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... Meanwhile in low latitude southern China, a series of Paleogene and Neogene fossil sites have been discovered and reported in recent years including, for example, the Eocene Changchang flora in Hainan, the Eocene to the Oligocene Maoming floras in Guangdong, the Oligocene Ningming, the Oligocene Baise and the late Oligocene Nanning floras in Guangxi, the Miocene Zhangpu flora in Fujian, and the early Oligocene Wenshan and Maguan floras in Yunnan (locations see Fig. 1). Studies on these floras revealed a Cenozoic vegetation transition from tropical to subtropical in China's low latitudes (Shi, 2010;Shi et al., 2014b;Quan et al., 2016;Herman et al., 2017;Huang, 2017;Jia, 2017;Jin et al., 2017;Wang et al., 2019;Liu et al., 2020;Wang et al., 2021) and characterized the prevailing monsoon signature of the palaeoclimate (Spicer et al., 2016;Spicer, 2017). ...
The antiquity of the tropical Asian flora is being revealed by recent detailed work on a number of Cenozoic plant megafossil sites, some of which have been radiometrically dated for the first time, but our knowledge of how the highly diverse modern biota came into being remains poor due to a sparsity of records. In this paper, we describe fossil plant assemblages from the Oligocene Dong Ho Formation of the Ha Long region, northern Vietnam. The Oligocene Ha Long megafossil flora has so far yielded 38 species, including conifers and angiosperms mainly belonging to Fagaceae, Lauraceae and Dipterocarpaceae, all with significant tropical Asian kinship. The Ha Long flora is similar to other Paleogene floras from southern China, especially those from the Pan Gulf of Tonkin region. The Ha Long floral composition is typical of a tropical-subtropical ecotone and the vegetation is reconstructed as a lowland tropical evergreen forest mixed with calcicole (limestone-loving) taxa. These taxa and the vegetation type they comprise still exist in this area. Palaeoclimate reconstruction made using both the Coexistence Approach and the Climate Leaf Analysis Multivariate Program indicate a mean annual temperature of ~20 °C, a coldest month mean temperature around 10 °C, and yearly precipitation averaging almost 2000 mm. These results suggest a warm and humid peripheral tropical environment. Floristic and climatic comparison within the Ha Long and other southern China palaeofloras reveals a long-term environmental, floristic and vegetational stability in this region since the Paleogene. This long-maintained plant diversity also provided a source for populating the East Asian flora and vegetation after the late Paleogene East Asian arid belt retreat.
... Climate signals from fossil floras show that South China saw much warmer temperature during the Paleogene epochs, e.g. Eocene (Feng et al. 2013;Herman et al. 2017) and Oligocene (Quan et al. 2016;Herman et al. 2017;Li et al. 2019), chiefly based on the the existence of tropical elements. This kind of megathermal climate is suggested to have persisted in some parts of the region into the mid Miocene (Shi and Li 2010;Shi et al. 2014;Jacques et al. 2015). ...
Sambucus L. (Adoxaceae) has a rich fossil record with a major concentration in Europe and North Asia but a scarcity in relatively low latitudes of the Northern Hemisphere. Herein, we report fossil endocarps of the genus from the late Pliocene Heqing Basin of northwestern Yunnan, South China, which are assigned to two species, namely S. alveolatisemina and S. heqingensis Huang et Zhou sp. nov. Sambucus alveolatisemina has been formerly described from the similar geological horizon of the nearby Lanping Basin in northwestern Yunnan and possibly represents the fossil equivalent of S. adnata, an extant species commonly seen in this and neighboring regions. Sambucus heqingensis is newly erected due to its exceptionally slender endocarp shape together with the irregularly ridged endocarp surface and straight lateral margins. Our fossil discovery, in combination with the two fossil taxa from the late Pliocene Lanping Basin, suggests that the diversity of Sambucus might have risen in South China by the late Pliocene. We conclude that, as compared to Europe and North Asia, the distribution and diversification of the genus in South China with much lower latitudes is likely to be a recent event. This can be properly explained by the fact that Sambucus is generally a temperate element while the climate in South China in prior to the Pliocene might be too warm for its inhabitation. We propose a hypothesis that the colonization and diversification of the genus in other low-latitude regions of the Northern Hemisphere might have been similarly late in time.
... The small-sized study specimen was kept in the collection for several decades under dry indoor conditions. In modern literature, xylitic fossils with preserved organic matter and unmineralized tissues have been referred to as mummified plant remains (Taylor et al. 2009(Taylor et al. , 2014Quan et al. 2016;Mustoe 2018;Huang et al. 2021). The occurrence of Cenozoic mummified wood, fossilized under anoxic burial conditions as present in lignitic deposits, is discussed in Hook et al. (2013). ...
We describe the first evidence of fossil Abies wood from the late early Miocene fossil plant assemblage of Wiesa in east Germany. The comparatively well-preserved piece of xylitic wood was recovered in the kaolin quarry at Hasenberg hill in Wiesa. The Wiesa assemblage is characterized as being allochthonous and partly parautochthonous mass deposits of diaspores, leaves, and wood. The latter component is rather incompletely studied so far. The described fossil is characterized by high rays, mostly uniseriate bordered pits, generally thick and pitted horizontal and tangential ray cell walls, but also partly smooth horizontal ray cell walls, absence of ray tracheids, the occurrence of traumatic resin canals, and rare occurrence of axial parenchyma of two types. This type of fossil wood has been described as Abietoxylon shakhtnaense Blokhina from the Oligo-Miocene of Sakhalin, Russia. Due to nomenclatural issues of Abietoxylon a recombination to Cedroxylon Kraus emend. Gothan is proposed following common practice for affiliation of abietoid fossil wood of Cenozoic age. Cedroxylon shakhtnaense comb. nov. shares anatomical characteristics with the wood of extant Abies Mill., in particular with sections Abies and Grandis , and is most closely related to section Grandis . The properly preserved fossil wood from Wiesa provides the opportunity of applying qualitative and quantitative analyses for testing and discussing its placement in relationship to intra-tree variability and ontogenetic aspects. The first evidence of fossil wood of Abies from Wiesa confirms again the presence of the genus in mid-latitude subtropical zonal vegetation during the beginning of the Miocene Climatic Optimum.
... There are many well-exposed Paleogene fossil-bearing basins in Guangxi (Bureau of Geology and Mineral Resources of Guangxi Zhuang Autonomous Region, 1985Region, , 2008Wang et al., 2015b;Quan et al., 2016;Ma et al., 2018;Li et al., 2019), one of which is the Ningming Basin (22 • 00 ′ -22 • 10 ′ N, 107 • 00 ′ -107 • 15 ′ E) in southern Guangxi. The Ningming Basin is well known for its important bentonite deposits and has received extensive attention in geological researches. ...
The Oligocene marked the beginning of the present ‘icehouse’ epoch and witnessed the development and evolution of the Asian monsoon system (AMS). In this paper, the early Oligocene Ningming flora of Guangxi, southern China, is analysed to investigate the AMS based on climate proxies derived from Climate Leaf Analysis Multivariate Program (CLAMP). CLAMP results suggest that the prevailing climate experienced by the Ningming flora was humid subtropical with hot summers and warm winters. Although the record of precipitation seasonality is muted, it is about half as strong as that seen today in monsoon climates of South China, indicating a very weak monsoonal signal. Despite suggesting weak rainfall seasonality, the position of the Ningming flora in physiognomic space indicates that leaves exhibit monsoon-adapted morphologies, comparable to today's vegetation exposed to the Indonesia–Australia monsoon (I-AM) and the transitional monsoon area (influenced by the East Asia monsoon, South Asia monsoon and I-AM). Leaf architectural signatures reveal that the Ningming flora grew under a humid subtropical climate with subtle monsoon signatures. Although it is difficult to distinguish the different domains of the Asian monsoon under such a subtle monsoon influence, based on leaf signatures from southern Asia, it can be inferred that the Ningming Basin during the early Oligocene was exposed to a climate regime similar to that today influenced by the I-AM. In addition, the moist enthalpy method was applied to quantitatively reconstruct the paleoelevation of the Ningming Basin. This approach suggests a paleoelevation estimate of ~1.24–1.35 ± 0.52 km for the early Oligocene, suggesting that a drop in paleoelevation of the Ningming Basin took place after the early Oligocene (Rupelian). The CLAMP results suggest that the early Oligocene Ningming area was at a middle-altitude and experienced a humid subtropical climate with subtle monsoon signatures.
Quercus is the largest genus within the Fagaceae and has a rich fossil record. Most of the fossil material is attributed to the subgenus Quercus based on leaves, pollen or rarely acorns and fruits. Fossil records of Q. section Cyclobalanopsis characterized by ring-cupped acorns are relatively few and especially those described based on fruits are scant. In this study, we described four new species of Quercus section Cyclobalanopsis based on mummified acorns and nuts: Q. paleodisciformis X.Y. Liu et J.H. Jin sp. nov., Q. paleohui X.Y. Liu et J.H. Jin sp. nov., Q. nanningensis X.Y. Liu et J.H. Jin sp. nov. and Q. yongningensis X.Y. Liu et J.H. Jin sp. nov. These species closely resemble the extant species Q. disciformis, Q. hui, Q. kerrii, and Q. dinghuensis. The occurrence of Q. section Cyclobalanopsis in the Oligocene stratum of Guangxi, South China, suggests that the section has diversified within its extant distribution center since the Oligocene. By combining records from other areas, we propose that the section first appeared in the middle Eocene of East Asia (Sino-Japan), has diversified in situ since the Oligocene with a few elements scattering into west Asia and South Europe, and finally became restricted in East Asia since the Pleistocene. This indicates that the section originated and diversified in East Asia, before spreading into West Asia no later than the Oligocene and into Southern Europe by the Pliocene. Subsequently it disappeared from South Europe and West Asia due to the appearance of the (summer dry) Mediterranean climate and widespread cooling during the Pleistocene.
Background and aims:
Theaceae, with three tribes, nine genera and more than 200 species, are of great economic and ecological importance. Recent phylogenetic analyses based on plastomic data resolved the relationships among the three tribes and the intergeneric relationships within two of those tribes. However, generic-level relationships within the largest tribe, Theeae, were not fully resolved. The role of putative whole genome duplication (WGD) events in the family and possible hybridization events among genera within Theeae also remains to be tested further.
Transcriptomes or low-depth whole-genome sequencing of 57 species of Theaceae, as well as additional plastome sequence data were generated. Using a dataset of low-copy nuclear genes, we reconstructed phylogenetic relationships using concatenated, species tree and phylogenetic network approaches. We further conducted molecular dating analyses and inferred possible WGD events by examining the distribution of the number of synonymous substitutions per synonymous site (KS) for paralogs in each species. For plastid protein-coding sequences (CDS), phylogenies were reconstructed for comparison with the results obtained from analysis of the nuclear dataset.
Based on the 610 low-copy nuclear genes (858,606 bp in length) investigated, Stewartieae was resolved as sister to the other two tribes. Within Theeae, the Apterosperma-Laplacea clade grouped with Pyrenaria, leaving Camellia and Polyspora as sister. The estimated ages within Theaceae were largely consistent with previous studies based mainly on plastome data. Two reticulation events within Camellia and one between the common ancestor of Gordonia and Schima were found. All members of the tea family shared two WGD events, an older At-γ and a recent Ad-β; both events were also shared with the outgroups (Diapensiaceae, Pentaphylacaceae, Styracaceae and Symplocaceae).
Our analyses using low-copy nuclear genes improved understanding of phylogenetic relationships at the tribal and generic levels previously proposed based on plastome data, but the phylogenetic position of the Apterosperma-Laplacea clade needs more attention. There is no evidence for extensive intergeneric hybridization within Theeae or for a Theaceae-specific WGD event. Land bridges (e.g. the Bering land bridge) during the Late Oligocene may have permitted the intercontinental plant movements that facilitated the putative ancient introgression between the common ancestor of Gordonia and Schima.
Co-evolutionary relationships of plants and fungi are of great importance for the phylogeny of both groups. Nyssa was widely distributed in the northern hemisphere during the Cenozoic. Extant species of Nyssa exhibit a disjunct distribution between eastern North America, Central America and East Asia. Here, a new species, Nyssa nanningensis Xu & Jin, is described based on fruit endocarps from the upper Oligocene Yongning Formation of the Nanning Basin, South China. This new fossil record of Nyssa expands the known palaeogeographical distribution of the genus to the low latitudes of East Asia. Associated fossil fungal fruiting bodies on Nyssa endocarps are assigned to the new fossil genus and species, Yongnicta nyssae Tobias & Maslova. This new genus is similar to some members of extant wood destructor taxa Coronophorales and Amphisphaeriales (Sordariomycetes, Ascomycota). About 3% of the Nyssa endocarps studied were affected by Yongnicta nyssae. Low frequency of fruit damage indicates that endocarps could be released from mesocarps by animals eating fleshy parts of fruits, making them potentially available to wood-destroying fungi.
Tree-ring cellulose oxygen isotope (δ18O) in monsoon Asia (MA) is affected collectively by local hydroclimate and remote oceanic-atmospheric variations. Variations of tree-ring δ 18 O have been widely used for quantitative reconstructions of monsoon-season precipitation, relative humidity and drought severity. However, local hydroclimate and remote large-scale circulation's influences on tree-ring δ18O has not been fully resolved. Here, we collected 24 tree-ring δ18O chronologies covering the period of 1884-1999 across a wide range of MA and investigated the common signals of these chronologies using principal component analysis. The first principal component (PC1) of the 24 tree-ring δ18O chronologies explained 25.2% of the total variances and showed significant positive correlations with the observed Asian summer monsoon oxygen isotope index (r=0.69) during the period of 1978-1999, suggesting that a common signal of precipitation δ18O does exist in MA and that it is highly correlated with El Niño-Southern Oscillation (ENSO) (r=0.72) and the South Asian summer monsoon precipitation (r=-0.66). South Asian summer monsoon and ENSO are the main factors controlling this common signal of tree-ring δ18O across MA. PC1 of tree-ring δ18O chronologies in MA also depicted a negative (positive) correlation with the Atlantic Multidecadal Oscillation (Pacific Decadal Oscillation), indicating the larger-scale, lower-frequency circulation influences. After removing the circulation influences on tree-ring δ18O chronologies, however, the residual tree-ring δ18O chronologies exhibit negative correlations with the regional hydroclimate, highlighting 75 the role of local hydroclimate on the individual tree-ring δ18O variations.
A new species, Tetradium nanningense sp. nov. (Rutaceae), is described on the basis of well-preserved mummified wood from the upper Oligocene Yongning Formation of Nanning Basin, Guangxi Province, South China. This species represents the most ancient fossil evidence of the genus Tetradium in Asia, the region of its modern distribution. Its occurrence in the late Oligocene is consistent with the diversification age of the modern Asian species within this genus as estimated by molecular dating: T. nanningense could be closely related to an ancestor of extant Tetradium species. The fossil record of Tetradium suggests that this genus migrated from North America to eastern Asia in the Oligocene. The presence of (semi-)ring-porous wood and helical thickenings on vessel walls in T. nanningense provides new evidence for the independent gains of these traits in the course of evolution among different plant groups from eastern and south-eastern Asia in the Oligocene. These wood features might have arisen in response to the increase in climate seasonality following the abrupt climate cooling across the Eocene–Oligocene boundary.
A large number of fossilized remains, consisting of leafy branchlets, seed cones, pollen cones, and seeds, of Metasequoia (Cupressaceae) recovered from Middle Eocene sediments of the Buchanan Lake Formation, Axel Heiberg Island, Canadian Arctic Archipelago are studied morphologically and anatomically. They are assigned to M occidentalis (NEWBERRY) CHANEY with an emendation, which is proposed to accommodate all the published Metasequoia fossils but M. milleri ROTHWELL et BASINGER. An emendation is made on the basis of detailed description of the associated leaf-bearing branchlets, leaves, pollen cones, pollen in situ, and seed cones, particularly the presence of helically arranged scales in some seed cones, which is a feature no longer represented in the extant Metasequoia. The most significant systematic emendation made is the morphology of pollen and arrangement pattern of seed cone scales. A comparison with extant and previously published fossil Metasequoia is made in detail and indicates a morphological stasis since Late Cretaceous/Paleocene. Slight differences from the extant species, however, have been found, such as narrower stomatal bands, smaller stomata, higher stomatal density, presence of hypodermis (like that of M. milleri), smaller pollen grains, gemmate exine but with more or less smooth gemmae, and seed cones with, in part, helically arranged scales in the fossil Metasequoia. The foliar cuticles of the Arctic fossil were compared with those from the populations representing all the natural distribution areas of Metasequoia in central China and the result demonstrates that the fossil shares morphological resemblance most closely to those of the extant Metasequoia from an isolated population in central China's Hunan Province, about 100 km southeast of the type locality in Hubei Province, central China. The fossil pollen in situ were explained as relatively immature due to only being extracted from the smaller pollen cones and having distinct morphology and anatomy under scanning and transmission electron microscopy. The immature pollen grains have ontogenetic developmental significance, indicating that the spinulate processes of the mature Metasequoia pollen are probably developed from smooth gemmae. The helical arrangement of seed cone scales occurs among about 22% of the more than 3200 seed cones surveyed. The size range of seed cones is well correlated to three ecorypic variations in the extant Metasequoia and indicates that M. occidentalis of Axel Heiberg with larger seed cones (bigger than 2 cm, including large and medium cones) lived in a nearby upland in the Eocene, while those with smaller seed cones (smaller than 2 cm) were distributed in moist or inundated lowlands.
Precambrian life fungi, bacteria and lichens algae bryophytes terrestrialization of the land the structure and organization of vascular plants early land plants with conducting tissue lycopods sphenophytes ferns progymnosperms origin and evolution of the seed habit palaeozoic seed ferns mesozoic seed ferns palaeozoic and mesozoic foliage cycadophytes ginkgophytes gymnsoperms with obscure affinities cordaites conifers flowering plants plant/animal interactions.
Megafossils from six discrete clay lenses at two sites in the Alcoa Anglesea open-cut coal mine were scored for frequency of 19 leaf types to determine if the observed distinctness of the floras was real. An analysis of the pollen/spore assemblages from the six lenses and from a vertical transect taken at the second site was also undertaken (a) to confirm the age of the deposit, (b) to determine if the microfloras of the lenses were distinctive and (c) to compare mega- and microcomponents of the flora. This analysis confirmed placement of the clay lenses at the onset of the Middle Nothofagidites asperus Zone of the late Middle Eocene age. No significant differences in the microfloras of the six lenses were observed. Accessory analysis of the geology of the locality revealed a sedimentation pattern consistent with a meandering stream system, perhaps containing local lacustrine elements.All megafossil taxa identifiable to family or lower (except Lauraceae) were found to be present in the combined pollen/spore flora, but comparative frequencies were not consistent.Extant vegetation from Noah Creek in N.E. Queensland was examined and considered to provide a possible model for the Anglesea fossil flora. Along one section of Noah Creek a mosaic of physiognomic and floristic elements occurs, in an area of similar size to the Anglesea deposit. This same flora contains many of the taxa (or most nearly related taxa) identified thus far at the Anglesea Locality, including some rare associations involving Gymnostoma, Orites and members of the Musgraveinae. Further tests for the model are proposed.
Abundant fossil plant remains are preserved in deposits of Middle Miocene age of the Ballast Brook Formation on Banks Island, Northwest Territories, Canada. Intact seed cones, logs, and stumps are preserved in situ as mummified remains and present an opportunity to reconstruct the composition, structure, and productivity of a Pinaceae-dominated forest that once grew north of the Arctic Circle (paleolatitude ca. 74°N). We mapped and measured 78 tree stumps exposed in three dimensions on a 0.12 ha peat layer. An analysis of the wood anatomy and seed cones indicates that a haploxylon pine dominated this lowland forest, although species of both Picea and Glyptostrobus were growing in the swamp as well. Stump diameters ranged from 7 cm to 108 cm (average = 42 cm). We utilized allometric relationships to predict tree heights based on the stump diameters in the fossil forest. Our results indicate that the average tree height of this Miocene forest may have been as large as 21 m. We used stump diameter data and predicted tree height to calculate the parabolic stem volume and stem biomass for the exposed area of fossil forest. Stem biomass (assuming an average wood density of 410 kg m− 3) may have been as great as 259 Mg ha− 1 or as little at 202 Mg ha− 1. The annual ring width of the stem wood sampled in the field was 1.26 mm for Pinus, 1.20 mm for Picea and 0.21 mm for Glyptostrobus. Based on these growth rates, our estimate of biomass sequestered aboveground as wood is at most 3.8 Mg ha− 1 y− 1. Based on our estimates, these lowland forest communities were of moderate biomass and productivity typical of modern cool temperate forests in North America.