Computed tomography is an increasingly popular technique for the non-destructivestudy of fossils. Whilst the science of X-ray computed tomography (CT) has greatlymatured since its first fossil applications in the early 1980s, the applications and limitationsof neutron tomography (NT) remain relatively unexplored in palaeontology. Thesehighest resolution neutron tomographic scans in palaeontology to date were conductedon a specimen of Austrosequoia novae-zeelandiae (Ettingshausen) Mays and Cantrillrecovered from mid-Cretaceous (Cenomanian; ~100–94 Ma) strata of the ChathamIslands, eastern Zealandia. Previously, the species has been identified with in situ fossilresin (amber); the new neutron tomographic analyses demonstrated an anomalouslyhigh neutron attenuation signal for fossil resin. The resulting data provided astrong contrast between, and distinct three-dimensional representations of the: 1) fossilresin; 2) coalified plant matter; and 3) sedimentary matrix. These data facilitated ananatomical model of endogenous resin bodies within the cone axis and bract-scalecomplexes. The types and distributions of resin bodies support a close alliance withSequoia Endlicher (Cupressaceae), a group of conifers whose extant members areonly found in the Northern Hemisphere. This study demonstrates the feasibility of NTas a means to differentiate chemically distinct organic compounds within fossils.Herein, we make specific recommendations regarding: 1) the suitability of fossil preservationstyles for NT; 2) the conservation of organic specimens with hydrogenous consolidantsand adhesives; and 3) the application of emerging methods (e.g., neutronphase contrast) for further improvements when imaging fine-detailed anatomical structures.These findings demonstrate that we are still far from reaching the conceptuallimits of NT as a means of virtually extracting fossils, or imaging their internal anatomyeven when embedded within a rock matrix.

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.

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 transition from the middle to late Permian (Guadalupian–Lopingian) is claimed to record one or more extinction events that rival the ‘Big Five’ in terms of depletion of biological diversity and reorganization of ecosystem structure. Yet many questions remain as to whether the events recorded in separate regions were synchronous, causally related, or were of a magnitude rivaling other major crises in Earth’s history. In this paper, we survey some major unresolved issues related to the Guadalupian–Lopingian transition and offer a multidisciplinary approach to advance understanding of this under-appreciated biotic crisis by utilizing records in Southern Hemisphere high-palaeolatitude settings. We focus on the Bowen-Gunnedah-Sydney Basin System (BGSBS) as a prime site for analyses of biotic and physical environmental change at high palaeolatitudes in the middle and terminal Capitanian. Preliminary data suggest the likely position of the mid-Capitanian event is recorded in regressive deposits at the base of the Tomago Coal Measures (northern Sydney Basin) and around the contact between the Broughton Formation and the disconformably overlying Pheasants Nest Formation (southern Sydney Basin). Initial data suggest that the end-Capitanian event roughly correlates to the transgressive “Kulnura Marine Tongue” in the middle of the Tomago Coal Measures (northern Sydney Basin) and strata bearing dispersed, ice-rafted gravel in the Erins Vale Formation (southern Sydney Basin). Preliminary observations suggest that few plant genera or species disappeared in the transition from the Guadalupian to Lopingian, and the latter interval saw an increase in floristic diversity.

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.

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.

Previously unrecognized anatomical features of the cone scales of the enigmatic Early Cretaceous conifer Krassilovia mongolica include the presence of transversely oriented paracytic stomata, which is unusual for all other extinct and extant conifers. Identical stomata arepresent on co-occurring broad, linear, multiveined leaves assigned to Podozamites harrisii, providing evidence that K. mongolica and P. harrisii are the seed cones and leaves of the same extinct plant. Phylogenetic analyses of the relationships of the reconstructed Krassilovia plant place it in an informal clade that we name the Krassilovia Clade, which also includes Swedenborgia cryptomerioides–Podozamites schenkii, and Cycadocarpidium erdmanni–Podozamites schenkii. All three of these plants have linear leaves that are relatively broad compared to most living conifers, and that are also multiveined with transversely oriented paracytic stomata. We propose that these may be general features of the Krassilovia Clade. Paracytic stomata, and other features of this new group, recall features of extant and fossil Gnetales, raising questions about the phylogenetic homogeneity of the conifer clade similar to those raised by phylogenetic analyses of molecular data.

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.

Computed tomography is an increasingly popular technique for the non-destructive

study of fossils. Whilst the science of X-ray computed tomography (CT) has greatly

matured since its first fossil applications in the early 1980s, the applications and limitations

of neutron tomography (NT) remain relatively unexplored in palaeontology. These

highest resolution neutron tomographic scans in palaeontology to date were conducted

on a specimen of Austrosequoia novae-zeelandiae (Ettingshausen) Mays and Cantrill

recovered from mid-Cretaceous (Cenomanian; ~100–94 Ma) strata of the Chatham

Islands, eastern Zealandia. Previously, the species has been identified with in situ fossil

resin (amber); the new neutron tomographic analyses demonstrated an anomalously

high neutron attenuation signal for fossil resin. The resulting data provided a

strong contrast between, and distinct three-dimensional representations of the: 1) fossil

resin; 2) coalified plant matter; and 3) sedimentary matrix. These data facilitated an

anatomical model of endogenous resin bodies within the cone axis and bract-scale

complexes. The types and distributions of resin bodies support a close alliance with

Sequoia Endlicher (Cupressaceae), a group of conifers whose extant members are

only found in the Northern Hemisphere. This study demonstrates the feasibility of NT

as a means to differentiate chemically distinct organic compounds within fossils.

Herein, we make specific recommendations regarding: 1) the suitability of fossil preservation

styles for NT; 2) the conservation of organic specimens with hydrogenous consolidants

and adhesives; and 3) the application of emerging methods (e.g., neutron

phase contrast) for further improvements when imaging fine-detailed anatomical structures.

These findings demonstrate that we are still far from reaching the conceptual

limits of NT as a means of virtually extracting fossils, or imaging their internal anatomy

even when embedded within a rock matrix.

Isolated conifer female reproductive structures are common fossil elements from Cenomanian (ca 99–94 Ma) charcoal- and resin-rich beds of theTupuangi Formation, Chatham Islands, southwest Pacific Ocean. Recent findings have proposed that these are the oldest fossil evidence of serotiny,a highly successful fire-adaptive reproductive strategy common among tree species living in fire-prone areas today. Herein, we systematicallydescribe the external morphological and anatomical features of these fossils, by employing a combination of manual extraction and neutron tomographytechniques. We propose a new species of conifer, Protodammara reimatamoriori, and a re-examination of fossil material of the Protodammaratype species facilitated an emendation of the genus. Protodammara shares numerous features with extant Cunninghamia, Taiwania, Athrotaxis, andseveral extinct taxa of Cupressaceae, and is interpreted as an extinct lineage of the early-divergent ‘taxodioid Cupressaceae’ stem group.

Several highly effective fire-adaptive traits first evolved among modern plants duringthe mid-Cretaceous, in response to the widespread wildfires promoted by anomalously highatmospheric oxygen (O2) and extreme temperatures. Serotiny, or long-term canopy seedstorage, is a fire-adaptive strategy common among plants living in fire-prone areas today,but evidence of this strategy has been lacking from the fossil record. Deposits of abundantfossil charcoal from sedimentary successions of the Chatham Islands, New Zealand, recordwildfires in the south polar regions (75°–80°S) during the mid-Cretaceous (ca. 99–90 Ma).Newly discovered fossil conifer reproductive structures were consistently associated withthese charcoal-rich deposits. The morphology and internal anatomy as revealed by neutrontomography exhibit a range of serotiny-associated characters. Numerous related fossils fromsimilar, contemporaneous deposits of the Northern Hemisphere suggest that serotiny was akey adaptive strategy during the high-fire world of the Cretaceous.

Fossil resin (amber) has been recently reported as common, but small, sedimentary components throughout thelower Upper Cretaceous (Cenomanian; 99–94 Ma) strata of the Tupuangi Formation, Chatham Islands, easternZealandia. From these deposits, resin has also been identified and obtained from well-preserved, coalified specimensof the conifer fossil Protodammara reimatamorioriMays and Cantrill, 2018. Here, we employed attenuatedtotal reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) to both dispersed and in situ amber specimens.These resulted in very similar chemical signatures, indicating that these fossils are likely from the same orclosely-related botanical sources. The FTIR data are typical of a conifer source within the ‘cupressaceous resins’category of Tappert et al. (2011). Carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) facilitatedthe probable identification of these ambers as ‘Class Ib' (sensu Anderson et al. 1992). Based on these spectraldata sets, the likely botanical sources of the amber were either Araucariaceae or Cupressaceae; both of these coniferfamilies were common and widespread in the Southern Hemisphere during the Cretaceous. However, themorphology and anatomy of P. reimatamoriori support an affinity to the latter family, thus indicating that the Cretaceousamber of the Chatham Islands was generally produced by members of the Cupressaceae. Comparing theFTIR data to the published spectra of modern resins, we also identify a band ratio which may aid in distinguishingbetween the FTIR spectra of Araucariaceae and Cupressaceae, and outline the limitations to this approach. A highconcentration of ester bonds in Chatham amber specimens, which exceeds typical Cupressaceae resins, is probablycaused by taphonomic alteration via thermal maturation. The source of thermal alteration was likely preburialwildfires,conditions forwhich P. reimatamoriori was adapted to as part of its life cycle. A comparison of ambersof the Chatham Islands with modern resins and amber from various localities in Australasia reveals that,taphonomic influences aside, Chatham amber has a unique signature, suggesting that members of the basalCupressaceae (e.g., Protodammara) were not major contributors to other documented Australasian amber deposits.The closest analogy to Chatham amber deposits appears to be the Upper Cretaceous Raritan Formation,USA, which is characterised by its rich amber, charcoal and Cupressaceae fossil assemblages. This study furthersupports the hypotheses that the early Late Cretaceous south polar forests were dominated by Cupressaceae,and regularly disturbed by wildfires.

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.

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.

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.

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 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.

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.

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.

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.

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.

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.

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.

The Northern Hemisphere dominates our knowledge of Mesozoic and Cenozoic fossilized tree resin (amber) with few fndings from the high southern paleolatitudes of Southern Pangea and Southern Gondwana. Here we report new Pangean and Gondwana amber occurrences dating from ~230 to 40 Ma from Australia (Late Triassic and Paleogene of Tasmania; Late Cretaceous Gippsland Basin in Victoria; Paleocene and late middle Eocene of Victoria) and New Zealand (Late Cretaceous Chatham Islands). The Paleogene, richly fossiliferous deposits contain signifcant and diverse inclusions of arthropods, plants and fungi. These austral discoveries open six new windows to diferent but crucial intervals of the Mesozoic and early Cenozoic, providing the earliest occurrence(s) of some taxa in the modern fauna and flora giving new insights into the ecology and evolution of polar and subpolar terrestrial ecosystems.

Lost World of Rēkohu explores the extraordinary fossil record of one of the most remote regions of the planet—the Chatham Islands. Once the home of the mysterious Moriori people, this archipelago approximately 850 km east of mainland New Zealand preserves a rock archive from a dynamic time in Earth’s history when the southern continents were land-locked together near the South Pole 100 million years ago. Isolated for 83 million years, we now know since the dawn of the new millennium that this ancient region was heavily forested with both avian and non-avian dinosaurs, and the warm waters hosted the largest sea monsters—marine reptiles—that ever lived. This diversity of life on land and in the sea tells a tale never told before in Zealandia, the Moriori’s magical land of the ‘Misty Skies’.

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.