation. Our findings reveal that while increased coupling strength generally promotes synchronization, the specific mix of neuron types and their spatial configuration crucially modulate both synchronization and firing pattern transitions, leading to phenomena such as cluster synchronization and global phase synchrony. The results indicate that the configuration with maximal separation and with mostly bursting neurons synchronizes more quickly. Firing pattern transitions are also configuration-dependent. For example, in the network with half tonic and half bursting, the configuration grouped closely undergoes diverse complex dynamics transition in the synchronized state, while the other configuration synchronize with chaotic bursting dynamics. Behaviors like cluster synchronization are observed in this network. The study underscores the significance of considering neuronal heterogeneity in understanding network dynamics.

Uncovering the drivers of CO2 emissions in the United States: The hidden spillover effects

This study explores the applicability of the Environmental Kuznets Curve (EKC) hypothesis in the United States (US) from 2006 to 2020, employing the Spatial Durbin Model (SDM) to analyze the cross-border effects of pollution among states. The results indicate that although economic growth initially decreases environmental degradation, it subsequently contributes to more significant environmental degradation, challenging the EKC hypothesis's validity at the US state level. Factors such as higher energy prices and reliance on fossil fuels are also identified as significant drivers of environmental deterioration, with varying impacts observed across states. Conversely, adopting renewable energy sources is crucial in mitigating pollution levels. The study underscores the importance of coordinated state-level efforts to harmonize economic growth with sustainable environmental practices. It highlights the complexities of policymaking in balancing economic development with environmental conservation and emphasizes the need for targeted interventions to address environmental challenges effectively. This research enhances our understanding of sustainable development pathways amidst diverse regional dynamics within the US by providing empirical evidence and policy insights.

Consequences of Local Conspecific Density Effects for Plant Diversity and Community Dynamics.

Conspecific density dependence (CDD) in plant populations is widespread, most likely caused by local-scale biotic interactions, and has potentially important implications for biodiversity, community composition, and ecosystem processes. However, progress in this important area of ecology has been hindered by differing viewpoints on CDD across subfields in ecology, lack of synthesis across CDD-related frameworks, and misunderstandings about how empirical measurements of local CDD fit within the context of broader ecological theories on community assembly and diversity maintenance. Here, we propose a conceptual synthesis of local-scale CDD and its causes, including species-specific antagonistic and mutualistic interactions. First, we compare and clarify different uses of CDD and related concepts across subfields within ecology. We suggest the use of local stabilizing/destabilizing CDD to refer to the scenario where local conspecific density effects are more negative/positive than heterospecific effects. Second, we discuss different mechanisms for local stabilizing and destabilizing CDD, how those mechanisms are interrelated, and how they cut across several fields of study within ecology. Third, we place local stabilizing/destabilizing CDD within the context of broader ecological theories and discuss implications and challenges related to scaling up the effects of local CDD on populations, communities, and metacommunities. The ultimate goal of this synthesis is to provide a conceptual roadmap for researchers studying local CDD and its implications for population and community dynamics.

The high-light-sensitivity mechanism and optogenetic properties of the bacteriorhodopsin-like channelrhodopsin GtCCR4

Channelrhodopsins are microbial light-gated ion channels that can control the firing of neurons in response to light. Among several cation channelrhodopsins identified in Guillardia theta (GtCCRs), GtCCR4 has higher light sensitivity than typical channelrhodopsins. Furthermore, GtCCR4 shows superior properties as an optogenetic tool, such as minimal desensitization. Our structural analyses of GtCCR2 and GtCCR4 revealed that GtCCR4 has an outwardly bent transmembrane helix, resembling the conformation of activated G-protein-coupled receptors. Spectroscopic and electrophysiological comparisons suggested that this helix bend in GtCCR4 omits channel recovery time and contributes to high light sensitivity. An electrophysiological comparison of GtCCR4 and the well-characterized optogenetic tool ChRmine demonstrated that GtCCR4 has superior current continuity and action-potential spike generation with less invasiveness in neurons. We also identified highly active mutants of GtCCR4. These results shed light on the diverse structures and dynamics of microbial rhodopsins and demonstrate the strong optogenetic potential of GtCCR4.

Mapping genome-wide diversity and population dynamics in Indian chicken breeds for targeted conservation and breeding

ABSTRACT 1. Genetic improvement and widespread use of artificial selection may have impacted the genetic make-up of Indian chicken breeds. The genetic architecture of contemporary chicken population of India needs to be assessed for future improvement and conservation programmes. This study utilised whole-genome sequences in 180 chicken samples from 16 indigenous breeds, along with the Red Jungle Fowl and the commercial White Leghorn. 2. A panel of 76 978 genome-wide single-nucleotide polymorphisms (SNP) was selected for comparative genome analysis after stringent screening. Breeds originating from the eastern regions of India exhibited higher genomic diversity, indicative of a rich repository of distinct germplasm. Conversely, the Uttara breed, from the northern hilly areas, display considerable genetic differentiation with diminished diversity compared to others, underscoring conservation concerns. The average coefficient (FIS) of 0.084 caution the need to mitigate risks associated with inbreeding. 3. The study revealed that the analysis of 76 978 genome-wide SNP will serve as a cornerstone in refining conservation strategies, to design interventions with greater precision. 4. The contribution of Red Jungle Fowl to the gene pool of all native breeds was supported by this study. Genetic structuring indicated a relationship among breeds based on geographical proximity, underscored by varying levels of admixture.

Intrahost evolution leading to distinct lineages in the upper and lower respiratory tracts during SARS-CoV-2 prolonged infection.

Accumulating evidence points to persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in immunocompromised individuals as a source of novel lineages. While intrahost evolution of the virus in chronically infected patients has previously been reported, existing knowledge is primarily based on samples from the nasopharynx. In this study, we investigate the intrahost evolution and genetic diversity that accumulated during a prolonged SARS-CoV-2 infection with the Omicron BF.7 sublineage, which is estimated to have persisted for >1 year in an immunosuppressed patient. Based on the sequencing of eight samples collected at six time points, we identified 87 intrahost single-nucleotide variants, 2 indels, and a 362-bp deletion. Our analysis revealed distinct viral genotypes in the nasopharyngeal (NP), endotracheal aspirate, and bronchoalveolar lavage samples. This suggests that NP samples may not offer a comprehensive representation of the overall intrahost viral diversity. Our findings not only demonstrate that the Omicron BF.7 sublineage can further diverge from its already exceptionally mutated state but also highlight that patients chronically infected with SARS-CoV-2 can develop genetically specific viral populations across distinct anatomic compartments. This provides novel insights into the intricate nature of viral diversity and evolution dynamics in persistent infections.

Mitochondrial DNA control-region and coding-region data highlight geographically structured diversity and post-domestication population dynamics in worldwide donkeys.

Donkeys (Equus asinus) have been used extensively in agriculture and transportations since their domestication, ca. 5000-7000 years ago, but the increased mechanization of the last century has largely spoiled their role as burden animals, particularly in developed countries. Consequently, donkey breeds and population sizes have been declining for decades, and the diversity contributed by autochthonous gene pools has been eroded. Here, we examined coding-region data extracted from 164 complete mitogenomes and 1392 donkey mitochondrial DNA (mtDNA) control-region sequences to (i) assess worldwide diversity, (ii) evaluate geographical patterns of variation, and (iii) provide a new nomenclature of mtDNA haplogroups. The topology of the Maximum Parsimony tree confirmed the two previously identified major clades, i.e. Clades 1 and 2, but also highlighted the occurrence of a deep-diverging lineage within Clade 2 that left a marginal trace in modern donkeys. Thanks to the identification of stable and highly diagnostic coding-region mutational motifs, the two lineages were renamed as haplogroup A and haplogroup B, respectively, to harmonize clade nomenclature with the standard currently adopted for other livestock species. Control-region diversity and population expansion metrics varied considerably between geographical areas but confirmed North-eastern Africa as the likely domestication center. The patterns of geographical distribution of variation analyzed through phylogenetic networks and AMOVA confirmed the co-occurrence of both haplogroups in all sampled populations, while differences at the regional level point to the joint effects of demography, past human migrations and trade following the spread of donkeys out of the domestication center. Despite the strong decline that donkey populations have undergone for decades in many areas of the world, the sizeable mtDNA variability we scored, and the possible identification of a new early radiating lineage further stress the need for an extensive and large-scale characterization of donkey nuclear genome diversity to identify hotspots of variation and aid the conservation of local breeds worldwide.

Viral diversity and co-evolutionary dynamics across the ant phylogeny.

Knowledge of viral biodiversity within insects, particularly within ants, is extremely limited with only a few environmental viruses from invasive ant species identified to date. This study documents and explores the viral communities in ants. We comprehensively profile the metagenomes of a phylogenetically broad group of 35 ant species with varied ecological traits and report the discovery of 3710 novel and unique ant-associated viral genomes. These previously unknown viruses discovered within this study constitute over 95% of all currently described ant viruses, significantly increasing our knowledge of the ant virosphere. The identified RNA and DNA viruses fill gaps in insect-associated viral phylogenies and uncover evolutionary histories characterized by both frequent host switching and co-divergence. Many ants also host diverse bacterial communities, and we discovered that approximately one-third of these new ant-associated viruses are bacteriophages. Two ecological categories, bacterial abundance in the host and habitat degradation are both correlated with ant viral diversity and help to structure viral communities within ants. These data demonstrate that the ant virosphere is remarkably diverse phylogenetically and genomically and provide a substantial foundation for studies in virus ecology and evolution within eukaryotes. We highlight the importance of studying insect-associated viruses in natural ecosystems in order to more thoroughly and effectively understand host-microbe evolutionary dynamics.

Variability of genetic diversity of spring barley by hordeincoding locus over a 40-year period of scientific breeding in the Krasnoyarsk Territory

The article discusses and summarizes the results of studies of polymorphism of hordeins (HRD) of spring barley by electrophoresis at the Krasnoyarsk Research Institute of Agriculture (KNIISH) for the period from 1988 to 2021. The analysis of the dynamics of the genetic diversity of barley varieties from the ecological and breeding nurseries of the KNIISKh, released and approved for use in the Krasnoyarsk Territory, showed a significant narrowing of the frequency of occurrence and the loss of a number of alleles characteristic of the conditions of the Yenisei Siberia, and the appearance of rare variants for the Siberian region. Based on long-term observations of the composition of hordeins of breeding samples (promising and rejection) created in different areas of breeding, a number of alleles were found to be associated with economically valuable traits.

Investigating the biological diversity and ecological dynamics of oceanic fishery resources in the Andaman Sea, Indian Ocean

This research paper investigates the oceanic fishery resources of the Andaman archipelago. The primary objective of this study is to gain a comprehensive understanding of the fishery and its dynamics including the environmental linkage surrounding these oceanic resources and to develop an effective strategy for sustainable exploration. Data were collected during an exploratory tuna long-line survey conducted between July 2022 and February 2023. The study documented a total of 13 species of fishes belonging to 11 genera, with tuna being the most abundant. Additionally, the study observed a significant increase in the population of pelagic stingrays, which nearly matched the number of hooked sharks (32). However, the hooking rates of sharks and bill fishes were observed to be gradually declining, resulting in a lower contribution to the overall species composition. One notable finding of the study was that site 11oN; 93oE (S4) exhibited the highest species diversity and potential. Furthermore, the aggregate hooking rates of fishes were particularly high between latitudes 11oN and 12oN. The study also analysed the seasonal distribution of each fish species and explored the correlation between environmental factors such as depth and temperature with species abundance and distribution. Statistical analysis indicates that there is no significant variation (p value = 0.20) between the environmental factors and the frequency of the species occurrence. Specifically, depth shows the highest correlation (r = 0.57) with the species distribution. In light of the diminishing hooking rate of oceanic fishery resources, the study puts forth several possible reasons and emphasizes the urgent need to implement conservation measures.

Profiling cell identity and tissue architecture with single-cell and spatial transcriptomics.

Single-cell transcriptomics has broadened our understanding of cellular diversity and gene expression dynamics in healthy and diseased tissues. Recently, spatial transcriptomics has emerged as a tool to contextualize single cells in multicellular neighbourhoods and to identify spatially recurrent phenotypes, or ecotypes. These technologies have generated vast datasets with targeted-transcriptome and whole-transcriptome profiles of hundreds to millions of cells. Such data have provided new insights into developmental hierarchies, cellular plasticity and diverse tissue microenvironments, and spurred a burst of innovation in computational methods for single-cell analysis. In this Review, we discuss recent advancements, ongoing challenges and prospects in identifying and characterizing cell states and multicellular neighbourhoods. We discuss recent progress in sample processing, data integration, identification of subtle cell states, trajectory modelling, deconvolution and spatial analysis. Furthermore, we discuss the increasing application of deep learning, including foundation models, in analysing single-cell and spatial transcriptomics data. Finally, we discuss recent applications of these tools in the fields of stem cell biology, immunology, and tumour biology, and the future of single-cell and spatial transcriptomics in biological research and its translation to the clinic.

RNA tertiary structure and conformational dynamics revealed by BASH MaP.

The functional effects of an RNA can arise from complex three-dimensional folds known as tertiary structures. However, predicting the tertiary structure of an RNA and whether an RNA adopts distinct tertiary conformations remains challenging. To address this, we developed BASH MaP, a single-molecule dimethyl sulfate (DMS) footprinting method and DAGGER, a computational pipeline, to identify alternative tertiary structures adopted by different molecules of RNA. BASH MaP utilizes potassium borohydride to reveal the chemical accessibility of the N7 position of guanosine, a key mediator of tertiary structures. We used BASH MaP to identify diverse conformational states and dynamics of RNA G-quadruplexes, an important RNA tertiary motif, in vitro and in cells. BASH MaP and DAGGER analysis of the fluorogenic aptamer Spinach reveals that it adopts alternative tertiary conformations which determine its fluorescence states. BASH MaP thus provides an approach for structural analysis of RNA by revealing previously undetectable tertiary structures.

The effect of the Tethyan seaway closure on the Oligo−Miocene marine benthic diversity and distribution around Eurasia

The Cenozoic evolution of the Tethyan seaway significantly shaped marine and terrestrial biota around Eurasia. The Tethys Ocean connected the Atlantic and the Pacific during the early Cenozoic, allowing marine faunal exchange. However, during the early Miocene, the ‘ Gomphotherium Landbridge’ developed, restricting the marine connection between the proto-Mediterranean in the west and the provinces of the eastern Tethys Ocean. In contrast to the well-documented phenomena of terrestrial mammalian exchange through the land connection brought about by the closure, little is known about its impact on the marine fauna. To assess the overall effect of this separation on the distribution and diversity of marine organisms, we studied the Oligo−Miocene fossil record of marine benthos including Cnidaria, Echinodermata, Foraminifera and Mollusca. We compiled 15 894 reported occurrences from the early Oligocene to late Miocene comprising 1477 genera, 404 families and 85 orders from four faunal provinces and evaluated their palaeobiogeographic patterns. Our study demonstrates that the proportion of genera shared between the eastern and western provinces decreased after the early Miocene. The majority of the non-shared families developed during or after the early Miocene. High faunal diversity during the early Miocene and increasing endemicity among the eastern provinces are consistent with the development of a shallow seaway that supported speciation and reduced biotic exchange. The considerable variation in the magnitude and timing of the response across taxonomic groups reflects the combined effects of preservation bias and the differential responses of fauna. Our study supports an early Miocene initiation of the Tethyan seaway closure, followed by intermittent connectivity before the complete closure. This closure and its climatic consequences influenced the evolution of the Eurasian biota. Future studies should use a multidisciplinary approach combining the fossil record, genetic divergence and climate proxies to fully understand the effects of environmental changes and the seaway closure on marine benthos diversity dynamics.