Calcified cyanobacteria and associated microfossils were systematically investigated in 10 shallow-marine carbonate sections – reefal and non-reefal – from Cambrian Series 2 of the Yangtze Platform, South China. A total of 15 species in 10 genera of calcified cyanobacteria and 5 species in 3 genera of Microproblematica were identified, including 2 new species (StreptubulariarobustusXianella mollisGirvanella, Subtifloria, Razumovskia, Acuasiphonoria, Xianella, and StreptubulariaKordephyton, Bija, Hedstroemia, and BotomaellaRenalcis, Izhella, and EpiphytonAcuasiphonoria, Razumovskia, Subtifloria, Xianella, Bija, and BotomaellaAcuasiphonoria
This study tests the hypothesis that benthic foraminiferal assemblages in Indonesian seas exhibit systematic depth zonation, with environmental controls shifting from physical factors in shallow waters to biochemical factors in deep waters. We established a comprehensive regional indicator set spanning six bathymetric zones (transitional, inner neritic, middle neritic, outer neritic, upper bathyal, and lower bathyal) based on 35 surface sediment samples collected from 0–4327 m water depths across the Indonesian seas. Statistical analysis, combining indicator value (IndVal), detrended correspondence analysis (DCA), and hierarchical cluster analysis using Bray–Curtis dissimilarity, successfully discriminated assemblages with 89 % classification accuracy based on bathymetric zones. Results demonstrate a systematic increase in the percentage of planktonic foraminifera in relation to the whole fauna (%P) from 0 %–0.6 % in transitional environments to > 90 % in lower bathyal settings. Benthic species richness peaked at middle-neritic depths (47 species per sample) before declining in deeper waters, while planktonic diversity increased continuously with depth. Primary indicator taxa show clear bathymetric segregation: AmphisteginaSphaerogypsinaQuinqueloculinaPseudorotaliaBrizalina, Gyroidina, and CibicidesUvigerina, Bulimina, and Globobulimina
Accumulation rates of biogenic carbonates and opal, mainly produced by marine algae such as coccolithophores and diatoms, have been widely used to understand when and why the late Miocene to early Pliocene biogenic bloom occurred and how long it lasted. Information is still limited on the synchronicity of its termination, as well as the compositional signatures of the main carbonate producers across ocean basins, although recent studies have started to address this question. A recent study demonstrated that the biogenic bloom ended at ∼ 3.3 MaMa. Notably, the synchronous decrease in low-latitude paleoproductivity was accompanied by significant restructuring of the calcareous nannoplankton assemblages, at least offshore NW Australia (IODP Site U1463). Since coccolithophores are the main drivers of carbonate export production during the Neogene, such compositional shifts have the potential to be used as a first-order, biostratigraphic tool to identify the end of the biogenic bloom across ocean basins. To test this hypothesis, we compared the calcareous nannofossil compositions at ODP Site 1264 to those observed at IODP Site U1463 across the early Pliocene (5–3 Ma). This comparison reveals that although the main stepwise decrease in carbonate fluxes at Site 1264 occurred between ∼ 4.2–4.0 Ma, and therefore closer to the proposed synchronous end of the biogenic bloom in low latitudes, it was not accompanied by a change in the dominant coccolithophores. The widespread Pliocene rise of small Gephyrocapsa, as observed in the Indian Ocean, never occurred in this section of the South Atlantic. Instead, small Reticulofenestra∼ 3.5 Ma. This indicates that regional contrasts in the dominant bloom-forming coccolithophores, which underpin export production, may explain the observed differences in the timing of early Pliocene declines in carbonate accumulation.
Ecdysozoa (molting animals) represent one of the most diverse and ecologically successful animal groups in both extant and fossil ecosystems. This study presents new microfossil cuticular evidence from the lower Cambrian (∼535 Ma) Yanjiahe Formation (southern China) for ecdysozoan diversity during the Fortunian Stage. Six forms are recognized mainly based on their ornamented cuticular patterns, as well as characters of spines and sclerites, including potentially new scalidophorans and possible fragments of appendage-bearing panarthropods. The fossil assemblage, preserved through phosphatization, includes specimens exceeding 2 mm in size and displays a wide array of cuticular ornamentations organized into three main categories: spiny/sclerite-bearing fragments, appendage-like elements, and other undetermined cuticular remains. Remains of possible appendages (e.g., panarthropods) provide tentative but potentially key insights into the tempo of ecdysozoan radiation. The diversity of cuticular structures suggests the co-occurrence of diverse ecdysozoan body plans during the Fortunian, paralleling the early radiation of other metazoan lineages.
Ontogenetic information remains limited for many cypridoid ostracods despite its importance for reliable taxonomy, species identification, and the interpretation of ecological patterns based on size and morphology. This is particularly relevant in paleoecological studies, where, usually, only valves are preserved. We investigated post-embryonic development in three asexual species of HeterocyprisHeterocypris exodontaHeterocypris incongruensHeterocypris salina
Building on historical research, we report the discovery of planktonic foraminifera in sediments offshore Abu Dhabi. Surprisingly, the samples are dominated by Neogallitellia vivans, a rare species typically found in the Indo-Pacific. Our detailed analysis of its shell structure suggests that this tiny organism is uniquely adapted to the extreme salinity of the southern Arabian Gulf. This finding highlights the ability of marine life to thrive in harsh, hypersaline environments.
This study reports the first documented occurrence of planktonic foraminiferal assemblages from core and grab samples collected from the United Arab Emirates (UAE) sector of the Arabian Gulf, specifically from offshore Abu Dhabi. Although planktonic foraminifera were found at only 4 out of 20 surveyed sites, representing less than 5 % of the total foraminiferal assemblage, their presence is notable. This finding demonstrates that planktonic foraminifera can be found far from their typical habitat near the oceanic inlet to the semi-enclosed Arabian Gulf – the Strait of Hormuz. The recovered material includes at least five species (three true planktonic foraminifera, one with a planktonic adult stage, and one incertae sedis): Neogallitellia vivans, Globigerinoides tenellus, and Turborotalita clarkei, as well as the benthic–planktonic species Tretomphalus bulloidesBachmayerellaN. vivansµm sieve. This work is part of a broader project to re-examine localities in the southeastern Arabian Gulf that were previously studied for benthic foraminifera, as well as to explore areas further offshore, which were previously uncharted for their foraminiferal content (particularly for the presence of planktonic foraminifera).
Over the last few years, rapid advances in artificial intelligence, especially the application of convolutional neural networks (CNNs), have created new opportunities for automated microscopic image identification. Here we introduce a two-step pipeline for the automated detection and identification of Devonian miospore species by integrating object detection with downstream classification. Our workflow focused on three biostratigraphically important species occurring in the upper Frasnian sedimentary sequences of Armenia: Teichertospora torquata, Geminospora lemurata, and Samarisporites triangulatus. A YOLOv11-based detector localized initially individual miospore specimens on slide images, producing background-free crops and a size measure based on bounding-box area. The detector reached 98 % precision on the test set. The cropped spore images were then classified with the use of three different CNN architectures (VGG16, ResNet-18, and EfficientNet-B0), with size included as an additional numeric feature alongside the image input. Among the three tested models, ResNet-18 performed the best, achieving 87.9 % of classification accuracy. Our results show that combining modern detection with compact classification and morphometric information provides a practical route toward semi-automated palynology for Devonian spores.
Evolutionary developmental biology seeks to elucidate the developmental mechanisms underlying phenotypic evolution. Central to this endeavor is the quantitative analysis of morphological variation, for which morphometric approaches have become indispensable tools. While morphometric methods have been extensively applied in paleontological research across diverse fossil groups, certain taxa remain underexplored. Among these, ostracods (Crustacea) represent a particularly promising yet underutilized group for such analyses. The suitability of ostracods for evolutionary and developmental investigations stems from several key attributes: their near-ubiquitous distribution across aquatic habitats, a remarkable taxonomic and morphological diversity, and an exceptional fossil record spanning geological time scales.Traditional morphometric approaches are constrained by the time-intensive nature of data acquisition, limiting the extent of achievable datasets. To address this bottleneck, we evaluate the efficacy of AutoMorph, a high-throughput imaging pipeline, for automated extraction of size and shape data from ostracod valves. We apply this approach to two ostracod species, Leucocythere dorsotuberosaLeucocytherella sinensis, sampled from six lakes across the Tibetan Plateau, a region offering aquatic ecosystems with high endemism, providing an ideal setting for investigating ecological and evolutionary responses through morphological approaches. Our findings demonstrate that the AutoMorph pipeline successfully extracts morphometric measurements and coordinate data from ostracod valves, substantially reducing processing time while minimizing subjective bias inherent in manual approaches.This methodological advancement facilitates the generation of extensive datasets, thereby enabling more comprehensive investigations of ecological and evolutionary processes on large spatial and temporal scales.
The Lopingian stratigraphic framework of the western Hubei–eastern Chongqing (WHEC) area, South China, remains insufficiently constrained, particularly regarding the precise age of the organic-rich intervals within the Dalong Formation that are considered to be favorable for shale gas exploration. To address this issue, a refined conodont biostratigraphic framework is established based on systematic sampling of the Longmenba, Huangping, and Tongmuyuan sections. A total of 17 conodont species belonging to four genera (Jinogondolella, Clarkina, Hindeodus, and Iranognathus) are identified, allowing recognition of a near-continuous succession spanning the late Wuchiapingian to the Changhsingian. Integration of biostratigraphic and lithostratigraphic data allows placement of the Wuchiapingian–Changhsingian boundary within the upper part of the Dalong Formation, with minor local variations attributable to facies differences and preservation potential. Importantly, the organic-rich, siliceous-shale interval in the lower Dalong Formation is shown to be temporally restricted to the late Wuchiapingian, mainly corresponding to the upper Clarkina guangyuanensisC. orientalisC. longicuspidata
This study presents a detailed palynofacies analysis integrated with lacustrine sequence stratigraphy to evaluate the role of climate-driven hydrological balance on basin infill and its impact on the organic matter accumulation in the Jurassic Cañadón Asfalto Formation, Cerro Cóndor depocentre, Extra-Andean Patagonia, Argentina. It provides valuable insights into the changes in the nature and taphonomic history of the organic matter throughout the different stages of a lacustrine system's evolution based on the analysis of 51 outcrop samples from the Cañadón Lahuincó “A” section. Two depositional sequences are recognised. Sequence I documents the evolution from underfilled to balanced-fill/overfilled lake stages. Underfilled conditions are characterised by extreme lake-level variability, while the transition to balanced-fill/overfilled conditions is marked by stacked coarsening-upward successions. Sequence II is bounded by an abrupt accommodation increase and initially records renewed underfilled conditions, followed by the establishment of a fully overfilled lake stage characterised by persistent progradational stacking patterns. The most conspicuous feature of the Cañadón Asfalto Formation's organic matter is the overall dominance of land-derived fraction. The variations between the allochthonous and autochthonous (algae and algal-derived amorphous organic matter) material suggests variable climatic conditions, with the alternation of wetter and drier periods at least during the Sequence I and part of the Sequence II. Four palynofacies types (PT-A to PT-D) were defined recording variations in depositional energy, redox conditions, and sediment–water balance. PT-A and PT-D indicate wetter periods, while PT-B indicates relatively drier intervals. PT-C shows the changes between these two opposite situations. The underfilled stage is characterised by the dominance of reworked terrestrial phytoclasts (indicating high-energy inflow events) and poor sporomorph preservation. Conversely, the balanced-fill stage shows sporomorph-rich palynofacies. In both lake stages, blooms of well-preserved strong fluorescence Botryococcus
A zonation for the London Clay Formation, based on foraminifera, is presented for the first time, and the assemblage is used to determine the palaeoecological changes recorded in the succession. Within the lower Eocene there is evidence of a sea level rise and fall within the Early Eocene Climatic Optimum (EECO), indicating that this might potentially be a glacio-eustatic response to the EECO warming. The occurrence of larger foraminifera in the Lutetian–Bartonian interval of the Whitecliff Bay, Selsey Bill, offshore Jersey, and Cotentin Peninsula (France) successions also indicates a warming event (Late Lutetian Thermal Event and Middle Eocene Climatic Optimum, MECO) that may also have generated a glacio-eustatic response.
Bolivar-Feriche et al. (2025) conducted an integrated biostratigraphic study of some stratigraphic sections cropping out at the Sierra de Marmolance (SE Spain), proposing a significant extension of the chronostratigraphic ranges of several well-established Paleogene larger benthic foraminifera (LBF) into the Neogene (Middle Miocene; Langhian–Serravallian). While we agree with the taxonomic attributions of the planktonic foraminifera, we just underline the fact that their sampling locations and stratimetric correlation, although crucial in the general rationale, remain rather vague. Our main concern is with regards to the interpretation of the LBF assemblages as autochthonous. We suggest the most plausible interpretation, i.e., the reworking of LBF within a prograding ramp system, thus rebutting the newly proposed biostratigraphic ranges, which are both implausible and also in conflict with well-constrained ranges calibrated in all sections measured elsewhere in the Tethyan realm and beyond.
The Maastrichtian–Danian time interval corresponds to one of the largest mass extinctions in the Earth's geological history. We investigate changes in planktic foraminiferal assemblages and TEX
Dinoflagellate cysts (dinocysts) have a long-standing use as proxies due to their global distribution and ecological significance. Their application to reconstruct past primary productivity has been frequently debated in the literature, and different dinocyst-based proxies have been proposed. Moreover, region-specific calibrations of modern dinocyst assemblages in relation to water parameters and sediment properties are needed to strengthen the reconstructions, specifically in regions where multiple environmental parameters co-vary. This study evaluates the potential of dinocysts as proxies for net primary productivity (NPP) using 37 core-top samples from the Baltic Sea, North Sea, and Atlantic Ocean. Our calibration dataset spans a wide gradient of NPP and other parameters, including sea surface temperature, salinity and nutrients, seasonality, bottom water oxygen, depth of the water column, distance to shoreline, sediment total organic carbon (TOC) content and origin, and grain size. After confirming recent sediment deposition via 234Thorium measurements and excluding inner Baltic Sea assemblages due to preservation bias in low-oxygen bottom waters, the canonical correspondence analysis (CCA) identified NPP as the main variable associated with dinocyst distribution in this region. Our results regarding established dinocyst-based productivity proxies show that (i) total dinocyst concentration and flux correlate better with TOC than with NPP, (ii) the heterotrophic 
Organophosphatic brachiopods, widely distributed across several Cambrian tectonic plates, are crucial in understanding the evolution of early brachiopods. Here, we report newly discovered material of Schizopholis yorkensisS. yorkensisSchizopholisSchizopholis yorkensisS. napuru
Further strengthening the multidisciplinary stratigraphic and paleo-environmental analysis of the Global Stratotype Section and Point (GSSP) Bartonian–Priabonian boundary of the Alano di Piave section (NE Italy), here, we present a data report of a highly resolved, quantitative marine palynological study emphasizing organic walled dinoflagellate cysts (dinocysts). The ensuing dataset is interpreted in an exploratory sense through empirical paleo-ecological grouping and spectral analysis.The palynological assemblages are rich, diverse, and well-preserved, dominated by cosmopolitan, open marine dinocyst taxa, indicating a persistently distal, open marine depositional setting. Overall, the assemblages are remarkably stable, with no significant biotic reorganization recorded across the GSSP level. Evident paleo-environmental change is linked to the Middle Eocene Climatic Optimum (MECO) and its aftermath, where a sapropelic interval likely reflects a pluvial phase with enhanced runoff. Spectral analysis reveals that the influx of marginal marine dinocysts is strongly paced by the 400 kyr long eccentricity cycle. This suggests that orbital-scale climate changes, likely related to monsoonal intensity and runoff, controlled sediment transport from proximal settings. This data report includes the formal description of one new genus (BujakidiniumImpagidinium gedliiGuersteinia châteauneufiiGuersteinia?
Using the FORCIS database, we mapped the distribution of planktonic goraminifera that record past ocean conditions. Our study reveals that these species mostly inhabit the upper ocean and thrive in waters ranging from −2 °C to over 31 °C. Their range is shifting, with species once limited to warm regions now appearing in cooler areas and smaller species increasing in number. This work refines our view of their biogeography and how climate change is reshaping ocean life.
Planktonic foraminifera (PF) shells are ubiquitous archives used as proxies in paleoceanography and play a crucial role in paleoclimate reconstructions. Species respond differently to abiotic and biotic factors and have shifted habitats with recent ocean warming. We re-evaluate the biogeographic limits of major PF species in the modern ocean, using the FORCIS data to extend the data coverage and explore potentially overlooked distributions of (small) species from the seminal works from the 1950s to the 1970s that were based on > 200 µm−2 to 31 °C, highlighting their remarkable thermal tolerance and/or adaptability to a wide range of temperatures. In addition, species that displayed a preferential habitat in lower latitudes in the 1950-to-1970 time interval (e.g. G. ruber) have been observed at higher latitudes over the last 50 years. Since the 1970s, medium-sized species have increased in abundance across all latitudes, from the tropical to polar oceans, a trend particularly evident in the extensive data from the eastern North Atlantic. The analysis of the FORCIS database updates the evolving biogeography of modern PF and advances our understanding of their ecology, providing revised benchmarks for paleoceanographic interpretations and the ecology of modern planktonic calcifiers.
The Eocene–Oligocene transition (EOT) was a critical interval of global cooling and circulation change that reshaped marine ecosystems. However, current knowledge of diatom diversity and community dynamics during this interval relies mainly on biostratigraphic compilations, which largely document common species and thus likely underestimate true diversity. This study provides a more complete picture of Southern Ocean diatom communities across the EOT by using comprehensive quantitative surveys from four sites spanning the Atlantic and Indian Ocean sectors. Results reveal a consistent pattern across sites, with two major shifts in community composition around 37–36 and 34 Ma, linked to major environmental change. Following a prolonged interval of diversification without substantial extinction in the late Eocene, we identify a pronounced extinction event approximately 1 Myr after the Eocene–Oligocene boundary (E–O, ∼33.9 Ma). This suggests that significant changes in surface ocean conditions lagged the boundary and varied across the Southern Ocean. These findings highlight the interplay between global climate changes and local environmental factors in shaping diatom communities. By capturing detailed patterns of diatom diversity and extinction, our study improves our understanding of past ecological responses.
The genus ToweiusToweiusReticulofenestraToweiusToweiusToweiusToweiusToweiusToweius∼ 3 µm) and thin (sub)circular coccoliths with a larger central area, lower mass estimate, and thus reduced calcification compared to ToweiusToweiusToweiusToweiusToweius
Calcareous nannofossils are abundant and globally distributed fossils that are widely used in the study of stratigraphy and palaeoclimate. A large number of nannofossil data have been generated over the past several decades, but the information is distributed across the published scientific literature in a wide variety of formats, and data compilation has focussed on the Cenozoic. In Cretaceous marine sediments, nannofossils are a key group of microfossils, and they have been extensively studied for both biostratigraphy and palaeoceanography. However, only a fraction of these data have been compiled. In order to exploit this archive of palaeontological information, we have (1) extended the capabilities of the Mikrotax database system to allow compilation of occurrence data, (2) tested this by compiling a large set of Cretaceous nannofossil occurrence records (Uneptune database), and (3) developed a suite of tools for displaying these data on the Nannotax database system, including biogeographic maps, time–latitude plots, and occurrence frequency range charts. For the Uneptune database, we selected a range of published high-quality Cretaceous nannofossil datasets, screening the data to standardise the taxonomy and revise the age models where appropriate. The resulting database includes around 7000 samples, 500 species, and 175 000 occurrence records, which is 3 times the size of the previous largest Neptune Cretaceous database.