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We evaluate the influences of elevation and climate on the spatio-temporal distribution of wetland and dryland biomes during the Pennsylvanian and early Permian in tropical Pangea. The longstanding "upland model" places drought-tolerant vegetation in elevated habitats, where slope and drainage created moisture-limited substrates under a humid climate that simultaneously promoted peat accumulation in contemporaneous lowlands. Upland plants were periodically transported to, and buried in, lowlands. Rare preservation of dryland vegetation thus reflects its general absence in basins, and taphonomic vagaries of long-distance transport. The alternative "climate model" proposes that drought-tolerant plants dominated tropical habitats when climate was seasonally dry, with wetland vegetation reduced to scattered refugia. Environmental changes attending glacial-interglacial cycles caused alternating wetter-drier conditions, and the relative abundance of wetland versus dryland biomes in basinal lowlands thus varied with climatic oscillations. The paucity of drought-tolerant plants reflects a preservational megabias against habitats with seasonal moisture deficits. The environmental signal of "mixed" plant-fossil assemblages, comprising taxa characteristic of both wetland and dryland biomes, may help resolve these debates. We review key Pennsylvanian and lower Permian mixed assemblages from tropical Euramerican Pangea, and interpret their original habitats and climatic contexts based on multidisciplinary lines of evidence, including sedimentology, taphonomy, physiology, and paleoecology. Evaluations also consider patterns of vegetational distribution and taphonomy in modern tropical environments. We suggest that even a cursory view of current tropical plant distribution exposes flaws in the upland model. Where tropical climate is sufficiently humid to support peat swamps, slopes and elevated habitats do not host drought-tolerant vegetation, but are occupied by plants similar to those in lowland settings. This occurs because equable, high precipitation strongly dampens water-table variation across entire landscapes. Furthermore, taphonomic studies indicate that most plant-fossil assemblages record vegetation living near the burial site. Fossil floras thus reflect environmental conditions near their growth site, excluding an upland origin for most occurrences of drought-tolerant taxa. Conversely, the climate model is consistent with modern tropical vegetational distribution and soundly explains late Paleozoic floristic patterns. When Pangean tropical lowlands experienced seasonally dry conditions, plants tolerant of moisture deficits dominated most habitats, whereas wetland vegetation was restricted to wetter sites with greater preservation potential. This occurred because topographic variations are magnified under seasonal precipitation regimes, creating a complex habitat mosaic with wetland patches in a landscape subject to seasonal drought. Accordingly, we propose that a macrofloral assemblage with even rare drought-tolerant taxa indicates seasonality in the broader landscape. At larger spatio-temporal scales, disagreement also persists about whether tectonic uplift or long-term climatic drying was the primary driver of changes in late Paleozoic floristic patterns and areal extent of tropical peat swamps. We argue that tectonic activity alone cannot explain the drastic reduction in peat swamps or coincident changes in dominance-diversity of wetland vegetation. Rates of plant dispersal and evolution far outpace that of mountain building, and peat-forming wetlands persisted in elevated habitats well into the Late Pennsylvanian. Therefore, progressive late Paleozoic aridification was the most probable driver of changing floral patterns and the distribution of wetland and dryland biomes in tropical Pangea. [ABSTRACT FROM AUTHOR]

The leaf morphology and epidermal anatomy of a species of Pterophyllum, a morphological genus of Bennettitales, were studied in detail based on leaf fossil collected from the Middle Jurassic Yaojie Formation in the Baojishan Basin, Gansu Province, northwestern China. The fossil lamia is large; the segments are broadly linear to rectangular, opposite, each segment containing ca. 20 thin veins. The leaf cuticle is thin, hypostomatic, possessing of syndetocheilic stomatal complex. According to a detailed comparison on the basis of leaf morphology and cuticle features to other similar fossil plants, the fossil material was attributed to Pterophyllum propinquum Goeppert, which add to the details of the rachis, leaf cuticles of the species. Combined with the characteristics of paleoclimate change during the Mesozoic in China, the responses of the palaeogeographical distribution of Pterophyllum to paleoclimate change in different periods of Mesozoic in China are discussed. Moreover, based on the fossil floral assemblage and the cuticle features of P. propinquum, we presumed that it is a warm and humid climate in the Middle Jurassic in Baojishan basin, where the P. propinquum is a typical plant member. [ABSTRACT FROM AUTHOR]

With over 300 extant species, the nearly worldwide‐distributed genus Frullania is one of the most species‐rich genera of leafy liverworts and the sole extant genus of Frullaniaceae. Amber fossil record of Frullania is also rather diverse, with inclusions known from several amber deposits. The earliest fossils are F. baerlocheri, F. cretacea, and F. partita from the mid‐Cretaceous Kachin amber, Myanmar. Here, we describe a new fossil species of Frullania as F. kachinensis sp. nov., based on seven sterile gametophyte fragments from three pieces of Kachin amber. This new species is characterized by leaf dorsal lobes mostly with rounded apexes, leaf ventral lobules inserted in approximately 30–90 μm distance to stem, lanceolate styli, and deeply bilobed underleaves with entire‐margined to toothed lobes and V‐shaped sinuses. Morphological comparisons indicate that F. kachinensis shows mosaic character combinations of two coeval species F. cretacea and F. partita. The leaf lobes of F. kachinensis resemble those of F. cretacea, while the underleaves are more similar to those of F. partita. But in taphonomy, F. kachinensis is preserved together with Protofrullania cornigera or F. baerlocheri in the same amber, which could indicate that these three species might live in the same habitat and even on the same tree. The fossils presented in this study provide additional evidence for the presence of a diverse liverwort flora, mostly composed of Frullaniaceae lineages in the mid‐Cretaceous Kachin amber forest. [ABSTRACT FROM AUTHOR]

Sterile and fertile fronds of dipteridacean ferns from the Paso Flores Formation (late Norian-Rhaetian) at Cañadón de Pancho area, south of the Neuquén Province, Patagonia (Neuquén Basin), Argentina, are described. The Paso Flores Formation specimens comprise an interesting mixture of features showing a unique combination that does not fit in the diagnosis of any of the known fossil genera of Dipteridaceae. Characters such as the number and shape of primary segments in each rachial arm, the coalescence of the primary segments at the base of the frond, the distribution of sori and the number of sporangia per sori allow to differentiate the Paso Flores Formation specimens from the other genera of the family. The new genus and species, Patagoniapteris artabeae is proposed. The specimens share some frond morphological features with the fossil genera Clathropteris, Digitopteris, Thaumatopteris, Sewardalea and with some species of the Dictyophyllum, as well as the characteristic of the sori with the living species Dipteris lobbiana. The Paso Flores Formation environments developed on the western margin of Gondwana under seasonal temperate-warm and humid to sub-humid climates with a marine influence from the west. The Cañadón de Pancho assemblages are late Norian-Rhaetian in age, being the youngest fossil flora recorded from Argentinian Triassic basins to date. [ABSTRACT FROM AUTHOR]

Although conceptual whole‐plants are occasionally reconstructed, disarticulation means that palaeobotanical taxonomy remains primarily the preserve of fragmented organ‐species, each bearing a Linnaean binomial. Thus, a "natural" taxon that would in any neobotanical classification bear a single valid binomial (any other epithets automatically being deemed synonyms) typically is a chimera, consisting of several binomials that are not only valid but also arguably essential, each representing a different organ of the original plant. The situation is further complicated by the fact that each organ can also carry multiple valid binomials that refer to contrasting preservation states, most commonly either adpression or permineralisation. Thus, a fossil plant is obliged to carry the heavy burden of not one but two or more parallel taxonomies. The two opposing logical approaches to clarifying this complex situation are (1) to coin additional formal names for organ‐species that are found in multiple modes of preservation but at present are named in only one mode, or (2) to attempt to gradually rationalise parallel preservational taxonomies through detailed character comparison, giving priority to whichever preservational mode typically offers a stronger suite of morphological characters and therefore the greater probability of approaching the biological reality necessary for meaningful evolutionary and ecological interpretation. We illustrate our preference for Option 2 using Palaeozoic rhizomorphic lycopsid genera in general and our antagonism to the recently erected permineralisation stem‐genus "Dimicheleodendron" in particular. [ABSTRACT FROM AUTHOR]

The Early Devonian Rhynie chert preserves the earliest terrestrial ecosystem and informs our understanding of early life on land. However, our knowledge of the 3D structure, and development of these plants is still rudimentary. Here we used digital 3D reconstruction techniques to produce the first well-evidenced reconstruction of the structure and development of the rooting system of the lycopsid Asteroxylon mackiei, the most complex plant in the Rhynie chert. The reconstruction reveals the organisation of the three distinct axis types – leafy shoot axes, root-bearing axes, and rooting axes – in the body plan. Combining this reconstruction with developmental data from fossilised meristems, we demonstrate that the A. mackiei rooting axis – a transitional lycophyte organ between the rootless ancestral state and true roots – developed from root-bearing axes by anisotomous dichotomy. Our discovery demonstrates how this unique organ developed and highlights the value of evidence-based reconstructions for understanding the development and evolution of the first complex vascular plants on Earth.

The new invertebrate trace fossil from paleosols of the Bijori Formation, Palliedaphichnium gondwanicum new ichnogenus new ichnospecies, which belongs to an upper Permian Gondwana sequence of India, makes a significant contribution to the meager records of invertebrate trace fossils from Permian and Indian paleosols. This trace fossil attributed to Diplopoda and composed of tunnels and chambers filled with pellets is also an important addition to the scarce record of Permian millipedes. The abundance of plant remains in the same paleosol indicates that these millipedes probably fed on leaf litter as other fossil and extant representatives. Chambers and abundant pellets in burrows indicate adverse conditions on the surface, at least seasonally. This finding contributes to the emerging scenario of invertebrate ichnofaunas from paleosols and points to a successive dominance of millipedes during the Paleozoic, crayfishes and earthworms in the Mesozoic, and insects in the Cenozoic. UUID: http://zoobank.org/4378c739-9bd1-4382-b084-e2176045e209 [ABSTRACT FROM AUTHOR]

Premise of research. Geochemical fingerprinting of fossil plants is a relatively new research field complementing morphological analyses and providing information for paleoenvironmental interpretations. Ginkgoales contains a single extant species but was diverse through the Mesozoic and is an excellent target for biochemical analyses. Methodology. Cuticles derived from fresh and fallen autumn leaves of extant Ginkgo biloba and seven fossil ginkgoalean leaf taxa, one seed fern taxon, and two taxa with bennettitalean affinity were analyzed by infrared (IR) microspectroscopy at the D7 beamline in the MAX IV synchrotron laboratory, Sweden. The fossil material derives from Triassic and Jurassic successions of Greenland. Spectral data sets were compared and evaluated by hierarchical cluster analysis (HCA) and principal component analysis performed on vector-normalized, first-derivative IR absorption spectra. Pivotal results. The IR absorption spectra of the fossil leaves all reveal signatures that clearly indicate the presence of organic compounds. Spectra of the extant G. biloba leaves reveal the presence of aliphatic chains, aromatic and ester carbonyl functional groups from polymer cutin and other waxy compounds, and polysaccharides. Interestingly, both the extant autumn leaves and the fossil specimens reveal the presence of carboxyl/ketone molecules, suggesting that chemical alterations during the initial stages of decomposition are preserved through fossilization. Two major subclusters were identified through HCA of the fossil spectra. Conclusions. Consistent chemical IR signatures, specific for each fossil taxon are present in cuticles, and sufficient molecular content is preserved in key regions to reflect the plants' original chemical signatures. The alterations of the organic compounds are initiated as soon as the leaves are shed, with loss of proteins and increased ester and carboxyl/ketone compound production in the fallen leaves. We further show that the groupings of taxa reflect a combination of phylogeny and environmental conditions related to the end-Triassic event. [ABSTRACT FROM AUTHOR]

Cone‐producing gymnosperms are important elements of the Mesozoic floras. Studying their cone organizations can potentially help us understand the evolutionary trends of seed plants through time and the origin of angiosperms. In this paper, we present a new and an undetermined species of Ixostrobus Raciborski, a fossil genus representing male cones of the Czekanowskiales from the Middle Jurassic Daohugou locality in Inner Mongolia, China. The holotype specimen of the new species was studied using the neutron tomography (NT) technique. The cone shows higher neutron attenuation than the surrounding matrix. To detect the different organic compounds, a volume rendering of tomographic reconstruction with false colour spectrum of relative neutron attenuation is presented. The highest concentration of organic material is in the axis and some parts of the sacs, the rest of the cone has lower concentration, and the surrounding matrix has the lowest concentration. It seems that the remnant organic materials are regularly differentiated in different parts of the cone probably because of the preservation and different taphonomic process of different type of cells. In addition to revealing more detailed morphological features of the cone by NT reconstruction, the application of NT is potentially important for detecting remnant organic materials preserved in fossil plants. [ABSTRACT FROM AUTHOR]

The unique co‐occurrence of thyriothecia belonging to three fossil genera of epiphyllous fungi, Stomiopeltites Alvin & Muir (Micropeltidaceae), Callimothallus Dilcher, and Trichothyrites Rosendahl (Microthyriaceae), are reported on the leaves of the same host plant, Cunninghamia shangcunica Kodrul, Gordenko & Sokolova from the Oligocene Shangcun Formation of the Maoming Basin, South China. In China, Stomiopeltites is identified for the first time, Callimothallus is known from the Oligocene and Miocene of Guangxi and Zhejiang provinces, and Trichothyrites previously has been found only in the Eocene palynological assemblages of the Maoming Basin. The presence of abundant and diverse epiphyllous micromycetes, together with the taxonomic composition of the Shangcun megaflora and pollen assemblage, as well as quantitative climatic estimates obtained using Climate Leaf Analysis Multivariate Program, confirm the existence of a warm and humid climate in this region during the late early Oligocene. The geographic and stratigraphic distributions, comparisons with extant analogues, as well as ecological and paleoclimatic implications of the fossil fungi are discussed. [ABSTRACT FROM AUTHOR]

Coal‐bearing, fine‐grained clastic rocks of the Pennsylvanian Pottsville Formation contain well‐preserved vertebrate and invertebrate trace fossils and disarticulated plant fossils. These fossil‐bearing rocks also contain small, circular imprints that resemble raindrop impressions but have also been interpreted as structures formed by gas bubble escape from wet sediment. Because rain prints are associated with arid, subaerially exposed depositional conditions and gas escape structures with water‐saturated, organic rich sediments, the interpretation of the circular structures profoundly impacts the palaeoenvironmental reconstruction and interpretation of the life habits of the trace‐makers. In this project, rain prints and gas escape structures were produced to compare these two hypotheses regarding mode of formation and to gain insight into interpretations of similar circular pits in the geological record. The results indicate that gas escape structures form most readily in fine‐grained sediment under water‐saturated conditions, in contrast to rain prints, which form most readily in unsaturated sand. A comparison with experimental structures suggests that the Pottsville shales preserve gas escape structures, not raindrop impressions, suggesting that the environment was rarely desiccated. Because rain prints and gas escape structures are superficially similar, genetic interpretations should not be based on these similarities, but rather on the differences observed between them. Reexamination of circular pits in the sedimentary rock record might require adjustment of environmental interpretations. [ABSTRACT FROM AUTHOR]

The flora of the Cianowice 2 borehole (c. 20 km NW of Cracow, Poland), dominated by cycadophytes (mainly bennettitaleans) and conifers, shows high taxonomic diversity relative to the low number of specimens. Twenty species were identified in the 96 determinable plant fragments found in 27 core samples: Cladophlebis sp. (ferns), Pachypteris rhomboidalis (Ettingshausen) Nathorst and Ptilozamites cycadea (Berger) Möller (seed ferns), Anomozamites nilssonii (Phillips) Seward, Nilssoniopteris solitaria (Phillips) Cleal & Rees, Otozamites mimetes Harris, Otozamites parallelus Phillips, Pterophyllum thomasii Harris, Pterophyllum cf. aequale (Brongniart) Nathorst, Ptilophyllum cf. okribense forma ratchiana Doludenko & Svanidze, Ptilophyllum pecten Phillips, Ptilophyllum sirkennethii Watson & Sincock, Cycadolepis sp. (bennettitaleans), Pseudotorellia grojecensis Reymanówna, Pseudotorellia samylinae Nosova & Kiritchkova, Pseudotorellia sp. (Gymnospermae incertae sedis), Bilsdalea dura Harris, Mirovia szaferi Reymanówna, and Brachyphyllum stemonium Kendall (conifers). The floristic composition is supplemented by palynological data. The taxa were connected to five depositional successions distinguished along the core: one, alluvial fans; two, four and five, meandering/ anastomosing river depositional systems with fluvial plain deposits; and three, lacustrine/backswamp environment developed on fluvial plain. The composition of the fossil plant assemblage changes with the depositional setting within the same range of taxa, seen mainly in changed combinations of taxa, which are most diverse in the fluvial plain deposits. Some taxa occur in a single depositional succession; some are present in two or three. The sporomorph assemblages of particular depositional environments differ significantly from the composition of the co-occurring macroflora: ferns occur sporadically in the macroflora of each depositional environment but they strongly dominate the sporomorph assemblage. Our proposed reconstruction of the palaeoenvironment is a slight rise descending into a valley with a depositionary basin, with gymnosperms on the slope and ferns at the base. Some species are shared between Cianowice and nearby Middle Jurassic localities in Grojec and Zabierzów, and the majority of taxa are known from the Middle Jurassic, suggesting that the Cianowice deposits are of that age. [ABSTRACT FROM AUTHOR]

The world-renowned Miocene Clarkia paleolake in northern Idaho (USA) is closely associated with Columbia River Basalt Group volcanism. The flood basalt dammed a local drainage system to form the paleolake, which preserved a plant fossil Lagerstätte in its deposits. However, the precise age and temporal duration of the lake remain unsettled. We present the first unequivocal U-Pb zircon ages from interbedded volcanic ashes at the P-33 type location, constraining the deposition to 15.78 ± 0.039 Ma. Using micro-X-ray fluorescence and petrographic and spectral analyses, we establish the annual characteristics of laminations throughout the stratigraphic profile using the distribution of elemental ratios, mineral assemblages, and grain-size structures, as well as organic and fossil contents. Consequently, the ~7.5-m-thick varved deposit at the type location P-33 represents ~840 yr of deposition, coincident with the end of the main phase of Columbia River Basalt Group eruptions during the Miocene Climate Optimum. The timing and temporal resolution of the deposit offer a unique opportunity to study climate change in unprecedented detail during global warming associated with carbon-cycle perturbations. [ABSTRACT FROM AUTHOR]

Premise: Microclimatic differences between the periphery and the interior of tree crowns result in a variety of adaptive leaf macromorphological and anatomical features. Our research was designed to reveal criteria for sun/shade leaf identification in two species of evergreen oaks, applicable to both modern and fossil leaves. We compared our results with those in other species similarly studied. Methods: For both Quercus bambusifolia and Q. myrsinifolia (section Cyclobalanopsis), leaves from single mature trees with well‐developed crowns were collected in the South China Botanical Garden, Guangzhou, China. We focus on leaf characters often preserved in fossil material. SVGm software was used for macromorphological measurement. Quantitative analyses were performed and box plots generated using R software with IDE Rstudio. Leaf cuticles were prepared using traditional botanical techniques. Results: Principal characters for distinguishing shade and sun leaves in the studied oaks were identified as leaf lamina length to width ratio (L/W), and the degree of development of venation networks. For Q. myrsinifolia, shade and sun leaves differ in tooth morphology and the ratio of toothed lamina length to overall lamina length. The main epidermal characters are ordinary cell size and anticlinal wall outlines. For both species, plasticity within shade leaves exceeds that of sun leaves. Conclusions: Morphological responses to sun and shade in the examined oaks are similar to those in other plant genera, pointing to useful generalizations for recognizing common foliar polymorphisms that must be taken into account when determining the taxonomic position of both modern and fossil plants. [ABSTRACT FROM AUTHOR]

The first pre-Quaternary representative of Alismataceae from South America is reported based on achenes of Sagittaria montevidensis from the Palo Pintado Formation (upper Miocene) in the south of Salta Province, Argentina. Achenes are laterally compressed, have a lateral beak and a single recurved seed inside them. The fruits were found both in the base (10 Ma) and the top of the formation (~5 Ma), suggesting similar environmental conditions during this time period. A cursory review of the Alismataceae family in the fossil record, with a special interest in those South American reports is given. During the Oligocene-Miocene Sagittaria may have arrived from tropical Africa to South America and thence to North America. [ABSTRACT FROM AUTHOR]

The Ribesalbes-Alcora Basin (Castelló Province, Spain) contains two lower Miocene units that are rich in fossils. The Unit B contains oil-shale and laminated bituminous dolomicrite related to a palaeolake, whereas the Unit C is composed of sandstone and mudstone beds from distal deltaic and shallow lacustrine environments. The La Rinconada and San Chils localities from the Unit B have yielded a fossil assemblage of plants, molluscs, arthropods, and vertebrates, while the localities from the Unit C in the Campisano ravine (Araia/Mas d'Antolino outcrop) are rich in mammalian record. Here we study a new palaeolake deposit of laminated lacustrine limestone beds in the Unit C named Foieta la Sarra-A. This new locality has provided an assemblage of charophytes, terrestrial plants, molluscs, arthropods, and teleosteans. The latter represent the only known fish record from the Ribesalbes-Alcora Basin to date. Although the specimens are generally poorly preserved, the presence of soft-body preservation due to the action of microbial mats at the lake bottom allows considering the Foieta la Sarra-A locality as a Konservat-Lagerstätte. The Foieta la Sarra-A palaeolake had a different water chemistry compared to that represented in the Unit B. Its depth was about a few metres and the water level suffered periodic fluctuations. This new locality sheds light on the palaeoenvironmental dynamics of the Ribesalbes-Alcora Basin during the early Miocene and provides a new approach to the palaeoecological reconstruction of the basin. [ABSTRACT FROM AUTHOR]

The Museo Naturalistico Archeologico dell'Appennino Pistoiese (MUNAP) at Gavinana (PT) hosts one of the most abundant and diverse collections of Late Palaeozoic plant fossils from the San Lorenzo Schists of the Pisani Mountains. More than 1200 rock slabs yielding plant fossils were collected from six different outcrops in Guappero Valley in the San Lorenzo a Vaccoli area (NE of the Pisani Mountains, near Lucca), the type-locality of the formation. The present study concerns two outcrops at Via Pari that are characterized by a wide range of plant fossils (20 taxa) belonging to the lycopsids (Stigmaria), sphenopsids (Calamites, Asterophyllites, Calamostachys, Sphenophyllum, Bowmanites), ferns (Acitheca, Diplazites, Cyathocarpus), seed ferns (Alethopteris, ?Autunia, gen. indet.), cordaites (Cordaites) and seeds (Carpolithes). This first description of the plant fossil collection and the revision of its stratigraphical context with respect to the surrounding famous fossiliferous sections of the Guappero Valley refine the stratigraphic and palaeoenvironmental framework of the Late Palaeozoic successions of the Pisani Mts. and more generally of the Apennine chain. The qualitative and quantitative analyses show significant environmental variations between neighbouring outcrops in the Via Pari area - i.e., more humid conditions in 'Via Pari Buca' than in 'Via Pari Smottamento' - and suggest a latest Carboniferous (Gzhelian) instead of an early Permian age as proposed by previous authors. Moreover, the differences in composition between the plant assemblages of the Via Pari sections with the historical assemblage of the nearby Monte Vignale outcrop (containing typical Permian and more xerophytic elements) in the De Stefani Collection of the Florence Natural History Museum is explained by a younger age (early Permian) of the latter. [ABSTRACT FROM AUTHOR]

The Aghdarband Basin in the Kopeh-Dagh Range (NE Iran) is one of the most important areas for unraveling the evolution of the Turan plate (southern margin of Eurasia) during the last phase of the closure of the Paleotethys and to reconstruct the history of the Cimmerian blocks just before their collision with Eurasia during the early Late Triassic. The youngest sediments affected by the Early Cimmerian orogeny are those of the Upper Triassic Miankuhi Formation, which covers unconformably the Upper Triassic (lower Carnian) marine beds of the Sina Formation by an interval of continental facies including local conglomerates, cross-bedded sandstones, mudstone layers, silty shales, an up to one-meter thick coal layer with plant remains, and shales. The plant assemblages represent a relatively wide variety of different forms (sphenophytes, ginkgophytes, conifers, and incertis sedis), documenting wetlands with lush vegetation typical of warm and humid environments. In this study, we describe a plant fossil assemblage from the base of the Miankuhi Fm., dominated by roots and vegetative organs of Neocalamites iranensis n. sp., with few plant fossils of uncertain botanical affinity. Palynological investigations of the basal part of the Miankuhi Formation confirm a latest early Carnian to late Carnian age for this interval and reveal, for the first time, a clear link between this plant-bearing bed, and a time of global environmental changes, the Carnian Pluvial Episode. This is the first report of the Carnian Pluvial Episode in the Turan plate (southern margin of Eurasia) and Iran. [ABSTRACT FROM AUTHOR]

Premise of research. Africa was declared the "odd man out" by P. W. Richards because its tropical forests have low species diversity and endemism relative to the Neotropics and Southeast Asia. A variety of hypotheses, including differences in climate, the geographic extent of aseasonal warm and wet conditions, landscape heterogeneity, historical contingencies, and a combination of these factors, have been proposed to explain this pattern. New paleofloral data are necessary to document when Africa became the "odd man out" and, when combined with paleoclimate reconstructions, can be used to test these hypotheses. Here, we present floral diversity and paleoclimate analyses from two sites on the Ethiopian Plateau that cross the Oligocene-Miocene boundary, hypothesized to be an interval of diversity decline in tropical Africa. Methodology. Floral diversity in the late Oligocene Chilga Basin and the early Miocene Mush Valley was quantified using large census collections from each site. Diversity at these sites was also compared with that of modern leaf assemblages from well-studied tropical forest plots. Mean annual precipitation was estimated for each fossil site using leaf area analysis, and additional climate variables were reconstructed for Chilga using an overlapping distribution analysis. Pivotal results. Floral diversity at Chilga was extremely high (comparable to that of modern South American leaf assemblages) and decreased at Mush. The Chilga paleoclimate was very humid and possibly aseasonal, on the basis of paleobotanical reconstructions and the presence of lignites. Conclusions. Chilga is among the most diverse fossil floras ever analyzed. The significant decline in Ethiopian tropical forest diversity observed here supports previous hypotheses of significant extinction in the African tropics across the Oligocene-Miocene boundary. We hypothesize that increased seasonality since the Oligocene is the first-order factor responsible for low plant diversity in the modern African tropics relative to South America. [ABSTRACT FROM AUTHOR]

Premise of research. In this contribution, the spectroscopic characterization of gymnosperm fossil remains belonging to Pteridospermophyta, Cycadophyta, Ginkgophyta, and Coniferophyta collected from the Anfiteatro de Ticó and Punta del Barco Formations (Baqueró Group; Aptian) and Springhill (Hauterivian-Barremian) and Piedra Clavada/Kachaike (Albian) Formations, outcropping in the Santa Cruz Province, Argentina, is presented. From these lithostratigraphic units, specimens of several fossil taxa showing the existence of a diverse plant assemblage during the Lower Cretaceous in Patagonia were selected. Methodology. The fossils consist of foliar compressions with very well-preserved cuticles, which are chemically characterized by Fourier transform infrared spectroscopy. Foliar remains are analyzed in two sample forms: (1) compressions (Cps; including coalified mesophyll and cuticles) and (2) cuticles (Cts). Additionally, semiquantitative data are evaluated through principal component analysis, revealing the functional groups preserved at the mesophyll and cuticle levels for all analyzed fossil taxa. Pivotal results. In general, the species from the Baqueró Group show similar chemical compositions between the Cp and Ct sample forms, whereas the chemistry of the foliar compressions from the Springhill and Piedra Clavada/Kachaike Formations reveals the presence of a high contribution of aromatic structures making up the cuticles. Conclusions. The compressions of Pseudoctenis ornata , Ginkgoites tigrensis , and Squamastrobus tigrensis probably underwent, during and after diagenesis, a natural oxidation process most likely caused by the recurrent volcanic activity that occurred during the Aptian sedimentation of the Baqueró Group. In contrast, Ruflorinia orlandoi , Ptilophyllum micropapillosum , and Ginkgoites skottsbergii have cuticles presumably composed of highly aromatic structures (such as phenylpropanoids and aromatic domains) in cutins and cutans as well due to the presence of other phenolic compounds. A new term, vitrinitic compression, is proposed here for G. skottsbergii , while P. ornata , G. tigrensis , S. tigrensis , P. micropapillosum , and R. orlandoi are called liptinitic compressions. [ABSTRACT FROM AUTHOR]

Premise of research. The role of sulfur dioxide (SO2) in plant responses to large igneous province volcanism is difficult to determine but important in relation to understanding ecosystem responses during mass extinction events. Leaf mass per area (LMA) is an important leaf measure for tracking plant responses to environmental pressures in the fossil record, but how it responds to SO2 exposure is unclear, particularly for nonangiosperm taxa. Methodology. Five gymnosperm species were grown in simulated paleoatmospheric conditions that included SO2 to determine how the plants responded. Pivotal results. All plants' growth in high SO2 showed a significant decrease in LMA compared with the control (with no SO2). When grown in a high CO2, low O2, and high SO2 treatment, most plants continued to show a decrease in LMA compared with the control but an increase compared with the high SO2 treatment with ambient CO2 and O2. Conclusions. These findings suggest that exposure to SO2 significantly decreases LMA, potentially reducing preservation potential in the fossil record. Exposure to combined SO2 and high CO2 reduces this effect, but this may also obscure the effects of SO2, leading to interpretations that ecosystem instability is primarily driven by increasing CO2, which may not be the case. [ABSTRACT FROM AUTHOR]

Unpublished data resulting from extensive palynological investigation of coal and carbonaceous rocks from more than thirty boreholes, drilled in the Czech sector of the Intra-Sudetic Basin in the second half of the 20th century, were taxonomically upgraded and analysed for stratigraphic and systematic evaluation. In total 78 genera and 322 miospore and pollen species have been recorded within a radioisotopically constrained ~21 Ma long interval from middle Bashkirian to early Asselian times, i.e. between 318 and 297 Ma. The miospore and pollen assemblages of coal seams are characteristic by the occurrence of stratigraphically important genera (e.g. Waltzispora, Radiizonates, Tripartites, Kosankeisporites, Gillespieisporites, Cadiospora, Angulisporites, Latensina, Lueckisporites, Spinosporites) and taxa recorded only within each member with the combination of quantitative data. Five new palynozones of the basin are recognised. All miospore and pollen taxa are divided into categories based on their plant affinity for the comparison of palynological and macrofloral records in terms of the diversity and vegetation patterns based on the combination of unpublished palynological and freshly published plant fossil records. [ABSTRACT FROM AUTHOR]

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This work describes the one-dimensional, thermo-hydraulic model of the sCO 2 cycle Sofia developed to investigate optimal control methods and the behaviour of the cycle during operation. This dynamic model includes all devices such as turbomachinery, heat exchangers, valves, and piping including heat loss, in line with concept of the 1 MWe sCO 2 cycle, to be realised in the site of a fossil power plant in the Czech Republic. The model assembly and calculations were conducted using the commercial Modelica-based library ClaRa + using the simulation environment Dymola and in combination with another Modelica-based library, UserInteraction; the real-time simulations, with some parameter changes during the calculation, are made and described in this paper. Nominal parameters were achieved during the steady-state simulation, except for the lower mass flow of sCO 2. Transient simulation of power turbine start-up from standby state and results are also presented in this paper. The nominal state is achieved with the semi-automatic procedure in approx. 3 h. The simulation results allow more detailed analyses of control methods and a better understanding of real device control and behaviour during start-up, shutdown, or other transients. Careful manipulation of turbine valves in coordination with the pressuriser operation was identified as crucial for optimal control of the system. Also, the initial amount of CO 2 in the pressuriser affects its behaviour during transients. • Models of the PCHE and BPHE heat exchangers were prepared, and turbomachines models determined by CFD simulations were used. • Control system of the electric heater, which is the largest facility in the Sofia cycle, was designed. • Real-time simulations were performed using ClaRa+ and UserInteraction Dymola libraries. • Careful trubine valves manipulation and corresponding pressuriser control were identified as key control interventions. • Initial amount of CO 2 in the pressuriser affects its behaviour during transients. [ABSTRACT FROM AUTHOR]

The document titled "From the Editor's Desk" is a letter from Dr. Nancy E. Todd, the new editor of the journal BIOS. Dr. Todd has a background in paleontology, evolution, anatomy, and environmental studies. She shares her academic journey, which includes studying archaeology and physical anthropology at Bryn Mawr College, working on zooarchaeological material in Zaire, and collaborating with renowned paleobiologists at the Smithsonian's Museum of Natural History. Dr. Todd's current research focuses on the anatomy and evolution of elephants, as well as investigating the impact of human activities on ecosystems. She expresses her enthusiasm for working with undergraduate students and supporting their research projects. Dr. Todd is honored to be a member of the Beta Beta Beta Biological Honor Society and looks forward to her role as the editor of BIOS. [Extracted from the article]

Mid to Late Devonian witnessed the emergence of the first forest and global flora prosperity on the Earth. West Junggar, a distinct sub-terrain of the Kazakhstan Paleoblock, in which Middle to Upper Devonian plant fossil-rich deposits are exposed, that significantly contribute to our understanding of Devonian plant diversity and flora evolution. In this study, we report a new plant assemblage from the Hongguleleng Formation in the Kekesayi and western Yangzhuang sections of West Junggar, Xinjiang, China. The dominant palynomorphs in this assemblage are retusoid and laevigate trilete spores with occasional scolecodonts. Macroplants of the assemblage consist of tree-like and herbaceous lycopsids. At least two floral turnovers were documented in West Junggar during the Devonian. The first one occurred at the end of the Givetian Age and saw the transformation of the Hujiersite Flora dominated of herbaceous lycopsids, turning into the flora with arborescent plants as typical of the Zhulumute Flora. The second turnover might occur near the Frasnian-Famennian boundary and saw the forest of the Zhulumute Flora shifting into the Hongguleleng Flora with more widely-distributed members. • A new Late Devonian plant assemblage from West Junggar, Xinjiang. • Macro- and micro- plant fossils from the Late Devonian Hongguleleng Flora • Two floral turnovers in West Junggar during the Devonian. • Potential plant dispersal between West Junggar and Laurussia, Gondwana, South China paleoplates. [ABSTRACT FROM AUTHOR]

A comprehensive anatomical and mineralogical study of fossil wood fragments from fields in the vicinity of Bečov and Břvany villages (NW Bohemia, Czech Republic) indicates that Taxodioxylon gypsaceum (Cupressaceae s.l.) predominates, but also identifies another coniferous wood: Pinuxylon parryoides (Pinaceae) and three angiosperms Quercoxylon böckhianum , Castanoxylon bavaricum and Lithocarpoxylon sp. (all Fagaceae). This paper therefore presents the first occurrence of Pinaceae and Fagaceae fossil wood in the volcanic rocks of the České Středohoří Mts. as well as its youngest palaeobotanical record in general, late Oligocene in age (26.56 ± 0.38 Ma). The samples were buried by alkaline pyroclastic deposits and were mineralized by carbonates. Two distinct depositional processes burying the fossil woods were identified. Closer to the vent, the woods occur in a near-vent pyroclastic fall deposits of the former pyroclastic cone, whereas more distant sites consist of pyroclastic flow deposits. Carbonate mineralization mostly consists of dolomite, but subordinate amounts of magnesite (likely the first time this is documented in fossil wood) as well as calcite and siderite are present. Only one sample collected in the same area, bearing clear signs of riverbed transport (Lithocarpoxylon sp.), was perfectly silicified, but its origin remains unclear. • Consideration of individual and interspecific variability in fossil wood anatomy. • Whole-plant concept and its application when defining new fossil plant taxa. • Unique mineralization of fossil wood with magnesite. [ABSTRACT FROM AUTHOR]

Exceptionally well-preserved impression fossils of Cyrillopteris (ex. Odontopteris) orbicularis (Halle) comb. et emend. nov. have been described from the lower part of the middle–upper Permian Upper Shihezi (Upper Shihhotse) Formation in Yangquan City, Shanxi Province, North China. For the first time, this typical Cathaysian seed fern is confirmed to have a bipartite frond with two bipinnate branches, comparable with that of C. genuina (Grand'Eury) Laveine et Oudoire from the Pennsylvanian of France. Entire-margined cyclopteriod elements occur in the proximal portion of the long petiole. With increasing proximity of the bifurcation, the cyclopteroid elements progressively differentiate into pinnae with individual pinnules. True intercalary pinnules, which would be fully inserted on the primary rachides, are not present. Characteristics of our new specimens provide new information on the frond architecture of C. orbicularis (Halle) comb. et emend. nov., and allow a relatively complete circumscription of the overall features of this taxon, an emendation of the species diagnosis, and the presentation of an accurate frond reconstruction. Specimens of C. orbicularis comb. et emend. nov. are preserved with mesophytes and xerophytes from the same interval, demonstrating the vegetation in the research area grew under a seasonal subhumid to semiarid climates during the late Guadalupian. • Cyrillopteris (ex. Odontopteris) orbicularis comb. et emend. nov. is proposed based on new materials. • It has a bipartite frond with two bipinnate branches with cyclopteroid elements. • Associated plant fossils indicate a seasonal subhumid to semiarid climate. [ABSTRACT FROM AUTHOR]

Crude oil is a mixture of hydrocarbons found underground in liquid form and is a valuable fuel with a complex chemical structure. Crude oil is known to come from decaying plants and animals as a fossil product that emerged from the anaerobic process millions of years ago. In the formation of oil, it is accepted that crude oil has an organic origin, and most of the crude oil is found in sedimentary rocks, and the sediments have an organic and inorganic content. In this study, a voltammetric method was developed for the analysis of nickel, one of the metals with the highest density as a heavy metal in crude oil. In the developed voltammetric method, the boron-doped diamond electrode was activated in the cathodic direction at −3.0 V in 0.5 M H 2 SO 4 media. As a result of this cathodic activation, nickel gave a very sensitive anodic signal around −0.15 V on the electrode surface. This anodic signal was determined to be linear in the range of 0.05–0.6 μM around −0.15 V in BR (pH 3.0) media by the anodic stripping voltammetry method. The limit of detection and the limit of quantification were determined to be 0.003 μM and 0.01 μM, respectively. The proposed method allowed the selective analysis of nickel in the crude oil sample without any separation and enrichment process. [Display omitted] [ABSTRACT FROM AUTHOR]

The colonization of the terrestrial surface by land plants involved the evolution of a complex ecosystem of plants, animals, fungi, algae and bacteria, within a mineral framework. The record of this advance is highly fragmentary and uncertain. However, a wealth of fossil evidence is preserved in the Lower Devonian Rhynie Chert lagerstätte, which is consequently considered to be the world's oldest preserved terrestrial ecosystem. The physical record of fossils in the Rhynie Chert is accompanied by a chemical record of molecular biomarkers and mineral diagenesis. The biomarkers include components derived from vascular and other higher plants, and decomposers fungi and bacteria. The chert contains the earliest record of the plant diterpane ent -beyerane, identified in this study. The biomarker profile is distinct from that in Lower Devonian organic-rich shales at Strathpeffer, 100 km to the west, where plants are not preserved and the environment was hypersaline. In addition to organic biomarkers, the chert contains mineralogical characters which imply biological activity, including pyrite framboids, strongly leached monazite and garnet, and pitted micas similar to grains altered by modern fungi. The molecular and mineral biomarkers combine with the fossil record and phylogenetic data in the toolbox available to document plant colonization and symbiosis on the terrestrial surface. • The plant-bearing Rhynie Chert contains both molecular and mineral biomarkers. • The chert contains the earliest record of the plant diterpane ent -beyerane. • Authigenic phases may be products of bacterial and fungal components in the Rhynie ecosystem. • Detrital monazite was leached to supply phosphate, which was required by fungi in symbiosis with plants. • Oxides also sequestered phosphate, and hence were a reservoir of phosphorus in the ecosystem. [ABSTRACT FROM AUTHOR]

Conifers of the order Voltziales were important components of Triassic floras. Their pollen is likewise abundant in microfloras from this period. Voltzialean pollen grains are known to have a considerable range of morphologies, but taxonomic distinctions based on these differences require thorough descriptions of in situ pollen from well-preserved male cones. We studied the pollen grains extracted from male cones from the palaeofloras of the Dont Formation in Italy, the Grès à Voltzia in France (both Anisian, lower Middle Triassic), and the Erfurt Formation in Germany (Ladinian, upper Middle Triassic). Pollen cones from the Dont Formation contain taeniate bisaccate pollen that are otherwise known only from Paleozoic conifers, as well as in one case multi-taeniate pollen grains resembling those commonly associated with seed ferns. By contrast, in situ pollen grains from the Grès à Voltzia and the Erfurt Formation are mostly comparable to Illinites , Angustisulcites or alete forms such as Voltziaceaesporites , Alisporites , and Klausipollenites. Malformations are usually rare, but notable are recurring patterns of smaller or larger than normal corpus sizes, which could lead to different taxonomic assignments if found dispersed. Overall, pollen grain sizes in general can vary considerably within a sample and even more between samples from different specimens of the same species. By contrast, size ranges of different species are overlapping significantly. • In situ conifer pollen show a variety of morphologies. • Pollen grain sizes can vary strongly within samples and species. • Malformed pollen grains with abnormal corpus sizes form a re-occurring pattern. • Details of pollen malformation may allow inferences on their causes. [ABSTRACT FROM AUTHOR]

The late Kungurian succession of Gorl in the Southern Alps yielded more than 200 plant fossils. The remains are very fragmented but occasionally exceptionally well-preserved with cuticle. The morphological and cuticular analyses confirm the presence of some seed ferns (Lodevia, Peltaspermum, Sphenopteris), ginkgophytes (Sphenobaiera), and conifers (Collia geinitzii, Feysia, Hermitia) for the Southern Alps. The cuticular analyses permitted, however, also the description of a leaf fragment putatively assigned to Germaropteris martinsii , and several different types of conifer shoots (Conifer morphotypes 1–3, Dwarf shoot 1–2). The cuticle of Collia geinitzii is described for the first time. Palynological studies integrate the floral composition, adding some more humid elements to the flora (lycophytes, ferns, cordaites), and increases the diversity of the seed ferns and conifers. The palynofacies analyses permit to reconstruct a near-shore depositional lacustrine environment with a fluctuating lake level. The exceptionally well-preserved cuticles even demonstrate Plant-animal interactions such as traces from piercing and sucking. • First Southern Alps Cisuralian plant fossils, yielding cuticles, are documented. • The assemblage from Gorl includes seed ferns, ginkgophytes and conifers. • Integrating micro- and macroflora, we document a diverse Cisuralian vegetation. • Palynofacies reconstructs fluctuating lake levels in a near-shore lacustrine setting. • Cuticles evidenced piercing and sucking damage along veins and targeting mesophyll. [ABSTRACT FROM AUTHOR]

With a rich sequence of floral and faunal remains spanning the past >65,000 years, Boomplaas Cave is among the more important paleoenvironmental archives from South Africa's southern Cape. However, over the last several decades, its paleoenvironmental records have been the subject of conflicting interpretations, fueling uncertainty over fundamental aspects of Quaternary climate change in the region. Most significantly, researchers have variably interpreted the fossil plant and animal assemblages dating to the Last Glacial Maximum (LGM) as indicating harsh and arid or humid and productive conditions. This review critically examines the paleoenvironmental evidence from Boomplaas Cave, focusing on its LGM deposits and how they relate to the contentious problem of moisture availability through time. We show that interpretations of aridity during the LGM either (i) lack robust ecological links between the evidence and the paleoenvironmental interpretation, or (ii) are based on spurious patterns arising from sampling effects. In contrast, interpretations of relatively humid conditions during the LGM are grounded in present-day ecological observations and are consistent with both local and regional paleoenvironmental datasets. Overall, the evidence strongly supports the characterization of the LGM as a time of relatively humid conditions, with the transition to the Holocene characterized by increasing aridity. Several lines of evidence from Boomplaas Cave further suggest that this phase of increased humidity was associated with a dominance of winter rainfall, in contrast to the aseasonal rainfall regime that characterizes the southern Cape today. • Boomplaas Cave is a critical but debated archive of LGM climate in southern Africa. • This study examines its paleo proxies and the interpretations derived from them. • The proxy records indicate greater moisture availability during the LGM. • The proxy records indicate a greater dominance of winter rainfall during the LGM. [ABSTRACT FROM AUTHOR]

Dr Peter Barlow, who died in 2017, was one of the most respected botanists and biologists of the latter half of the 20th Century. His interests covered a wide range of plant biological topics, e.g. root growth and development, plant cytoskeleton, effects of gravity, plant intelligence, pattern formation, and evolution of eukaryotic cells. Here we consider Peter’s numerous contributions to the: elucidation of plant patterns; understanding of root biology; role of the plant cytoskeleton in growth and development; influence of the Moon on terrestrial vegetation; Cell Body concept; and plant neurobiology. In so doing we attempt not only to provide an overview of Peter’s important work in many areas of plant biology, but also to place that work in the context of recent advances in plant and biological sciences.

Background: Celastraceae is a morphologically heterogeneous family. For this reason, the inclusion of some taxa within this group is controversial. Recently this problem has become significant since its fossil record is recognized as an important source of information for evolutionary studies, especially those using molecular clocks which require a robust, reliable fossil record. Questions: What are the most reliable fossil records of Celastraceae? What morphological characters are used to assign fossils in the family? Study site and dates: Compilation of records contained in paleontological databases, and paleobotanical literature, covering publications from 1869 to 2018. Methods: Published information on the Celastraceae fossil record was compiled and analyzed using the most recent classification system and specialized literature on the family. Results: A total of 168 fossil records were examined, of which nine are proposed for use as molecular clock calibration points. Each specimen has a description based on a character set used for its identification, a photograph and/or illustration, their geological age is well supported, their geographic origin is known, and the specimens are in accredited home institutions with publicly accessible collections. Conclusions: The identification and establishment of relationships between fossil and extant taxa have important limitations that depend on the critical interpretation of morphology in a phylogenetic context. Therefore, it is essential to incorporate only those morphological studies in Celastraceae that help clarify its fossil record.

The Aghdarband Basin in the Kopeh-Dagh Range (NE Iran) is one of the most important areas for unraveling the evolution of the Turan plate (southern margin of Eurasia) during the last phase of the closure of the Paleotethys and to reconstruct the history of the Cimmerian blocks just before their collision with Eurasia during the early Late Triassic. The youngest sediments affected by the Early Cimmerian orogeny are those of the Upper Triassic Miankuhi Formation, which covers unconformably the Upper Triassic (lower Carnian) marine beds of the Sina Formation by an interval of continental facies including local conglomerates, cross-bedded sandstones, mudstone layers, silty shales, an up to one-meter thick coal layer with plant remains, and shales. The plant assemblages represent a relatively wide variety of different forms (sphenophytes, ginkgophytes, conifers, and incertis sedis), documenting wetlands with lush vegetation typical of warm and humid environments. In this study, we describe a plant fossil assemblage from the base of the Miankuhi Fm., dominated by roots and vegetative organs of Neocalamites iranensis n. sp., with few plant fossils of uncertain botanical affinity. Palynological investigations of the basal part of the Miankuhi Formation confirm a latest early Carnian to late Carnian age for this interval and reveal, for the first time, a clear link between this plant-bearing bed, and a time of global environmental changes, the Carnian Pluvial Episode. This is the first report of the Carnian Pluvial Episode in the Turan plate (southern margin of Eurasia) and Iran.

Taphonomic studies were carried out at Laguna Flecha Negra locality (Bahía Laura Complex, Middle-Late Jurassic), Santa Cruz Province, Argentina. Sedimentary facies and preservational styles were defined to recognize plant taphofacies in the studied sequence. Eleven taphofacies were identified and plant sources within a volcanic and geothermal system are proposed. Plant remains are of autochthonous to para-autochthonous origin and best preservation was found in distal facies of siliceous hot spring (sinter) systems. Lateral and vertical taphonomic differences were found in the studied sequence. These are due to changes in the sedimentary input and distance to the geothermal fluids. Results enable the reconstruction of the depositional history of this region of the Deseado Massif geological Province. We infer formation of a hot-spring (sinter) system that was subsequently destroyed by a phreatic eruption process at the margin of an andesitic effusive dome in partially reworked fall pyroclastic subfacies. After the destruction of the geothermal system, a fluvial and lacustrine epiclastic subfacies developed preserving a plant community typical of the Middle-Late Jurassic of Gondwana. Later, volcanic activity produced pyroclastic subfacies, with thick ash-fall and flow deposits from different sources and separated by a time gap that promoted fossilization of an in situ forest. Taphonomic studies of these plant communities allowed reconstruction of a chain of geological events and how these processes have influenced the preservation of a Jurassic flora from Patagonia, thus contributing to an understanding of the paleoecology of the Deseado Massif geological province. [ABSTRACT FROM AUTHOR]

Fossil pollen believed to be related to extant Hagenia abyssinica were discovered in the early Miocene (21.73 Ma) Mush Valley paleoflora, Ethiopia, Africa. Both the fossil and extant pollen grains of H. abyssinica were examined with combined light microscopy, scanning electron microscopy, and transmission electron microscopy to compare the pollen and establish their relationships. Based on this, the fossil pollen grains were attributed to Hagenia. The presence of Hagenia in the fossil assemblage raises the questions if its habitat has changed over time, and if the plants are/were wind pollinated. To shed light on these questions, the morphology of extant anthers was also studied, revealing specialized hairs inside the anthers, believed to aid in insect pollination. Pollen and anther morphology are discussed in relation to the age and origin of the genus within a molecular dated phylogenetic framework, the establishment of complex topography in East Africa, other evidence regarding pollination modes, and the palynological record. The evidence presented herein, and compiled from the literature, suggests that Hagenia was an insect‐pollinated lowland rainforest element during the early Miocene of the Mush Valley. The current Afromontane habitat and ambophilous (insect and wind) pollination must have evolved in post‐mid‐Miocene times. [ABSTRACT FROM AUTHOR]

The appearance and subsequent evolution of land plants is among the most important events in the earth system. Plant resulted in a change of earth surface albedo and the hydrological cycle, as well as increased rock weatherability thereby causing a persistent change in atmospheric CO2 and O2. Land plants are, however, themselves dependent on O2 for respiration and long‐term survival, something not considered in current geochemical models. In this perspective, we highlight two aspects of land plants' dependency on O2 relevant for the geobiological community: (a) fossil root systems can be used as a proxy for minimum levels of past atmospheric O2 consistent with a given fossil root depth; and (b) by identifying a positive feedback mechanism involving atmospheric O2, root intensity, terrestrial primary production and organic carbon burial. As an example, we consider archaeopterid fossil root systems, resembling those of modern mature conifers. Our soil–plant model suggest that atmospheric O2 with 1 SD probably reached pressures of 18.2 ± 1.9 kPa and 16.8 ± 2.1 kPa by the Middle and Late Devonian, respectively, that is 86 ± 9% and 79 ± 10% of the present‐day 21.2 kPa. [ABSTRACT FROM AUTHOR]

Premise of research. Fossil assemblages of the Battery Point Formation are among the most diverse occurrences of Early Devonian permineralized plants worldwide. The plant fossils host microbial, putative fungal, and fungal fossils that have not been surveyed previously. Here we provide a first synopsis of the morphological diversity of these fossils. Methodology. The fossils originate from the southern shore of Gaspé Bay (Quebec, Canada), where Emsian (400–395 Ma) layers deposited in fluvial to coastal environments host allochthonous fossil plant assemblages. Fossils were studied in serial anatomical sections produced with the cellulose acetate peel technique. Pivotal results. The fossils comprise spores, hyphae, and cellular aggregates found within zosterophyll, trimerophyte, and rhyniophyte axes. The spores include large types showing characters of extant glomeromycetes, small spores with wrinkly walls suggestive of algal cysts, and a variety of globose spores that occupy inter- and intracellular positions. The hyphae comprise septate and aseptate forms, some similar to Carboniferous plant endophytes, others associated with structures with potential blastocladiomycete affinities. Putative cellular aggregates, including elongated, spherical, and moniliform types, have morphologies suggestive of asexual fungal structures, prokaryotes, or protist colonies; some are distributed in concentric patterns by morphological type within a rhyniophyte axis. Miscellaneous structures interpreted as putative sexual reproductive structures, as well as animal eggs and egg cases and one suggestive of a larval case, are also present. Conclusions. The rich and diverse fossil assemblages of the Rhynie chert have been the only source of information on Early Devonian plant-fungal and plant-microbial interactions, until now. The new diverse fossils documented in the Battery Point Formation reemphasize the importance of permineralized fossils for uncovering plant-microorganism interactions, open a new window on the history of these interactions deep in the fossil record, and broaden the spectrum of plant-associated microorganisms known from the Early Devonian. [ABSTRACT FROM AUTHOR]

A new fossil species of Corylopsis (Hamamelidaceae), C. grisea Quirk & Hermsen sp. nov, based on seeds from the early Pliocene Gray Fossil Site (GFS), eastern Tennessee, USA, is described. The assignment of the seeds to Hamamelidaceae, subfamily Hamamelidoideae, is based on the overall size of the seeds, smooth testa, lack of a seed wing, and the presence of a terminal hilar scar. The assignment to the genus Corylopsis is based on seed size as well as the presence of a hilar facet, in addition to the hilar scar. Although Corylopsis persists only in East Asia today, its fossil record indicates that the genus was widespread across the Northern Hemisphere in the past. Prior to its discovery at GFS, Corylopsis was only known from the Paleogene in North America. The presence of C. grisea at GFS extends the fossil record of Corylopsis in North America to the Neogene and reinforces the interpretation of GFS as a forested refugium that provided a relatively moist, equable environment where subtropical to warm temperate plants could persist during a time of cooling and drying in the continental interior of North America. Its presence provides additional evidence for the biogeographic connection between the GFS paleoflora and the modern flora of eastern Asia. [ABSTRACT FROM AUTHOR]

Few fossil‐based environmental and climate records in northern Europe are dated to Marine Isotope Stage (MIS) 5a around 80 ka BP. We here present multiple environmental and climate proxies obtained from a lake sequence of MIS 5a age in the Sokli basin (northern Finland). Pollen/spores, plant macrofossils, NPPs (e.g. green algae), bryozoa, diatoms and chironomids allowed an exceptionally detailed reconstruction of aquatic and telmatic ecosystem successions related to the development of the Sokli Ice Lake and subsequent infilling of a relatively small and shallow lake confined to the Sokli basin. A regional vegetation development typical for the early half of an interglacial is recorded by the pollen, stomata and plant macrofossil data. Reconstructions of July temperatures based on pollen assemblages suffer from a large contribution of local pollen from the lake's littoral zone. Summer temperatures reaching present‐day values, inferred for the upper part of the lake sequence, however, agree with the establishment of pine‐dominated boreal forest indicated by the plant fossil data. Habitat preferences also influence the climate record based on chironomids. Nevertheless, the climate optima of the predominant intermediate‐ to warm‐water chironomid taxa suggest July temperatures exceeding present‐day values by up to several degrees, in line with climate inferences from a variety of aquatic and wetland plant indicator species. The disequilibrium between regional vegetation development and warm, insolation‐forced summers is also reported for Early Holocene records from northern Fennoscandia. The MIS 5a sequence is the last remaining fossil‐bearing deposit in the late Quaternary basin infill at Sokli to be studied using multi‐proxy evidence. A unique detailed climate record for MIS 5 is now available for formerly glaciated northern Europe. Our studies indicate that interglacial conditions persisted into MIS 5a, in agreement with data for large parts of the European mainland, shortening the Last Glacial by some 50 ka to MIS 4‐2. [ABSTRACT FROM AUTHOR]