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To obtain insight into the natural variability of the coastal ecosystems off southern Kalimantan, late Holocene environmental conditions between ca. 2850 and 990 cal yr BP in the Java Sea were investigated. A 134-cm-long sediment core collected ∼50 km off the Pembuang River mouth was analysed for organic-walled dinoflagellate cysts, pollen/spores and biogeochemical parameters, e.g. organic carbon (Corg), total nitrogen (N) and calcium carbonate (CaCO3) as well as carbon and nitrogen stable isotope composition (δ13C, δ15N). Sediments consist of mixed terrestrial as well as marine organic matter, are characterised by low nutrient uptake and suggest generally low river discharge that is supported by very low pollen and spore concentrations (256 pollen grains cm-3 and 20 spores cm-3 at maximum, respectively). Foraminifera and coccolithophores dominated the plankton over cyst-producing dinoflagellates and diatoms. Dinoflagellate cyst assemblages are composed mainly of oxidation-resistant species of the genera Operculodinium and Spiniferites with a minor contribution of Impagidinium (mainly I. strialatum). The percentages of round brown and peridinioid cysts are low and decrease from the bottom of the core to the top. Palynological and biogeochemical data appear well correlated and synchronously reflect changes in the marine environment. It is reconstructed that after ca. 2480 cal yr BP, bottom waters became increasingly ventilated. A typical open-water dinoflagellate cyst association is gradually replaced by a more coastal association between ca. 2480 and 1530 cal yr BP that is most likely attributed to El Niño-induced seasonal differences between dry and wet periods of the year. After 1530 cal yr BP, a more pronounced influence of the Pembuang River is indicated by an increase in δ15N and decreased δ13C which is supported by the occurrence of nutrient-sensitive Lingulodinium machaerophorum and Nematosphaeropsis labyrinthus. The overall results indicate short-scale local environment fluctuations attributed to abiotic factors.
Until now it was presumed that the first major expansion of the dinoflagellate cyst subfamily Wetzelielloideae occurred during the Early Ypresian, with the appearance of Dracodinium (= Wetzeliella) astra at ∼55 Ma, i.e. ∼1 My after the Paleocene/Eocene boundary and after the onset of the negative Carbon Isotope Excursion (CIE), which is coeval with the Paleocene-Eocene Thermal Maximum (PETM) event. Palynological studies of lowest Eocene sections in northern Kazakhstan (former Turgay Strait) and France (southeastern part of the former North Sea Basin) indicate that the first strong radiation of the dinoflagellate cyst subfamily Wetzelielloideae occurred in two stages: the first major diversity corresponds to the late stage of the PETM (at least 16 new taxa from seven genera) at about 55.8 Ma and the second one a little later, after the PETM (three new taxa), but probably several hundred thousand years before the first appearance of Dracodinium astra. In both geographical areas, all newly described wetzelielloideans seem to disappear before the first occurrences of Dracodinium astra and Dracodinium lobiscum. Therefore, the first important radiation of the Wetzelielloideae occurred earlier (by about 800,000 y) than was previously postulated - thus closer to 56 than to 55 Ma. New wetzelielloidean taxa include 14 new formally described species, Axiodinium sparnacium, Dracodinium? modestum, Epelidinium brinkhuisii, Epelidinium leptotoichum, Epelidinium normandiense, Petalodinium lenisium, Stichodinium elegantulum, Stichodinium galliciense, Stichodinium parisiense, Stichodinium prostimus, Stichodinium sympagicum, Vallodinium heilmannii, Vallodinium picardicum and Wilsonidium modicum. The emended diagnosis of the genus Stichodinium is proposed.
To investigate the extent of ancient agriculture on Easter Island, this study examines pollen, phytoliths and starch preserved in dryland soils at 11 sites across the island. Taxa are variably represented by different types of microfossils, with Arecaceae and Poaceae over-represented, and dicotyledons, Cyperaceae and ferns under-represented. Phytoliths show better preservation than pollen. The identification of four Polynesian-introduced cultigens, at seven sites, provides botanical evidence for island-wide horticulture. The cultigens identified, Broussonetia papyrifera, Colocasia esculenta, Ipomoea batatas and Musa sp., have differential representation in microfossil spectra, partly because of variable production of microfossil types and amounts, which could give a false impression of the importance of past species. The identification of phenolic inclusions represents a new microfossil type for C. esculenta. Large differences in microfossil proportions at one of the two high-altitude sites compared with lowaltitude sites provide evidence for impact of the higher altitude climatic conditions on cropping across Easter Island.
We show the first conclusive evidence that Melitasphaeridium choanophorum, a dinoflagellate cyst species until recently considered extinct, is still living in the northern Gulf of Mexico. This suggests the Gulf of Mexico may have acted as a refugium for some warm-water dinoflagellates during past glaciations. Melitasphaeridium choanophorum can be considered a living fossil because cysts with cell contents were found among 15 of the 39 surface sediment samples analyzed from the northern Gulf of Mexico, and from five of 12 samples from a dated core (1962–1997). Melitasphaeridium choanophorum comprises a minor component of the total dinoflagellate cyst assemblages, with a maximum of 1.4% or 15 cysts g-1. It was found in surface sediments with overlying sea-surface temperatures of 16.6 to 31.2 °C (winter and summer), and summer sea-surface salinities of 21.0 to 31.7 psu. The relationship of M. choanophorum with modern sea-surface conditions can be used to infer past oceanographic conditions.
Cissus (Vitaceae) occurs naturally in all states of Brazil and others countries of South America. This work was realized out the analysis of morphological characteristics of pollen of 30 Brazilian species. The pollen grains were processed with lactic acetolysis method to be measured, described and illustrated in light microscopy and non-acetolysed for analysis in scanning electron microscopy. Statistically the species were identified using principal component analysis (PCA) and hierarchical cluster analysis (HCA). As a result it was observed that pollen grains are medium in most species, 3-colporate. The ornamentation of the sexine varied and was an important character in the delimitation of species. We was concluded that the attributes of pollen distinguish most of the taxa of the genus, thus confirming the heterogeneity of pollen. It is hoped that his study contributes to a better understanding of the taxonomy of the genus and provides data for future phylogenetic analysis.
The present investigation deals with a study of diversity in pollen features of 84 tree species of the Andaman Islands including 14 endemics (Alstonia kurzii, Brassaiopsis andamanica, Calophyllum soulattri, Canthium gracilipes, Dillenia andamanica, Knema andamanica, Macaranga andamanica, Maesa andamanica, Mangifera andamanica, Neonauclea calycina, Pemphis acidula, Planchonia andamanica, Semecarpus kurzii and Vitex diversifolia). Pollen grains of these species were acetolysed, and we recorded the pollen morphological characters using a trinocular research microscope with the aim of identifying the diversity of pollen in these species, viz. size, shape, symmetry, polarity, apertural pattern and ornamentation, and recorded the similarities and dissimilarities between the species of the same genus and also between different genera. This study provides palynological data of the tree species which will be of immense help in future taxonomic studies and will also be very useful for any work on pollen-based vegetation reconstruction, especially of endemic and threatened species.
Palynological examination of 18 honey samples (BG-1–18) procured from nine localities in the Bongaigaon District, Assam, India, produced a assemblage of pollen in terms of quantity and diversity. According to palynological assessment of the honey samples, 12 were unifloral (five in terms of Brassica campestris, two from Elaeocarpus rugosus and one each from Mimosa pudica, Xanthium strumarium, Syzygium cumini, Salmalia malabaricum and Meliaceae). Six were multifloral; the dominant taxa include Mimosa, Brassica, Coriandrum, Ziziphus mauritiana and Salmalia. Taxa such as Cassia fistula, Acacia catechu, Toona ciliata, Butea monosperma, Lagerstroemia parviflora, Lamiaceae, Malvaceae and Oleaceae were minor sources of nectar and bee forage, as indicated by low frequencies of their pollen. The numerous pollen types and their diversity show that bees travel considerable distances to collect nectar for honey production. The study could be helpful in evaluating the allergenicity of some honeys in the area of investigation, causing hay fever, asthma, dermatitis and other disorders, where composition is mainly of ‘Compositae allergic’ pollen such as Xanthium (BG-2; 57.78%; unifloral) and Eupatorium (BG-4; 37.64%; unifloral).
A new pollen record from south western Madhya Pradesh, central India provides a palaeoenvironmental record for the core monsoon zone (CMZ) of India. The 2m deep lacustrine sediment profile demonstrates that between ∼5679 and ∼4939 cal yr BP, open vegetation occurred in the region, indicative of a dry climate with reduced monsoonal precipitation. This was replaced by a mixed tropical deciduous forest under a warm and humid climate with increased monsoonal precipitation between ∼4939 to ∼3762 cal yr BP. From ∼3762 cal yr BP to the present day, a dense mixed tropical deciduous forest has existed under a warm and relatively more humid climate indicating a further increase in monsoonal precipitation. Cereal-based agricultural practice is evident during the most recent two phases.
Amazonia covers nearly 50% of Brazil. The history of this biome is marked by many changes in the landscape caused mainly by the Central and Northern Andes uplift. This event has influenced the palaeogeography of the Amazon and therefore its biogeography and possibly biodiversity. Herein we present palynological and lithostratigraphical results from the Solimões Formation in the well 1AS-33-AM. It was drilled in the Solimões Basin, Amazonas State, Brazil, reaching 405 m in depth. We identified 152 palynomorphs, in 32 samples, among them some biostratigraphical markers, such as Crassoretitriletes vanraadshoovenii, Fenestrites spinosus, Cichoreacidites longispinosus, Ladakhipollenites? caribbiensis and Echitricolporites mcneillyi, allowing us to recognise four biozones sensu Lorente (1986): Crassoretitriletes Interval Zone (399.10–276.70 m), Asteraceae Interval Zone (276.70–262.00 m), Psilatricolporites caribbiensis Interval Subzone (239.90–70.00 m) and Echitricolporites-Alnipollenites Interval Subzone (70–32 m). The palynological and lithostratigraphical results indicate two environmental phases. The palynomorph association presents a change marked by the sudden appearance and predominance of Grimsdalea magnaclavata from 239.90 m upwards and a general increase in the number of species. The lithostratigraphy shows from approximately the same depth greater amounts of sandstones towards the top of the well, suggesting a change from a paralic to a fluvial environment of higher energy. The first phase can be associated with the Pebas/Acre depositional systems, wetlands composed by lakes and swamps with seasonal floods that existed from 23 to 7–5 Ma. The second phase indicates a fluvial system that may be interpreted as a record of the modern Amazon transcontinental fluvial system, which was already established in the Pliocene.
Peter K. Bijl, Henk Brinkhuis, Lisa M. Egger, James S. Eldrett, Joost Frieling, Arjen Grothe, Alexander J. P. Houben, Jörg Pross, Kasia K. Śliwińska, Appy Sluijs
The taxonomic revision of the dinoflagellate cyst subfamily Wetzelielloideae by Williams et al. (2015) places primary emphasis on the type of archaeopyle, and secondarily on wall ornamentation. Williams et al. (2015) argues that this provides more clarity for taxonomic differentiation within the subfamily of Wetzelielloideae, and adds to the stratigraphical significance of species within. We find, however, that their proposed revision (1) introduces taxonomic criteria that divert drastically from these in other dinoflagellate cyst subfamilies, (2) unnecessarily erects and emends many new genera and species, and (3) poses serious practical limitations, which together (4) lead to profound reduction of the stratigraphical applicability of many marker species. In this contribution, we substantiate our concerns regarding the approach and criteria used by Williams et al. (2015). We propose to retain the generic definitions of Wetzelielloideae that existed prior to the revisions by Williams et al. (2015), until a revision supported by the community is available.
The paper by Williams et al. (2015) concerning a proposed taxonomic revision of the subfamily Wetzelielloideae has led to a comment by Bijl et al. (2016) that questions the validity of our assumptions regarding recognition of the equiepeliform, latiepeliform, hyperepeliform and soleiform archaeopyle types and their significance at the generic level. In this response we address the points that they raise, which are: the introduction of taxonomic criteria allegedly not followed in other fossil subfamilies; the erection of too many taxa; the unworkable nature of the proposed classification; and the reduction of stratigraphic applicability of many significant marker species. We have organised our response under the following topics: pragmatism versus theory; generic criteria: intergroup consistency; the genus Apectodinium and operculum attachment; stratigraphic utility; the number of taxa; and recognition problems. We also discuss specimens illustrated in the two plates included with the comment. The variations in archaeopyle shapes and types of attachment of the operculum (the latter concept has been modified following more recent research) that we have used in part to separate the genera within the Wetzelielloideae have been previously applied to other peridiniacean subfamilies, most notably the Deflandreoideae. As with that subfamily, we consider that our focus on archaeopyle shape and operculum attachment for differentiating wetzelielloidean genera introduces an approach that may help refine the stratigraphic ranges of individual species. While it is a fundamental truth that there are no ‘correct’ taxonomic ideas, we consider that new approaches should be tested with usage over time, not rejected out of hand prior to careful study.
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