This study presents a new analysis of the Late Ordovician to earliest Silurian melanosclerites from the Kaugatuma core on Saaremaa Island, Estonia. By observing a large number of fossil melanosclerites, this study carefully reviews previous records and makes taxonomic emendations. Twelve species (including one in open nomenclature) that can be assigned to nine genera are identified, including the most typical elements, which were first reported by Alfred Eisenack eight decades ago. Based on a revised dataset of melanosclerite occurrences from 21 localities around the world, the Palaeozoic palaeogeographical occurrences of these organisms with uncertain affinity are then plotted on an up-to-date map to determine their palaeogeographical potential. Although the spatial distribution of melanosclerites shows patchy occurrences resulting from sparse research efforts, a tendency to occur in low-latitude, warm-water regions can be detected. All the reported occurrences are confined within the tropics and subtropics, with most of them restricted to 30° north and south of the equator during the Early Palaeozoic. This distribution pattern is compared with that of Palaeozoic hydroids, showing an overlap in palaeogeographical distribution, with both occurring in Baltica, Laurentia, Siberia, South China, and the northeastern part of Gondwana, but absent from high-latitude regions. If future work can confirm their postulated close biological affinity, the palaeogeography of the two types of fossils can be combined to complement each other.

The biota of the brackish-water Lake Pannon in the Pannonian Basin is characterised by remarkable endemism due to the isolated evolution of the lake for 8 myr after the last Miocene marine connection ceased (∼11.6 Ma). A conspicuous feature of this endemism is the large, probably ecophenotypic variation in the morphology of brackish-water dinoflagellate cysts that challenges taxonomy and complicates biostratigraphical and ecological interpretations. We conclude that a widely debated Lake Pannon genus, Pontiadinium, includes several proximate dinoflagellate cyst species with prominent apical and antapical protuberances, and we show how the genus differs from the morphologically similar gonyaulacacean cyst genera Impagidinium, Leptodinium, Cribroperidinium and Komewuia. The generic description of Pontiadinium is emended together with the species descriptions of Pontiadinium inequicornutum, Pontiadinium obesum and Pontiadinium pecsvaradanesis. A new species is described as Pontiadinium szentaiae sp. nov. from Našice (northern Croatia) that is characterised by unique trabeculate sutural septa formed from a beaded tegillum supported by columellae or rod-like luxuriae. The dinoflagellate cyst assemblages of the long-lived brackish-water Lake Pannon clearly demonstrate that dinoflagellate cysts in low-salinity, isolated epicontinental seas display greater morphological plasticity than their normal-marine relatives. The development of an antapical horn appears to be a previously undocumented example of phenotypic morphological features that developed in response to subnormal salinities within at least two dinoflagellate cyst genera endemic to Lake Pannon and the Post-Paratethyan seas of the Ponto-Caspian realm. This ecophenotypic variation resulted in a higher level of morphological adaptation, leading to the evolutionary development of new dinoflagellate cyst species and genera.

Ilha Grande is a Brazilian island that has a high vegetal biodiversity with a well-documented prehistoric human occupation but has few paleoenvironmental studies developed in this area. In view of this, multiproxy analysis of lagoonal sediments including radiocarbon dating were carried out on a 139cm-long continental sediment core. The aim of our study was to recognise and explain environmental dynamics in this region during the Holocene (∼5200 cal yr BP). The palynomorphs indicate the continuous presence of Atlantic Forest under humid conditions during the last Holocene sea-level highstand, after 5200 cal yr BP. A phase of low palynomorph concentrations was followed by a marked increase in palynomorph accumulation and diversity which may be linked to the subsequent drop of the sea-level. Dinoflagellate cysts showed a higher accumulation at the base of the sediment core. The high accumulation of charcoal particles identified between approximately 3700 and 3000 cal years BP might indicate human activity related to the long-lasting bonfires kept burning by the inhabitants of the archaeological site of Ilhote do Leste.

A palynological investigation was carried out on 24 samples from the Oligocene Dabaa Formation, which cuts across the Amana-1X well, located in the Abu El Gharadig Basin, north Western Desert, Egypt. Palynological evidence presented here suggests an early Oligocene age for the studied Dabaa Formation. In addition, the palynological assemblages provide supplementary evidence for depositional environments. They are generally indicative of outer-shelf to upper slope environment under oxic to anoxic conditions for the lower part of the studied Dabaa Formation, but infrequent occurrences of more diverse assemblages suggest an inner neritic marine environment for strata at some levels in the upper part of the studied section. It was during the Oligocene that marked floral changes leading to the development of modern plant associations began such as temperate deciduous forests (with e.g., Acer and Betulaceae) which expanded greatly in the mid latitudes. A distinctive vegetational pattern could be outlined within the deposition of the Dabaa Formation. This pattern includes mangroves represented by taxa such as Zonocostites ramonae, Psilatricolporites crassus and Verrucatosporites usmensis. Another considerably different association with plenty of the freshwater algae Botryococcus and Pediastrum spp. at this level or tropical forests at slightly elevated altitudes (ever wet climate) are dominated by a variety of tropical forest taxa including Malvaceae and Striatricolpites, together with Retitricolporites irregularis, Psilatricolporites operculatus, Retibrevitricolporites ibadanensis, Retitricolporites spp. and Psilamonocolpites spp. in addition to ferns and tree ferns where tropical floras dominate. Also recognized are elements of savanna or open woodland (less humid climate) taxa like Poaceae pollen (grass) such as Monoporopollenites annulatus associated with Amaranthaceae (e.g., Chenopodipollis multiplex), Cyperaceae spp., Echiperiporites estelae, Proteacidites cooksonii, Cicatricosisporites dorogensis and Pteris. Finally, the montane ecosystems may have occurred at the slopes of mountains including rare pollen assigned to Sapotaceae (Psilastephanocolporites spp.) and Anacardiaceae (Retitricolpites simplex) which are probably part of the palynoflora due to long-distance transport.

Due to overlapping in several of the primary pollen morphological attributes (viz. aperture type and exine sculpturing) throughout the subfamilies and tribes of Rubiaceae, these attributes are less important for delineating the majority of the taxa at subfamilial and tribal levels than at generic and specific levels. This in turn creates difficulties in the identification of rubiaceous pollen grains in various palynological studies. In such cases, where the two major pollen morphological attributes (apertural type and exine ornamentation pattern) are more or less common, we intended to explore whether an additional pollen morphological character could reliably be used in the demarcation of taxa. The present work deals with the pollen morphological details of 17 species of Rubiaceae from the Darjeeling and Arunachal Himalayas. This eurypalynous family exhibits a wide array of pollen morphological attributes, particularly aperture type, exine ornamentation pattern and variable sculpturing on colpus membrane. Principal component analysis (PCA) was performed to determine the major pollen morphological variables responsible for delimiting the studied species; this analysis indicated that variation in colpus membrane ornamentation (psilate, granulate, scabrate, verrucate) is a key attribute in characterizing the studied eastern Himalayan rubiaceous taxa to generic and specific levels.

An overview of the history of a taxon name and its current status are critical in taxonomy; and selecting the correct name from among synonyms is commonly important in applied studies. This often onerous task can be facilitated by working with databases that can be used to develop an overview of the number of species within a genus as well as their spatial and temporal distributions and their frequency of use. For example, a quantitative analysis of the use of competing names can inform formal proposals to conserve, protect, or reject names. Currently, palynologists can consult two extensive databases, Palynodata and the John Williams Index of Palaeopalynology, both of which were discontinued, in 2006 and 2015, respectively. As new data accumulates, analyses require augmentation from uncurated online resources such as Google Scholar. Here, we conducted a case study for four Mesozoic genera relevant for example in studying the Triassic–Jurassic transition in the Germanic Basin. The genera contain a total of 65 species. The study compared the output from the two databases of references and an online source for the species inventory over time by analysing more than 2000 citations and their cross-occurrences. We found that the John Williams Index is the most accurate and extensive, but it can only be consulted in person in London. Palynodata, available as a dataset or online, is the more accessible source of information. Our study also shows that no significant difference results from whether one combines the John Williams Index or Palynodata with Google Scholar since using any two of these sources provide a recovery of at least 75% of all citations compared to using all three. In conclusion, each database has its own advantages and disadvantages, and when working under time pressure, the choice of database depends on the research question asked.

Odd palynomorphs are identified in sediments in a shallow core from the Rømø barrier island in the Danish Wadden Sea. The palynomorphs occur in five stratigraphic samples of lacustrine mud, peat and sand. The sand has a chaotic structure and was deposited by a tsunami associated with the Storegga slide in the North Atlantic Ocean, 8150 years ago. The palynomorphs are very common in the lower samples from in situ gyttja and peat and are less common in the overlying sand bed. Reworked lumps of peat occur in the sand and the palynomorphs are therefore also considered reworked into the sand during the tsunami event. The variable morphology of the palynomorphs is considered to represent the ontogeny as well as the specific morphology of fern annuli. The wall tissue of the sporangium is coherent with annulus cells and reveals the fern relationship. The tissue shows a characteristic succession of elongated, rectangular cells in the sporangium wall with stomium and annulus. The palynomorphs are interpreted as parts of annuli from sporangia of leptosporangiate ferns. The modern fern species Hemionitis glabella has a comparable sporangium morphology, and the palynomorphs are considered to come from a fern relative. Hemionitis is cosmopolitan but absent in Europe north of France. This annulus type and the derived palynomorph types have not been described from fossil material before.

Allium (Amaryllidaceae) is diverse and taxonomically problematic, with controversial subdivisions and polymorphic species. In Egypt, the genus has not been investigated satisfactorily in terms of palynology. The present study aims to provide palynological information on the endemic and near-endemic species of Allium for the first time in Egypt and to characterise the pollen diversity of the investigated taxa. The pollen morphology of 21 Allium taxa was studied comprehensively via Scanning Electron Microscopy. Twenty-five traits were surveyed, then subjected to hierarchical cluster analysis (HCA) and principal coordinate analysis (PCoA). Pollen grains are monads, heteropolar, monosulcate, or trisulcate, small to medium-sized (polar axis (P) = 10.44–29.76 µm, equatorial diameter (E) = 18.97–59.24 µm), and peroblate or oblate in shape. The sulcus may be anasulcate, meridionosulcate, or subzonasulcate. Sulcus ends are blunt, pointed, rounded, or undulated. The exine ornamentation is variable and diversified between the distal pole and the equator. The current study highlights the importance of pollen characteristics such as pollen size parameters, pollen shape, aperture type, polar outline, sulcus size parameters, sulcus type and end shape, distance between sulcus ends, exine ornamentation, presence or absence of perforations on the exine, and perforation size and density for the discrimination of Allium taxa in Egypt. The HCA confirms that pollen morphology has limited taxonomic usefulness at the sectional level for the studied taxa. The PCoA results, on the other hand, were more informative to visualise the infrageneric classification based on the studied palynological traits. A dichotomous identification key for 21 Allium taxa in Egypt based on palynological data is presented.

A major and recurrent issue in nomenclature and taxonomy is synonymy and the occurrence of competing names for a taxon. Formal proposals for conservation, protection, or rejection of names are a painstaking but necessary work, which for extant plants, often requires consulting the frequency of use of competing names in floras. In palaeopalynology, such information can be gathered by tedious consultation of the literature or by working with palaeopalynological databases, which provide easily accessible quantitative data on how frequently each given taxon name is used. Here, we show that such information can be employed not only for taxonomic revisions in plant microfossils, but also to calculate three new simple metrics, i.e. Citation Share (CS), Citation Rate (CR), and Establishment Index (EI), and quantify how widespread the use of a name is on its own, or in comparison to potentially competing name(s). Using three case studies, we demonstrate how our proposed metrics can easily be used to present how the use of a name of a taxon changed over the decades, especially for competing names. Independently of the study question, our proposed metrics provide a fast overview of popularity of names and abundance of the respective taxa in species inventories (CS and CR), and a concise compound metric to represent the standing of a name for competing names today (EI). Their advantage is that they encode information that would otherwise require rather lengthy enumerations and space-consuming visual representations. They are therefore an effective tool to represent data in a short and concise way to clarify cumbersome taxonomical and nomenclatural problems, and can support informed proposals for either conservation, protection or rejection, which are typically very limited in space for the respective argument.

Diverse and well-preserved terrestrial palynomorphs occur in the Padeha, Khoshyeilagh, and Mobarak formations in the Khoshyeilagh area, northeastern Alborz, northern Iran. The spore assemblages consist of 36 species belonging to 24 genera. The vertical distribution of index spores allows the erection within these strata of five local biozones (BT, FF, LE, LN, and VI). The data show that assemblages recorded from the Khoshyeilagh section can be correlated with the VCo, LE, LN, and VI Miospore biozones of Europe, Canada, and USA. Many of the palynomorph species, such as Archaeoperisaccus ovalis, Ancyrospora ampulla, Diducites mucronatus, D. versabilis, Grandispora cornuta, G. echinata, Indotriradites explanatus, Retispora lepidophyta, Retusotriletes incohatus, R. phillipsii, Rugospora flexuosa, Teichertospora torquata, Tumulispora malevkensis, Vallatisporites pusillites, Verrucosisporites bulliferus, and Verrucosisporites nitidus, are closely comparable with coeval assemblages recorded from Belgium, Portugal, Canada, North Africa, South America, and North America. This indicates the close relationship of the Iranian Platform to other parts of the northern Gondwana and southern Laurentian domain during this time interval. Moreover, parent plants of the Late Devonian miospores in the Khoshyeilagh area generally belong to herbaceous Class Rhyniopsida (orders: Rhyniales, Trimerophytales), Zosterophyllopsida, and various classes such as, Lycopsida (herbaceous order: Isoetales, Selaginellales, Protolepidodendrales), Progymnospermopsida (Order Archaeopteridales and Aneuropthytales), and Filicopsida. The presence of marine shelly macrofauna (brachiopods and corals) suggest a nearshore depositional environment comprising rivers, fluvial deltas, tidal flats, and lagoons for the Upper Devonian and lowermost Carboniferous deposits studied herein.

Napeantheae is a monogeneric tribe of Gesneriaceae (with Napeanthus Gardner), that presents species with different morphology from other Gesnerioideae, being herbs with rosulate leaves that grow in pits, banks or at the base of rocks in humid forests. The tribe's palynology is poorly known. Thus, the aim of this study was to investigate the pollen morphology of the Brazilian native species of Napeanthus (Napeantheae) in order to expand the morphological knowledge of the tribe and compare it with existing studies on Gesneriaceae. For the analysis, the pollen grains were removed from flower buds of exsiccatae deposited in herbaria; they were acetolyzed, measured, photographed using light microscopy (LM) and scanning electron microscopy (SEM), and described qualitatively. The analyzed species present differences in amb, polar area, shape, size of ectoapertures, type of endoapertures and exine thickness. The pollen grains are monads, isopolar, small, tricolporate, circulaperturate, ectoaperture rounded at the polar ends and without margo; the exine is semitectate, microreticulate-fossulate, sexine is thicker than nexine. An artificial pollen key is presented to help distinguish species. Quantitative pollen grain data confirm the qualitative differences observed, especially in relation to the type of endoaperture. The microreticulate-fossulate exine ornamentation observed in Napeanthus has not previously been recorded for Gesneriaceae, especially in Gesnerioideae.

Vegetation reconstruction from fossil pollen records depends on an adequate understanding of the relationship between modern pollen-rain and the extant vegetation. Modern pollen assemblages, that reflect the extant vegetation of an area, have been documented through the palynological analysis of 30 modern moss cushions from Rourkela, Sundargarh District (Odisha State), India. The study demonstrated the dominance of non-arboreal pollen taxa (NAPs; herbs) over the arboreal pollen taxa (APs; trees and shrubs). Tree pollen taxa, among the APs, contributed with an average sum of 23% of the total pollen sum, whereas shrubby taxa have an average pollen sum of 17%. Among the herbs (NAPs), Poaceae is the dominating herbaceous taxon in the total pollen-rain, whereas Cerealia and other cultural pollen taxa are the other prominent herbaceous taxa of the pollen-rain, besides Asteroideae. The overall pollen assemblages suggest an open nature of the forest around the study area. Insights into pollen source, representation (production and dispersal), transport and preservation of certain taxa around the study area have been also provided. Comparison of the pollen assemblages in present study with the pollen assemblages from other areas (especially from central India) has been also been made in order to have a broad overview of such study around the study area. The present study could improve our understanding of the modern pollen-rain/vegetation relationship and further aid in calibration and interpretation of the fossil pollen records.

Abbreviations: APs: arboreal pollen; NAPs: non-arboreal pollen; TPS: total pollen sum; ISM: Indian summer monsoon; SWSM: South west summer monsoon; BSIP: Birbal Sahni Institute of Palaeosciences

A large population of the acritarch genus Pyloferites Quadros 1999 was recovered from the Devonian strata of the Paraná Basin, Alto Garças Sub-basin (Brazil), at the Jaciara section. Based on a literature review and the examination of new material, including morphometric analyses, Pyloferites shows wide morphological variability, and, therefore, is herein emended. Additionally, a species emendation and a new species are instituted: Pyloferites escobaides (Cramer 1964) Daners et al. 2017 emend. nov., and Pyloferites paranaensis sp. nov. The stratigraphical distribution of P. escobaides is extended from the middle–late Pragian to the Famennian, while P. paranaeinsis is restricted to the Pragian to early Emsian, or possibly middle Emsian, of the Paraná Basin. The presence of Pyloferites in Brazil, Bolivia, Uruguay, and Spain supports a Gondwanan and Perigondwanan palaeobiogeographical distribution.