Review of Palaeobotany and Palynology最新文献

The general purpose of this study is the first identification of vegetal basketry remains from the Late Cycladic Akrotiri (island of Thera, Greece) where after the eruption of the Theran volcano (c.1600 BC) products of the basket-making craft have been preserved in an excellent stage. The application of archaeobotanical analysis in combination with Scanning Electron Microscopy made possible the taxonomic identification of very challenging basketry remains below the traditional sample size. This contributed to the methodology for the analysis of perishable archaeological plant remains and illustrated the potential that such perishable plant remains have for the study craft practices in the past.

Sedimentary interbeds between lava flows of the Early Jurassic Kirkpatrick Basalt, East Antarctica, are long known to contain abundant fossil wood, including in situ-preserved tree trunks. Following an initial brief report containing only preliminary taxonomic assessments, however, these trunks have never been studied in greater detail. Here, we provide a detailed wood-anatomical description of in situ trunks and associated float specimens of fossil wood from several localities in the Mesa Range. Four genera are identified: Agathoxylon Hartig, Brachyoxylon Hollick et Jeffrey, Mixoxylon Chernomorets et Sakala and Protocupressinoxylon-type wood. This set completely challenges the image that prevailed until now of a little diversified paleoxyloflora in Antarctica during the Jurassic.

The dinoflagellate genus Alexandrium contains a number of species that produce paralytic shellfish toxins and have been the focus of attention as toxic plankton for harmless algal studies. Among Alexandrium species, A. catenella and A. pacificum form ellipsoidal-shaped resting cysts, which are preserved in marine sediments, and have attracted attention as potential seeds for future proliferation after favorable environmental conditions environmental improvement. However, although these cysts are preserved in surface of marine sediments, there is no record of their occurrence from solidified sediments as fossils. In order to clarify the reason for this, we investigated the differences in the chemical composition of cyst walls between colorless cyst of Alexandrium catenella/pacificum and Lingulodinium machaerophorum, Polysphaeridium zoharyi, Spiniferites spp. by measuring the thickness of cyst walls and using Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy. The results showed that the cyst wall of A. catenella/pacificum and L. machaerophorum were all composed of cellulosic organic matter. However, A. catenella/pacificum have the higher percentage of α −/β-glucosidic linkages and that the thickness of their cyst walls is about one-third of that of L. machaerophorum. Therefore, these are reasons for the cysts of A. catenella/pacificum being more easily degraded in the sediment.

Phytoliths are a good tool for investigating vegetation change in northern Australia. However, there is a lack of phytolith reference material across the Australian continent, particularly for woody plants. The development of reference material from woody plants is critical to understand regional patterns of phytolith production and preservation. This study analyses phytolith material from 40 woody plants to examine morphological and anatomical variation in phytolith production among Australian plant families. This is paired with phytolith assemblages from nine surface sediment samples to assess the representation and preservation of woody plant phytolith morphotypes. All woody plant species examined produce identifiable phytolith morphotypes, but most morphotypes cannot be differentiated between woody eudicots, monocots, and conifers. However, some woody plant morphotypes do have good potential for taxonomic or anatomical discrimination of plant groups. The analysis of surface sediment phytolith assemblages reveals that not all woody plant morphotypes preserve equally in surface sediments, potentially restricting their ability for taxonomic discrimination. Finally, the relevance of phytolith morphotypes for palaeoecological reconstruction is discussed.

A palynological study was carried out based on 157 samples collected from four representative stratigraphic sections of the Maastrichtian-Danian deposits of the La Colonia Formation outcropping in northern Chubut Province, Patagonia, Argentina. About 240 palynomorphs were recognized. Plant communities were dominated in terms of richness by ferns and angiosperms, but algae and gymnosperms are also well-represented. In this contribution, we present the systematic study of bryophyte, lycophyte, and fern spores. Bryophytes comprise eight species (10% of spore diversity), including representatives of Marchantiophyta, Bryophyta, and Anthocerotophyta. Lycophytes encompass 15 species (20% of spore diversity) and are represented by the families Lycopodiaceae and Selaginellaceae. Ferns comprise 53 species (70% of spore diversity), including members of Anemiaceae, Dicksoniaceae, Dipteridaceae, Gleicheniaceae, Lygodiaceae, Marsileaceae, Matoniaceae, Osmundaceae, Polypodiaceae, Salviniaceae, and Schizaeaceae, among others of uncertain affinities. Four new species are erected: a lycophyte (Neoraistrickia loconiensis sp. nov.), a salvinialean (Thecaspora polygonalis sp. nov.), and two fern species of unknown affinities (Clavatosporis varians sp. nov. and Microreticulatisporites patagonicus sp. nov.). The recorded palynoflora reinforces previous environmental interpretation of the La Colonia deposits as coastal plains bathed by shallow seas and barrier island/lagoon complexes and the presence of freshwater bodies where aquatic plant communities developed. The vegetational history of the bryophytes, lycophytes, and ferns in the studied sections of the La Colonia Formation indicates the lack of a significant floristic change across the K–Pg interval at the local scale.

Nuskoisporites dulhuntyi is considered one of the biostratigraphic marker species for the Lopingian of Europe. A morphological comparison between Kungurian (Cisuralian) and Wuchiapingian (Lopingian) Nuskoisporites dulhuntyi prepollen (dispersed from five outcrops and in situ from one cone) from the Southern Alps has been carried out. Dispersed Nuskoisporites dulhuntyi prepollen grains from the Kungurian (Cisuralian) of the Athesian Volcanic District (AVD) and the Wuchiapingian (Lopingian) of Bletterbach have been compared with the in situ prepollen grains isolated from an Ortiseia cone of the Bletterbach outcrop. Using light microscopy, we measured overall size, central body size, and laesurae length of the prepollen grains revealing significant overlaps in morphological characteristics between the different assemblages. The main difference is the bigger size of the in situ pollen grains in comparison with the dispersed ones, but a significant overlap is still observed. This implies that the prepollen grains from the Kungurian sedimentary successions of the Athesian Volcanic District can be assigned confidentially to the dispersed prepollen species Nuskoisporites dulhuntyi and hence, represent the so far oldest record of this taxon, extending the species range from the Guadalupian back to the late Cisuralian.

Palynology, the study of pollen and spores, plays a crucial role in various scientific disciplines, including earth sciences (paleovegetation and paleoclimatology), botany, allergy, archaeology, forensic sciencs and cosmetics. This study delves into the critical question in fossil pollen analysis studies: the minimum count of pollen grains required for accurate estimation of vegetation composition. Various statistical methods have been proposed over the years to address this question. Our research introduces an alternative technique, the orderly count, tailored to the nature of palynological analysis. We apply this method to diverse sediment catchments, including peat bogs, marine and lake sediments, from different geographical locations. Additionally, we revisit the reliability coefficients and propose adjustments for more accurate results. Our findings suggest that relying on statistical methods without considering the specific characteristics of palynological data may lead to low reliability. We advocate for the integration of dissimilarity criteria and the orderly count in sample size assessments for enhanced accuracy in palynological analyses. Our study emphasizes the importance of choosing appropriate methodologies aligned with the unique aspects of palynology to ensure robust and reliable results.

A new tree fern of the family Tempskyaceae, Tempskya hailunensis sp. nov., is described herein based on a silicified trunk from the Cretaceous of Hailun City, Heilongjiang Province, Northeast China. The new species is composed of dichotomizing large stems surrounded by a mesh of adventitious roots, petioles, and leaf-like structures, constituting a solid and compact false trunk. The dorsiventral stems contain solenosteles that have long internodes with mostly two leaf traces. The stem cortex consists of a sclerenchymatous outer zone and a parenchymatous inner zone, and the stem pith is divided into a parenchymatous outer zone and a sclerenchymatous inner zone. Wide multicellular scales are attached to the stem epidermis. Leaf-like structures embedded among adventitious roots in the trunk are isobilateral, thick, and without distinct intercellular spaces. Also present are dispersed annuli of sporangia, which are only few cells long and apparently uniseriate. Though it cannot be fully ruled out that these vegetative and fertile remains belong to epiphytes that colonized the Tempskya trunk, the consistent and exclusive occurrence of these particular types of remains makes it likely that they belonged to the Tempskya plant itself. This new species represents only the second fossil record of Tempskya from China, increasing the known diversity of this genus during the Cretaceous both in Asia and globally. Moreover, it provided evidence for recognizing probable leaf structure and growth habit of Tempskya.

The Jurassic formations within the Essaouira − Agadir Basin are of considerable interest for petroleum exploration, owing to their reservoir facies and hydrocarbon potentiality. These formations exhibit a scarcity of macrofossils, and their age is determined through lithological correlation.

The Agadir − Essaouira Basin is a Mesozoic − Cenozoic sedimentary basin, part of the Tethyan Realm, precisely belonging to the Central Atlantic province which extends the Tethys westward. The material studied originates from five boreholes (GTE-1, MKL-110, NDK-2, NDK-3 and ESS-1) located at the center the basin along an East−West axis. The organic residue of the studied samples revealed a diverse dinoflagellate cyst assemblage with specific associations incorporating globally recognized marker taxa.

The Early Callovian is distinguished by species such as: Ctenidodinium combazii, Ctenidodinium continuum, Ctenidodinium cornigerum, Dichadogonyaulax sellwoodii, and Impletosphaeridium varispinosum. The Late Callovian is characterized by the presence of marker cysts including: Compositosphaeridium polonicum, Endoscrinium galeritum Gonyaulacysta centriconnata, Liesbergia liesbergensis, Wanaea thysanota. The Early Oxfordian is marked by the association of species including: Gonyaulacysta jurassica subsp. jurassica, Rhynchodiniopsis cladophora, Scriniodinium crystallinum, Systematophora areolata, Systematophora penicillata, and Trichodinium scarburghense.

The Late Oxfordian to basal Kimmeridgian is characterized by an association of dinoflagellate cysts including: Cribroperidinium globatum, Dichadogonyaulax? panneum, Downiesphaeridium polytrichum, Egmontodinium polyplacophorum, Endoscrinium galeritum, Gochteodinia mutabilis, Perisseiasphaeridium pannosum, Prolixosphaeridium anasillum, Scriniodinium crystallinum, Systematophora areolata, Systematophora penicillata, Surculosphaeridium vestitum, Systematophora? daveyi, and Wallodinium krutzschii.

Our associations have been correlated with those in contemporary basins within other paleogeographic realms, contributing to the formulation of a global paleobiogeographic pattern. This pattern complements previous research on the distribution of dinoflagellate cysts during the Callovian − Early Kimmeridgian time interval.

Abundant and diversified Mesozoic fossil wood records have been reported in China. However, fossil woods have never been reported in the Guyang Basin, northern China. Here, a new calcified fossil wood specimen was discovered from the Lower Cretaceous Guyang Formation in the Guyang Basin. The present fossil are characterized by araucarian radial tracheid pitting and circopore cross-field pitting, typical of the genus Protocircoporoxylon. The specimen described here are mostly distinguishable from other fossil species of Protocircoporoxylon by the araucarian radial tracheid pitting and the number of pits per cross-field. Therefore, the present wood fossil is established as a new species, Protocircoporoxylon guyangensis Xu X.H. et Zhao Y.M. sp. nov. Up to now, the fossil detail records of Protocircoporoxylon have predominantly been found in the Triassic and Jurassic periods thus far. However, this discovery in Inner Mongolia, northern China indicates that the genus Protocircoporoxylon still into the Early Cretaceous period. The quantitative growth rings analysis of P. guyangensis sp. nov. indicates that it is an evergreen gymnosperm with a leaf retention time of 5–7 years. The fossil wood living in an environment with complacent water supply and weak seasonal fluctuations.