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This study aims at finding new morphological characters to evaluate the taxonomic position of species in the genus Chrysolaena (Vernonieae, Asteraceae) as suggested by the current classification of tribe Vernonieae. We have characterized the morphology of pollen grains in all 18 species of Chrysolaena. Results show that all the studied species possess pollen grains of type “C”, which is therefore characteristic of the genus. This pollen type is 3-colporate, echinolophate, oblate-spheroidal, with a total of 29 lacunae, including the polar lacuna, but lacking the equatorial lacuna. Chrysolaena is considered stenopalynous due to the fact that the pollen type in most of the species is similar. Nevertheless, variation in the size of pollen grains allowed us to identify three groups of taxa: small, medium-sized and large. Pollen morphology is a useful taxonomic marker, in addition to other morphological and molecular characters defining the genus.
The pollen morphology, with special reference to exine sculpture, of some species of the Family Asteraceae from the Deosai Plateau of northern Pakistan has been analysed. Scanning electron microscopy of high-altitude Himalayan pollen taxa has been attempted for the first time. The pollen are all tricolporate and echinate. The exine sculpture is echinolophate (fenestrate) in Taraxacum tibetanum. The spines are reduced in two species of Artemisia and in Tanacetum gracile. By contrast, spine development exhibits greater diversity in the reminder of the species. The exine sculpture and spine morphology are important for the differentiation of species. Pollen fertility ranges from 82% to 94%, which indicates that the selected plant species are well established in the Alpine Zone.
The miospore Retusotriletes loboziakii sp. nov. is described from rocks containing the problematic algae Protosalvinia spp. from two localities in eastern Kentucky, USA. Both sections are from the Upper Devonian (Famennian) Ohio Shale Formation. Single, dispersed specimens of Retusotriletes loboziakii sp. nov. are morphologically identical to spores within dispersed tetrads. Moreover the dispersed tetrads are identical to in situ tetrads within Protosalvinia thalli, and Retusotriletes loboziakii sp. nov. is therefore considered to be the dispersed miospore of Protosalvinia spp. Other taxa in the dispersed miospore assemblage suggest that the Protosalvinia-bearing samples investigated should be assigned to the Famennian VCo Miospore Biozone.
Cicatricose spores have been described from Cretaceous basins worldwide. A complete revision of previous records from Argentina and other parts of South America is presented here, as well as the results of a detailed taxonomic study of the species found in the La Yesera and Lagarcito formations (north and central-western Argentina, respectively). Four genera and 11 species are described: Cicatricosisporites cuneiformis, C. pramparoana, C. sp. 1, Fisciniasporites sp. cf. F. brevilaesuratus, F. sp., Nodosisporites sp., Ruffordiaspora australiens is, R. cardielensis, R. ludbrookiae, R. cf. R. ticoensis and R. sp. 1. The genus Fisciniasporites is recorded for the first time in Argentina (in the La Yesera Formation), and similarly Nodosisporites in the San Luis Basin. The abundance of cicatricose spores is higher in the La Yesera Formation (8–54.2% of the total assemblage) than in the Lagarcito Formation (2–16%). An acme of cicatricose spore diversity in Argentina was recognised during the Aptian—Albian interval. Taxonomic studies of these types of spores are very important as they constitute a useful example of accurate descriptions and illustrations within a morphological group that has many misidentifications, and also considering the biostratigraphical significance of some species, e.g. Cicatricosisporites cuneiformis in Australia.
This is the first palynological study using pollen stored by Tetragonisca angustula (Apidae: Meliponini) in the Lower Amazon region, Pará, Brazil. The samples were directly collected from the pollen pots of T. angustula in apiaries located in Belterra and Santarém. The samples were dried, weighed, diluted in warm water and ethanol, centrifuged and then processed using the acetolysis method. After mounting the samples on slides, we identified and counted at least 500 pollen grains per sample. The results indicate that the main pollen combinations in the pollen pots of T. angustula in Belterra include pollen from Byrsonima, Cecropia and Eriope, and the combinations from Santarém include pollen from Byrsonima, Cecropia, Clidemia hirta, Davilla kunthii, Myrcia and Vismia guianensis. Most pollen types came from the families Fabaceae and Asteraceae. The pollen diversity (H') ranged from 0.03 to 1.95, and the evenness (J') ranged from 0.04 to 0.79, with the average trend indicating heterogeneity in the collection pattern. Temporary specialisation events typified five of the samples that we studied, directly detecting pollen from Byrsonima, Cecropia and Clidemia hirta. Such events appear to be unrelated to the direct processes of effective pollination. The pollen spectra obtained corroborate the pollen types that have previously been described in palynological analyses involving Tetragonisca angustula in other areas of Brazil.
The distribution of non-pollen palynomorphs (NPP) in a core from Cook's Bay, Lake Simcoe, Ontario, Canada shows a response to changes in water quality accompanying agriculture, urbanization, and industrialization. Low concentrations of nutrients in sediments with little non-arboreal pollen (NAP) record low disturbance prior to European settlement around the 1850s. These sediments are rich in desmids such as Cosmarium spp., Euastrum spp., and Staurastrum spp., an assemblage indicative of oligotrophic conditions. A decline in desmids, together with an increase in dinoflagellate cysts and thecamoebians up-core is consistent with increased nutrients. Abundant phytoliths in sediments that are relatively rich in Poaceae and other NAP records the draining of the Holland Marshes. A sharp increase in nutrient levels, together with a transition from high nitrite (N02) to high nitrate (N03) concentrations, records a sudden increase in biological oxygen demand leading to depletion of dissolved oxygen associated with the creation of polders in the 1920s and 1930s. A second influx of phytoliths immediately preceded the sharp rise in Ambrosia, recording rapid land clearing accompanying the five-fold post-World War II population boom in the Cook's Bay watershed. These Ambrosia-rich sediments are rich in metals and have high total phosphorus and N03, with abundant Pediastrum spp. and Peridinium spp., notably Peridinium willei and Peridinium volzii, recording eutrophication. The abundance of the ciliate Codonella cratera and the difflugiid thecamoebians Cucurbitella tricuspis and Difflugia protaeiformis in palynological preparations, as well as in washed thecamoebian samples from the upper part of the core, records low dissolved oxygen associated with continued eutrophication of Cook's Bay.
The statistical analysis of published Paleocene-Late Miocene palynological data from Patagonia supports several major stages of vegetation. These stages represent distinctive floral assemblages, both in composition and structure. Detrended correspondence analysis shows that during the Paleocene, southern South America was dominated by Australasian, Neotropical and Pantropical phytogeographical elements (Gondwanic paleoflora). The climate was warm and very humid. The Early Eocene was dominated by Neotropical and Pantropical taxa (Subtropical Gondwanic Paleoflora) and a reduced proportion of Australasian and a low proportion of Antarctic elements. The Middle Eocene and Oligocene were characterized by the ‘Mixed Paleoflora’ with the exception of the Sloggett Formation. The climate was less humid due to the onset of the Antarctic glaciation. The presence of Antarctic palynomorphs (Nothofagaceae, Podocarpaceae, Proteaceae) in Patagonia is consistent with the global cooling trend during the Late Eocene and Early Oligocene. By the Late Oligocene-Early Miocene, warm climates allowed the southward dispersal of Neotropical elements (palms, Cupania, Alchornea, Rubiaceae, Combretaceae), adding megathermal elements to the local Gondwanic floras. The appearance of some Neotropical families (Symplocaceae, Euphorbiaceae Alchornea) may indicate the Late Oligocene global warming event. The rise of xerophytic and halophytic shrubby-herbaceous elements (Convolvulaceae, Asteraceae, Poaceae, Chenopodiaceae and Ephedraceae) during the Late Oligocene, becoming more abundant during the Early Miocene began to give a modern appearance to plant communities. The Early-Middle Miocene corresponds to the Transitional Paleophytogeoprovince of central and southeastern Argentina, defined by a mix of Neotropical and Austral components. The Middle—Late Miocene was characterized by the final demise of megathermal elements in Patagonia, coupled with an increasing diversity and abundance of xerophytic adapted taxa, including Asteraceae, Chenopodiaceae and Convolvulaceae. Late Miocene vegetation was similar to the present vegetation, with the steppe expanded across extra-Andean Patagonia and the forest restricted to western areas where rainfall was still abundant.
A lineage of latest Jurassic-Early Cretaceous dinoflagellate cysts possessing arcuate process clusters from Madagascar is described. The lineage has helped to reveal the true identity of a group of skolochorate dinoflagellate cysts, bearing numerous long processes and process clusters, which have been reported as species of Systematophora. The revelation is that that group does not belong to Systematophora, but affiliates with the Madagascan lineage. A new genus, Palaecysta, is proposed. Seven new species: P. integra (type species), P. crispabaculata, P. foveoreticulata, P. melakyensis, P. morondavaensis, P. pectita and P. virgae; eight new subspecies: P. integra subsp. digitata, P. integra subsp. mahajangaensis, P. crispabaculata subsp. delicata, P. foveoreticulata subsp. madagascarensis, P. palmula subsp. ankamotraensis, P. pectita subsp. merinai, P. virgae subsp. externa and P. virgae subsp. lanceolata; and three new combinations: P. complicata (Neale & Sarjeant, 1962), P. palmula (Davey, 1982) and P. silyba (Davey, 1979a) are described. Palaecysta shares some morphological features with Systematophora, including being skolochorate, having intra- to penitabular features, and having sexiform paratabulation and an apical archeopyle. It differs in having arcuate process clusters and two unlinked isolated paracingular processes in each paracingular paraplate, as opposed to nearly penitabular, annulate process clusters and two linked (by a low basal ridge) paracingular processes in each paracingular paraplate in the latter genus. Palaecysta occurred globally from the Tithonian to the Hauterivian. Its rapid evolution provides useful timelines for biostratigraphy; six assemblage zones are established. The zonation is compared with that from neighbouring regions in Australia and Papua New Guinea. The morphological differences and similarities between Palaecysta and the related genera, Systematophora, Kilwacysta and Amphorulacysta gen. nov., are discussed. The significance of the arcuate dinoflagellate cyst group and the interrelationship amongst their member genera, reflected in the geological record, are commented upon. The genus Amphorula is emended.
Palynological investigations of Deccan volcanic-associated intertrappean deposits of the Late Cretaceous-Early Paleocene of central and western India were carried out. The study shows the presence of abundant triprojectate pollen grains, particularly AquilapollenitesRouse 1957, JiangsupollisSong 1980inSong et al. 1980 and FarabeipollisNandi & Chattopadhyay 2002. The data on the triprojectate group from the Indian subcontinent shows that Aquilapollenites spp. were widely distributed in the Late Cretaceous (Maastrichtian) sediments, and Farabeipollis and Jiangsupollis are less common. The post-Cretaceous record of triprojectate pollen from the Indian subcontinent is poor, and only a few species of Aquilapollenites survived the Cretaceous-Paleocene transition.
Graptodinium is a new genus of proximate dinoflagellate cysts with an apical archaeopyle, a cladopyxiacean tabulation and a distinctive intratabular ornamentation. It is represented by Graptodinium inconditum sp. nov. and Graptodinium omnireticulatum sp. nov. These species range from the Middle Eocene to at least the Early Oligocene in New Zealand. Graptodinium ranges geographically from the Arctic to the high southerly latitudes.
Diverse and well-preserved latest Permian phytoplankton assemblages are described from four sections of the Yangtze Block, South China from localities in Zhongzhai (Guizhou Province), Shangsi (Sichuan Province), Xiakou (Hubei Province) and Dongpan (Guangxi Province). Most of the species have been reported previously from other upper Permian sections worldwide. The South Chinese phytoplankton taxa are generally very small in size, usually displaying diameters of about 20 µm and commonly include the genera Micrhystridium, Veryhachium and Leiosphaeridia. However, larger taxa with vesicles often exceeding 80 µm in diameter, such as Dictyotidium, are also abundant in the Shangsi section. Due to the presence of large populations of Micrhystridium and Veryhachium, a simple classification scheme for the Micrhystridium/Veryhachium complex is proposed, based on the geometrical shape of the vesicle. We propose dividing the complex into five groups: the Veryhachium cylindricum group, representing all ellipsoidal specimens; the Veryhachium trispinosum group, all with triangular-shaped vesicles; the Veryhachium lairdii group, all with rectangular forms; the Micrhystridium pentagonale group, all with pentagonal specimens; and the Micrhystridium breve group, which includes all spherical forms.
Since the publication of a major literature compilation issued in mid 2012, 94 further contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued recently (i.e. during late 2012 and early 2013). These studies are mostly on the Late Jurassic and Early Cretaceous of Europe, and are listed herein with a description of each item as a string of keywords.
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