Marine Micropaleontology最新文献

{"title":"Benthic ostracods as environmental proxies in Nile Delta Coastal Lagoon","authors":"Sherif M. El Baz ,&nbsp;Abd-ElMonsef A. El-Badry ,&nbsp;Pamela Hallock ,&nbsp;Ahmed M. BadrElDin","doi":"10.1016/j.marmicro.2025.102469","DOIUrl":"10.1016/j.marmicro.2025.102469","url":null,"abstract":"<div><div>The coastal Nile Delta wetlands are essential in the protection of the cultivated deltaic land against sea level rise and are major resources for biodiversity and fisheries productivity. The Manzala Lagoon ranks highly polluted among the lacustrine coastal environments of the Nile Delta of Egypt. The environmental quality of the lagoon plummeted a few decades ago with the increase in massive quantities of untreated mixed discharges (agricultural, industrial, and municipal). To evaluate the environmental status of the lagoon requires both geochemical analyses and bioindicators. Total organic carbon and concentrations of seven potentially toxic elements (Pb, Cu, Cd, Zn, Ni, Co, Fe) were determined in 25 sediment samples collected during summer 2014, from which three pollution indices were calculated (Contamination Factor, Degree of Contamination, and Pollution Loading Index). In addition, ostracod assemblages were assessed in the very-fine and fine sand-size fractions of the sediments. The lagoonal environment is characterized by low total dissolved solids, abundant organic matter, heavy metal contamination by Pb, Co, Ni, and especially Cd, and low diversity ostracod assemblages. Six fresh- and brackish water ostracod species were documented, but the assemblage was overwhelmingly dominated (&gt;98 %) by stress-tolerant <em>Cyprideis torosa.</em> While this species correlated strongly with total dissolved solids and fine sediment textures, overall, the limited ostracod diversity and dominance of a stress-tolerant species reflects the compromised ecological quality of Manzala Lagoon.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"197 ","pages":"Article 102469"},"PeriodicalIF":1.5,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868944","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":"Ostracod and foraminiferal assemblages in Tébessa (Northeast Algeria): Insights into Santonian cooling effects","authors":"Sakina Nemouchi ,&nbsp;Sihem Salmi-Laouar ,&nbsp;Ahmed Awad Abdelhady ,&nbsp;Amor Deghaichia ,&nbsp;Mostafa M. Sayed ,&nbsp;Youssef Bazeen ,&nbsp;Michael Hesemann ,&nbsp;Mohamed Ahmed ,&nbsp;Mabrouk Boughdiri","doi":"10.1016/j.marmicro.2025.102468","DOIUrl":"10.1016/j.marmicro.2025.102468","url":null,"abstract":"<div><div>A well-exposed Coniacian-Santonian stratigraphic section in the Bir Mokadam Mountains, west of Tébessa (Algeria), was investigated through biostratigraphic and paleoenvironmental analyses focusing on planktic foraminifera and ostracods, respectively. The studied interval encompasses deposits from the Essen Formation, consisting predominantly of clayey marls. A total of 318 samples were collected and examined, leading to the identification of 26 planktic foraminiferal species distributed across 11 genera. The Coniacian is characterized by the presence of the <em>Dicarinella primitiva</em> and <em>Marginotruncana sinuosa</em> biozones, whereas the Santonian is distinguished by <em>Sigalia carpatica, Dicarinella asymetrica</em>, and <em>Globotruncanita elevata</em> biozones. The quantitative analyses revealed significant differences between the Coniacian and Santonian stages. The Coniacian and the lower parts of the Santonian exhibit higher diversity, characterized by a greater abundance of smooth ostracods, keeled and globular foraminifera. In contrast, the upper part of the Santonian is marked by a notable decrease in diversity and an increase in dominance of the ostracods and the also the planktonic foraminifera, indicating a less balanced ecological structure. The decline in diversity is herein tentatively attributed to a climate cooling and/or bottom-water minor dysoxia. Notably, there is a negative relationship between ostracod and foraminiferal abundances, the cause of which remains unclear and requires further investigations.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"197 ","pages":"Article 102468"},"PeriodicalIF":1.5,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847486","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":"Are there marine sedimentary losses and transgressions in the Southeast Bohai Sea during MIS 2-MIS 3?","authors":"Qingtong Wang ,&nbsp;Gayan Bandara ,&nbsp;Wenqin Jiang ,&nbsp;Feifei Wang ,&nbsp;Hongxian Chu ,&nbsp;Meiling Yin ,&nbsp;Chuanxiu Luo","doi":"10.1016/j.marmicro.2025.102461","DOIUrl":"10.1016/j.marmicro.2025.102461","url":null,"abstract":"<div><div>Sedimentary architecture dominated by transgression–regression cycles in the shallow Bohai shelf region contains information about global sea-level, climate and local tectonics. However, previous studies of transgression–regression cycles in this region at orbital timescales that extend back to the early Pleistocene are sparse. In this study, we present an integrated sedimentological, paleontological study of a 32.49 m (93kyr BP) core (HZK02) recovered from the Bohai Sea, China, for which an AMS ¹⁴C and five OSL dates-based age model is available. Compared with previous pollen study in the Bohai area, the results show that there were two significant transgressions that occur in MIS 5c, top part of MIS 2 and MIS 1, with abundant foraminifera from the near shore shallow sea of the continental shelf, corresponding with prevailing arboreal pollen dominated by <em>Pinus</em> and <em>Quercus</em>. While, terrestrial herbs such as <em>Artemisia</em> and Chenopodiaceae dominated during colder periods, such as MIS 4, MIS 5b, when sea levels dropped significantly, corresponding with a scarcity of foraminifera in terrestrial sediment layers from MIS 5b, MIS 5a, MIS 4, and MIS 3. We find that at depth of 8.18–6.10 m, with depth of only 2.08 m and very high sediment rate, the duration age last from 64,100 yr BP to 10,500 yr BP, which might indicate some missing part of the deposition of MIS 3 and MIS 2. The transgressions signal has been found in top part of MIS 2 sediment, hardly in MIS 3.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"196 ","pages":"Article 102461"},"PeriodicalIF":1.5,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704042","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":"Siliceous plankton flux and radiolarian community structure in the highly oligotrophic Ionian Sea (Eastern Mediterranean) – Imprints of climate variability","authors":"Marie Cueille ,&nbsp;Taniel Danelian ,&nbsp;Dimitra-Ioli Skouroliakou ,&nbsp;Elisavet Skampa ,&nbsp;Maria Triantaphyllou ,&nbsp;Alexandra Gogou ,&nbsp;Georgia Kambouri ,&nbsp;Ioanna Stavrakaki ,&nbsp;Koen Sabbe","doi":"10.1016/j.marmicro.2025.102460","DOIUrl":"10.1016/j.marmicro.2025.102460","url":null,"abstract":"<div><div>Based on sediment-trap material collected at 700 m depth from the oligotrophic southern Ionian Sea (Nestor site), this study explores for the first time the impact of seasonal and multiannual (2015–2017) climate variability on the siliceous plankton flux and radiolarian community structure at species level in the Eastern Mediterranean Sea. A total of 143 radiolarian taxa were identified, most of them at the species level. Juveniles represented 35–70 % of the total radiolarian flux. Thirty-nine diatom taxa were identified, including some freshwater species. Coinciding with organic carbon, opal and total mass fluxes, radiolarians and diatoms displayed rather similar pattern in seasonal flux variations, including two seasonal peaks. The first one was recorded in late winter (late February) 2015; it is regarded as the result of late winter intensification of water column mixing. The second peak in the siliceous plankton flux was recorded in late summer to early fall (August – September) of both years 2015 and 2017. This peak is interpreted to be the result of a local upwelling event following the reduced influence of the Pelops anticyclonic gyre. A third productivity event was recorded in April and May 2016, and is interpreted as being influenced by North African dust depositions. Despite the incompleteness of our sediment trap data series, our dataset is valuable as it is the first ever study conducted to the species level on polycystine radiolarian vertical export rates in the Mediterranean Sea, combined with insights into the temporal dynamics of siliceous zoo- and phytoplankton fluxes in the EMed.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"196 ","pages":"Article 102460"},"PeriodicalIF":1.5,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704044","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":"Phyletic evolution of calcareous nannofossil species Reticulofenestra oamaruensis: An example of microevolution preserved at IODP Site U1553 (Southern Pacific Ocean)","authors":"Valentina Catelli ,&nbsp;Davide Persico ,&nbsp;Davide Righi ,&nbsp;Isabella Raffi ,&nbsp;Chiara Fioroni ,&nbsp;Giuliana Villa","doi":"10.1016/j.marmicro.2025.102452","DOIUrl":"10.1016/j.marmicro.2025.102452","url":null,"abstract":"<div><div>The IODP Expedition 378 in the Southern Ocean (Campbell Plateau) recovered a Paleogene sedimentary section at Site U1553, cored through multiple holes (A - E) in the late Eocene-early Oligocene interval. Stratigraphic continuity and good preservation of calcareous nannofossils offered the opportunity to study the phyletic origin of <em>Reticulofenestra oamaruensis</em>, the biostratigraphic marker for the Eocene/Oligocene Transition (EOT) in the Southern Ocean (SO). We performed biometric and morphological analyses on <em>R. oamaruensis</em> and the related species <em>Reticulofenestra clatrata</em>, revealing intermediate morphotypes with characters between <em>R. clatrata</em> and <em>R. oamaruensis</em>. These transitional morphotypes, labeled <em>Reticulofenestra</em> transitional form 1 (<em>R</em>. t1) and <em>Reticulofenestra</em> transitional form 2 (<em>R</em>. t2), differ in size from the end members and are distinguished in two size categories: 10–12 μm and 12–14 μm respectively. The intraspecific evolutionary trend shows a gradual size increase of <em>R. clatrata</em>(8–10 μm) that, through intermediate steps represented by <em>R.</em> t1 and <em>R.</em> t2, leads to <em>R. oamaruensis</em> (≥14 μm). The two morphotypes are included in the species identification of <em>R. oamaruensis</em> and enter the stratigraphic record at successive levels, thus delineating a “lineage zone” useful in SO biostratigraphy. <em>R. clatrata</em> and medium – large <em>R. oamaruensis</em> disappear close to the Eocene/Oligocene Boundary. Based on the morphological homology, the progressively increasing size trend from <em>R. clatrata</em> to <em>R. oamaruensis</em>, their stratigraphic range continuity, and their same geographical distribution, we document a phyletic strain endemic to high southern latitudes, of which <em>R. clatrata</em> would represent the archetype.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"196 ","pages":"Article 102452"},"PeriodicalIF":1.5,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487764","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":"An integrative analysis of Plectocapillus antarcticus gen. et sp. nov. from Antarctica: Morphology, chemical composition, and phylogeny","authors":"Somin Lee ,&nbsp;Michael A. Kaminski ,&nbsp;Fabrizio Frontalini ,&nbsp;Jisu Yeom ,&nbsp;Nayeon Park ,&nbsp;Wonchoel Lee","doi":"10.1016/j.marmicro.2025.102451","DOIUrl":"10.1016/j.marmicro.2025.102451","url":null,"abstract":"<div><div>In this study, <em>Plectocapillus antarcticus</em> gen. et sp. nov., belonging to the Family Pseudobolivinidae Wiesner, 1931, Superfamily Spiroplectamminoidea Cushman, 1927, was described from Maxwell Bay, King George Island, Antarctica. The species is distinguished by its elongate, slender, and entirely biserial test, fragile, thin agglutinated wall, a globular, organic proloculus, and the areal, rounded to arch-like aperture. Notably, this species previously assigned taxonomically as <em>Spiroplectammina filiformis</em> Earland, 1934 or <em>Textularia tenuissima</em> Earland, 1933<em>,</em> in nearby areas. However, morphological comparison revealed differences in chamber arrangement, biserial pair number, test width, and proloculus wall composition. SEM-DES analysis identified Al, Ca, Fe, Mg, Si, and Ti as major chemical elements present in the test wall, along with the traces of K, Mn, Na, P, Ce, Cl, F, S, Sr, and Zr. Phylogenetic analysis of partial SSU rRNA and mitochondrial COI gene sequences confirmed that <em>P. antarcticus</em> forms a well-supported clade, sister to <em>Spiroplectammina biformis</em>. The slender, flexible test, organic proloculus, and inclusion of heavy element-rich minerals suggests potential adaptation to hypoxic or interstitial habitats. By integrating morphological, chemical, and molecular data, this study contributes to the expanding fundamental database and understanding of Antarctic foraminiferal diversity and emphasizes the necessity for continued research in the region.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102451"},"PeriodicalIF":1.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444261","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":"Sessile foraminifera from mobile substrates: Hidden organisms and big mistakes – The essential is invisible to the eyes","authors":"Joicce Dissenha ,&nbsp;Sibelle Trevisan Disaró ,&nbsp;José Rodolfo Angulo ,&nbsp;Rodrigo Aluizio","doi":"10.1016/j.marmicro.2025.102450","DOIUrl":"10.1016/j.marmicro.2025.102450","url":null,"abstract":"<div><div>Two case studies conducted on the inner continental shelf off southeastern Brazil revealed an unexpectedly high abundance and diversity of foraminifera attached to or encrusted in sediment grains. Samples were stained with Rose Bengal, fixed in formalin, and subjected to trichloroethylene flotation to isolate free foraminifera. Following screening, the residual fraction was rigorously examined, uncovering numerous attached individuals and robust agglutinate forms that incorporate sediment grains into their tests. This fauna includes little-known genera rarely documented in unconsolidated mobile substrates. Comparisons between floated and residual fractions revealed notable discrepancies, emphasizing the underestimation of sessile and robust forms when residual fractions are overlooked. Neglecting these forms can compromise environmental and paleoenvironmental interpretations, as rarefaction curves illustrate, particularly in high-hydrodynamic regions typically seen as challenging environments for fauna. This study underscores the importance of including sessile foraminifera in biodiversity assessments in dynamic marine areas. We propose a new zone, the “high-hydrodynamic inner coastal shelf,” for Murray's (1973) ternary diagram. Additionally, our findings indicate that inadequate screening methods may leave significant gaps in taxonomic records. Many attached foraminifera remain “invisible to the eye” of researchers, often due to their shape, a lack of prior knowledge, or insufficient attention, resulting in underestimations of their density and richness. Consequently, these organisms are often overlooked in environmental characterizations, taxonomic records, and especially in paleoecological studies and monitoring efforts.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102450"},"PeriodicalIF":1.5,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463598","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":"Dinoflagellate cyst assemblages in recent sediments of Iran's tropical mangrove forests","authors":"Gilan Attaran-Fariman ,&nbsp;Sima Abir ,&nbsp;Faezeh Dolatabadi ,&nbsp;Ehsan Abedi ,&nbsp;Fatemeh Sayareh","doi":"10.1016/j.marmicro.2025.102449","DOIUrl":"10.1016/j.marmicro.2025.102449","url":null,"abstract":"<div><div>We investigated the distribution and composition of dinoflagellate cysts, including potential harmful algal bloom (HAB) species, in Iranian mangroves bordering the Persian Gulf and Oman Sea. Sediment samples were collected from 62 stations across 10 locations in three provinces (Bushehr, Hormozgan, Sistan &amp; Baluchestan) in autumn 2020. Analysis of dinoflagellate cysts revealed a diverse assemblage encompassing 56 species, including 10 known to be triggers of harmful algal blooms (HABs). Genus <em>Protoperidinium</em> was dominant, exhibiting a 21.4 % abundance and comprising 14 species across 60 sampling stations. In contrast, genus <em>Margalefidinium</em> was present in 34 stations with only a single species. <em>Margalefidinium polykrikoides</em> was the key species of dissimilarity between provinces, driving distinct compositions in all pairwise comparisons. <em>Scrippsiella acuminata</em> was a significant contributor to the dissimilarity observed between the Bu and S&amp;B, as well as the Ho and S&amp;B assemblages. DistLM, dbRDA, and marginal tests confirmed that environmental parameters significantly (<em>P</em> &gt; 0.05) influenced cyst composition across the provinces. Regular monitoring of environmental parameters alongside analyses of dinoflagellate cyst assemblages is a potential use for predicting HABs and also provide valuable insights into the well-being of essential mangrove ecosystems.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102449"},"PeriodicalIF":1.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378431","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":"Orbital-scale biotic and paleoceanographic changes in Japan Sea during the late Miocene global cooling (LMGC)","authors":"Mizuki Tojima ,&nbsp;Masayuki Ikeda ,&nbsp;Kenji M. Matsuzaki","doi":"10.1016/j.marmicro.2025.102448","DOIUrl":"10.1016/j.marmicro.2025.102448","url":null,"abstract":"<div><div>The late Miocene global cooling (LMGC; ca. 7.9–5.8 Ma) was accompanied by global environmental changes including monsoon intensity, ocean circulation, and biotic turnover. Recent studies have revealed drastic environmental and biotic changes in the Japan Sea across the LMGC; the radiolarian fauna in the Japan Sea suggested decreased inflow of Pacific Central Water (PCW) species <em>Tricolocapsa papillosa,</em> increased subarctic species <em>Cycladophora sphaeris</em> and extinction of a dominant endemic radiolarian <em>Cycladophora nakasekoi</em>. These radiolarian fluxes showed ∼100-kyr eccentricity signals; however, the dominant paleoclimatic/paleoceanographic signal during the LMGC appeared to be ∼40-kyr obliquity cycle, which was not detected in the radiolarian fluxes possibly due to lower sampling resolution. Thus, orbital-scale variations of these radiolarian fluxes and their potential forcing mechanisms remain unclear.</div><div>In this study, we establish changes in the abundance of selected radiolarian species with a resolution that exceeds the 10-kyrs and suggest obliquity-paced changes in the paleoceanography in the Japan Sea during the LMGC. We detected ∼40-kyr cycles in abundance of <em>T</em><em>.</em> <em>papillosa</em>, suggesting that PCW inflow into the Japan Sea was controlled by a 40-kyr obliquity-paced glacial cycle. We also detected a ∼ 40-kyr signal in <em>C</em><em>.</em> <em>sphaeris</em> abundance, implying that the obliquity-paced winter monsoon probably promoted the inflow of subarctic water into the Japan Sea. Contrary, variation in <em>C</em><em>.</em> <em>nakasekoi</em> abundance lacks a ∼ 40-kyr signal. A 100-kyr cycle is also observed in a summer monsoon proxy from lacustrine sediment in China. Hence, it is possible that <em>C</em><em>.</em> <em>nakasekoi</em> decreased with weakened summer monsoon across the LMGC.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102448"},"PeriodicalIF":1.5,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148817","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":"The biostratigraphy and palaeobiogeography of the Late Jurassic dinoflagellate cysts from the Binalud Mountains, NE Iran","authors":"Behnaz Kalanat ,&nbsp;Elham Davtalab ,&nbsp;Ahmad Raoufian","doi":"10.1016/j.marmicro.2025.102446","DOIUrl":"10.1016/j.marmicro.2025.102446","url":null,"abstract":"<div><div>This study investigates the dinoflagellate cysts from the upper part of the Dalichai Formation in the Binalud Mountains (NE Iran, western Tethys), where the deposits are primarily consist of shale and marlstone layers. The analyzed section yielded common and diverse dinoflagellate cyst assemblages comprising 46 species belonging to 33 genera. These assemblages are correlated with the DSJ24–DSJ33 dinoflagellate cyst Zones of the Late Jurassic (late Oxfordian–Tithonian) in the Northern Hemisphere. Key bioevents identified in this interval included the last occurrences of <em>Compositosphaeridium polonicum</em> in the late Oxfordian, the last occurrence of <em>Ctenidodinium ornatum</em> at the Oxfordian–Kimmeridgian boundary, the last occurrences of <em>Tubotuberella eisenackii</em> and <em>Scriniodinium crystallinum</em> in the early Kimmeridgian, and the last occurrence <em>Endoscrinium luridum</em> around the Kimmeridgian–Tithonian boundary. The dinoflagellate cyst assemblages exhibit strong similarities to the flora of the western Tethys (the Middle East, Europe, eastern North America, and North Africa) and are marked differences from coeval assemblages of the eastern Tethys (Australasia, eastern Asia, and northeastern India), reflecting significant provincialism between the western and eastern Tethys during the Late Jurassic.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102446"},"PeriodicalIF":1.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098473","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}