Mass Extinction Research Articles

Enhanced anti-welding and arc erosion performance of Ag-8 wt%SnO2 contact material with different addition of graphene nanoplatelets

To improve the welding resistance of Ag-8 wt%SnO2 contact material at large current, the graphene nanoplatelets (GNPs) was selected as the additive, and Ag-8 wt%SnO2 contact materials with different GNPs addition were prepared by powder metallurgy route. The electrical contact tests were performed under 36 V/16 A and 36 V/25 A, the welding, material transfer behavior and their mechanism were investigated combined with the analysis of arc duration, arc power and eroded morphology. The results show that 0.2 wt% GNPs addition decreases the welding frequency and welding force significantly, this can be attributed to the arc extinction effect and the weaken effect of the welding area. However, the excessive GNPs addition in turn aggravates the welding, the reason is that excessive GNPs addition weakens the bond between eroded layers, resulting in the decrease of arc stability and the generation of the small protrusion which cause the concentration of the contact stress and the electric field, which further results in the serious welding. Furthermore, 0.2 wt% GNPs addition decreases the mass loss rate, increasing the combination performance of Ag-8 wt%SnO2 contact material.

The influence of climate change on the future distribution of two Thymus species in Iran: MaxEnt model-based prediction

Within a few decades, the species habitat was reshaped at an alarming rate followed by climate change, leading to mass extinction, especially for sensitive species. Species distribution models (SDMs), which estimate both present and future species distribution, have been extensively developed to investigate the impacts of climate change on species distribution and assess habitat suitability. In the West Asia essential oils of T. daenensis and T. kotschyanus include high amounts of thymol and carvacrol and are commonly used as herbal tea, spice, flavoring agents and medicinal plants. Therefore, this study aimed to model these Thymus species in Iran using the MaxEnt model under two representative concentration pathways (RCP 4.5 and RCP 8.5) for the years 2050 and 2070. The findings revealed that the mean temperature of the warmest quarter (bio10) was the most significant variable affecting the distribution of T. daenensis. In the case of T. kotschyanus, slope percentage was the primary influencing factor. The MaxEnt modeling also demonstrated excellent performance, as indicated by all the Area Under the Curve (AUC) values exceeding 0.9. Moreover, based on the projections, the two mentioned species are expected to undergo negative area changes in the coming years. These results can serve as a valuable achievement for developing adaptive management strategies aimed at enhancing protection and sustainable utilization in the context of global climate change.

The Fossil Record and Diversity of Pycnodontiform Fishes in Non-Marine Environments

Pycnodont fishes were a successful clade of neopterygian fishes that are predominantly found in shallow marine deposits. However, throughout their long 180 million year reign (Late Triassic–end Eocene), they made multiple incursions into both brackish and freshwater environments. This fossil record mostly consists of fragmentary dental material, but articulated specimens are known from Early Cretaceous lacustrine localities in Spain. This review article aims to document all non-marine occurrences of Pycnodontiformes throughout most of the Mesozoic and early Paleogene. This review highlights two interesting trends in the history of non-marine habitat colonization by pycnodonts: (1) a huge spike in non-marine occurrences during the Cretaceous; and (2) that most occurrences in non-marine localities occurred at the latest Cretaceous period, the Maastrichtian. The high number of colonization events within the Cretaceous lines up with extreme climatic events, such as high temperatures resulting in high sea levels which regularly flooded continental masses, allowing pycnodonts easier access to non-marine habitats. The increased presence of pycnodonts in brackish and freshwater habitats during the Maastrichtian might have played a role in their survival through the K/Pg extinction event. Freshwater habitats are not as vulnerable as marine ecosystems to environmental disturbance as the base of their food chain relies on detritus. Pycnodonts might have used such environments as a refuge and began to occupy marine waters after the K/Pg extinction event.

Geochemistry of siltstones in the North Qilian Zhongbao–Mayinggou formations (Late Ordovician–Early Silurian): implications for paleoclimate, paleoweathering, and tectonic setting

The Late Ordovician–Early Silurian period witnessed the Phanerozoic mass extinction, glacial events, and volcanic events. Paleoweathering indexes chemical index of alteration (CIA), chemical index of weathering (CIW), and plagioclase index of alteration (PIA) indicated that the source area weathering changed from weak to moderate to intense. CIA values in the upper Zhongbao formation ranged from 66.71% to 73.97%, indicating a drier and colder climate. Upward, the CIA values on the bottom of the Mayinggou formation returned to the high value quickly (from 73.86% to 81.31%), suggesting that the ice age ended, the climate became warmer and wetter, and the sea level rose. The Al2O3–(CaO*+Na2O)–K2O triangular plots, Hf-La/Th, and SiO2–Al2O3/TiO2 bivariate plots inferred that the source of the siltstones in the two formations is mostly from the felsic igneous rocks. The samples from the Zhongbao–Mayinggou formations have chondrite-normalized rare earth element (REE) patterns similar to that of the North Qilian volcanic arc rocks. Geochemical discrimination plots displayed that the sediments of the Zhongbao–Mayinggou formations came from the active continental margin setting.

Marine redox dynamics and biotic response to the mid-Silurian Ireviken Extinction Event in a mid-shelf setting

The early Silurian Llandovery–Wenlock boundary interval was marked by significant marine perturbations and biotic turnover, culminating in the Ireviken Extinction Event (IEE) and the Early Sheinwoodian Carbon Isotope Excursion (ESCIE). Here, we apply multiple independent redox proxies to the early Wenlock Buttington section, which was deposited in a mid-shelf location in the Welsh Basin, UK. To account for regional geochemical variability in marine sediments due to factors such as sediment provenance, we first define oxic baseline values for the Welsh basin, utilizing deeper water, well-oxygenated intervals of late Llandovery age. Our approach documents unstable, oscillating redox conditions on the mid shelf at Buttington. We suggest that these dynamic redox fluctuations are likely to relate to changes in the position of the chemocline or a migrating oxygen minimum zone. Benthic biota such as trilobites, brachiopods, bivalves and gastropods appear to have been relatively unaffected by fluctuating oxic-ferruginous conditions, but were more severely impacted by the development of euxinia, highlighting the inhibiting role of toxic sulfides. By contrast, the redox perturbations appear to have placed extreme stress on graptolites, causing many extinction losses regardless of the specific development of euxinia. Thematic collection: This article is part of the Chemical Evolution of the Mid-Paleozoic Earth System and Biotic Response collection available at: https://www.lyellcollection.org/topic/collections/chemical-evolution-of-the-mid-paleozoic-earth-system Supplementary material: https://doi.org/10.6084/m9.figshare.c.7165009

The Influence of Fragmented Landscapes on Speciation.

In the face of unprecedented global transformations, unraveling the intricate mechanisms governing biodiversity patterns is imperative for predicting and interpreting species responses. An important element in this interplay is fragmentation and the spatial mosaic or arrangement of suitable sites within the landscape. Beyond its well-documented impact on biodiversity loss, fragmented landscapes also influence the origin of biodiversity, by influencing speciation dynamics. This research employs a model that integrates spatial configuration and dispersal abilities of individuals to investigate the impact of landscape configuration on species' evolutionary trajectories. Specifically, we propose a microevolutionary model where individuals are characterized by their dispersal ability and a genome, allowing population evolution and diversification. Space is explicitly characterized by suitable and unsuitable sites that define fragmented landscapes. Our model demonstrates how intermediate dispersal abilities enhance diversification. However, simulations of more fragmented landscapes result in a lower total number of individuals and a lower percentage of occupied sites by individuals, particularly when species have limited dispersal abilities. Furthermore, we have found that intermediate levels of fragmentation can stimulate greater species richness, while higher levels of speciation and extinction events tend to occur under higher fragmentations. Our results also show a non-monotonic dependence of richness on dispersal, supporting the intermediate dispersal hypothesis as promotor of diversification, demonstrating the synergistic effects of landscape configuration and species dispersal ability in the processes of speciation, extinction, and diversification. This impact of fragmentation poses a real challenge for biodiversity in the context of a dynamic world.

Potential effects of brown howler monkey extinction on dispersal services in fragmented forests void of large dispersers.

The dispersal of large-seeded species strongly depends on medium-sized and large frugivores, such as primates, which are highly susceptible to population declines. In the Atlantic Forest, brown howler monkeys Alouatta guariba are medium-sized folivorous-frugivorous species that are likely to occur in small to large fragments where the largest frugivores are extinct. However, populations of this primate have been suffering from forest fragmentation, habitat loss, hunting, and the direct and indirect effects of yellow fever outbreaks, which increase the importance of understanding their role as seed dispersers and the impacts of their potential loss. The richness and abundance of large-seeded species might also be reduced in smaller fragments, which could directly affect the magnitude of the potential impact of disperser extinction on plant recruitment. Here, we tested the following mutually exclusive predictions on the effect of fragment size on plant richness and relative density of medium- and large-seeded species consumed by brown howler monkeys in fragments smaller than 1500ha: the number and the relative density of plant species potentially affected by the local extinction of these monkeys will be (1) directly related to forest fragment size, or (2) not related to forest fragment size. Plant richness and the relative density of large- and medium-sized seed species consumed by brown howler monkeys did not vary with fragment size, corroborating our second prediction. Thus, the local extinction of brown howler monkeys would have a similar potentially negative impact on plant regeneration for the range of tested fragment sizes. We discuss the limitations of our results and suggest other lines of enquiry for the refinement of our conclusions.

Warning sign of an accelerating decline in critically endangered killer whales (Orcinus orca)

Wildlife species and populations are being driven toward extinction by a combination of historic and emerging stressors (e.g., overexploitation, habitat loss, contaminants, climate change), suggesting that we are in the midst of the planet’s sixth mass extinction. The invisible loss of biodiversity before species have been identified and described in scientific literature has been termed, memorably, dark extinction. The critically endangered Southern Resident killer whale (Orcinus orca) population illustrates its contrast, which we term bright extinction; namely the noticeable and documented precipitous decline of a data-rich population toward extinction. Here we use a population viability analysis to test the sensitivity of this killer whale population to variability in age structure, survival rates, and prey-demography functional relationships. Preventing extinction is still possible but will require greater sacrifices on regional ocean use, urban development, and land use practices, than would have been the case had threats been mitigated even a decade earlier.

Robust sulfur and oxygen isotope evidence for a highly anoxic paleoenvironment in Late Devonian seawater: Insights from marine anhydrites in the Zaige Formation, South China

A global-scale mass extinction event occurred in the Late Devonian, and its triggering mechanisms have remained a subject of controversy. The key to resolving this controversy lies in elucidating paleoenvironmental characteristics and their coupling relationship with the mass extinction. Marine evaporites serve as sensitive indicators that can be used for reconstructing the geochemical history of ancient oceans. In this study, we present a dual sulfur and oxygen isotopic dataset of marine anhydrites in the Lunatian gypsum deposit (Yunnan, China), and investigate its paleoenvironmental significance within the framework of the Late Devonian mass extinction. These anhydrites originate in arid and hot continental margin seas near convergent plate boundaries, forming as a result of the dehydration of marine gypsums during burial processes. Anhydrites exhibit a conspicuous positive anomaly in δ34S values (23.6–25.1‰, averaging 24.3‰), primarily attributed to bacteria-mediated sulfate reduction. The δ18O values of the Lunatian anhydrites (12.2–15.2‰, averaging 12.0‰) indicate a slightly higher oxygen isotope composition for Late Devonian seawater (8.7–11.7‰, averaging 10.5‰) compared to those of contemporary seawater (9.5–10.1‰). Such an oxygen isotopic characteristic for the Lunatian anhydrites is intricately associated with the chemical processes that occur during the diffusion of sulfides into the upper seawater. The anhydrite-forming evaporating system has a noticeable brine layering where the surface seawater is less dense than the deeper brine, and bacterial processes gradually increase δ34S in the deep brine. When the deep brine and surface seawater rapidly mix, it leads to a significant positive shift in the sulfur isotope composition of the resulting evaporites. Our sulfur and oxygen isotope data from Lunatian anhydrites validate the existence of an exceedingly anoxic marine environment during the Late Devonian, potentially serving as a pivotal factor in the mass extinction event.

Complexity of avian evolution revealed by family-level genomes.

Despite tremendous efforts in the past decades, relationships among main avian lineages remain heavily debated without a clear resolution. Discrepancies have been attributed to diversity of species sampled, phylogenetic method, and the choice of genomic regions 1-3. Here, we address these issues by analyzing genomes of 363 bird species 4 (218 taxonomic families, 92% of total). Using intergenic regions and coalescent methods, we present a well-supported tree but also a remarkable degree of discordance. The tree confirms that Neoaves experienced rapid radiation at or near the Cretaceous-Paleogene (K-Pg) boundary. Sufficient loci rather than extensive taxon sampling were more effective in resolving difficult nodes. Remaining recalcitrant nodes involve species that challenge modeling due to extreme GC content, variable substitution rates, incomplete lineage sorting, or complex evolutionary events such as ancient hybridization. Assessment of the impacts of different genomic partitions showed high heterogeneity across the genome. We discovered sharp increases in effective population size, substitution rates, and relative brain size following the K-Pg extinction event, supporting the hypothesis that emerging ecological opportunities catalyzed the diversification of modern birds. The resulting phylogenetic estimate offers novel insights into the rapid radiation of modern birds and provides a taxon-rich backbone tree for future comparative studies.

Novel litchi-like Au[sbnd]Ag nanospheres driven dual-readout lateral flow immunoassay for sensitive detection of pyrimethanil

Pyrimethanil (PYR) is a fungicide that is harmful to consumers when present in foods at concentrations greater than maximum permitted residue levels. High-performance immunoprobes and dual-readout strategy may be useful for constructing sensitive lateral flow immunoassay (LFIA). Herein, the prepared litchi-like AuAg bimetallic nanospheres (LBNPs) exhibited high mass extinction coefficients and fluorescence quenching constants. Benefiting from LBNPs and dual-readout mode, the limits of detection of LBNPs-CM-LFIA and LBNPs-FQ-LFIA for PYR were 0.957 and 0.713 ng mL−1, which were 2.54- and 3.41-fold lower than that of gold nanoparticles-based LFIA, respectively. The limits of quantitation of LBNPs-CM-LFIA and LBNPs-FQ-LFIA were 3.740 and 1.672 ng mL−1, respectively. LBNPs-LFIA was applied to detect PYR in cucumber and grape samples with satisfactory recovery (90%–111%). LBNPs-LFIA showed good agreement with LC-MS/MS for the detection of PYR in the samples. Accordingly, this sensitive and accurate dual-readout LFIA based on LBNPs can be effectively applied for food safety.

Long-term variations in terrestrial carbon cycles and atmospheric CO2 levels: Exploring impacts on global ecosystem and climate in the aftermath of end-Cretaceous mass extinction

The short-term climate and environmental consequences (<∼1.0–10 Kyr) immediately following the end-Cretaceous extinction have been attributed to transient effects originating from Deccan volcanism and the Chicxulub impact. These two events have received significant attention for their role in precipitating extreme climate conditions. In contrast, the long-term (> ∼100 Kyr) climate and environmental changes of the post-extinction have been extensively studied in the marine systems, yet their ramifications within terrestrial ecosystems are less well-characterized and require further elucidation. This study presents a carbon isotope analysis of pedogenic carbonates from matured calcisols in the Nanxiong Basin, South China, to reconstruct carbon cycles and atmospheric CO2 concentrations (pCO2) spanning from 76.0 Ma to 62.0 Ma, aiming to decipher the long-term terrestrial environmental and climatic conditions. Results show that δ13C values range from −12.4‰ to −5.0‰ (mean − 9.0‰) and pCO2 varies between ∼250 ppmV and ∼ 2200 ppmV (mean 920 ppmV). When combined with δ13C data from Songliao Basin, NE China, the carbon cycle variation exhibits a 13C collapse and smooth towards subsequent rebound, indicating a process of ∼600 Kyr deterioration, ∼600 Kyr stabilization and ∼ 400 Kyr recovery in the terrestrial ecosystem. The fluctuation of estimated pCO2 aligns with the change pattern of sea surface temperatures, attesting to the strong perturbation of climate and environment at the same pace as the carbon cycle variations. It is proposed that ecosystems and environments in both terrestrial and surface ocean experienced a more unstable, difficult and erratic recovery process and were much more sensitive to climatic changes than in deep ocean for ∼1.5 million years in the aftermath of the end-Cretaceous mass extinction. In addition, the divergence of proxy variations from expected effects implies the Deccan eruption and Chicxulub impact could not have played a long-term role in governing the climatic and environmental perturbations following the Cretaceous-Paleogene Boundary.

Tectonic trigger to the first major extinction of the Phanerozoic: The early Cambrian Sinsk event.

The Cambrian explosion, one of the most consequential biological revolutions in Earth history, occurred in two phases separated by the Sinsk event, the first major extinction of the Phanerozoic. Trilobite fossil data show that Series 2 strata in the Ross Orogen, Antarctica, and Delamerian Orogen, Australia, record nearly identical and synchronous tectono-sedimentary shifts marking the Sinsk event. These resulted from an abrupt pulse of contractional supracrustal deformation on both continents during the Pararaia janeae trilobite Zone. The Sinsk event extinction was triggered by initial Ross/Delamerian supracrustal contraction along the edge of Gondwana, which caused a cascading series of geodynamic, paleoenvironmental, and biotic changes, including (i) loss of shallow marine carbonate habitats along the Gondwanan margin; (ii) tectonic transformation to extensional tectonics within the Gondwanan interior; (iii) extrusion of the Kalkarindji large igneous province; (iv) release of large volumes of volcanic gasses; and (v) rapid climatic change, including incursions of marine anoxic waters and collapse of shallow marine ecosystems.

A new freshwater lonchidiid hybodontiform shark (Chondrichthyes, Elasmobranchii) from the Upper Triassic Momonoki Formation in Yamaguchi, Japan

ABSTRACT We describe an assemblage of isolated hybodontiform shark teeth from the nonmarine Upper Triassic (Carnian) Momonoki Formation in the town of Ominecho in Mine, Yamaguchi, Japan. These teeth were first reported in 1996 and tentatively referred to the genus Hybodus, but their taxonomy was not rigorously evaluated in an apomorphy-based context, and they have since been mostly overlooked. Herein, we assign them to a new species, Parvodus ominechonensis, based on a combination of synapomorphies of the lonchidiid genus Parvodus and autapomorphic character states. A diversity of Triassic hybodontiforms is known from Japan, but of these, Parvodus ominechonensis sp. nov. is the only taxon known from nonmarine deposits and the first reported occurrence of Lonchidiidae. Parvodus ominechonensis fills a gap in the stratigraphic record of Parvodus between occurrences in Middle Triassic (Anisian) and Middle Jurassic (Bajocian) strata. The global Triassic record of Parvodus comprises Parvodus huizodus from the Olenekian of China, Parvodus sp. from the Anisian of China, and Parvodus ominechonensis from the Carnian of Japan, of which Parvodus ominechonensis and Parvodus huizodus are known from nonmarine deposits. After the Triassic, Parvodus is known from marine and nonmarine strata across Laurasia and in South America until its extinction during the Early Cretaceous. This suggests that Parvodus may have originated in freshwater habitats in the South China region of Pangea following the end-Permian mass extinction and diversified throughout the Triassic in present day East Asia before attaining a global distribution later in the Mesozoic. http://zoobank.org/urn:lsid:zoobank.org:pub:42B4D1C1-F4BE-4296-896B-01B048BDE25F

Mimicking Pain Conditioning Using an Electrolyte‐Gated Organic Synaptic Transistor

AbstractPain‐perceptual Nociceptors (PPNs) in the biological sensory system are critical for the human body to perceive noxious stimuli from the outside world and start appropriate motor responses to minimize potential physical damage. Realization artificial nociceptors with unique synaptic and pain‐perceptual functions of the human nervous system is a key step to develop the next‐generation artificial intelligence systems. Here, an artificial pain‐perceptual device based on an ionic liquid‐polymer solid‐state electrolyte‐gated poly(3‐hexylthiophene) (P3HT) transistor is reported. With the drift motion of mobile ions in the electrolyte layer and the formation of an electric double layer (EDL) at electrolyte/semiconductor interface under an applied electric field, the channel conductance can be tuned progressively to exhibit synaptic weight modulation function. On top of the artificial synaptic functions, the P3HT/electrolyte‐based transistor successfully emulates the pain‐perception process in a biological nociceptor, with all unique features of threshold, no adaptation, sensitization/desensitization, and relaxation. Moreover, the pain conditioning process (i.e., hyperalgesic response, and pain extinction effect) through associative learning is demonstrated using the artificial synaptic transistor, indicating its potential application in bio‐inspired neural systems.

Seismic expression of shallow-water carbonate structures through geologic time

Shallow-water carbonate structures are characterized by different shapes, sizes, and identifying features, which depend, among other factors, on the age of deposition and on the carbonate factory associated with a specific geologic period. These variations have a significant impact on the imaging of these structures in reflection seismic data. This study aims at providing an overall, albeit incomplete, picture of how the seismic expression of shallow-water carbonate structures has evolved through deep time. Here, 297 shallow-water carbonate systems of different ages, spanning from Precambrian to present, with a worldwide distribution of 159 sedimentary basins, have been studied. For each epoch, representative seismic examples of shallow-water carbonate structures are described through the assessment of a selection of discriminating seismic criteria or parameters. The thinnest structures, commonly represented by ramp systems, usually occurred after mass extinction events and are mainly recognizable in seismic data through prograding clinoform reflectors. The main diagnostic seismic features of most of the thickest structures, which are found to be Precambrian, Late Devonian, Middle-Late Triassic, Middle-Late Jurassic, some Early Cretaceous presalt systems, “middle” and Late Cretaceous, Middle-Late Miocene, and Plio-Pleistocene, are steep slopes and reefal facies. Slope-basinal resedimented seismic facies are mostly observed in thick steep-slope platforms, and they are more common, except for megabreccias, in post-Triassic structures. Seismic-scale early karst-related dissolution features are mostly observed in icehouse platform deposits. Pinnacle structures and the thickest margin rims are concentrated in a few epochs, such as Middle-Late Silurian, Middle-Late Devonian, earliest Permian, Late Triassic, Late Jurassic, Late Paleocene, Middle-Upper Miocene, and Plio-Pleistocene, which are all characterized by high-efficiency reef builders.

Management and research efforts are failing dolphins, porpoises, and other toothed whales

Despite being subject to intensive research and public interest many populations of dolphins, porpoises, and other toothed whales (small cetaceans) continue to decline, and several species are on the verge of extinction. We examine small cetacean status, human activities driving extinction risk, and whether research efforts are addressing priority threats. We estimate that 22% of small cetaceans are threatened with extinction, with little signs of improvement in nearly thirty years. Fisheries and coastal habitat degradation are the main predictors of extinction risk. Contrary to popular belief, we show that the causal impact of small-scale fisheries on extinction risk is greater than from large-scale fisheries. Fisheries management strength had little influence on extinction risk, suggesting that the implementation of existing measures have been largely ineffective. Alarmingly, we find research efforts for priority threats to be vastly underrepresented and so a major shift in research focus is required. Small cetaceans are among the lower hanging fruits of marine conservation; continued failure to halt their decline bodes poorly for tackling marine biodiversity loss and avoiding an Anthropocene mass extinction.

Combined cadmium and chromium isotopes record a collapse of bioproductivity across the Cretaceous—Paleogene boundary in the Danish basin

Cadmium (Cd) isotope signatures (δ114Cd) deduced from modern and ancient marine deposits are often used as a proxy for bioproductivity and for micronutrient cycling, whereas chromium (Cr) isotope signatures (δ53Cr) are used as a potential proxy for oxygenation. The Cretaceous—Paleogene (K/Pg) boundary records one of Earth's five big mass extinctions, which contains geochemical fingerprints of the Chixculub asteroid impact and is coeval with the Deccan Trap volcanism. Here we present for the first time a combined record of Cd and Cr isotopes from the Danish Basin to interrogate the effects on bioproductivity across the K/Pg boundary. The δ114Cd values range between −0.28‰ and 0.27‰ defining an average of 0.05‰ ± 0.24 (2σ, n = 87). Authigenic δ53Cr values range between 0.06‰ and 1.06‰ and define an average of 0.59‰ ± 0.51 (2σ, n = 81). An abrupt jump, across the K/Pg boundary layer, from consistently positively fractionated Cd and Cr isotope signatures recorded in Late Maastrichtian white chalks towards less positively fractionated δ114Cd values and heterogeneous δ53Cr values in the Early Danian carbonates, likely indicates a decrease in surface water bioproductivity. This decrease is accompanied by redox fluctuations in the water column as a consequence of environmental changes either related to the Chixculub impact event and/or to the Deccan volcanic eruptions coeval with this boundary. Assuming an efficient removal of Cd and Cr through consumption and/or adsorption by primary producers, or by incorporation into the skeleton/shells of calcifiers, and using the fractionation factor of Cd into carbonates, we reconstruct surface water conditions during the Late Masstrichtian—Early Danian that are compatible with those of modern oceans, with δ114Cd varying from 0.17 to 0.72‰. Overall, the combined Cr-Cd isotope fluctuations over the K/Pg boundary are consistent with a scenario characterized by climate-induced changes of nutrient availability and concomitant responses of primary production levels, ultimately related to the asteroid impact and to the proceeding volcanic activities that influenced the ocean's chemistry. We anticipate our results to point for further studies of other stratigraphic sections worldwide to reveal an extensive Cd-Cr record for the Cretaceous—Paleogene boundary and its corresponding collapse of bioproductivity and decreasing ocean oxygenation.

Nourishing Earth, Nourishing Ourselves Part 3: Locally Adapted Communities as Medicine for an Ailing Planet

Once a species reliant on nature for food, medicine, clothing, and shelter, Homo sapiens is in the process of being consumed by the fossil fuel-based agricultural and technological economies that enabled warming climates, natural disasters, and the sixth mass extinction. These economies, based in competition rather than cooperation around natural resources, cause man-made shortages of clean water, fertile soil, biodiversity, wholesome foods, and unpolluted air. The resources that enabled unprecedented biophysical transformations are now diminishing in availability and increasing in costs. These changes are a defining moment that may lead to mankind’s demise or may catalyze the rebirth of a vastly different ecological economy. The challenge is to create economies where communities benefit from locally sourced plants and animal products, produced in ways that nurture relationships among soil, water, plants, animals, and people to sustain a collective wellbeing. To do so, humans will need to relearn what it means to be a part of nature’s communities and transform from a technological to an eco-logical relationship with landscapes. If up to that challenge, Homo sapiens will remember what it means to be locally co-evolving with one another and the environment. Ultimately, the trials faced in addressing these critical issues have little to do with the issues per se, and everything to do with healing divides that polarize and isolate people.

Unravelling the mishmash: A new phylogeny for the family Empheriidae (Psocodea, Trogiomorpha) with a new genus and species from Cretaceous Charentese amber

The order Psocodea, including barklice, booklice, and parasitic lice, is diverse and widely distributed since the Cretaceous. That is particularly the case for the speciose extinct family Empheriidae (Psocodea, Trogiomorpha, Atropetae), recently fused with the ‘Archaeatropidae’. Understanding the evolution of barklice is dependent in part on studying this family, as its representatives have been found from the Early Cretaceous to the Eocene, surviving the K/Pg extinction event. The phylogenetic relationships of Empheriidae in relation to other families, such as Lepidopsocidae or Psoquillidae, have been extensively debated. However, distinguishing diagnostic characters for the Empheriidae has proven challenging. In this study, we describe the new empheriid Santonipsocus mimeticusgen. et sp. nov. from Cretaceous Charentese amber (France). It is the third empheriid species found in this locality. The new genus is compared with the other genera in the family, and Proprionoglaris guyoti and Proprionoglaris axioperierga are revised based on the type material and new specimens. We explore the phylogeny of Empheriidae, both the relationships with other families and the inner relationships between the genera, through maximum parsimony analysis and Bayesian inference analysis. Our results suggest that Empheriidae may represent a paraphyletic evolutionary grade to the rest of Atropetae. The phylogenetic relationships between genera align with the biogeography of the family and support previous hypotheses. In addition, we discuss the possible biology of the members of the family, shedding light on the evolutionary history of Empheriidae.