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This paper presents a quantitative study of dinoflagellate cysts (dinocysts) and palynofacies of the Campanian–Danian marly succession at the village of Tattofte (western External Rif, northwestern Morocco). The paleoenvironmental and paleoclimatic interpretations, inferred from this palynologic analysis, are compared to coeval sequences of other areas in the Northern Hemisphere. Changes in the relative abundances of dinocyst taxa, which are paleoenvironmental indicators, throughout the section suggest a deposition in a marine inner to outer neritic setting. The upper Campanian dinocyst assemblage is characterized by the presence of outer neritic-oceanic and low productivity indicator taxa (e.g., Spiniferites spp., Odontochitina spp.) and cold-water taxa (e.g., Manumiella spp., Chantangiella spp., Laciniadinium spp.), whereas, the lower Maastrichtian assemblage is characterized by inner neritic, high productivity and warm-water indicator taxa (e.g., Palaeocystodinium spp., Andalusiella spp.). The upper Maastrichtian dinocyst assemblage displays a return to an outer neritic environment under a transgressive regime, but with a cooling pulse and a moderate productivity. However, the Cretaceous–Paleogene (K/Pg) boundary interval records remarkable changes in the relative abundances of dinocyst taxa, indicating an inner neritic (coastal) setting, which is the most proximal in the study section; such changes reflect instable paleoenvironmental conditions which may be related to global cooling periods, likely caused by the Deccan volcanism in India and/or the Chicxulub asteroid impact in Mexico at the K/Pg boundary. In the Danian, the dinocyst relative abundances indicate a gradual return to stable environmental conditions. A quantitative analysis of the kerogen plots (palynomorphs, phytoclasts and amorphous organic matter (AOM)) reveals five types of palynofacies, generally indicating oxic to suboxic marine environments. The upper Campanian and upper Maastrichtian (lowermost part) strata are characterized by a playnofacies (V), indicating a distal shelf, while the lower Maastrichtian and lower Danian (uppermost part) strata record a playnofacies (III), reflecting an intermediate inner-outer neritic environment. However, the K/Pg boundary transition is characterized by playnofacies types (I) and (II), indicating a proximal (coastal) environment.

Sea surface temperature (SST) reconstructions based on isoprenoid glycerol dialkyl glycerol tetraether (isoGDGT) distributions from the Eocene southwest (SW) Pacific Ocean are unequivocally warmer than can be reconciled with state-of-the-art fully coupled climate models. However, the SST signal preserved in sedimentary archives can be affected by contributions of additional isoGDGT sources. Methods now exist to identify and possibly correct for overprinting effects on the isoGDGT distribution in marine sediments. Here, we use the current proxy insights to (re-)assess the reliability of the isoGDGT-based SST signal in 69 newly analyzed and 242 reanalyzed sediments at Ocean Drilling Program (ODP) Site 1172 (East Tasman Plateau, Australia) following state-of-the-art chromatographic techniques. We compare our results with paleoenvironmental and paleoclimatologic reconstructions based on dinoflagellate cysts. The resulting ∼ 130 kyr resolution Maastrichtian–Oligocene SST record based on the TetraEther indeX of tetraethers with 86 carbon atoms (TEX86) confirms previous conclusions of anomalous warmth in the early Eocene SW Pacific and remarkably cool conditions during the mid-Paleocene. Dinocyst diversity and assemblages show a strong response to the local SST evolution, supporting the robustness of the TEX86 record. Soil-derived branched GDGTs stored in the same sediments are used to reconstruct mean annual air temperature (MAAT) of the nearby land using the Methylation index of Branched Tetraethers with 5-methyl bonds (MBT'5me) proxy. MAAT is consistently lower than SST during the early Eocene, independent of the calibration chosen. General trends in SST and MAAT are similar, except for (1) an enigmatic absence of MAAT rise during the Paleocene–Eocene Thermal Maximum and Middle Eocene Climatic Optimum, and (2) a subdued middle–late Eocene MAAT cooling relative to SST. Both dinocysts and GDGT signals suggest a mid-shelf depositional environment with strong river runoff during the Paleocene–early Eocene progressively becoming more marine thereafter. This trend reflects gradual subsidence and more pronounced wet/dry seasons in the northward-drifting Australian hinterland, which may also explain the subdued middle Eocene MAAT cooling relative to that of SST. The overall correlation between dinocyst assemblages, marine biodiversity and SST changes suggests that temperature exerted a strong influence on the surface-water ecosystem. Finally, we find support for a potential temperature control on compositional changes of branched glycerol monoalkyl glycerol tetraethers (brGMGTs) in marine sediments. It is encouraging that a critical evaluation of the GDGT signals confirms that most of the generated data are reliable. However, this also implies that the high TEX86-based SSTs for the Eocene SW Pacific and the systematic offset between absolute TEX86-based SST and MBT'5me-based MAAT estimates remain without definitive explanation.

Improvements in our capability to reconstruct ancient surface-ocean conditions based on organic-walled dinoflagellate cyst (dinocyst) assemblages from the Southern Ocean provide an opportunity to better establish past position, strength and oceanography of the subtropical front (STF). Here, we aim to reconstruct the late Eocene to early Miocene (37–20 Ma) depositional and palaeoceanographic history of the STF in the context of the evolving Tasmanian Gateway as well as the potential influence of Antarctic circumpolar flow and intense waxing and waning of ice. We approach this by combining information from seismic lines (revisiting existing data and generating new marine palynological data from Ocean Drilling Program (ODP) Hole 1168A) in the western Tasmanian continental slope. We apply improved taxonomic insights and palaeoecological models to reconstruct the sea surface palaeoenvironmental evolution. Late Eocene–early Oligocene (37–30.5 Ma) assemblages show a progressive transition from dominant terrestrial palynomorphs and inner-neritic dinocyst taxa as well as cysts produced by heterotrophic dinoflagellates to predominantly outer-neritic/oceanic autotrophic taxa. This transition reflects the progressive deepening of the western Tasmanian continental margin, an interpretation supported by our new seismic investigations. The dominance of autotrophic species like Spiniferites spp. and Operculodinium spp. reflects relatively oligotrophic conditions, like those of regions north of the modern-day STF. The increased abundance in the earliest Miocene of Nematosphaeropsis labyrinthus, typical for modern subantarctic zone (frontal) conditions, indicates a cooling and/or closer proximity of the STF to the site . The absence of major shifts in dinocyst assemblages contrasts with other records in the region and suggests that small changes in surface oceanographic conditions occurred during the Oligocene. Despite the relatively southerly (63–55∘ S) location of Site 1168, the rather stable oceanographic conditions reflect the continued influence of the proto-Leeuwin Current along the southern Australian coast as Australia continued to drift northward. The relatively “warm” dinocyst assemblages at ODP Site 1168, compared with the cold assemblages at Antarctic Integrated Ocean Drilling Program (IODP) Site U1356, testify to the establishment of a pronounced latitudinal temperature gradient in the Oligocene Southern Ocean.

The article summarizes the results of the study of paleontology and biostratigraphy of the Jurassic of the Piennine Zone of the Ukrainian Carpathians by domestic and foreign researchers. For the first time, a summary paleontological description of these sediments is presented, taking into account numerous published data on identified macro- and mictofossils. A correlation biozonal scale has been created, as well as complex biostratigraphic schemes for each Jurassic series of its region in accordance with the International Stratigraphic Scale (2020). Because the stratigraphic sequence was disturbed by disjunctive dislocations, these schemes were developed by analysis of fragmentary sections. At present, three series of the Jurassic are determined by ammonites, belemnites, pelecypods, brachiopods, the Lower and Upper series are also dated by dinocysts, the Upper also by foraminifera and tintinnids. The stages and standard zones of the modern international scale are determined by ammonites: Liasicus of the Gettangian; Bucklandi, Obtusum, Raricostatum of the Sinemurian; Jamesoni, Emaciatum of the Pliensbachian; Tenuicostatum, Serpentinum, Bifrons, Thouarcense of the Toarcien; Opalinum, Murchisonae, Bradfordensis, Concavum of the Aalenian; Propinquans, Humpriesianum, Parkinsoni of the Bajocian; Zigzag, Aurigerus, Subcontractus, Bremeri, Retrocostatum of the Bathonian; Athletа of the Callovian; Plicatilis і Bifurcates of the Oxfordian; Divisum, Acanticum і Cavouri of the Kimmeridgian. Continuous dinocyst zonation is traced in the Upper Jurassic – Fibrata Аcme (Upper Oxfordian), Parvula Acme, Moluccana і Borzai (Kimmerigian), Pulla, Tithonica, Malmica, Semiradiata (Lower Tithonian) and all standard tintinnide zones of Tithonian — Chitinoidella (підзони Dobeni і Boneti), Praetintinnopsella, Crassicollaria. The boundaries of the stages from the Gettangiean to the Oxfordian are not determined. The boundaries between the Lower and Upper Oxfordian as well as between the Kimmeridgian substages are determined by ammonites as well as the boundary between the Kimmeridgian and Tithonian is determined by dinocysts, and the boundary between the Jurassic and Cretaceous is determined by tintinnids (corresponds to the boundary between the zones Crassicollaria of Tithonian and Calpionella of Berriassian). Stratigraphic unconformities were revealed by the macro- and mictofossils: the regional erosion on the boundary between the Aalenian and Bajocian as well as in Early Callovian, and short gap on the boundary between the Lower and Upper Bajocian.

Most previous Black Sea palynology studies have used pollen-spore assemblages as proxies for climate and landscape changes, and dinocyst assemblages as proxies for surface water salinity. However, there are few data on within-region variations in these assemblages using large sets of surface samples and a full suite of palynomorphs, including terrigenous pollen + spores, freshwater algal spores, and organic remains of marine microplankton, micro- and meiobenthos. Here we fill this knowledge gap, using results from a palynological study of 43 surface samples from water depths of 71–905 mbsl on the Ukrainian Shelf and adjoining continental slope, NW Black Sea. The palynology samples were collected in conjunction with water and sediment chemistry data, grain-size, micropaleontological and meiobenthos data from the EU-FP6 project HERMES “Hotspot Ecosystems Research on the Margins of European Seas”. This dataset uniquely covers shelf and upper slope areas east and west of the Odessa-Sinop Fault Zone (OSFZ) that delimits areas of lower and higher hydrocarbon gas contents, respectively. The new data show that on the wide shelf with a shallow (ca. 80 m) oxycline, pollen assemblages differ from classical models for marine pollen transport. On the Ukrainian Shelf, pollen concentrations are extraordinarily high far offshore and the grains are often pyrite-infilled. These features apparently reflect high pollen preservation potential in low oxygen sediments, probably enhanced by cross-shelf transport of land-derived particulate organic matter. The new data have important consequences for accurate modelling of carbon burial and storage in epicontinental seas, and they provide a baseline for evaluating marine pollen concentrations expected to reflect the early Neolithic farming on the Ukrainian shelf. Furthermore, although large concentrations of dinocysts comprise more than half of the total Non-Pollen Palynomorphs (NPP), the high pollen concentrations skew the P:D index (pollen:dinocyst ratio) commonly used to evaluate changes in paleo-shoreline (proxy sea-level) positions. Despite the discharge of several large rivers to the Ukrainian Shelf, there are negligible traces of freshwater algae in the HERMES samples except at Sta. 15 where Pediastrum is abundant. Overall, palynomorphs of terrestrial origin make up about half (52%) of the acid-resistant organic-walled particles on the outer NW Black Sea Shelf and adjacent slope. The abundances of the major micro- and meiobenthic palynomorph groups show the same trends east and west of the OSFZ as the micropaleontological data reported for the HERMES samples taken at the same sites. The combined microzooplankton and zoobenthos surface assemblage data provide an important new baseline for evaluating historical and past changes in biodiversity and aquatic foodweb structure in the now polluted NW Black Sea. Comparison can also be made with foodweb reconstructions for Permian black shales.

Eocene silicofossils (diatoms and silicoflagellates), dinoflagellate cysts, and continental palynomorphs of two boreholes in the Cis-Donetsk and Pavlovsk–Kantemirovka structural-facies zones of the Donets Syncline were studied. The Veshenskaya Formation, characterized by the dinocyst assemblage of the Stenodinium meckelfeldense Zone, is assigned to the early Ypresian. The Tishki and Kasyanоvka formations, with assemblage of the Bipalla oamaruensis diatom zone and first appearance of silicoflagellate Corbisema hexacantha, as well as a dinocyst assemblage with Enneadocysta pectiniformis, are dated as the late Lutetian–early Priabonian. The microfossil assemblages are typical of shallow-water marginal parts of the epicontinental paleobasin.

The results of a palynological study of the Upper Cretaceous and Paleogene sediments of three boreholes drilled in the South Transurals are presented. The Upper Cretaceous Kuznetsovo, Kamyshlov, Zaikovo, Fadyushino, and Gan’kino formations are exposed by Boreholes 3, 9, and 13, which contain four spore and pollen biostratons. Five dinocyst biostratons are identified for the first time: local zone with Chatangiella spectabilis, local zone with Spinidinium sverdrupianum, local zone with Chatangiella chetiensis, local zone with Chatangiella manumii–Dinogymnium spp., and local zone with Cerodinium diebelii. The comparison of the Late Cretaceous dinocyst assemblages of the southern and northern territories of Western Siberia shows that, in spite of significant provincialism of dinoflagellates, there is a series of stratigraphic intervals in the middle–upper Turonian, lower Coniacian, lower Santonian, Campanian, and lower Maastrichtian, which have interregional correlation potential. In the Talitsa, Serov, Irbit, and Chegan formations, intervals of six zones of the Thanetian–Bartonian age of the dinocyst scale of Western Siberia are identified in Borehole 9 (Alisocysta margarita, Apectodinium hyperacanthum, Deflandrea oebisfeldensis (acme), Dracodinium simile, Rhombodinium draco, and Rh. ornatum), as well as five local zones by spores and pollen. The Kurtamysh Formation is characterized by a Rupelian spore and pollen assemblage. Significant sedimentation hiatuses in the Cretaceous–Paleogene sequence corresponding to the upper part of the Maastrichtian, the most part of the Danian and Selandian, the lowermost parts of the Ypresian, middle–upper Ypresian, Lutetian, the upper parts of Bartonian, Priabonian, and the lower parts of the Rupelian are established.

Optical examination employing transmitted light and UV-fluorescence microscopy of palynological preparations of eighteen cutting samples representing the Alam El Bueib Member (Hautervian-Barremian), Kharita/lower Bahariya (Cenomanian), and Abu Roash (Turonian-Santonian) formations collected from the Faghur Hj5-1 well, north Western Desert, Egypt, allows the identification of three different palynological assemblages from the studied rock units. These assemblages are mainly non-marine but apparently marine at the base of the Alam El Bueib Member, as evidenced by dinocyst occurrence. In addition, the presence of the Pediastrum and chlorophycean algae ecozone, recognised in previous works, is a good datum for the Abu Roash Formation in the north Western Desert of Egypt. Three associations of palynofacies linked to lithofacies changes are recognised and employed in identification of depositional environments. The Alam El Bueib samples yielded mixed kerogen assemblages of non-marine and marine organic facies. The Kharita/lower Bahariya interval is mostly barren, possibly due to prevailing sandstone lithofacies, except for one sample at its upper part which contains a diverse palynological assemblage. The overlying Abu Roash Formation has a homogeneous kerogen composition comprising mainly granular fluorescent AOM and algae as well as rare palynomorphs. Qualitative as well as quantitative variations of palynofacies allow the reconstruction of the depositional environment. The obtained data have the potential for discriminating spatial and redox status differences and providing also information about terrestrial/freshwater influxes. Results support the model that the Alam El Bueib Member was deposited in a marginal dysoxic-anoxic to distal suboxic-anoxic basin. The Kharita/lower Bahariya unit in the studied well was deposited under marginal dysoxic-anoxic conditions whereas the overlying Abu Roash Formation in a distal suboxic-anoxic basin. Palynofacies results also show that the studied material comprises two distinct facies of kerogen. First, Type II > I kerogen (AOM-rich) is overwhelmingly dominant in the Abu Roash Formation and a few samples from the Alam El Bueib Member which are presumed highly oil-prone, whereas Type III kerogen (phytoclast-rich) is particularly common in the Alam El Bueib Member and Kharita/lower Bahariya unit which are considered gas-prone. Thermal maturity determinations obtained from colour changes of smooth-walled palynomorphs reveal that Alam El Bueib samples belong to immature to mature stages; however, Kharita/lower Bahariya and Abu Roash samples are within the immature phase.

Makassar Strait encompasses high fisheries resources and high biodiversity and primary productivity. Algae blooms often occur in these areas, but there is a lack of studies that have been carried out on HABs in these locations specifically determining the collection and abundance of dinocyst. The study aimed to determine species assemblages of dinoflagellate cysts from three estuaries of Makassar Strait. Sampling was conducted at three locations, i.e., Jeneberang, Maros and Pangkep Estuaries during July 2020. Each location of sampling consisted of 4 stations and 3 substations as a sampling replication. Variables that were measured in this study were dinoflagellate cysts abundance species assemblages and distribution. Results showed that there was no clear group of dinoflagellate cysts assemblages between locations, however dinoflagellate cyst assemblages from Jeneberang Estuary was significantly grouped. We recorded 48 dinoflagellate cysts species that belonged to 5 families, namely Goniodomaceae, Gonyaulacaceae, Gymnodiniacea, Peridiniaceae and Protoperidiniaceae. The dominant species of dinoflagellate cysts from Jeneberang Estuary was Scrippsiella crystallina, meanwhile the dominant dinoflagellate cyst from Maros and Pangkep Estuary was Gonyaulax verior and Pentapharsodinium tyrrhenicum, respectively. Scrippsiella trifida was a dinoflagellate cysts species was contributed to the dissimilarity of cyst assemblages between locations. We also found potential five toxic dinoflagellate cyst species. In conclusion, the dinoflagellate cysts species composition, diversity, species richness and cyst abundance was not significant difference between stations of all locations. The abundance of dinoflagellate cysts was significantly correlated by sediment grain size. All sampling sites has a potentially occurred of HABs due to the five potential cysts toxic and harmful species discovered.

Microfossils of the upper Bajocian Garantiana garantiana Zone of the Kyafar River (a tributary of the Bolshoi Zelenchuk River, Karachay-Cherkess Republic) are studied. The zone is represented by dark gray claystone-like clay series with sporadically scattered nodules, often forming interlayers, and is recognized in the upper subformation of the Djangura Formation. The taxonomic composition and distribution in the section of foraminifers, ostracods, dinoflagellate cysts, and miospores are studied. The range of foraminiferal and dinocyst biostratigraphic units and their correlation with the ammonite scale are established. On the basis of benthic foraminifera, these are Beds with Ophthalmidium caucasicum, corresponding to most of the Garantiana Zone, and Beds with Sublamarckella terquemi, corresponding to the upper part of the Garantiana Zone and the lower part of the Parkinsoni Zone. The Beds with Globuligerina dagestanica, recognized on the basis of planktonic foraminifera, are compared with the entire studied interval from the Garantiana Zone to the bottom of the lower Bathonian inclusive. The Beds with Meiourogonyaulax valensii and Rhynchodiniopsis? regalis (dinocysts) are considered equivalent to the entire range of the Garantiana Zone to the lower part of the Parkinsoni Zone inclusive. The key fossils are illustrated.

Centennial‐to‐millennial temperature records of the past provide a context for the interpretation of current and future changes in climate. Quaternary climates have been relatively well studied in north‐east North America and the adjacent Atlantic Ocean over the last decades, and new research methods have been developed to improve reconstructions. We present newly inferred reconstructions of sea surface temperature for the north‐western Atlantic region, together with a compilation of published temperature records. The database thus comprises a total of 86 records from both marine and terrestrial sites, including lakes, peatlands, ice and tree rings, each covering at least part of the Holocene. For each record, we present details on seasons covered, chronologies and information on radiocarbon dates and analytical time steps. The 86 records contain a total of 154 reconstructions of temperature and temperature‐related variables. Main proxies include pollen and dinocysts, while summer was the season for which the highest number of reconstructions were available. Many records covered most of the Holocene, but many dinocyst records did not extend to the surface, due to sediment mixing, and dendroclimate records were limited to the last millennium. The database allows for the exploration of linkages between sea ice and climate and may be used in conjunction with other palaeoclimate and palaeoenvironmental records, such as wildfire records and peatland dynamics. This inventory may also aid the identification of gaps in the geographic distribution of past temperature records thus guiding future research efforts.

The results of palynological study of the middle–upper Eocene interval of the Kheu reference section are presented. The dinocyst zones such as Enneadocystaarcuata, Costacystabucina, Enneadocystapectiniformis, Rhombodiniumdraco, Reticulatosphaeraactinocoronata, and Talladinium? angulosum were recognized in the studied part of the section. Based on the first order calibrations with calcareous nannoplankton, their stratigraphic boundaries are established as well as the lowermost occurrences of stratigraphically important species are refined. New microplankton data suggest the early Lutetian age of the uppermost Cherkessk and Keresta formations; the Kuma Formation is dated by late Lutetian–earliest Priabonian, while the lowermost Belaya Glina Formation corresponds to the Priabonian. Analysis of ratios of marine and terrestrial palynomorphs in the Kheu section permits to interpret the paleoenvironments during the Lutetian–Priabonian in the studied part of the eastern Peri-Tethys.

The results of palynological study of the MidUpper Eocene sediments of the Aktumsuk key-section (Ustyurt Plateau, Uzbekistan), calibrated with nannoplankton data, are presented. Dinocyst stratigraphical distribution permitted to recognize five Dinoflagellate zones from the Peri-Tethys zonation: Costacysta bucina, Enneadocysta pectiniformis, Rhombodinium draco, Rhombodinium perforatum, and Thalassiphora reticulata. First-order calibration with nannoplankton zones permitted to precise the lowermost occurrences of the key dinocyst species. Based on the dinocyst and nannoplankton data, two important stratigraphic hiatuses, corresponding to the upper Ypresian and Upper BartonianLower Priabonian, were recognized. Analysis of quantitative fluctuations of different groups of palynomorphs through the section indicates paleoenvironmental changes in this part of the Peri-Tethys during the LutetianPriabonian: the beginning of significant transgressive phase in the early Lutetian, relative deepening in the Mid Lutetian; after the break in sedimentation at the end of Bartianianbeginning of Priabonian the sedimentation continues again in the open-marine (outer neritic) environment.

Surface sediment samples from the East Siberian and Chukchi seas have been analyzed for the quantitative distribution, taxonomic composition, and ecological structure of diatom and dinoflagellate cyst assemblages. According to the results, the diatom and dinocyst distribution in surface sediments indicates the distribution of different water masses in the region.

The chemical composition of recent and fossil organic-walled dinoflagellate cyst walls and its diversity is poorly understood and analyses on single microscopic specimens are rare. A series of infrared spectroscopic experiments resulted in the proposition of a standardized attenuated total reflection micro-Fourier transform infrared-based method that allows the collection of robust data sets consisting of spectra from individual dinocysts. These data sets are largely devoid of nonchemical artifacts inherent to other infrared spectrochemical methods, which have typically been used to study similar specimens in the past. The influence of sample preparation, specimen morphology and size and spectral data processing steps is also assessed within this methodological framework. As a result, several guidelines are proposed which facilitate the collection and qualitative interpretation of highly reproducible and repeatable spectrochemical data. These, in turn, pave the way for a systematic exploration of dinocyst chemistry and its assessment as a chemotaxonomical tool or proxy.

Little is known about the marine palynology of the neotropical oceans. Here, we present the first comprehensive study of organic-walled dinoflagellate cyst assemblages in 52 surface marine sediment samples from the southern Caribbean (SC) and the eastern tropical Pacific (ETP) and explain how these assemblages relate to sea-surface parameters. Multivariate analyses show that of the several environmental parameters considered, sea-surface salinity (SSS), phosphate concentrations, and nitrate concentrations best explain the relative abundances and the geographic distribution of dinoflagellate cysts in the studied area. Consistent with regional differences in marine productivity, dinoflagellate cyst concentrations were markedly different in the SC (1979 ± 1053 cysts/g) and the ETP (3105 ± 1956 cysts/g). Sediments of the SC are characterized by high relative abundances of the Spiniferites spp. group, cysts of Protoceratium reticulatum, and the presence of rare dinocyst taxa. The dinocyst assemblages from the ETP are characterized by higher relative and absolute abundances of Bitectatodinium spongium, Brigantedinium spp., and Echinidinium aculeatum. This pattern is explained by the more eutrophic nature of the ETP compared to the highly saline and oligotrophic SC. Average values of the Shannon Index (H′) from the ETP are higher compared to the SC, demonstrating that dinocysts respond to the greater climatic variability that characterizes the ETP. Brigantedinium spp. abundances are negatively correlated to H′ diversity supporting its dominant character within the dinocyst community. This work fills a gap in our knowledge on modern dinocyst distribution in neotropical oceans and provides a modern reference for interpreting down core dinocyst variations and paleocenographical reconstructions in the region.

The data presented here are related to the research article “Miocene Atlantic transgressive-regressive events in northeastern and offshore Patagonia: A palynological perspective” (Guler et al. 2021; https://doi.org/10.1016/j.jsames.2021.103239 ). A total of 60 drilled cutting samples from a 580 m-thick subsurface stratigraphic section (YPF.Ch.PV.es-1 borehole) in Peninsula Valdes, Chubut Province, Argentina, collected every 10 m, were processed for palynological analysis. The quantitative data were statistically evaluated. In detail, the database contain: 1) raw palynological data – proxy data – from counting under transmitted light microscope; 2) four paleoenvironmental variables selected to conduct a multivariate analysis: terrestrial/marine ratio, acritarchs, outer neritic dinocyst taxa and warm-water dinocyst taxa; 3) transformed variables used for the Principal Component Analysis (PCA) and 4) the principal component scores obtained, stratigraphically ordered from the top to bottom of the borehole. Data from future studies in new sites combined with here presented data, can be useful to refine paleoenvironment models applied to basin analysis.

The results of palynological study of the mid-upper Eocene sediments of the Aktumsuk key-section (Ustyurt Plateau, Uzbekistan), calibrated with nannoplankton data, are presented. Dinocyst stratigraphical distribution permitted to recognize five Dinoflagellate Zones from the Peri-Tethys zonation: Costacysta bucina, Enneadocysta pectiniformis, Rhombodinium draco, Rhombodinium perforatum, and Thalassiphora reticulata. First-order calibration with nannoplankton zones permitted to precise the lowermost occurrences of the key dinocyst species. Based on the dinocyst and nannoplankton data, two important stratigraphic hiatuses, corresponding to the upper Ypresian and upper Bartonian-lower Priabonian, were recognized. Analysis of quantitative fluctuations of different groups of palynomorphs through the section indicates paleoenvironmental changes in this part of the Peri-Tethys during the Lutetian-Priabonian: the beginning of significant transgressive phase in the early Lutetian, relative deepening in the mid Lutetian; after the break in sedimentation at the end of Bartianian-beginning of Priabonian the sedimentation continues again in the open-marine (outer neritic) environement.

Reconstructions of sea‐surface conditions during the Holocene were achieved on two sediment cores from the northwest Greenland margin (AMD14‐204) and Kane Basin (AMD14‐Kane2B) based on dinoflagellate cyst assemblages. On the northwest Greenland margin, sea‐surface conditions were cold with an extended sea ice cover prior to 7750 cal a bp associated with the end of the deglaciation. A major change occurred around ca. 7750 cal a bp with enhanced influence of warmer water from the West Greenland Current, and optimal sea‐surface conditions were observed around 6000 cal a bp. After 3350 cal a bp, results reflect the establishment of the modern assemblages. In the Kane Basin, sea‐surface conditions were not favourable for dinocyst productivity prior to 7880 cal a bp, as the basin was still largely covered by ice. The presence of warmer water is recorded between 7880 and 7200 cal a bp and the highest primary productivity between 5200 and 2100 cal a bp, but sea‐surface conditions remained cold with an extended sea ice cover throughout the Holocene. Overall, the results from this study revealed the strong influence of meltwater discharges and oceanic current variability on the sea‐surface conditions. -- Keywords : Baffin Bay ; dinoflagellate cysts ; Kane Basin ; Melville Bay ; sea‐surface conditions.

The lower Oligocene (Rupelian) successions are climate record archives of the early icehouse world in the Cenozoic. Even though the number of studies focussing on the generally cold Oligocene is increasing, little is known about climatic variations in the mid-latitudes to high latitudes of the Northern Hemisphere. One of the major obstacles is the lack of stratigraphically complete uppermost Eocene to Oligocene successions in these regions. This study focusses on dinoflagellate cysts (dinocysts) from a thick nearly complete Rupelian succession in the Syracuse Oils Norge A/S well 11/10-1 drilled in 1969 in the Norwegian part of the North Sea basin. The well provides a record of mid-latitude dinocyst assemblages, which yield key biostratigraphical and palaeoenvironmental information. All the analyses were undertaken on ditch cutting samples. The dinocyst assemblages confirm that the well penetrates about 600 m of Rupelian sediments and (as supported by correlation with the Nini-1 well) that the lowermost Rupelian (below the top or the last occurrence of Areosphaeridium diktyoplokum) is expanded. These assemblages also indicate the presence of two hiatuses: the first extends from the Lutetian to the Priabonian (equivalent to the D9nb–D12nb zones), and the second spans the Rupelian–Chattian boundary (equivalent to the D14nb subzone or the NSO-5 zone). Despite the risk of caving, the dinocyst assemblages support the existing sequence stratigraphic framework. The assemblages reflect a clear transition from distal to proximal deposition in the vicinity of the site (across the regional seismic sequences OSS-1 – OSS meaning Oligocene seismic sequence – to OSS-2). The proximal deltaic deposits of the OSS-2 regressive system tract (RST) are characterised by pulses of high sea-surface productivity and pronounced shifts in the dinocyst assemblages, reflecting a highly dynamic environment in a restricted marine to marginal marine setting. The Rupelian succession penetrated by well 11/10-1 yields one new species, Areoligera? barskii sp. nov., which is described here in detail. The cold-water-tolerant dinocyst Svalbardella cooksoniae is present in two intervals in the studied succession. These intervals are related to the early Oligocene cooling maxima (the Oi-1a and the Oi-2 events). Furthermore, these two intervals correlate with two local sequence boundaries, suggesting that they are most probably of glacioeustatic origin. From these observations, I postulate that the early icehouse climate played an important role in the depositional development of the Oligocene succession in the North Sea basin. Even though the Eocene–Oligocene transition interval is not complete (i.e. Lutetian to Priabonian is either missing or condensed), well 11/10-1 merits high-resolution studies of the early icehouse climate for the North Sea region. Although any detailed studies should ideally be undertaken on conventional cores instead of ditch cuttings, no such samples spanning the Eocene–Oligocene transition exist in this area.

Samples from two wells implanted at the level of the dark gray clay outcrop of Bingerville were the subject of this palynological study. The main objective of this work is to inventory all the palynomorphs encountered, to propose a local palynostratigraphy and to reconstitute the paleobotany of our study area during the Tertiary formations north of the lagoon fault. The samples were processed according to the classical procedure of extraction and concentration of palynomorphs. The high populations of dinocysts of the genus Lejeunecysta lata, Opreculodinium centrocarpum and Selenopemphix quanta as well as those of spores and pollens of the genre Magnastriatites howardii, Perfotricolpites digitatus, Pachydermites diederixi, Bombacacidites bombax, Retitricolporites irregularis, Retitriporites sp. Verrucatosporites usmensis are tributary to Oligocene. At the palaeobotanical and palaeoecological level, the highlighted palynoflora made it possible to characterize three environments, including mangroves, coastal plain, and rainforests.

A palynological analysis and study of calpionellids and calcareous dinoflagellate cysts across the Jurassic–Cretaceous (J/K) boundary succession in the Outer Western Carpathians, Bruzovice section is presented. It is a one of few sections of the Tethyan Realm suitable for the palynological study. The lower part of the section is formed by anoxic deposits consisting of dark grey calcareous claystones. The upper part of the profile is represented by flysch-like alternation of grey limestones, spotted claystones and marlstones. The section spans the stratigraphic range from the upper Tithonian, Cadosina semiradiata calcareous dinoflagellate Zone to the lower Berriasian, calpionellid Calpionella elliptica Subzone. The J/K boundary is marked by a high abundance of small forms of Calpionella alpina. The Tithonian–Berriasian succession of non–calcareous dinoflagellates is as follows: the base of the section is correlated with the dinocyst Semiradiata Zone along with the presence of Glossodinium dimorphum. The first occurrence (FO) of Amphorula metaelliptica and the last occurrence (LO) of Prolixosphaeridium anasillum are recorded in the Cadosina semiradiata Zone followed by the Cadosina tenuis–Colomisphaera fortis Zone. An aboudance of the spherical C. alpina indicates the onset of the Calpionella Zone and the Calpionella alpina Subzone at the base of the Berriasian Stage. The FO of Diacanthum hollisteri is situated in the lower part of the Calpionella alpina Subzone. The FO of Dichadogonyaulax bensonii coincides approximately with the base of the calpionellid Remaniella ferasini Subzone, and the FO's of Muderongia longicorna, M. tabulata and Spiniferites cf. ramosus were found in the upper part of the calpionellid Remaniella ferasini Subzone. The FO of Achomosphaera neptunii was found in the lower part of the Calpionella elliptica Subzone. The work is a contribution to the ICS Berriasian Working Group.

The section of well 768, depth 362 m, which opened the Eocene and Maikopian deposits is comprehensively studied and can serve as a reference one for both the Northern Ergeny and the entire northern part of Paratethys. The data on lithology, mollusks, and benthic foraminifera made it possible to break up the Oligocene part of the Maikop Group into formations and subformations: Tsimlyansk, Solenovian and Kalmyk parts, compare them with neighboring and distant parts of Parathethys, with a regostage scale, restore basic sedimentation conditions. Based on nannoplankton and dinocyst composition, these units were compared with the global zonal scale (Gradstein et al., 2012), and according to the spore-pollen data, the evolution of the climate of the Parathethys northern margin was restored. The phytoplankton, foraminiferal and paleomagnetic data show a strong reduction of the section in the Eocene part, where only negatively magnetized fragments of the Keresta, Kuma and Belaya Glina formations separated by unconformity surfaces were distinguished. In the lower Oligocene part we saw the full set of biotic and paleomagnetic zones. The lower part of the Solenovian formation (50 m) is rarely complete, unlike most of the Ciscaucasian sections. The Kalmyk formation in this section is probably incomplete and responds only to the first half of the Chattian.

For the first time, a dinoflagellate cyst analysis is provided for the Upper Cretaceous–lower Paleogene transition in the Dababiya borehole, near Luxor, southern Egypt. Rich and relatively well-preserved dinoflagellate cyst assemblages have been recovered; a total of 173 species and subspecies have been identified. Many of these were not previously known from Egyptian material. The biostratigraphical dinoflagellate cyst events recorded in the present study have allowed us to propose the first K/Pg boundary dinocyst zonation scheme for Egypt and to compare this with existing dinoflagellate cyst zonations worldwide. In ascending order, the observed latest Maastrichtian dinoflagellate cyst events include successively the last occurrence (LO) of Cannosphaeropsis utinensis, the first occurrences (FOs) of Apteodinium fallax, Disphaerogena carposphaeropsis, Kenleyia leptocerata and the LOs of Alisogymnium euclaense, Dinogymnium spp. and Pterodinium cretaceum. The most significant early Danian dinoflagellate cyst events used in this study are the FOs of Danea californica, Carpatella cornuta, Cassidium fragile, Lanternosphaeridium reinhardtii, Senoniasphaera inornata and Membranilarnacia? tenella. The dinoflagellate cyst biostratigraphical results, calibrated with data from benthic and planktonic foraminifera and calcareous nannoplankton from the same set of samples, have enabled a more accurate identification of the Cretaceous–Paleogene (K/Pg) boundary than previously suggested for the succession studied.

This paper is the first systematic documentation of Eocene organic-walled dinoflagellate cyst (dinocyst) assemblages from the northwestern shelf of the Tethys. A taxonomic list of the rich and well-preserved dinocyst assemblages found within 28 samples collected at the Adelholzen section in southeastern Germany is presented herein. The sediments accumulated during the Lutetian and Priabonian stages at a ramp-type margin. One-hundred organic-walled dinocyst species were found at the section, which is riddled with unconformities. The composition of the successive dinocyst assemblages reflects the sea-level changes within the depositional area. Areoligera coronata and Cordosphaeridium gracile dominate the assemblage within the glauconite-rich siliciclastic sandstone (lower Adelholzen beds) of the lower transgressive system tract, which spans the calcareous nannoplankton sub-Zones NP15a and NP15b. A hiatus comprising at least c. 1.5 million years truncates these deposits and indicates an erosional episode. Rapid sea-level rise in Biochron NP16 caused a new transgression and the deposition of calcareous marlstone and limestone rich in nummulitids. In this part of the section (middle Adelholzen beds), Homotryblium tenuispinosum is by far the most abundant dinocyst species, and rare but consistent occurrences of Impagidinium spp. suggest a more open marine environment. A lithological shift from limestone to marlstone, a change from nummulitids to discocyclinids, and finally the complete disappearance of larger benthic foraminifera indicates continuous deepening of the environment. An increase in Spiniferites spp., Operculodinium spp., and occurrences of Homotryblium floripes characterize the dinocyst assemblage of this marlstone (upper Adelholzen beds). A 0.5 m thick condensed layer, which consists essentially of iron-coated glauconite grains and scattered phosphate nodules, represents the maximum flooding surface of the transgressive sequence, for which a paleodepth of c. 300 m is assumed. The overlying marlstone (“Stockletten”) of the highstand system tract is punctuated by a hiatus of c. 4.3 million years spanning the entire Bartonian. The stratigraphically important species Rhombodinium longimanum, Rhombodinium perforatum, Distatodinium ellipticum, Nematosphaeropsis labyrinthus and Selenopemphix nephroides have their lowest occurrences in the Priabonian (Zones NP18 and NP19) of the section.

A palynological study was performed using the core obtained from the Integrated Ocean Drilling Program (IODP) Expedition 346 Site U1430 in the Eastern South Korea Plateau in the East Sea, to reveal variability of paleoclimate and paleoceanography during the late Pliocene to early Pleistocene climate transition period (56.0–68.0 meters below sea floor [mbsf]). Two pollen and dinocyst zones are established with a boundary at ca. 3.0 Ma. Prior to ca. 3.0 Ma (first pollen and dinocyst zone), long-term oscillation of the East-Asian winter monsoon (EAWM) is indicated by fluctuations in the abundance of pollen taxa, representing cold–dry and cool–wet climates. After ca. 3.0 Ma (second pollen and dinocyst zone), an increase in cold–dry conifer pollen indicates an enhanced and stable EAWM. In addition, the prevalence of the xerophytic herb, Artemisia, increases markedly after 3.0 Ma, suggesting open grassland on the exposed South Yellow Sea shelf during the sea level lowstand under cold–dry climate conditions. Artemisia pollen are interpreted as having been delivered to the coast through fluvial channels in this grassland environment, and subsequently transported to the East Sea by inflow of a weak Tsushima Warm Current (TWC) through the narrow Korea Strait. The TWC intrusion signal is represented by an influx of Tuberculodinium vancampoae, a warm water dinoflagellate species, in the western Pacific region. The high abundances of cold–dry conifer pollen and cold water dinocyst elements after ca. 2.8 Ma suggest an intensified EAWM. Meanwhile, a short-term increase in moisture-loving Tsuga pollen after ca. 2.5 Ma was likely due to soil moisture derived from snowfall caused by evaporation of heated seawater from the weak TWC in the East Sea under cold climate conditions. The palynological studies reported here help verify the linkages between the EAWM, TWC, precipitation and vegetation responses in/around the East Sea region.

Understanding the long-term environmental forcings driving Caspian Sea (CS) water levels is of utmost importance, not only owing to its large size, or to the surrounding developing economies but also to improve global climate models and forecasts. However, Late Quaternary CS level changes and their amplitude are mostly documented from incomplete coastal sediment records. Because of the CS idiosyncrasies, that behaves neither as a sea nor as a lake, the methods used to reconstruct water levels in the global ocean or in freshwater lakes do not always apply. Here, we propose a first step toward the use of dinoflagellate cysts records to reconstruct qualitative changes in water mass, focusing on new and published deep-water sedimentary sequences from the south and middle CS basins. Trends in water level changes are reconstructed on the relative proportions of dinocyst assemblages with different levels of brackishness. A higher highstand than previously seen is reconstructed post-Mangyshlak lowstand. A reverse water flow gradient from S to N, not previously detected, is identified at 8.5–8 to 4 cal ka BP. A major turnover in dinocyst assemblage is found at 4 cal ka BP. While the Volga River is the main source of water nowadays, we propose that the source of water to maintain the 8.5–8 to 4 cal ka BP highstand is the now-disconnected drainage basin of the Amu-Darya. The CS was at that time most likely strongly influenced by low latitude climates, with more precipitation over the Karakum and, perhaps, even indirect monsoonal influence.

The Upper Cretaceous to lower Eocene sediments from the "12 Freres" borehole in Fresco, southwestern Cote d’Ivoire are here subject of a palynological study: systematic, palynostratigraphy and paleogeography . Eight thousand eight hundred and ten palynomorphs , including 68 species of dinoflagellate cysts (dinocysts), 14 species of spores and pollen grains and Chlorophyceae were identified. The biostratigraphy based on dinocyst marker events and compared with various reference sections from the Northern Hemisphere allowed us to refine to the stage level the Maastrichtian , Paleocene and Eocene deposits of the section. The dinocyst events, recorded from the base to the top of the studied section, include the last occurrences of Odontochitina operculata, Andalusiella ivoirensis, Cerodinium granulostriatum, Dinogymnium spp., Andalusiella spp., Cerodinium diebelii, highest relative abundances of Adnatosphaeridium vittatum, Kallosphaeridium yorubaense and highest relative abundances of Apectodinum spp. According to Lentin and Williams (1980), the observed dinocyst assemblages suggest a tropical to subtropical province for the studied deposits.

The dinoflagellate cyst assemblages on the Nanji Island in the East China Sea, are documented at the first time to construct a quantitative overview of the cyst bank from 2014 to 2015. Thirty-four morphotypes from six groups are identified and quantified at eight sampling sites around the island, including a high proportion of potentially toxigenic species (14%). Autotrophic dinocysts constitute 74% of the total cyst counts, which is relatively low (two to thirty-three per millilitre sediment) compared with previous studies in adjacent areas. Scrippsiella trochoidea and Protoperidinium avellana are the most abundant autotrophic and heterotrophic species, respectively. A multivariate analysis is performed to assess associations between dinocysts and abiotic or biotic variables. Differentiation among seasons is evident in the detrended correspondence analysis (DCA) ordination plot, while a spatial pattern is not clearly revealed despite heterogeneity of the hydrodynamic conditions between sampling sites. Soluble reactive phosphate, the ratio of nitrogen to phosphorus concentrations and Karenia mikimotoi bloom are the three factors significantly (P

Pentadinium dababiyaense is a new, organic-walled dinoflagellate cyst (dinocyst), described herein from Upper Cretaceous core material from the Dababiya borehole, Upper Nile Valley, Egypt. It is characterized by having a distinctive cavate apical horn and cavate sutural crests with lace-like perforations in the periphragm. The sutural crests, together with the precingular type P archeopyle indicate a gonyaulacoid tabulation. The species has a very short stratigraphic range within the latest Maastrichtian and may constitute a useful stratigraphic marker.

The palynological study was carried out on middle Eocene to early Oligocene sediments from the Ben Aattaya section, located in the Taza region, eastern External Rif, northeastern Morocco. The palynological content is dominated by dinoflagellate cysts (dinocyst), while spores and pollen are rare. Very known dinocyst event markers were used for dating the Ben Attaya section. The first occurrences (FO) of Cerebrocysta bartonensis, Glaphyrocysta semitecta, Lentinia serrata, Operculodinium divergens indicate the Bartonian. The FOs of Deflandrea heterophlycta, Schematophora speciosa, Stoveracysta ornata were used to recognize the Priabonian. While the FOs of Chiropteridium lobospinosum and Wetzeliella gochtii, as well as the last occurrences (LO) of Achilleodinium biformoides, Charlesdowniea coleothrypta subsp. coleothrypta, Enneadocysta pectiniformis, Glaphyrocyst semitecta, Hemiplacophora semilunifera, Lentinia serrata, Operculodinium divergens, Rhombodinium perforatum, Schematophora speciosa and Stoverocysta ornata highlight the Rupelian . The changes in relative abundances of selected dinocyst groups and sporomorphs (pollen and spores) suggest a lagoonal to coastal inner neritic marine environment during the Bartonian and Priabonian, which was interrupted by a short phase of outer neritic conditions at the basal part of the section and ended by a marked decrease in the sea level, probably due to a regression during the Priabonian. The Rupelian deposits indicate a middle neritic marine environment marked by a progressive rise during the transgression.

The Eocene interval of the section in the Belaya River valley is continuously exposed and is represented (from the bottom up) by green clays of the Cherkessk Formation, the marl–clayey member of the Keresta Formation, bituminous marls of the Kuma Formation, and light intensely bioturbated marls of the Belaya Glina Formation. There are gradual transitions between formations without signs of hiatuses. Eocene deposits are characterized by rich assemblages of nannoplankton, planktonic and benthic foraminifers (PF, BF), and organic-walled phytoplankton. The shallower water facies are recorded in the composition of benthos and mollusks at the boundaries of formations. The data on these groups of fossils make it possible to trace an almost complete zonal characterization of nannoplankton, dinocysts and PF and to compare these subdivisions of the middle–upper Eocene and early Oligocene both with other reference sections of the Eastern Peri-Tethys and standard zones and stages of the international stratigraphic scale. The following zones are distinguished: the upper part of the Cherkessk Formation—nannoplankton (NP15) and Acarinina bullbrooki PF zones; the Keresta Formation—nannoplankton (NP15+NP16) and Hantkenina “alabamensis” PF zones; the Kuma Formation—the nannoplankton (NP16+NP17) zones, Hantkenina “alabamensis” (at the lower boundary of the formation) and Subbotina turсmenica PF zones (above basal part), and Areosphaeridium diktyoplokum–Rhombodinium porosum dinocyst zone; the Belaya Glina Formation—nannoplankton (NP18, NP19+NP20, NP21) zones, Turborotalia centralis–Globigerinatheka tropicalis PF zone, and Charlesdowniea clathrata angulosa dinocyst zone; the lower part of the Pshekha Formation—nannoplankton (NP21) zone, Globigerina officinalis PF zone, and Phtanoperidinium amoenum dinocyst zone. These data make it possible to clearly correlate the Belaya River section with the sections studied in detail in Ciscaucasia (Kheu, Kuban, and Gubs rivers) and to reconstruct the conditions of sedimentation.

New palynological, ostracod and foraminiferal data are presented from a long outcrop section in the Jeirankechmez river valley, Azerbaijan, near the western coast of the Caspian Sea. The interval studied includes the upper part of the Pliocene Productive Series and overlying Plio-Pleistocene Akchagylian (Akchagyl) and Apsheronian (Apsheron) regional stages. Productive Series sediments were deposited in a closed fluvio-lacustrine basin, isolated from any marine influence. The onset of Akchagyl deposition is marked by a lithological change associated with a significant flooding event that, at its maximum extent, reached the Sea of Azov and into present-day Iran, Kazakhstan, Turkmenistan and Russia. At the Jeirankechmez locality, the lowermost beds of the Akchagyl contain predominantly freshwater assemblages with very minimal marine or brackish content showing that the onset of Akchagyl deposition was not a marine induced event. Reworked Mesozoic palynomorphs occur frequently in this lowermost interval, including the reworked pollen taxa Aquilapollenites-Triprojectus that were eroded from the north or north-east.Significant marine influence is evident ca. 30 m above the base of the Akchagyl in the studied outcrop, marked by the ‘Cassidulina Beds’ which contain a distinct but low diversity assemblage of foraminifera that occurs widely and can be correlated in many parts of the greater Caspian region. Dinoflagellate cysts (dinocysts) in the marine interval include frequent specimens very similar to Algidasphaeridium capillatum (Matsuoka and Bujak), a species only previously recorded from the northern Bering Sea. The combined evidence from these dinocysts and foraminifera suggests that a marine (i.e. seaway) connection existed briefly between the Arctic Ocean and the Caspian Sea at the very end of the Pliocene.Re-examination of core material from the Adriatic Sea shows that Cassidulina reniforme (Nørvang) was present in the Mediterranean during and shortly after the Last Glacial Maximum. The possibility that the end Pliocene marine incursion came from the Mediterranean via the Black Sea region to the Caspian Sea cannot be entirely ruled out but is considered unlikely. Biometric analyses are applied to obtain a better understanding of the palaeoenvironmental significance of the assemblages dominated by cassidulinids.An interval >300 m thick is assigned to the Apsheron regional stage on the basis of predominantly brackish ostracod and dinocyst associations. The dinocysts are of ‘Peri-Paratethyan’ affinity and closely resemble species first described from Miocene and Pliocene sediments in the Pannonian and Dacic basins of Eastern Europe. Many similarities exist in the microplankton records (dinocysts and acritarchs) between the Caspian Sea, the Black Sea and Central Paratethys.

The presence of upwelling systems and oceanic fronts makes the Southwest Atlantic Ocean a region of high primary productivity. These same conditions are present in San Jorge Gulf (SJG) along the southern Argentinian coast, where dinoflagellates and diatoms dominate primary production. The distribution of these microorganisms, including the cysts produced by some dinoflagellates during their life cycles, is controlled in marine environments by oceanographic parameters that include salinity, surface water temperature, ice cover duration, and productivity. The objective of this study is to document the modern distribution of dinoflagellate cyst assemblages in surface sediments so that the environmental preferences of each taxon can be inferred and used to reconstruct paleoenvironmental conditions. The dinoflagellate cyst (dinocyst) assemblages of 52 surface samples collected in 2014 aboard R/V Coriolis II in the SJG were described and compared to surface oceanographic conditions and grain size data. The results indicate dinocyst concentrations vary between 64 cysts g–1 and 45,848 cysts g–1 dry sediment, with Spiniferites ramosus and Operculodinium centrocarpum the dominant species, accompanied by Spiniferites mirabilis, Dubridinium sp., cysts of Polykrikos kofoidii, and cysts of Brigantedinium simplex, Brigantedinium auranteum, and Brigantedinium spp. We have defined two spatial domains based on the distribution of dinocysts in and near the SJG: northern/southern-central gulf and offshore domains. We found an increase in dinocyst concentrations along a north-south gradient in the SJG and minimum concentrations at offshore sites. In addition, multivariate analyses reveal the relationships among the relative abundances of dinocysts, fine grain size data (

Dinoflagellates are part of the marine plankton and about 200 species produce a cyst (dinocyst) during their life cycle, these organic-walled sexually-produced cysts being fossilizable in sediments for hundreds of millions of years. Over the past 40–50 years, dinocysts have led to major advances on Mesozoic-Cenozoic research, in terms of biostratigraphy and paleogeogeography. Dinocyst taxonomy has then been continuously revised, with the tabulation being the main morphological link between living dinoflagellates and fossilized cysts. Over the Quaternary, and based on the principle of uniformitarianism (i.e. species ecology did not change through time), relationships between modern assemblages and present-day environmental factors controlling their distribution also allow for dinocyst-based quantitative reconstructions derived from transfer function calculations. This paper presents a non-exhaustive review of the dinocyst literature allowing the reader to get a perspective about how they were discovered and defined, but also how they are applied in (paleo)ecological studies according to the timescale considered allowing then to provide useful insights into the future climate change and its associated ecological repercussions.

The analysis of Albian dinoflagellate cysts, or dinocysts, along an inshore–offshore transect across the Iberian Margin reveals the environmental influence on the assemblages composition. Two biodiversity metrics are used to analyze changes in the assemblage structure. The stress associated to environmental instability is identified as the main factor influencing the dinocyst biodiversity. The relative frequency distribution of dinocysts is analyzed to identify associations of taxa sharing similar environmental preferences. Seven dinocyst associations are identified. The environmental affinities of the seven dinocyst associations are inferred from lithological data and assemblage structure. Association 1 dominated the most proximal and unstable environments. Associations 2 and 3 characterized inner-middle neritic environments. Taxa in the Association 2 preferred stable mesotrophic conditions, whereas, taxa in the Association 3 were tolerant to variations in salinity and nutrient input. Associations 4 and 5 are indicative of open marine distal environments. Taxa in the Association 4 were tolerant to limited environmental fluctuations. Taxa in the Association 5 were restricted to stable open marine conditions. The widespread distribution of taxa in the Association 6 is interpreted as revealing their ubiquitous character. The taxon in the Association 7 is considered as cosmopolitan because its widespread distribution was conditioned to nutrients availability.

Variegated limestones, a transitional series between red, Upper Jurassic radiolarite and whitish, Lower Cretaceous Maiolica limestone in the Pieniny Klippen Belt deposits in the Polish part of the Western Carpathians, have yielded rich microfossil assemblages with common calcareous dinoflagellate resting stages, hereafter, dinocysts. We found an undescribed dinocyst species in red-greenish limestone of a deep water, pelagic habitat in the Branisko succession of the Pieniny Klippen Basin and named it Cadosinopsis rehakovii sp. nov. The new species has a spherical to oval calcareous test ranging from 34 to 59 μm in length and 30 to 50 μm in width, with two layered wall. The inner layer is built of coarse–thick, plate-shaped calcite crystals and is white in transmitted light. The outer layer is built of fibrous crystals, vitreous (transparent) in transmitted light. The aperture is wide and seen only in the inner layer. We compared the detailed morphological characteristics of the new species with another species from the same genus in the Jurassic and Cretaceous Tethyan deposits. Specimens have been measured, grouped and interpreted using cluster analysis, principal component analysis (PCA) and canonical variate analysis (CVA). Among them, the new species shows a resemblance in cross-section to other species of Cadosinopsis, C. nowaki Borza, 1984, and C. andrusovi Scheibner 1967, previously described in literature. However, the two species are easily distinguishable by some features. Cadosinopsis. nowaki is bigger in size (length from 50 to76 μm and width from 43 to 67 μm), its inner layer is thicker and consists of vitreous-sparite calcite, and it has less centrically located chamber. C. andrusovi is much bigger in size as its length ranges from 68 to 108 μm and width ranges from 60 to 80 μm, and the cyst is more oval and its chamber less spherical. The new species is the third Cadosinopsis species described in the Tethyan realm and about two hundred and sixty-first fossil species (morphotype) described in the world so far.