Review of Palaeobotany and Palynology最新文献

Palynological studies from Europe and North America have repeatedly considered the Carboniferous miospore genus Vestispora a useful biostratigraphic indicator, resulting in a detailed review and discussion of its variable morphotypes. This was not the case in Gondwana, where Vestispora has rarely been reported. However, a few studies from India and South America used the absence of this taxon as an argument for a Permian age.

The present work introduces a well-preserved and diverse record of five species of Vestispora from the Pennsylvanian (Moscovian-Gzhelian) of the Dhiffah Formation, north Western Desert (NWD), Egypt. Moreover, a detailed review of previous records of Vestispora was introduced in a trial to understand its regional distribution in Gondwana. It turned out that Vestispora is restricted to the Tethyan realm or the vegetation belt stretching North of Gondwana. However, the genus seems to exhibit a wider stratigraphic range in the Tethyan realm of Gondwana than in the Euramerican Province, with the youngest occurrences up to the top of the Carboniferous.

Modern pollen assemblages from moss polsters, topsoils, and lake surface sediments are crucial for interpreting palaeovegetational and palaeoclimatic conditions from fossil pollen records. While a large number of modern pollen assemblages exist from Yunnan Province, SW China, few are derived from lake surface sediments with depositional environments similar to those of fossil pollen records. In this study, we present modern pollen assemblages from lake surface sediments across 36 lakes in Yunnan, spanning spatially from the southeast to the northwest of the region. These lakes encompass a range of vegetation types, varying from alpine meadow grasslands to tropical seasonal and montane rainforests. Our findings demonstrate that modern pollen assemblages from lake surface sediments can effectively identify various vegetation zones. Redundancy analysis (RDA) reveals a strong correlation of pollen assemblages with climate factors (e.g., temperature and precipitation) but a weak correlation with human activities. This study suggests that modern pollen assemblages from lake surface sediments in Yunnan can be used not only to reflect changes in vegetation and climate, but also as reliable indicators for reconstructing the history of human activities to some extent.

This study presents a 40,000-year-old pollen record from Los Tollos Lake in the Baetic-Rifan region of southernmost Spain. The data offer insights into the past ecosystems of a current biodiversity hotspot situated at the ecotone between the Atlantic and the Mediterranean. This new sequence encompasses Mediterranean and Ibero-North African sclerophylls, broad-leaf trees, conifers, and Tertiary relicts. The full-glacial abundance of mesothermophytes, particularly oaks, is among the highest recorded for the European Quaternary. Notably, the presence of ecologically significant pollen taxa, which are poorly dispersed and currently occur outside the study area, suggests that this biodiversity hotspot was more extensive in the Pleistocene. During the period of c. 40.8–36.5 ka, three Artemisia maxima at 40.6, 38.9, and 36.9 ka coincide with decreases in Quercus, indicating the spread of steppes in response to the abrupt coolings of the GS10, GS9 (HS4), and GS8 events. Similarly, increases in Quercus around 41, 40, and 37.2–38.3 ka parallel the GI10, GI9, and GI8 warm events. A forested period from 36.5–32 ka includes oak expansions during the GI7 and GI6 interstadials. From 32 to 19.2 ka, more xerophytic vegetation is observed, including the HS3, GS5-GS3, HS2, and GS2.1b-c cold spells, although the correlation with vegetation changes is not synchronous. As early as approximately 21 ka, Artemisia definitively declines, while the region was reforesting, likely due to the presence of stationary populations of broadleaf trees and conifers in the southern Baetic mountains. From approximately 12 ka onwards, the highest values of angiosperm trees are recorded, with oaks dominating throughout most of the Holocene. The pollen record and the correlation with marine records suggest a more intense hydrological regime during the first half of the Holocene, but there is also archaeobotanical evidence for human activity during the second half, resulting in a more open landscape, making it difficult to discriminate the impact of each factor. Some abrupt aridity events during the Holocene coincide with small variations in tree cover, particularly at 9.2, 8.2, 6.8, 5.5–4.8, 4.2, and 2.8 ka. Since the Neolithic and during the metallurgic stages, forest species, especially broad-leaf trees, experienced range retraction accompanied by population extinctions. The region's plant communities have been subject to fire regimes since the Pleistocene, seemingly dependent on the available tree biomass.

The Sauce Grande Formation of the Ventania System and Claromecó Basin, east-central Argentina, is a geological unit of glaciomarine origin showing evidence of the glaciation that affected the supercontinent of Gondwana during the late Paleozoic. The age of this unit was previously determined from scarce and poorly preserved fossils, but mainly from radiometric dating and the fossil content of the overlying geological units. This study presents a palynological assemblage obtained from the Sauce Grande Formation in the PANG 0002 borehole, drilled in the Upper Paleozoic Claromecó Basin. Based on the identification of key species, such as Converrucosisporites confluens, Pakhapites ovatus, P. fusus, Vittatina spp., and Weylandites magmus, an age no older than Gzhelian is inferred for the interval studied. The inferred age allows us to relate the glaciomarine deposits of the Sauce Grande Formation to the last episode of the late Paleozoic Ice Age. The palynological assemblage of the Sauce Grande Formation is correlated with the Converrucosisporites confluens-Vittatina vittifera (CV) Biozone of the Claromecó Basin. Based on updated information and new correlations of the CV Biozone with palynostratigraphic schemes established in neighboring basins (Chacoparaná, Paraná, and central-western Argentina), its age is adjusted to the Gzhelian-late Artinskian interval, encompassing the Carboniferous-Permian boundary. This new information contributes to refining the current biostratigraphic scheme of the late Paleozoic Claromecó Basin.

After the ecological discontinuity of the Aptian/Albian boundary, new biocoenoses were established. In the continental domain, ecosystems in which angiosperms began to play a role appeared, and soon became the framework for the success of this group, with considerable consequences. However, little is known about the palaeobiogeography of this period. The study of new wood fossils from south-western Europe together with bibliographical data shows that continental biogeography was compartmentalised there, with a strong north–south gradient. A weaker east–west gradient is also suggested.

Ukraine has a rich Proterozoic to Quaternary fossil record of photosynthetic microbes and plants. Particularly rich and scientifically important fossils of early multicellular organisms have been documented from the Ediacaran, early land plants from the Silurian–Devonian, coal-forming floras from the Carboniferous, typical post-extinction recovery vegetation and coal swamp forests from the Triassic and Jurassic, and well-preserved angiosperms and conifers from the Cretaceous and Cenozoic. These fossil floras help elucidate the temporal changes in the vegetation at the junction of Europe, Asia and the Tethyan microcontinental terranes and highlight biogeographic linkages between various floral provinces through deep time. The rich and variably preserved floras offer great scope for further taxonomic, palaeoecological, palaeoclimatic and biogeographic research. Extensive fossil collections are stored in several major institutional repositories scattered across Ukraine. Some of these institutions have now been occupied by Russian forces, and others have been damaged and remain under threat, risking potential loss for future research. The impact of the war on Ukrainian museums and scientific collections has implications for how fossil specimens are stored and what procedures are enacted to preserve collections in other parts of the world in the event of war, civil disturbance, or natural disasters.

Representatives of ginkgoaleans from the Middle Jurassic of the Stoilensky opencast mine in the Belgorod Region and the Mikhailovsky opencast mine in the Kursk Region, European Russia are described for the first time. Remains of ginkgoaceous affinity dominate in some samples and are represented by leaf fragments of Sphenobaiera angrenica (Samylina) Nosova, originally described from the Middle Jurassic Angren Formation in Uzbekistan where they are associated with female reproductive structures (collar complexes) of Nagrenia samylinae Nosova. Rare fragments of the collars were also found in the Stoilensky mine. These remains are assigned to Nagrenia sp. As well as in the Angren Formation, seeds of Allicospermum budantsevii Gordenko are recorded in the Stoilensky mine.

A high-resolution, radiocarbon dated, pollen sequence of the ecotone between the Grassland and Savanna Biomes, was extracted from a 2.5 m peat core at the Colbyn wetland in South Africa. The lithology indicates transitions between organic sediment, clay, and well-preserved peat layers. The pollen and micro-charcoal records suggest interactions between the seasonal climate, burning and possible human and other disturbance. The vegetation development over the last 4000 cal yr BP is compared with chronologically parallel pollen sequences from the nearby Moreleta River and Rietvlei Dam sequences. The study, that can be correlated with wider regional isotopic records of the region, shows drier conditions c. 3800 to 3400 cal yr BP, and around 800 cal yr BP, and a wetter phase at Colbyn c. 3000–1500 cal yr BP.

The Early Devonian plant fossil record provides evidence of large vegetation turnover events in addition to rapid morphological and anatomical changes among vascular plants. The Ardenno-Rhenish Massif has historically yielded a vast number of these plant fossils allowing us to obtain a nearly unparalleled snapshot of Early Devonian vegetation. Nonetheless, the interest for describing or redescribing fossil floras from this region has waned in recent years despite their inherent value to understand Early Devonian plant diversity dynamics. Here, we describe a newly collected macrofossil flora from the middle Emsian Schuttbourg Formation at Consthum Quarry (Luxembourg). Six different plant macrofossil taxa were identified, including Drepanophycus spinaeformis and Psilophyton cf. princeps, in addition to putative macroalgal and fungal remains. The flora also includes other equivocal specimens resembling Sawdonia, Huvenia and Zosterophyllum. The composition of the assemblage is extremely similar, at generic level, to older Pragian–early Emsian and coeval floras from nearby localities, which indicates that there was no major floral turnover until the latter part of the Emsian in this region. Taxonomic descriptions also highlight many of the underlying issues in identifying Early Devonian sterile specimens. Inconsistencies in plant fossil identifications from this region call for a thorough revision of Belgian and German floras that together could provide a high-resolution picture of plant diversity changes in the Early Devonian.