The enigmatic acid-resistant mesofossil genus Kuqaia isemended, anew species (Kuqaia scanicus) isinstituted, and three established species are described from the Lower Jurassic (lower Pliensbachian) ofthe Ka ̈ vlinge BH-928 core, insouthern Sweden. Kuqaia has adistribution across the middle northern latitudes ofPangaea and isrestricted toLower tolower Middle Jurassic strata. Morphological characters support Kuqaia being the ephippia (resting egg/embryo cases) ofCladocera (Crustacea: Branchiopoda), and aprobable early stemgroup taxon ofthe Daphnia lineage. The paleoecology ofthe small planktonic crustaceans indicate purely fresh-water environments, such as lakes orponds, all occurrences being in continental deposits, and the Kuqaia specimens possibly represent dry-season resting eggs. Chemical analyses ofthese and similar fossils, and ofextant invertebrate eggs and egg cases are recommended toimprove resolution ofthe biological affiliations ofsuch mesofossil groups.

The end-Triassic mass extinction (ETE; ~201.6 million years ago) led to dramatic changes in terrestrial eco­ systems including the extinction of several seed-plant groups. Among the most intriguing features in the vege­ tation signal is the dominance of the peculiar pollen, Ricciisporites tuberculatus Lundblad, across large areas of the Northern Hemisphere immediately prior to and during the ETE. The parent plant of this pollen has remained unknown for 70 years. Here, we demonstrate that the ‘seed-fern’ Lepidopteris ottonis (Go¨ppert) Schimper (Pel­ taspermales) produced R. tuberculatus in permanent tetrads. We show that R. tuberculatus is a large, abnormal form of the small smooth-walled monosulcate pollen traditionally associated with L. ottonis, which disappeared at the ETE, when volcanism induced cold-spells followed by global warming. We argue that the production of aberrant R. tuberculatus resulted from ecological pressure in stressed environments that favoured asexual reproduction in peltasperms. The expansion of dry environments led to the dominance of drought-tolerant plants in the Early Jurassic of northern middle latitudes.

Lycophytes were an important group of plants in the late Permian (Lopingian) vegetation of Southwest China. However, our understanding of these lycophytes is based mostly on the study of megafossil specimens. Here, we describe a unique lycophyte megaspore, Paxillitriletes permicus Sui, McLoughlin et Feng sp. nov., from the Lopingian Xuanwei Formation of Yunnan Province, Southwest China. This trilete megaspore is characterized by prominent membraneous triradiate flanges, long bifurcate spines, an arcuate ridge expanded into a zona, and triangular to polygonal reticulate sculpture. Ultrastructural analysis reveals that the megaspore wall consists of four layers. The innermost layer is the foot layer, which forms a thin and solid basal lamina. It is covered by a dense layer containing small and parallel sporopollenin grains. A thick spongy layer is developed exterior to the dense layer and consists of elongate, curved, and intersected sporopollenin units with porous zones. The outermost layer is dense, of variable thickness, and forms the processes. Morphological and ultrastructural features indicate that the new megaspore belongs to a herbaceous isoetalean. This is the first detailed investigation of megaspores from the Lopingian of China using scanning and transmission electron microscopy. Our discovery represents the oldest occurrence of Paxillitriletes, and adds to the diversity of late Permian lycophytes in the Cathaysian Flora in the paleotropics of the eastern Tethys Ocean.

The end-Permian extinction event (EPE; 252 million years ago) was the most extreme mass extinction in Earth’s history (Stanley, 2016) and has been linked to rapid, planet-scale warming (Frank et al., 2021). The Australian stratigraphic record offers a globally unique opportunity to explore the severity and pace of terrestrial carbon sinks in response to this hyperthermal event across a broad latitudinal range. The Bowen, Sydney and Tasmania basins of eastern Australia collectively represent a ~2500 km north-south transect (Fig. 1) of contemporaneous continental depositional environments and floras during the Late Permian and Early Triassic (palaeolatitudes:~45–75°S). From the Sydney Basin, our team has built a robust chronostratigraphic framework (Fig.2), with which we have reconstructed the timeline of continental environmental and floral changes in the region (Fielding etal., 2019, 2021; Mays et al., 2020, 2021b; Vajda et al., 2020; McLoughlin et al., 2021). More recently, we have successfully applied our chronostratigraphic scheme to the Bowen Basin to constrain the ages of the climatic and floristic changes (Frank et al., 2021). The poorly studied Tasmania Basin is the highest palaeolatitude Permian–Triassic basin of Australia, and can provide chronostratigraphic and biogeographic links between Antarctica and the other basins of eastern Australia.

Wildfire has been implicated as a potential driver of deforestation and continental biodiversity loss during the end-Permian extinction event (EPE; ~ 252 Ma). However, it cannot be established whether wildfire activity was anomalous during the EPE without valid pre- and post-EPE baselines. Here, we assess the changes in wildfire activity in the high-latitude lowlands of eastern Gondwana by presenting new long-term, quantitative late Permian (Lopingian) to Early Triassic records of dispersed fossil charcoal and inertinite from sediments of the Sydney Basin, eastern Australia. We also document little-transported fossil charcoal occurrences in middle to late Permian (Guadalupian to Lopingian) permineralized peats of the Lambert Graben, East Antarctica, and Sydney and Bowen basins, eastern Australia, indicating that even vegetation of consistently moist high-latitude settings was prone to regular fire events. Our records show that wildfires were consistently prevalent through the Lopingian, but the EPE demonstrates a clear spike in activity. The relatively low charcoal and inertinite baseline for the Early Triassic is likely due in part to the lower vegetation density, which would have limited fire spread. We review the evidence for middle Permian to Lower Triassic charcoal in the geosphere, and the impacts of wildfires on sedimentation processes and the evolution of landscapes. Moreover, we assess the evidence of continental extinction drivers during the EPE within eastern Australia, and critically evaluate the role of wildfires as a cause and consequence of ecosystem collapse. The initial intensification of the fire regime during the EPE likely played a role in the initial loss of wetland carbon sinks, and contributed to increased greenhouse gas emissions and land and freshwater ecosystem changes. However, we conclude that elevated wildfire frequency was a short-lived phenomenon; recurrent wildfire events were unlikely to be the direct cause of the subsequent long-term absence of peat-forming wetland vegetation, and the associated ‘coal gap’ of the Early Triassic.

The upper part of the upper Permian succession in the Bowen Basin of Queensland, NE Australia, was investigated to ascertain the timeline and character of environmental changes in this high southern palaeolatitudinal setting leading up to the End-Permian Extinction (EPE). The study focused on (in ascending order) the Peawaddy Formation, Black Alley Shale, and Bandanna Formation, and laterally correlative units. In the western Bowen Basin, the base of the Peawaddy Formation (257 Ma) records the onset of thrust loading and volcanic activity associated with the Hunter-Bowen contractional orogeny. The Peawaddy Formation comprises a series of coarsening-upward, terrigenous clastic intervals interpreted as the product of repeated progradation of deltas into shallow, open marine environments. The overlying Black Alley Shale also comprises multiple deltaic coarsening-upward cycles, which accumulated in stressed, restricted marine environments. The uppermost Bandanna Formation and equivalents formed in extensive coastal plain to estuarine environments. All three formations accumulated under the influence of explosive volcanic activity from the emerging continental volcanicarc to the east of the foreland basin. Volcanism peaked during deposition of the Black Alley Shale around the Wuchiapingian–Changhsingian transition. Abundant dispersed gravel and glendonites (calcite pseudomorphs after ikaite) indicate that the Peawaddy Formation formed under the influence of cold conditions and possible glacial ice (P4 Glaciation; Wuchiapingian Stage). Direct evidence of cold conditions ends at the top of the Peawaddy Formation (254.5 Ma); however, Chemical Index of Alteration (CIA) data suggest that surface conditions remained cold through the accumulation of the Black Alley Shale, and the lower Bandanna until c. 253 Ma, before gradually rising through the upper Bandanna Formation. The end of P4 glaciation is also characterized by a major spike in the abundance of marine acritarchs (Micrhystridium evansii Acme Zone), reflecting the development of a regional restricted basin of elevated nutrient concentrations but reduced salinity. In contrast to this short interval of stressed marine conditions, the fossil floras indicate remarkably consistent terrestrial ecosystems throughout the late Lopingian until the EPE. The terrestrial EPE is recorded by adistinctive, laminated mudrock bed (‘Marker Mudstone’) that records a palynological ‘dead zone’ above the uppermost coal seam or equivalent root-penetrated horizon followed by spikes in non-marine algal abundance. Overall, the time interval 257–252 Ma represented by the studied succession does not record a simple monotonic change in palaeoenvironmental conditions, but rather a series of intermittent stepwise changes towards warmer, and more environmentally stressed conditions leading up to the EPE in eastern Australia.

Since the establishment of spore-pollen analysis as a method for biostratigraphic subdivision of Mesozoic rocks in Ukraine, several schools have undertaken palynological research since the middle of the 20th century. Palynologists M.I. Ustynovska, T.B. Hubkyna, N.N. Zhuhan, S.Y. Yehorova, H.Y. Ivankevych, O.Z. Isahulova, Y.V. Semenova, R.O. Rotman, and N.S. Kyrvel worked at the Kyiv school (central Ukraine); L.A. Portnyahina, H.A. Orlova-Turchyna, N.Y. Teslya, M.I. Burova, M.E. Ohorodnik, and A.S. Andreeva-Grigorovich carried out research in the Lviv school (western Ukraine); and A.K. Kruzina, A.A. Mikhelis among others worked in the Artemivsk school (eastern Ukraine). The scientific works of M.A. Voronova are basic analyses of the spores-pollen assemblages of the Lower Cretaceous. From 1963 to 2002, M.A. Voronova established the basic methodological principles of palynological research on Lower Cretaceous strata of Ukraine and elucidated important issues concerning the emergence of angiosperms, migration and evolution of the Late Jurassic and Early Cretaceous flora of ferns, developed criteria for palaeolandscape reconstructions and palaeo-weathering. G.G. Janowska focused on the palynostratigraphy of the Jurassic deposits of Crimea and Preddobrudzha. In 1952–1953, for the first time, G.V. Shramkova and A.M. Laptyeva carried out a detailed biostratigraphic division of the Jurassic–Lower Cretaceous deposits of the Dnieper-Donetsk Basin and the north-western Donbass with the help of spore-pollen analysis. E.V. Semenova characterized the Triassic and Lower Jurassic deposits of the Donbas and the Dnieper-Donetsk Basin.Despite the significant contributions of Ukrainian palynologists to the study of Mesozoic sediments, many problems remain that need to be addressed. Today, at the Institute of Geological Sciences of the National Academy of Sciences of Ukraine biostratigraphic subdivision and correlation of Mesozoic strata using palynological analysis is carried out by O.A. Shevchuk and student D.O. Pustovoitova. A comprehensive approach to the study of microresidues from Jurassic and Cretaceous samples are covered in the dissertation of O.A. Shevchuk “Stratigraphy of the Middle Jurassic–Cretaceous of Ukraine on microfossils” 2021 and in other publications. The main groups that we have studied and that are important for stratigraphy are spores and pollen, megaspores and dinocysts, along with dispersed cuticles, tracheids, remnants of structured wood, green algae (prasinophytes and Botryococcus), fungi, insects, animal body parts, acritarchs, microforaminifera, microsclerites, scolecodonts, bacteria, sclerenchyma and pseudomicrofossils. We apply a comprehensive approach to the study of microfossils, which provides a broader understanding of the palaeogeographical conditions of the region of Ukraine in the Mesozoic. The effectiveness of complex palynological studies of marine and continental Mesozoic deposits of Ukraine for stratigraphic purposes is substantiated by their application to hydrogeology and hydrocarbon exploration.

A small assemblage of plant macrofossils incorporating representatives of Glossopteris, Vertebraria, Dictyopteridium, Samaropsis and Schizoneura is described from the Little River Coal Measures in northeast Queensland, Australia. The assemblage is interpreted to be of Lopingian age based on taxa shared with units in the Bowen Basin to the south. The fossil assemblage represents the northernmost late Permian flora yet described from Australia but has a typical representation of Gondwanan taxa and lacks evidence of Cathaysian elements. The only evidence of an associated fossil fauna is in the form of possible oviposition scars on some Glossopteris leaves. The assemblage is associated with coal beds and is considered to reflect growth in peat-forming alluvial plain settings under a mid-latitude humid temperate climate.

Organisms that colonize wood are subject to a taphonomic tragedy—the richer and more diverse they become, the greater the deterioration of the host wood and the less likely such communities are to be fossilized. Moreover, palaeobotanical studies of fossil wood usually focus on the plant tissue, neglecting the evidence of parasitic, saproxylic, and other contained organisms. Such a case involved a relatively well-known fossil wood assemblage from the Santonian (Late Cretaceous, ca 84 Ma) of southeast Africa. In a set of 150 thin sections of silicified wood stored in the Senckenburg Museum for more than half a century, we discovered evidence of a diverse biotic community comprising bacteria, fungi, nematodes, several types of arthropods, and marine bivalves. These body fossils and traces, together with growth-ring features, fossil log size and shape, and the distribution of glauconite, facilitated interpretation of the multi-stage evolution of a wood-hosted biocoenosis of unprecedented diversity. This record is unique for the Mesozoic and is of importance for understanding the taphonomic pathways to preservation and the evolution and diversification of saproxylic and other wood-hosted communities in terrestrial and marine settings.

The Leigh Creek Coal Measures incorporate unusually low-rank coals from the Upper Triassic of South Australia. Associated fluviolacustrine deposits contain well-preserved, partly mummified plant remains dominated by corystosperm seed ferns. The assemblage comprises seven species of Dicroidium, including D. odontopteroides, D. lineatum, D. dubium, D. zuberi, and Dicroidium spp. A, Band C, and associated reproductive organs, including various fragments of cupulate structures (Umkomasia sp. cf. U. quadripartita and Fanerotheca sp. cf. F. waldeckiformis) and pollen organs (Pteruchus africanus), all having excellent cuticle preservation. Based on a comprehensive analysis of more than 550 individual specimens, we (1) document diagnostic epidermal and cuticular features forfoliage and reproductive organs, (2) provide an identification key for the Dicroidium species present, and (3) infer affiliations between reproductive organs and particular leaf species based on correspondence in epidermal anatomy and cuticle micromorphology and on mutual-occurrence data. Collectively, the Leigh Creek material contributes towards a more robust and realistic systematic classification of Umkomasiaceae, offers a rare chance for whole-plant reassembly of individual species, and refines reconstruction of the Dicroidium dominated forest ecosystems in the middle to high latitudes of the Late Triassic greenhouse world.

Nurse logs are common in modern forests from boreal to temperate and tropical ecosystems. However, the evolution of the nurse-log strategy remains elusive because of their rare occurrence in the fossil record. We report seven coniferous nurse logs from lowermost to uppermost Permian strata of northern China that have been colonized by conifer and sphenophyllalean roots. These roots are associated with two types of arthropod coprolites and fungal remains. Our study provides the first glimpse into plant—plant facilitative relationships between late Paleozoic gymnosperms and sphenopsids. Detritivorous arthropods and fungi appear to have been crucial for the utilization of nurse logs in Permian forests. The phylogenetically distant roots demonstrate that nurse-log interaction wasa sophisticated seedling strategy in late Paleozoic humid tropical forests, and this approach may have been adopted and developed by a succession of plant groups leading to its wide representation in modern forest ecosystems.

It    is    with    sadness    that    I    announce    to    the    IOP    community    the    untimely    death    of    our    dear     colleague,     Dr.     Nathalie     Nagalingum.     Nathalie     passed     away     on     August     22nd this     year,    surrounded    by    her    family    in    Melbourne,    Australia,    after    a    long    battle    with    ovarian    cancer.Nathalie    was    born    in    Melbourne    on    17th March,    1975,     the    daughter    of    Mauritian    immigrants.    She    excelled    in    biological    science    at    school    and    later    studied    botany    at    the    University    of    Melbourne.    She    completed    both    her    BSc    Honours    (in    1996)    and    PhD    (in    2002)    projects,    under    the    supervision    of    Prof Andrew    Drinnan    and    myself    at    that    institution.    Her    BSc    (Honours)    project    dealt    with    Early     Cretaceous     conifers     (particularly    an    apparently     deciduous     form     that     she    later    described    as    Bellarinea    richardsii) from    the    Gippsland    Basin    of    southeastern    Australia. Her    PhD    shifted    towards    an    investigation    of    the    systematics    of    Early    Cretaceous    ferns    from    Australia    and    Antarctica—incorporating     material     from     both     Museum     Victoria     in     Melbourne     and     the     British    Antarctic    Survey    in    Cambridge.

The Swedish Museum of Natural History (Naturhistoriska riksmuseet: NRM), under the authority of the Swedish Ministry of Culture, is the largest museum in Sweden in terms of research and collections. Although officially founded in 1819 by the Royal Swedish Academy of Sciences, some collections held at the museum date back to donations received by the academy following its foundation in 1739. The museum includes six research departments (Palaeobiology, Zoology, Botany, Geology, Bioinformatics, and Environmental Science) along with separate divisions for exhibitions and education. Palaeobotanical research is currently carried out within the Department of Palaeobiology (PAL). The department’s homepage can be found at: https://www.nrm.se/ en/forskningochsamlingar/paleobiologi.9000584.html. The department hosts about two million palaeontological specimens; around 400,000 of these are fossil plants, algae and fungi—making this one of the world’s largest palaeobotanical resources. The department currently hosts 24 palaeontologists, of which seven are full-time permanent employees (Vajda & Skovsted, 2021). The remainder are emeriti, students, postdoctoral researchers and additional researchers funded through scholarships, fellowships and other grants.

Life on Earth has experienced some terrifyingly close calls in the past four billion years—cataclysmic events in which the species driven to extinction outnumbered the survivors. The worst crisis occurred 252 million years ago, at the end of the Permian Period. Conditions back then were the bleakest that animals ever faced. Wildfires and drought scoured the land; oceans became intolerably hot and suffocating. Very few creatures could survive in this hellscape. Ultimately more than 70 percent of land species and upward of 80 percent of ocean species went extinct, leading some paleontologists to call this dismal episode the Great Dying.

Upper Triassic deposits of the Leigh Creek Coal Measures in South Australia yield exquisitely preserved plant fossils of a typical mid- to high-latitude Gondwanan flora. Here, we presenta detailed cuticular analysis of the ginkgoalean leaf Sphenobaiera insecta J.M. Anderson et H.M.Anderson nov. emend., which is characterized by an unlobed or once-lobed, elliptic to oblanceolate lamina, abundant round to fusiform resin bodies, and absence of interveinal striae. We also propose an emendation to the genus diagnosis so that Sphenobaiera encompasses also unlobed leaves such as most of those attributed to S. insecta. Such leaves may be distinguished from morphologically similar co-occurring leaf taxa, such as Heidiphyllum elongatum (Pinales) and Rochipteris spp. (Petriellales), based on the characteristic resin bodies and sporadic occurrence of vein dichotomies in the central lamina. Sphenobaiera insecta leaves show common evidence of a particular type of herbivory damage along the leaf margin in the form of small (1–1.5-mm-long) semi-circular patches each lined by a crescent-shaped, darkened reaction rim.

Longitudinally aligned borings attributed to the ichnotaxon Dekosichnus meniscatus in the inner secondary wood of a silicified Middle–Late Jurassic conifer from Argentina contain finely granular frass particles arranged in meniscoid laminae. Synchrotron X-ray computed tomographic reconstruction of the borings reveals new characters of this ichnotaxon, such as opposing orientations of menisci in some adjacent borings, regular spacing of minor and major meniscoid laminae, a scarcity of tunnel branching, and rare occurrences of cylindrical–spherical terminal chambers on excavations. Architectural and distributional features of the galleries suggest excavation by cerambycid beetle larvae, thus representing one of the earliest potential fossil records of this group. The borings are confined to the inner wood of a young tree that experienced a moderately seasonal climate in a volcanically influenced landscape. By detecting subtle heterogeneities in composition, this study demonstrates that high-energy synchrotron X-ray tomography can characterize anatomical features and complex ecological interactions within even densely permineralized (silicified) plant fossils.

The collection of Ediacaran algal flora is stored in the Institute of Geological Sciences of the National Academy of Sciences of Ukraine. These fossils were collected by Andrii Martyshyn in southwestern Ukraine. Within the framework of the priority topic “Integration of large-scale geological data to solve fundamental and applied problems of Ukraine”, which is being carried out at the Institute, the collection was revised. New fossil specimens of giant tubularstructures were also added, which we recently discovered in sediments (argillites, siltstones, sandstones) of the Mohyliv-Podilska series of the Ediacaran (Dniester river valley, southwestern Ukraine). The material is represented by three taphonomic variants of these remains: three-dimensionally preserved rods, phytoleimes and rods with charred shell fragments. We have collected a large number of fossils of soft-bodied organisms, trace fossils, macroalgae and problematic remains. Analysis of our findings suggests that some known and new fossils are likely to be the remains of algae. This interpretation is based on findings that demonstrate the different taphonomic states of preservation. The material of the new species of the previously described genus Harlaniella Sokolov in argillitic strata of the Kanylivka Group was described as traces of movement of worm-like creatures. These fossils look like straight or curved rods with oblique hatching on the lower surface of the rock. There are no trace fossils with similar morphology in the fossil record of the Phanerozoic. Our new material shows that the fossils were organic tubes with a smooth surface and an obliquely transverse sculpture on the inner surface of the wall. We found specimens with examples of the transition from smooth tubes into hatched rods and carbonaceous compression fossils (phytoleims). Similar phytoleims are widespread in this stratum and are described as remnants of probable brown algae Vendotaenia Gnilovskaja. New finds demonstrate a morphology different from the holotype: numerous branching segments and elasticity of deformed tubes. We did not detect holdfasts attaching bodies to the substrate, indicating a probable planktonic habit for these putative algae.

The collection of Ediacaran algal flora is stored in the Institute of Geological Sciences of the National Academy of Sciences of Ukraine. These fossils were collected by Andrii Martyshyn in southwestern Ukraine. Within the framework of the priority topic “Integration of large-scale geological data to solve fundamental and applied problems of Ukraine”, which is being carried out at the Institute, the collection was revised. New fossil specimens of giant tubularstructures were also added, which we recently discovered in sediments (argillites, siltstones, sandstones) of the Mohyliv-Podilska series of the Ediacaran (Dniester river valley, southwestern Ukraine). The material is represented by three taphonomic variants of these remains: three-dimensionally preserved rods, phytoleimes and rods with charred shell fragments. We have collected a large number of fossils of soft-bodied organisms, trace fossils, macroalgae and problematic remains. Analysis of our findings suggests that some known and new fossils are likely to be the remains of algae. This interpretation is based on findings that demonstrate the different taphonomic states of preservation. The material of the new species of the previously described genus Harlaniella Sokolov in argillitic strata of the Kanylivka Group was described as traces of movement of worm-like creatures. These fossils look like straight or curved rods with oblique hatching on the lower surface of the rock. There are no trace fossils with similar morphology in the fossil record of the Phanerozoic. Our new material shows that the fossils were organic tubes with a smooth surface and an obliquely transverse sculpture on the inner surface of the wall. We found specimens with examples of the transition from smooth tubes into hatched rods and carbonaceous compression fossils (phytoleims). Similar phytoleims are widespread in this stratum and are described as remnants of probable brown algae Vendotaenia Gnilovskaja. New finds demonstrate a morphology different from the holotype: numerous branching segments and elasticity of deformed tubes. We did not detect holdfasts attaching bodies to the substrate, indicating a probable planktonic habit for these putative algae.

The Palaeobotany Department of the Swedish Museum of Natural History was established in the late 1800s and has supported research on a diverse range of plants of all ages. The Department hosts, manages, and regularly contributes additional material to, one of the largest fossil plant collections in Europe. The fossil collections have provided the basis for several thousand scientific publications by staff and visiting scientists over the course of its history. In addition to the work of its staff, the department has hosted many hundreds of visiting scientists over the past 140 years. It will continue to provide an invaluable resource for research on the evolution of plant and fungal life on Earth for long into the future. Now under the management of just its sixth administrative Head since 1884, the department is forging new pathways in palaeobotanical research utilizing cutting-edge technologies to provide advances in plant systematics, phylogeny, biogeography, biostratigraphy, palaeoenvironmental analysis, plant-animal interactions, and fossil fungal/microbial studies. The department is aware of multiple risks facing the survival of palaeontological collections in the 21st century and has put in place strategies to maintain access to and relevancy of the collections for future generations.

Although its geology is dominated by pre-Cambrian crystalline rocks, Sweden’s palaeobotanical research output is substantial. Over 150 years of dedicated research has yielded several hundred papers on Sweden’s palaeobotanical and palynological heritage spanning much of the geological column. Studies have targeted all categories of plant and protist remains from Proterozoic microfossils to Quaternary woods, and marine microplankton to animal-plant interactions, and fossil microbes of the deep biosphere. Sweden is particularly renowned for its research on Proterozoic–Cambrian carbonaceous microfossils, Triassic-Jurassic floras, Santonian–Campanian (Late Cretaceous) charcoalified, mummified, adpression and permineralized angiosperms and gymnosperms, and Quaternary high-latitude spore-pollen records. Although a vast body of work has been carried out on these floras, there is great potential for further work on all these assemblages with regard to fossil plant systematics, biostratigraphy, biogeography, plant-animal-fungal interactions, and palaeoclimate/palaeoenvironmental research.

Ukraine hosts extensive strata containing plant and algal fossils. Owing to their location on southern flank of Laurasia, Ukrainian fossiliferous deposits potentially play an important role, not only in local biostratigraphy, but also in understanding climate changes and biogeographic interchange between Europe, Africa, northern Asia, India and the Cimmerian terranes of the Mesozoic Tethys. However, much of the past work in Ukraine has been little recognized in western scientific literature, partly owing to language bariers and difficulties accessing provincial literature. Of particular note are past studies on the following fossil assemblages and regions: the Ediacaran biotas in the Dniester River area of western Ukraine; Silurian and Early Devonian plants and nematophytes from Podolia, western Ukraine; extensive Carboniferous floras associated with the coals of the Donbas region; the little-studied early Permian flora from the western Donets Basin; the rich but relatively little-known Triassic flora on the Donets Basin; Middle Jurassic palynofloras from the Dnieper–Donets Basin; Early Cretaceous megaspores and other sporomorphs from southern Ukraine; late Albian leaf and wood floras from the Kaniv area, central Ukraine; Late Cretaceous floras from western Ukraine and adjacent areas of Poland; Miocene–Pliocene macro- and palynofloras from shallow deposits of the Ukrainian Plain that are helping to build palaeoclimatic and marine incursion models for the Central and the Eastern Paratethys region; late Pliocene permineralized woods from Transcarpathian region in southwestern Ukraine; and extensive Quaternary palynofloras for studies of forest-steppe fluctuation over the past 2 million years.Ukraine has 21 major herbaria (78 in total) with >116 staff and about 4.8 million specimens. As of May, 2022, many of these are in conflict zones directly impacted by the Russian invasion. Of note, the CWU herbarium at Karazin University in Kharkiv has been damaged and the contents require urgent protection. Ukraine also hosts major palaeontological collections that are now threatened: particularly, the National Science and Natural History Museum of the National Academy of Sciences of Ukraine, Kyiv, and the National Museum of Natural History, Lviv. Staff at many of Ukraine’s museums have been busy hiding art and collections in basements, returning loans, loaning material abroad for safekeeping, and reopening the museums as bomb shelters. To support Ukrainian science and culture, funding was provided by the Swedish Royal Academy, Swedish Research Council, Swedish Strategic Fund and Collegium Palynologicum Scandinavicum for four Ukrainian palynologists to attend the 11th EPPC, and for several others to submit poster presentations. We welcome our Ukrainian colleagues to the conference.

Modern marine hydrothermal vents occur in a wide variety of tectonic settings and are characterized by seafloor emission of fluids rich in dissolved chemicals and rapid mineral precipitation. Some hydrothermal systems vent only low-temperature Fe-rich fluids, which precipitate deposits dominated by iron oxyhydroxides, in places together with Mn-oxyhydroxides and amorphous silica. While a proportion of this mineralization is abiogenic, most is the result of the metabolic activities of benthic, Fe-oxidizing bacteria (FeOB), principally belonging to the Zetaproteobacteria. These micro-organisms secrete micrometer-scale stalks, sheaths, and tubes with a variety of morphologies, composed largely of ferrihydrite that act as sacrificial structures, preventing encrustation of the cells that produce them. Cultivated marine FeOB generally require neutral pH and microaerobic conditions to grow. Here, we describe the morphology and mineralogy of filamentous microstructures from a late Paleoproterozoic (1.74 Ga) jasper (Fe-oxide- silica) deposit from the Jerome area of the Verde mining district in central Arizona, USA, that resemble the branching tubes formed by some modern marine FeOB. On the basis of this comparison, we interpret the Jerome area filaments as having formed by FeOB on the deep seafloor, at the interface of weakly oxygenated seawater and low-temperature Fe-rich hydrothermal fluids. We compare the Jerome area filaments with other purported examples of Precambrian FeOB and discuss the implications of their presence for existing redox models of Paleoproterozoic oceans during the “Boring Billion.”

The newly defined Frazer Beach Member of the Moon Island Beach Formation is identified widely across the Sydney Basin in both outcrop and exploration wells. This thin unit was deposited immediately after extinction of the Glossopteris flora (defining the terrestrial end-Permian extinction event). The unit rests conformably on the uppermost Permian coal seam in most places. A distinctive granule-microbreccia bed is locally represented at the base of the member. The unit otherwise consists of dark gray to black siltstone, shale, mudstone and, locally, thin lenses of fine-grained sandstone and tuff. The member represents the topmost unit of the Newcastle Coal Measures and is overlain gradationally by the Dooralong Shale or with a scoured (disconformable) contact by coarse-grained sandstones to conglomerates of the Coal Cliff Sandstone, Munmorah Conglomerate and laterally equivalent units. The member is characterized by a palynological “dead zone” represented by a high proportion of degraded wood fragments, charcoal, amorphous organic matter and fungal spores. Abundant freshwater algal remains and the initial stages of a terrestrial vascular plant recovery flora are represented by low-diversity spore-pollen suites in the upper part of the unit in some areas. These assemblages are referable to the Playfordiaspora crenulata Palynozone interpreted as latest Permian in age on the basis of high precision Chemical Abrasion Isotope Dilution Thermal Ionization Mass Spectrometry (CA-IDTIMS) dating of thin volcanic ash beds within and stratigraphically bracketing the unit. Plant macrofossils recovered from the upper Frazer Beach Member and immediately succeeding strata are dominated by Lepidopteris (Peltaspermaceae) and Voltziopsis (Voltziales) with subsidiary pleuromeian lycopsids, sphenophytes, and ferns. Sparse vertebrate and invertebrate ichnofossils are also represented in the Frazer Beach Member or in beds immediately overlying this unit. The Frazer Beach Member is correlative, in part, with a thin interval of organic-rich mudrocks, commonly known as the “marker mudstone” capping the Permian succession further to the north in the Bowen, Galilee and Cooper basins. The broad geographic distribution of this generally <5-m-thick mudrock unit highlights the development in eastern Gondwana of extensive, short-lived, shallow lacustrine systems with impoverished biotas in alluvial plain settings in the immediate aftermath of the end-Permian biotic crisis.

An extensive survey of literature on the Permian floras of Gondwana reveals over 500 discrete arthropod–herbivory–damage/plant–taxon/stratigraphic–unit associations spanning all regions of the supercontinent from the earliest Asselian to the latest Changhsingian. Margin– and apex–feeding damage is the most common style of herbivory but hole– and surface–feeding, galling, and oviposition damage are locally well represented. Evidence for skeletonization and mucivory is sparse and that for leaf mining is equivocal. Wood and root boring is recognized widely but only where depositional conditions were conducive to the permineralization of plant axes. Wood boring and detritivory may have been especially favoured arthropod feeding strategies in Permian high latitudes where living foliage was scarce during the polar winters. Herbivory damage is most strongly apparent on glossopterid remains; other groups of broad–leafed gymnosperms and sphenopsids host moderate levels of damage. Damage features are under–represented on lycophytes, ferns and spine– and scale–leafed conifers. A survey of insect body fossils from the Gondwanan Permian reveals that most records are from a small number of rich assemblages that are dominated by Blattodea,Hemiptera, Grylloblattida, Mecoptera and Protelytroptera, accompanied by significant representations of Coleoptera, Glosselytrodea, Miomoptera, Neuroptera, Odonata, Protorthoptera, Palaeodictyopteroida, Paoliida, Paraplecoptera, Plecoptera, Psocoptera, Thysanoptera and Trichoptera, which collectively adopted a broad range of feeding styles. Oribatid mites and collembolans appear to have been important components of the wood–boring and detritivorous communities. Although temporal trends in herbivory styles and diversity are difficult to resolve from mostly incidental observations and illustrations of plant damage across Gondwana, the results of this study provide a baseline of qualitative data for future studies that should adopt a quantitative approach to the analysis of herbivory, spanning the shift from icehouse to hothouse conditions through the Permian of the Southern Hemisphere.

New fossil discoveries are reported from the Grammajukku Formation at Luobákte south of Lake Torneträsk in northern Swedish Lapland, including a fauna of Small Shelly Fossils (SSF) from a limestone bed in the uppermost part of the formation and new occurrences of brachiopods and trilobites in siltstones of the lower part of the formation. The moderately diverse SSF fauna is the first of its kind reported from the Swedish Caledonides and includes the first record of the tommotiid Lapworthella schodackensis and the bradoriid spine Mongolitubulus spinosus from Baltica, together with fragmentary specimens of Bradoria sp. and remains of one additional bradoriid arthropod, a protoconodont and a helcionelloid mollusc. In addition, the limestone bed yields abundant specimens of the brachiopods Botsfordia cf. caelata and Eoobolus cf. priscus and an unidentified ellipsocephalid trilobite. Lower down in the Grammajukku Formation, specimens of both brachiopod taxa, orthothecid hyoliths, the trilobite Ellipsocephalus cf. gripi and an unidentified holmiid trilobite were found at several levels in a siltstone, previously regarded as unfossiliferous. These discoveries markedly increase the known diversity of the palaeobiota from the Grammajukku Formation in northern Lapland and provide new insights into the biostratigraphy and palaeoenvironment of the lower Cambrian in Scandinavia and the palaeobiogeography of Cambrian faunas in general.

Gymnosperms represent a broad range of seed-bearing plants that differ from flowering plants in not having seeds enclosed within carpels. Gymnosperms are probably monophyletic, having arisen among ‘progymnosperm’ stock in the Devonian. Key adaptations involving retention of the megagametophyte within a protective coating to form a seed on the parent sporophyte, dissemination of the microgametophyte in durable pollen, production of complex root systems, and extensive development of secondary xylem in the stem, provided gymnosperms with opportunities to exploit upland and drier habitats in the late Paleozoic that had not been occupied by earlier free-sporing plant groups. Gymnosperms diversified in the late Paleozoic and were prime contributors of organic matter to some of the world's largest coal deposits, which accumulated at that time. After suffering widespread extinctions at the close of the Permian, gymnosperms re-radiated in the Triassic and dominated the global floras until the mid-Cretaceous, after which they were progressively supplanted by angiosperms. Gymnosperms are represented in the modern flora by over 1000 species, but their diversity and distribution have contracted greatly since the Mesozoic. They still dominate large tracts of the Northern Hemisphere boreal forests, and are locally dominant in more restricted vegetation types in other parts of the world. Extant gymnosperms provide a range of food, industrial and medical resources to modern society.

Harmful algal and bacterial blooms linked to deforestation, soil loss and global warming are increasingly frequent in lakes and rivers. We demonstrate that climate changes and deforestation can drive recurrent microbial blooms, inhibiting the recovery of freshwater ecosystems for hundreds of millennia. From the stratigraphic successions of the Sydney Basin, Australia, our fossil, sedimentary and geochemical data reveal bloom events following forest ecosystem collapse during the most severe mass extinction in Earth’s history, the end-Permian event (EPE; c. 252.2 Ma). Microbial communities proliferated in lowland fresh and brackish waterbodies, with algal concentrations typical of modern blooms. These initiated before any trace of post-extinction recovery vegetation but recurred episodically for >100 kyrs. During the following 3 Myrs, algae and bacteria thrived within short-lived, poorly-oxygenated, and likely toxic lakes and rivers. Comparisons to global deep-time records indicate that microbial blooms are persistent freshwater ecological stressors during warming driven extinction events.

Neutron tomographic reconstructions, macrophotography, transmitted light microscopy and fluorescence microscopy are employed to assess the quality of organic preservation, determine organ associations,identify insect damage, and document fungal interactions with selected Santonian–lower Campanian plant fossils from the northern Kristianstad Basin, southern Sweden. Fricia nathorstii (Conwentz) comb. nov., is proposed for a composite fossil comprising an anatomically preserved (permineralized) cupressacean conifer cone and its subtending, concealed, leafy axis (preserved asa mould) in the Ryedal Sandstone. Several other impressions of conifer and angiosperm leaf-bearing axes and isolated leaves are described under open nomenclature. Three cuticle types are described from the non-marine plant-bearing beds in the basal part of the succession exposed at Åsen, but these are only assigned to informal morphotypes pending a comprehensive review of the extensive fossil cuticle flora. Two species of ascomycote epiphyllous fungi from Åsen are established: Stomiopeltites ivoeensis sp. nov. (Micropeltidales) and Meliolinites scanicus sp. nov. (Meliolales). The latter provides an important calibration point for dating the divergence of Meliolales, being the first pre-Cenozoic representative of the order. Various additional fungal remains, including thyriothecia, scolecospores, chlamydospores, putative germlings, and hyphae, are described from the cuticular surfaces of conifer and angiosperm leaves from Åsen. Insect herbivory is expressed in the form of both margin-feeding and piercing-and-sucking damage on angiosperm leaves. The Santonian–early Campanian vegetation is inferred to have grown in strongly humid, mid-latitude, coastal plain settings based on the depositional context of the assemblages, leaf morphology, and the pervasive distribution of epiphyllous fungi.

Rapid climate change was a major contributor to the end-Permian extinction (EPE). Although well constrained for the marine realm, relatively few records document the pace, nature, and magnitude of climate change across the EPE in terrestrial environments. We generated proxy records for chemical weathering and land surface temperature from continental margin deposits of the high-latitude southeastern margin of Gondwana. Regional climate simulations provide additional context. Results show that Glossopteris forest-mire ecosystems collapsed during a pulse of intense chemical weathering and peak warmth, which capped ∼1 m.y. of gradual warming and intensification of seasonality. Erosion resulting from loss of vegetation was short lived in the low-relief landscape. Earliest Triassic climate was∼10–14 °C warmer than the late Lopingian and landscapes were no longer persistently wet. Aridification, commonly linked to the EPE, developed gradually, facilitating the persistence of refugia for moisture-loving terrestrial groups.

The abundance, diversity and extinction of non-marine algae are controlled by changes in the physical and chemical environment and community structure of continental ecosystems. We review a range of non-marine algae commonly found within the Permian and Triassic strata of Gondwana and highlight and discuss the non-marine algal abundance anomalies recorded in the immediate aftermath of the end-Permian extinction interval (EPE; 252 Ma). We further review and contrast the marine and continental algal records of the global biotic crises within the Permian–Triassic interval. Specifically, we provide a case study of 17 species (in 13 genera) from the succession spanning the EPE in the Sydney Basin, eastern Australia. The affinities and ecological implications of these fossil-genera are summarised, and their global Permian–Triassic palaeogeographic and stratigraphic distributions are collated. Most of these fossil taxa have close extant algal relatives that are most common in freshwater, brackish or terrestrial conditions, and all have recognizable affinities to groups known to produce chemically stable biopolymers that favour their preservation over long geological intervals. However, these compounds (e.g., sporopollenin and algaenan) are not universal, so the fossil record is sparse for most algal groups, which hinders our understanding of their evolutionary histories. Owing partly to the high preservational potential of Zygnematophyceae, a clade of freshwater charophyte algae and sister group to land plants, this group has a particularly diverse and abundant Permian–Triassic fossil record in Gondwana. Finally, we review and contrast the marine and continental algal records of the global biotic crises within the Permian–Triassic interval. In continental settings, Permian algal assemblages were broadly uniform across most of southern and eastern Gondwana until the EPE; here, we propose the Peltacystia Microalgal Province to collectively describe these distinct and prolonged freshwater algal assemblages. In the immediate aftermath of the EPE, relative increases in non-marine algae have been consistently recorded, but the distributions of prominent taxa of Permian freshwater algae became severely contracted across Gondwana by the Early Triassic. We highlight the paucity of quantitative, high-resolution fossil evidence for this key group of primary producers during all biotic crises of the Permian and Triassic periods. This review provides a solid platform for further work interpreting abundance and diversity changes in non-marine algae across this pivotal interval in evolutionary history.

Upper Permian to Lower Triassic coastal plain successions of the Sydney Basin in eastern Australia have been investigated in outcrop and continuous drillcores. The purpose of the investigation is to provide an assessment of palaeoenvironmental change at high southern palaeolatitudes in a continental margin context for the late Permian (Lopingian), across the end‐Permian Extinction interval, and into the Early Triassic. These basins were affected by explosive volcanic eruptions during the late Permian and, to a much lesser extent, during the Early Triassic, allowing high‐resolution age determination on the numerous tuff horizons. Palaeobotanical and radiogenic isotope data indicate that the end‐Permian Extinction occurs at the top of the uppermost coal bed, and the Permo‐Triassic boundary either within an immediately overlying mudrock succession or within a succeeding channel sandstone body, depending on locality due to lateral variation. Late Permian depositional environments were initially (during the Wuchiapingian) shallow marine and deltaic, but coastal plain fluvial environments with extensive coal‐forming mires became progressively established during the early late Permian, reflected in numerous preserved coal seams. The fluvial style of coastal plain channel deposits varies geographically. However, apart from the loss of peat‐forming mires, no significant long‐term change in depositional style (grain size, sediment‐body architecture, or sediment dispersal direction) was noted across the end‐Permian Extinction (pinpointed by turnover of the palaeoflora). There is no evidence for immediate aridification across the boundary despite a loss of coal from these successions. Rather, the end‐Permian Extinction marks the base of a long‐term, progressive trend towards better‐drained alluvial conditions into the Early Triassic. Indeed, the floral turnover was immediately followed by a flooding event in basinal depocentres, following which fluvial systems similar to those active prior to the end‐Permian Extinction were re‐established. The age of the floral extinction is constrained to 252.54 ± 0.08 to 252.10 ± 0.06 Ma by a suite of new Chemical Abrasion Isotope Dilution Thermal Ionization Mass Spectrometry U‐Pb ages on zircon grains. Another new age indicates that the return to fluvial sedimentation similar to that before the end‐Permian Extinction occurred in the basal Triassic (prior to 251.51 ± 0.14 Ma). The character of the surface separating coal‐bearing pre‐end‐Permian Extinction from coal‐barren post‐end‐Permian Extinction strata varies across the basins. In basin‐central locations, the contact varies from disconformable, where a fluvial channel body has cut down to the level of the top coal, to conformable where the top coal is overlain by mudrocks and interbedded sandstone–siltstone facies. In basin‐marginal locations, however, the contact is a pronounced erosional disconformity with coarse‐grained alluvial facies overlying older Permian rocks. There is no evidence that the contact is everywhere a disconformity or unconformity.

The first megaspores recovered from Ukrainian Lower Cretaceous strata are described and illustrated by reflected light and scanning electron micrography. Four lycopsid megaspore taxa are identified in core samples from north of Kherson (Khersons'ka Oblast), in the Black Sea Basin, southern Ukraine. Miospore assemblages recovered from the same samples reveal a slightly higher diversity of lycopsid microspores and, in conjunction with previous foraminiferal biostratigraphy, indicate an Aptian-Albian age for the strata. The megaspore suite shares genera with mid-Mesozoic assemblages from widely distributed parts of the world, but most of the Ukrainian specimens have subtle morphological differences from congeneric forms established in other regions. The megaspores accumulated in fluvial floodplain facies and highlight the potential of this region for investigating other Cretaceous mesofossils including early flowers.

We review recent advances on glossopterid reproductive biology and their implications for seed plant phylogeny and the ecology of this widespread Permian Gondwanan group. Microsporangiate organs are interpreted to have been arranged in loose compound cones—an organization that evokes comparisons with Ginkgoales, Cordaitales and early conifers. The pollen was typically taeniate, bisaccate, and primarily adapted to wind dispersal. The diverse ovuliferous organs generally incorporated some form of marginal flange or wing. In most cases, the wing was probably protective, wrapping around the ovules during early development. However, we postulate that some conspicuous flanges were potentially analogous to angiosperm petals, functioning as corolla-like guides to attract insect pollinators. The arrangement of seed-bearing polysperms adnate to the subtending leaf to form a fertiliger in glossopterids represented another means of protecting the ovules. In some cases, highlighting the polysperm against the attached leaf might have increased the showiness of the ovule-bearing part for pollinators. In other cases, detachment of the fertiliger may have aided anemochory by retarding seed fall through rotation analogous to dispersal in extant Tilia. The microgametophyte in glossopterids is characterized by a short, weakly branched, haustorial tube, and the release of motile sperm cells. At least some seeds of glossopterids express polyembryony. Mature seeds possessed various micropylar modifications for the entrapment of pollen, and winged or bulbous expansions of the outer integument to aid anemochory or possibly hydrochory. Vegetative regeneration as a response to damage occurred via epicormic buds and possibly by the development of lignotubers.

Nineteen ichnotaxa, together with algal and invertebrate remains, and various pseudo-traces and sedimentary structures are described from the Torneträsk Formation exposed near Lake Torneträsk, Lapland, Sweden, representing a marked increase in the diversity of biotic traces recorded from this unit. The “lower siltstone” interval of the Torneträsk Formation contains mostly simple pascichnia, fodinichnia and domichnia burrows and trails of low-energy shoreface to intertidal settings. The assemblage has very few forms characteristic of high-energy, soft-sediment, foreshore or upper shoreface environments (representative of the Skolithos ichnofacies).

Uranium-lead (U-Pb) LA-ICPMS analysis of zircon from a thin claystone layer within the “lower siltstone” interval yielded a maximum depositional age of 584 ± 13 Ma, mid-Ediacaran. Most of the zircon is represented by rounded detrital grains that yield dates between 3.3 and 1.0 Ga. Although the age of the basal sandstone-dominated interval of the Torneträsk Formation remains elusive owing to the absence of fossils, the ichnofossil suite from the overlying “lower siltstone” interval lacks deep arthropod trackways, such as Rusophycus and Cruziana, and is suggestive of a very early (Terreneuvian, possibly Fortunian) Cambrian age. The ichnofauna is otherwise similar to early Cambrian trace fossil assemblages from other parts of Baltica, regions further south in modern Europe, and from Greenland.

When people think of fossils, they usually picture slabs of rock bristling with bones, or the shells of ammonites or trilobites. Most do not even consider that delicate organisms, such as fungi or bacteria, can even fossilize – they seem too fragile to be preserved as they lack a hard skeleton. In many cases this is true. Microscopic organisms that lack hard parts have fewer chances of being fossilised but, despite the odds, delicate fungi have a fossil record that is more extensive than generally thought.

A distinctive burrow form, Reniformichnus australis n. isp., is described from strata immediately overlying and transecting the end-Permian extinction (EPE) horizon in the Sydney Basin, eastern Australia. Although a unique excavator cannot be identified, these burrows were probably produced by small cynodonts based on comparisons with burrows elsewhere that contain body fossils of the tracemakers. The primary host strata are devoid of plant remains apart from wood and charcoal fragments, sparse fungal spores, and rare invertebrate traces indicative of a very simplified terrestrial ecosystem characterizing a ‘dead zone’ in the aftermath of the EPE. The high-paleolatitude (~ 65–75deg S) setting of the Sydney Basin, together with its higher paleoprecipitation levels and less favorable preservational potential, is reflected by a lower diversity of vertebrate fossil burrows and body fossils compared with coeval continental interior deposits of the mid-paleolatitude Karoo Basin, South Africa. Nevertheless, these burrows reveal the survivorship of small tetrapods in considerable numbers in the Sydney Basin immediately following the EPE. A fossorial lifestyle appears to have provided a selective advantage for tetrapods enduring the harsh environmental conditions that arose during the EPE. Moreover, high-paleolatitude and maritime settings may have provided important refugia for terrestrial vertebrates at a time of lethal temperatures at low-latitudes and aridification of continental interiors.

Current large-scale deforestation poses a threat to ecosystems globally, and imposes substantial and prolonged changes on the hydrological and carbon cycles. The tropical forests of the Amazon and Indonesia are currently undergoing deforestation with catastrophic ecological consequences but widespread deforestation events have occurred several times in Earth’s history and these provide lessons for the future. The end-Permian mass-extinction event (EPE; ∼252Ma) provides a global, deep-time analogue for modern deforestation and diversity loss. We undertook centimeter-resolution palynological, sedimentological, carbon stable-isotope and paleobotanical investigations of strata spanning the end-Permian event at the Frazer Beach and Snapper Point localities, in the Sydney Basin, Australia. We show that the typical Permian temperate, coal-forming, forest communities disappeared abruptly, followed by the accumulation of a 1-m-thick mudstone poor in organic matter that, in effect, represents a ‘dead zone’ hosting degraded wood fragments, charcoal and fungal spores. This signals a catastrophic scenario of vegetation die-off and extinction in southern high-latitude terrestrial settings. Lake systems, expressed by laterally extensive but generally less than a few-metres-thick laminated siltstones, generally lacking bioturbation, hosting assemblages of algal cysts and freshwater acritarchs, developed soon after the vegetation die-off. The first traces of vascular plant recovery occur ∼1.6m above the extinction horizon. Based on analogies with modern deforestation, we propose that the global fungal and acritarch events of the Permo-Triassic transition resulted directly from inundation of basinal areas following water-table rise as a response to the abrupt disappearance of complex vegetation from the landscape. The δ13Corg values reveal a significant excursion toward low isotopic values, down to −31ppt (a shift of ∼4deg), across the end-Permian event. The magnitude of the shift at that time records a combination of changes in the global carbon cycle that were enhanced by the local increase in microbial activity, possibly also involving cyanobacterial proliferation. We envisage that elevated levels of organic and mineral nutrients delivered from inundated dead forests, enhanced weathering and erosion of extra-basinal areas, together with local contributions of volcanic ash, led to eutrophication and increased salinity of basinal lacustrine–lagoonal environments. We propose that the change in acritarch communities recorded globally in nearshore marine settings across the end-Permian event is to a great extent a consequence of the influx of freshwater algae and nutrients from the continents. Although this event coincides with the Siberian trap volcanic activity, we note that felsic–intermediate volcanism was extensively developed along the convergent Panthalassan margin of Pangea at that time and might also have contributed to environmental perturbations at the close of the Permian.

Terminologi, nomenklatur och namngivning har under perioder diskuterats intensivt bland svenska geovetare och behovet av en nationell samordning kring geologiska namn i Sverige har varit stort. Darfor ar det ett stort steg fram at att Svenska geologiska namnkommitten nu antligen har bildats.

An assemblage of permineralized conifer and angiosperm woods collected from Paleogene marine strataon Seymour Island during the Swedish Antarctic expedition of 1901–1903 includes many specimens with internal damage caused by an array of xylophagous organisms. Short, broad, clavate borings referable to Gastrochaenolites clavatus are attributed to pholadid bivalves. Elongate borings with carbonate linings referable to Apectoichnus longissimus were produced by teredinid bivalves. Slender, cylindrical tunnels cross-cutting growth rings and backfilled in meniscoid fashion by frass composed of angular tracheid fragments were probably produced by a terrestrial beetle borer. They are most similar to tunnels generated by modern cerambycid and ptinid coleopterans. Less regular, spindle-shaped cavities and degraded zones flanking growth rings are similar to fungi-generated modern white pocket rot. Larger chambers in the heartwood referable to the ichnotaxon Asthenopodichnium lignorum were produced by an alternative mode of fungal degradation. The biological interactions evident in the fossil woods illustrate additional terrestrial trophic levels enhancing the known complexity of ecosystems on and around the Antarctic Peninsula shortly before the initial pulse of mid-Cenozoic glaciation in Antarctica that caused extirpation of the majority of plants and animals in that region.

Ten embedded fossil logs sampled in situ from the middle Eocene volcano-sedimentary rocks close to Suffield Point in the Fildes Peninsula, King George Island,Antarctica, are assigned to Protopodocarpoxylon araucarioides Schultze-Motel ex Vogellehner, Phyllocladoxylon antarcticum Gothan, Agathoxylon antarcticum (Poole & Cantrill) Pujana et al., A. pseudoparenchymatosum (Gothan) Pujana et al. andan unidentified angiosperm wood. Differences in the taxonomic representation and growth-ring characters of the Eocene woods on King George Island and coeval assemblages from Seymour Island, on the western and eastern sides of the Antarctic Peninsula respectively, are interpreted to result from environmental and climatic gradients across the Peninsula Orogen during the early Palaeogene. In particular, a precipitation gradient inferred across the Peninsula at that time might have been induced by a rain-shadow effect.

The collapse of late Permian (Lopingian) Gondwanan floras, characterized by the extinction of glossopterid gymnosperms, heralded the end of one of the most enduring and extensive biomes in Earth’s history. The Sydney Basin, Australia, hosts a near continuous, age-constrained succession of high southern paleolatitude (∼65–75°S) terrestrial strata spanning the end-Permian extinction (EPE) interval. Sedimentological, stable carbon isotopic, palynological, and macrofloral data were collected from two cored coal-exploration wells and correlated. Six palynostratigraphic zones, supported by ordination analyses, were identified within the uppermost Permian to Lower Triassic succession, corresponding to discrete vegetation stages before, during, and after the EPE interval. Collapse of the glossopterid biome marked the onset of the terrestrial EPE and may have significantly predated the marine mass extinctions and conodont-defined Permian–Triassic Boundary. Apart from extinction of the dominant Permian plant taxa, the EPE was characterized by a reduction in primary productivity, and the immediate aftermath was marked by high abundances of opportunistic fungi, algae, and ferns. This transition is coeval with the onset of a gradual global decrease in δ13Corg and the primary extrusive phase of Siberian Traps Large Igneous Province magmatism. The dominant gymnosperm groups of the Gondwanan Mesozoic (peltasperms, conifers, and corystosperms) all appeared soon after the collapse but remained rare throughout the immediate post-EPE succession. Faltering recovery was due to a succession of rapid and severe climatic stressors until at least the late Early Triassic. Immediately prior to the Smithian–Spathian boundary (ca. 249 Ma), indices of increased weathering, thick redbeds, and abundant pleuromeian lycophytes likely signify marked climate change and intensification of the Gondwanan monsoon climate system. This is the first record of the Smithian–Spathian floral overturn event in high southern latitudes.

The assembly of the supercontinent Pangea resulted in a paleoequatorial region known as Euramerica, a northern mid-to-high latitude region called Angara, and a southern high paleolatitudinal region named Gondwana. Forested peat swamps, extending over hundreds of thousands of square kilometers, grew across this supercontinent during the Mississippian, Pennsylvanian, and Permian in response to changes in global climate. The plants that accumulated as peat do not belong to the plant groups prominent across today’s landscapes. Rather, the plant groups of the Late Paleozoic that are responsible for most of the biomass in these swamps belong to the fern and fern allies: club mosses, horsetails, and true ferns.  Gymnosperms of various systematic affinity play a subdominant role in these swamps, and these plants were more common outside of wetland settings. It is not until the Permian when these seed-bearing plants become more dominant. Due to tectonic activity associated with assembling the supercontinent, including earthquakes and volcanic ashfall, a number of these forests were buried in their growth positions. These instants in time, often referred to as T0 assemblages, provide insight into the paleoecological relationships that operated therein. Details of T0 localities through the Late Paleozoic demonstrate that the plants, and plant communities, of the coal forests are non-analogs to our modern world. Analysis of changing vegetational patterns from the Mississippian into the Permian documents the response of landscapes to overall changes in Earth Systems under icehouse to hothouse conditions.

A walk in the Carboniferous-and-Permian woods of the Late Paleozoic, a time known as the Late Paleozoic Ice Age (LPIA), would not be a walk in the woods comparable to today’s Holocene forests. The vegetation that colonized and inhabited the landscapes during glacial∗ and interglacial episodes are non-analogs with the world we witness around us. Unlike continents covered in seed-bearing forests, the systematic affinities of the largest trees, and many shrubs, groundcover, vines (lianas), and epiphytes lie with the spore-producing ferns and fern allies. These ferns and fern allies, including the club mosses (lycopsids) and horsetails (sphenopsids), dominated both organic-rich (peat) and mineral-substrate soils from the Mississippian until the latest Pennsylvanian. Even the gymnosperm groups, which commonly grew in mineral-rich soils, are unfamiliar and subdominant components of these landscapes.The extinct pteridosperms and cordaitaleans, and the extant ginkgoalean, cycad, and conifer clades, ultimately diversify and occupy better drained soil conditions that developed in response to global climate change from icehouse∗ to hothouse conditions. Beginning in the latest Pennsylvanian and increasing their dominance in the Permian, seed-producing clades expanded their biogeographic ranges, displacing the former fern and fern-ally giants. This change in diversity occurs during a unique interval in the history of Earth’s biosphere. The LPIA is the only time, other than the Neogene, since the evolution and colonization of terrestrial plants, when the planet experienced prolonged icehouse and greenhouse conditions. Extensive tropical peat swamps, similar in physical properties to current analogs in Southeast Asia, accumulated in coastal plain lowlands. These forests extended over thousands of square kilometers during periods when global sea level was low in response to the development of extensive Gondwanan glaciation at the southern pole. When these ice sheets melted and sea-level rose, the tropical coastal lowlands were inundated with marine waters and covered by nearshore to offshore ocean sediments. The waxing and waning of glacial ice was influenced by short- and long-term changes in global climate that were, in turn, controlled by extraterrestrial orbital factors. As the LPIA came to a close, a new forested landscape appeared, more familiar but, still, distant.

Premise of research. Permineralized peats are prized for hosting three-dimensionally preserved plant remains that provide insights into fossil plant anatomy and the composition of coal-forming ecosystems. A new record of siliceous permineralized peat is documented from a Lopingian-aged (upper Permian) strata from the southern Sydney Basin. It represents the fifth Permian permineralized peat identified from eastern Australia.

Methodology. The single permineralized peat block was cut into smaller blocks, and both cellulose acetate peels and standard thin sections were prepared for study using transmitted light microscopy. Quantitative analysis of the peat was carried out using point counts perpendicular to bedding. One block examined using synchrotron X-ray computed tomography (CT) revealed the three-dimensional anatomy of abundant fossil seeds.

Pivotal results. The peat contains a plant assemblage dominated by glossopterid leaves, seeds, and axes; although degraded, probable pteridophyte remains represent a significant subsidiary component of the assemblage. A new leaf form (Glossopteris thirroulensis McLoughlin et Mays sp. nov.) and a new type of seed (Illawarraspermum ovatum McLoughlin et Mays gen. et sp. nov.) are described. Leaf-, wood/seed-, and fine detritus-rich organic microfacies with gradational boundaries are evident within the peat.

Conclusions. Regular growth rings in the small permineralized axes, together with the occurrence of autumnal mats of glossopterid leaves, signify a strongly seasonal climate. The presence of abundant charcoal in the peat indicates that fire was a significant influence on the high-paleolatitude mire ecosystem. Differentiation of organic microfacies within the peat profile indicates subtle variation in the contribution of plant components to the peat through time. The absence of mineral grains in thin section and CT, together with the presence of authigenic sulfides, indicates accumulation of organic matter in a stagnant mire away from the influence of clastic input.

Past studies of the end-Permian extinction (EPE), the largest biotic crisis of the Phanerozoic, have not resolved the timing of events in southern high-latitudes. Here we use palynology coupled with high-precision CA-ID-TIMS dating of euhedral zircons from continental sequences of the Sydney Basin, Australia, to show that the collapse of the austral Permian Glossopteris flora occurred prior to 252.3 Ma (~370 kyrs before the main marine extinction). Weathering proxies indicate that floristic changes occurred during a brief climate perturbation in a regional alluvial landscape that otherwise experienced insubstantial change in fluvial style, insignificant reorganization of the depositional surface, and no abrupt aridification. Palaeoclimate modelling suggests a moderate shift to warmer summer temperatures and amplified seasonality in temperature across the EPE, and warmer and wetter conditions for all seasons into the Early Triassic. The terrestrial EPE and a succeeding peak in Ni concentration in the Sydney Basin correlate, respectively, to the onset of the primary extrusive and intrusive phases of the Siberian Traps Large Igneous Province.

In the aftermath of Earth’s greatest biotic crisis 251.9 million years ago - the end-Permian mass extinction - a group of plants arose that would come to dominate the flora of the Southern Hemisphere. Recovery of the vegetation from the end-Permian crisis was slow; but steadily, one group of seed plants, typified by the leaf fossil Dicroidium, began to diversify and fill the dominant canopy-plant niches left vacant by the demise of the Permian glossopterid forests.

Stereoscopic microwear and 3D surface texture analyses on the cheek teeth of ten Upper Triassic to Lower Cretaceous tritylodontid (Mammaliamorpha) taxa of small/medium to large body size suggest that all were generalist feeders and none was a dietary specialist adapted to herbivory. There was no correspondence between body size and food choice. Stereomicroscopic microwear analysis revealed predominantly fine wear features with numerous small pits and less abundant fine scratches as principal components. Almost all analyzed facets bear some coarser microwear features, such as coarse scratches, large pits, puncture pits and gouges pointing to episodic feeding on harder food items or exogenous effects (contamination of food with soil grit and/or dust), or both. 3D surface texture analysis indicates predominantly fine features with large void volume, low peak densities, and various stages of roundness of the peaks. We interpret these features to indicate consumption of food items with low to moderate intrinsic abrasiveness and can exclude regular rooting, digging or caching behavior. Possible food items include plant vegetative parts, plant reproductive structures (seeds and seed-bearing organs), and invertebrates (i.e., insects). Although the tritylodontid tooth morphology and auto-occlusion suggest plants as the primary food resource, our results imply a wider dietary range including animal matter.

Early Carboniferous (Mississippian) permineralized woods from Australia with multiseriate rays have been customarily assigned or compared to the European genus Pitus, despite the absence of information on their primary vascular anatomy. In the context of continuing work on the diversity of Late Devonian andMississippian floras of Gondwana, we studied new silicified woods with secondary xylem similar to that of Pitus (multiseriate rays, araucarioid radial pitting) from two sedimentary basins of Queensland, Australia. In the Drummond Basin, three morphotypes of wood of Viséan age can be distinguished based on ray size in tangential section. Although this variation is similar to that observed between the various European species of Pitus, information on the primary vascular anatomy of the trees provided by three incomplete specimens excludes an affinity with Pitus for at least two taxa. In the Yarrol Basin, two well-preserved late Viséan trunks also have characters similar to Pitus but can be distinguished from that genus and other previously described Mississippian trees, in particular by the anatomy of their primary vascular system and departing leaf traces. They are assigned to a new genus, Ninsaria. Collectively, the new specimens from Queensland show that wood traditionally referred to “Pitus” from Australia actually belongs to several other types of trees that are not known from Europe or North America, indicating probable floristic provincialism between the Northern and Southern hemisphere floras at this time. These new fossils corroborate the existence of a global Mississippian diversification of (pro)gymnosperm trees already noted in Laurussia. They also indicate that the Mississippian floras of Australia were more diverse and complex than traditionally inferred.

In this study, we investigate the molecular structural characteristics of organic remains in various cellular organelles from a 180 Ma Jurassic royal fern belonging to the Osmundaceae family of ferns, and compare their carbon isotopic compositions to a now-living species of royal fern (Osmunda regalis). We discovered molecular structural variations indicated by Raman and infrared spectral parameters obtained from various fossilized cellular organelles. The organic remains preserved in the chromosomes and cell nuclei show marked structural heterogeneities compared to the cell walls during different stages of the cell cycle. The fossil and extant fern have similar δ13C values obtained from bulk samples, supporting evolutionary stasis in this plant lineage and an unchanged metabolic pathway of carbon assimilation since the Jurassic. The organic remains in the cellular organelles of the fossil seem to be less heterogeneous than those in the extant fern, likely due to the preferential preservation of certain cellular compounds during fossilization. Taphonomic processes appear to have diminished the subcellular isotopic heterogeneities. Our research sheds light on the functioning of ancient plant cellular organelles during mitosis, provides insights to the taphonomic processes operating at molecular and isotopic levels, and shows the practicability of in situ techniques in studying the evolution and behaviors of ancient cells.