Marine Micropaleontology最新文献

{"title":"Distribution of Miocene dinoflagellate cysts in the paralic basins of Tunisia: Paleogeographic and paleoecological reconstruction and eustatic movements","authors":"Nadia Ben Moktar ,&nbsp;Amel Mahjoubi-Ghanmi ,&nbsp;Beya Mannai-Tayech","doi":"10.1016/j.marmicro.2025.102443","DOIUrl":"10.1016/j.marmicro.2025.102443","url":null,"abstract":"<div><div>The Miocene deposits of northeastern and central-eastern Tunisia are primarily of clastic, deltaic-type. These deposits are organized into complex sedimentary sequences shaped by tectonic activity, eustatic fluctuations, and changes in climatic conditions. This study presents the evolution of dinoflagellate cysts associations extracted from Miocene-age deposits. These deposits ranged from 16 million to 5.3 million years ago. They are taken from three boreholes and three sections in northeastern and central Tunisia. Dinocysts serve as valuable indicators of climatic variations and sea-level fluctuations. Their study supports the results obtained from the analysis of pollen grains. It sheds light on paleoecology, paleogeography, and eustatic conditions during that period.</div><div>Various associations (oceanic, neritic, climatic, etc.) were established based on the ecological preferences of these marine microorganisms. Oceanic conditions are characterized by the presence of <em>Impagidinium</em>. Shallow marine environments are defined by the presence of <em>Cordosphaeridium inodes minimus</em>. Meanwhile, <em>Nematosphaeropis</em> and <em>Tectatodinium</em> indicate a neritic to oceanic environment. It is confirmed by the abundance of <em>Lejeunecysta</em>, <em>Operculodinium</em>, <em>israelianum</em>, <em>Polysphardium zoharyi</em>, <em>Homotryblium</em>, <em>Spiniferites</em>, <em>Cleistosphaeridium</em>, and <em>Lingulodinium machaerophorum</em>. These results align with lithological and biostratigraphic data related to paleobathymetry and paleogeography.</div><div>Changes in dinocyst taxa relative abundances helped track the shoreline's evolution during the Miocene. Variations in the relative abundance of <em>Impagidinium</em> and <em>Cordosphaeridium inodes minimus</em>, or their absence, indicate environmental shifts. This shift reflects a transition from a neritic environment (Aïn Grab Formation) to an oceanic one (Mahmoud Formation). The Saouaf Formation is marked by a eustatic drop at its base (Unit I). However, Units II and III are defined by eustatic rises in pulsations. The Somaa sands were deposited in a neritic and/or epicontinental environment, followed by a return to an oceanic setting (Melquart Formation).</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102443"},"PeriodicalIF":1.5,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine Learning for identification and classification of Foraminifera: Testing on monothalamids","authors":"Anna Sabbatini ,&nbsp;Francesca Caridi ,&nbsp;Domenico Potena ,&nbsp;Alessandra Negri","doi":"10.1016/j.marmicro.2025.102442","DOIUrl":"10.1016/j.marmicro.2025.102442","url":null,"abstract":"<div><div>Here we propose an AI-based approach using machine learning (ML) to assist species identification and reduce morphotype redundancy in the study of monothalamous foraminifera. In fact, this group of protists, is often overlooked in taxonomic studies due to their morphological simplicity and diversity. These single-celled organisms with “soft” tests are poorly studied, with only a few species identified, while many morphotypes remain undescribed. Taxonomic research on monothalamids is limited by challenges in identification, lack of fossilization, and the time-intensive nature of the work. This gap may lead to underestimating biodiversity and hinder detecting ecosystem degradation. Despite these challenges, monothalamids play key roles in marine ecosystems, making their diversity crucial for conservation and resource management. With this in mind, we analyzed images from the scientific literature, extracting key morphological traits, such as chamber shape, shell type, composition, and aperture type, through objective human annotation to build a dataset processed by ML algorithms. Clustering techniques, such as K-Means, revealed that basic shape, followed by shell type and composition, were the primary features distinguishing clusters. This approach enabled more objective morphotype classification, improving consistency and reducing human bias.</div><div>These findings align with recent taxonomic revisions and demonstrate that applying unsupervised ML methods enhances species identification accuracy and streamlines the analysis of high-dimensional datasets.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102442"},"PeriodicalIF":1.5,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphometric analysis of coccolithophore genus Reticulofenestra: Insights into taxonomy and evolution during late Eocene to early Oligocene","authors":"Ruigang Ma ,&nbsp;David Bord ,&nbsp;Xiaobo Jin ,&nbsp;Chuanlian Liu","doi":"10.1016/j.marmicro.2024.102435","DOIUrl":"10.1016/j.marmicro.2024.102435","url":null,"abstract":"<div><div>The coccolithophore <em>Reticulofenestra</em> is key to understanding late Cenozoic climate change, but taxonomic identification remains challenging. This study uses morphometric and mixture analysis to evaluate taxonomic criteria for late Eocene to early Oligocene <em>Reticulofenestra</em>. The method enables a systematic comparison between the taxonomic morphotypes and the components recognized through Gaussian mixture modeling of parameters of distal shield length, circularity, and central opening ratio. At the species level, a total of nine morphotypes were studied from 6700 data points collected across three study sites in the mid–low latitude Atlantic–Indian Oceans. The results demonstrate that length and circularity effectively distinguish groups, validating their uses as primary taxonomic criteria. Nevertheless, central opening ratio exhibits high intra–group variability, limiting its standalone application. In addition, our integrated data reveal three evolutionary phases: (1) initial diversification during late Eocene cooling; (2) extinction following peak diversity after the Eocene–Oligocene Transition; and (3) early Oligocene stabilization reflecting adaptation in smaller species. This work provides statistical references for the validation of semi-quantitative morphologic descriptions, which may help establish a robust framework for identifying this ecologically vital lineage and enhance our understanding of phytoplankton responses to past environmental changes. Future genomic studies will be crucial for elucidating genotype-phenotype-environment relationships in <em>Reticulofenestra</em> evolution.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102435"},"PeriodicalIF":1.5,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-resolution Danian–Selandian benthic foraminifera-based paleoenvironmental reconstruction and response to sequence stratigraphy: Inferences from the Elles section, El Kef Basin, Tunisia","authors":"Sherif Farouk ,&nbsp;Islam El-Sheikh ,&nbsp;Sreepat Jain ,&nbsp;Fayez Ahmad ,&nbsp;Zaineb Elamri ,&nbsp;Jenö Nagy ,&nbsp;Khaled Al-Kahtany ,&nbsp;Youssef S. Bazeen","doi":"10.1016/j.marmicro.2024.102433","DOIUrl":"10.1016/j.marmicro.2024.102433","url":null,"abstract":"<div><div>High-resolution (123 samples) benthic foraminiferal distribution patterns were analyzed for paleoenvironmental reconstruction from a section located at the southern edge of the El Kef Basin (El Haria Formation; Tunisia) spanning the Danian–Selandian interval (planktic foraminifera P1a–P4b zones). Five distinct clusters were identified, each representing different paleoenvironments and depths ranging from inner neritic to upper bathyal, with significant variations in species diversity, paleoproductivity, and bottom water oxygenation. The Dan-C2 hypothermal event is characterized by moderately oxygenated bottom waters, high species diversity, and lowered paleoproductivity within an upper bathyal setting. The LDE is marked by high species diversity, higher paleoproductivity, moderately oxygenated bottom waters, abundance of epifaunal species, and shallowing to middle neritic depths. The Danian-Selandian boundary records (a) a sudden abundance of the inner neritic infaunal species <em>Bulimina strobila</em>, (b) an increase in species diversity, (c) moderately‑oxygenated bottom waters, (d) a positive δ¹³C excursion, and (e) deepening, from inner to middle neritic settings. Four transgressive-regressive (T-R) cycles based on benthic foraminiferal assemblage-derived bathymetry, P% and the transfer function-based estimate mirror each other, and distinctly mirror paleodepth changes, correlating with global eustatic cycles but also reflecting local tectonic influences.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102433"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-pollen palynomorphs as indicators of local environmental conditions in a Neotropical Estuary (Northeast Brazil)","authors":"Pietro Martins Barbosa Noga ,&nbsp;Anne de Vernal ,&nbsp;Daniela Mariano Lopes da Silva ,&nbsp;Doriedson Ferreira Gomes","doi":"10.1016/j.marmicro.2024.102424","DOIUrl":"10.1016/j.marmicro.2024.102424","url":null,"abstract":"<div><div>Non-pollen palynomorphs (NPPs) are organic-walled microfossils derived from diverse aquatic and terrestrial organisms, frequently observed in palynological studies. This study documents the distribution of NPPs in surface sediment samples from the two main rivers of Camamu Bay (Northeast Brazil), analyzed to explore their response to estuarine environmental and nutritional gradients. Using standard palynological techniques, 69 NPP taxa were identified, spanning 40 divisions, including dinoflagellates, foraminiferal linings, chlorophytes, cyanobacteria, ciliates, amoebozoans, scolecodonts, zoological fragments, and fungal spores. Assemblages were dominated by fungal spores across most stations. Distinct environmental gradients were reflected in NPP distribution, for instance upstream stations with low salinity (3 psu) and high nutrient ratios favored chlorophytes, while downstream stations with higher salinity (up to 35 psu) and lower N:P ratios (&lt;40 μM) were dominated by foraminiferal linings. Multivariate statistic analyses revealed that salinity and nutrient stoichiometry were significant drivers of assemblage composition. These findings highlight the utility of NPPs as indicators of environmental and biogeochemical conditions, particularly in low-latitude estuarine systems, and underscore their potential applications in paleoecological reconstruction.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102424"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benthic foraminiferal population dynamics at the Goban Spur off Southwest Ireland reveal glacial-interglacial bottom water ventilation and organic flux variability over the last 420,000 years","authors":"Stanislaus Glenndy Fabian ,&nbsp;Stephen J. Gallagher ,&nbsp;David De Vleeschouwer","doi":"10.1016/j.marmicro.2024.102432","DOIUrl":"10.1016/j.marmicro.2024.102432","url":null,"abstract":"<div><div>Benthic foraminiferal assemblages from Deep Sea Drilling Project (DSDP) Site 548 on the Goban Spur off southwestern Ireland shed light on the changes in bottom water oxygenation and organic matter flux to the sea floor during the late Quaternary. Correlations of benthic foraminiferal δ¹⁸O values, the relative abundance of <em>Neogloboquadrina pachyderma</em> (%NP), and Ice Rafted Debris (IRD) concentration to global and regional and North Atlantic datasets suggest the upper 60 m of DSDP Site 548 extend to 420,000 years. Downcore variations of &gt;63 μm benthic foraminifera assemblages, abundance, and diversity reveal changes in dissolved oxygen concentration and organic fluxes to the seafloor related to glacial-interglacial cyclicity. <em>Cassidulina laevigata</em> and low dissolved oxygen indicator taxa such as <em>Bolivina</em> spp. and <em>Globobulimina</em> spp. characterised colder climates associated with lighter benthic δ¹³C values, suggesting minimal organic flux and/or weaker bottom water ventilation. In contrast, warmer interglacials are typified by heavier benthic δ¹³C, increased %CaCO₃, common high dissolved oxygen indicator taxa such as <em>Globocassidulina subglobosa</em> and phytodetritus sensitive taxa such as <em>Alabaminella weddellensis</em> and <em>Epistominella exigua</em>, suggest a more ventilated bottom water and increased organic fluxes to the seafloor, possibly associated with the invigoration of the Mediterranean Outflow Water (MOW).</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102432"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleoecological and paleoenvironmental insights from Ornatorotaliidae (larger foraminifera)","authors":"Andrea Benedetti ,&nbsp;Antonino Briguglio ,&nbsp;Lorenzo Consorti ,&nbsp;Cesare Andrea Papazzoni","doi":"10.1016/j.marmicro.2024.102423","DOIUrl":"10.1016/j.marmicro.2024.102423","url":null,"abstract":"<div><div>The present study deals with the ecology and phylogenetic relationships among species of the genera <em>Ornatorotalia</em>, <em>Granorotalia</em>, and <em>Risananeiza</em> belonging to the Family Ornatorotaliidae. The microfacies analyses allowed us to assign each taxon to its life paleoenvironment within the shallow-water carbonate setting, and to make a comparison with extant species belonging to the family Calcarinidae. While different species of <em>Ornatorotalia</em> and <em>Granorotalia</em> thrived only in the inner ramp, <em>Risananeiza</em> spp. possibly inhabited also deeper environments up to the middle ramp. The phylogenetic relationships among genera and species are here briefly discussed, nonetheless it's still impossible to identify any unambiguous ancestor of this group.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102423"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controls on barium incorporation into tests of benthic foraminifera from the Aegean Sea (Eastern Mediterranean Sea) – Towards a species-specific Ba/Ca calibration","authors":"Jassin Petersen ,&nbsp;Gerhard Schmiedl ,&nbsp;Jacek Raddatz ,&nbsp;André Bahr ,&nbsp;Jörg Pross ,&nbsp;Meryem Mojtahid","doi":"10.1016/j.marmicro.2024.102431","DOIUrl":"10.1016/j.marmicro.2024.102431","url":null,"abstract":"<div><div>We have analysed Ba/Ca ratios of live and dead benthic foraminifera (<em>Uvigerina mediterranea</em> and <em>Melonis affinis</em>) from core tops of seven sites located in the Aegean Sea by laser ablation ICP-MS. There are no significant Ba/Ca differences in live and dead specimens of <em>U. mediterranea</em>. For <em>M. affinis</em> we apply a threshold criterion for extremely high Ba/Ca in live specimens in order to highlight the overall uniform Ba/Ca signal. The Ba/Ca intra-test variability varies between 16 and 24 % relative standard deviation per specimen. It is attributed to biomineralisation processes i.e., vital effects. The Ba/Ca ratios of <em>M. affinis</em> are significantly higher than those of <em>U. mediterranea</em> throughout most of the sites and their respective samples from different sediment depths. The influence on Ba/Ca of both species by biomineralisation processes and/or microhabitat effects remains open. Linking the Ba/Ca ratios to measured Ba concentration of bottom waters from one of the studied sites, shows partition coefficients of D_Ba = 0.34, and D_Ba = 0.49 for <em>U. mediterranea</em> and <em>M. affinis</em>, respectively. We could not identify trends of Ba/Ca ratios to observed/ modelled gradients of relevant environmental factors between the seven analysed sites, such as primary productivity and associated C_org fluxes or TOC concentrations. Despite the demonstrated limited proxy potential in these parts of the Aegean Sea, we suggest that it is possible to employ Ba/Ca of infaunal benthic species in order to reconstruct export productivity in deep-sea areas with a less complex linkage between primary productivity and nutrient distribution in bottom waters.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102431"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolutionary, paleoecological and taphonomic aspects of new agglutinated foraminifer Devonodendron scopulum from the Frasnian of Holy Cross Mts, Poland","authors":"Grzegorz Racki","doi":"10.1016/j.marmicro.2024.102434","DOIUrl":"10.1016/j.marmicro.2024.102434","url":null,"abstract":"<div><div>Regularly bifurcated tubiform (tree-like) microfossils, although illustrated three decades ago from the Frasnian of the Holy Cross Mts (southern Poland), have not been studied in detail until now. In this paper, the distinctive microproblematic is interpreted as a calcite-cemented agglutinated foraminifer belonging to <em>Devonodendron scopulum</em> sp. et gen. nov., appearing in a major radiation after the Givetian Revolution. Based on the study of isolated three-dimensional specimens, this Devonian species is the best documented of the early branching foraminifera. It resembles living arborescent representatives of the family Schizamminidae (such as <em>Schizammina arborescens</em> and <em>S. andamana</em>), but also the family Dendrophryidae (<em>Psammatodendron arborescens</em>), which has already been reported in the fossil record (Cretaceous; questionable Silurian). However, in light of genetic studies of modern monothalamids, phylogenetic inferences based on such simple morphology are risky. The tree-like branching system of this species suggests erect attached and filter feeding life habit. <em>Devonodendron scopulum</em> shows a pronounced microhabitat selectivity, being dominantly restricted to mid-slope metazoan-microbial mud-mounds. The buildups provided microniches for flourishing a very abundant and diverse calcareous microbiota, including taxa with known (<em>Nanicell</em>a) and presumed (<em>Eifeliflabellum</em>) foraminiferal affinities. The environment was characterized by a specific diagenetic setting for the fossilization of micritic-organic tubular tests due to rapid microbially mediated lithification and overwhelming recrystallization processes. As a result, microfossils are largely preserved as stacked homogeneous rhomboidal calcite plates. Many specimens in some sites are actually just coalesced sparry calcite ‘pseudomorphs’ mimicking the original test morphology.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102434"},"PeriodicalIF":1.5,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eocene to Early Miocene dinoflagellate cysts from the southern Gulf of Mexico","authors":"Alessandro-Cesare Bruno,&nbsp;Javier Helenes","doi":"10.1016/j.marmicro.2024.102422","DOIUrl":"10.1016/j.marmicro.2024.102422","url":null,"abstract":"<div><div>This paper documents the Eocene to Miocene dinoflagellate cyst assemblages found at Site 94 in the southern part of the Gulf of Mexico. Four unique dinoflagellate cyst assemblages representing depositional periods from the Early Eocene to the Early Miocene are defined in this study. The Early to Middle Eocene assemblage presents the highest average concentrations of dinoflagellate cysts, is dominated by <em>Operculodinium</em>, and contains few heterotrophic taxa. The Early Oligocene assemblage has medium concentration and is dominated by <em>Deflandrea</em>. The Late Oligocene also has high average concentrations of dinoflagellate cysts, is dominated by <em>Homotryblium</em>, and contains few heterotrophic taxa. The Early Miocene assemblage has lower average concentrations of dinoflagellate cysts, is dominated by <em>Pyxidinopsis</em>, and lacks heterotrophic taxa. Our palynological data is related to significant regional paleogeographic and paleoceanographic changes. Namely, the Early to Middle Eocene free flow of tropical water masses from the south and the Late Eocene restriction of this flow by a land bridge connecting northern South America to Cuba in the north. The Oligocene gradual return of the tropical water masses and finally, the Early Miocene emergence of the Florida Platform when the Gulf of Mexico reached modern oceanographic conditions. The stratigraphic ranges of selected dinoflagellate cysts fit in age with previous microfossil data from the site and allowed us to define the Early Oligocene - Late Oligocene transition. The presence of well-preserved dinoflagellate cysts allowed the identification of 60 species and the discovery of three new species: <em>Achomosphaera psilata</em> sp. nov., <em>Carpatella reticulata</em> sp. nov., and <em>Hystrichosphaeropsis gulficum</em> sp. nov.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"193 ","pages":"Article 102422"},"PeriodicalIF":1.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}