Background:The double burden of malnutrition (DBM) in the same individual is a neglected public health concern, especially in low- and middle-income countries (LMICs). The DBM is associated with increased risks of non-communicable diseases, childbirth complications, and healthcare costs related to obesity in adulthood. However, evaluating low prevalence outcomes in relatively small populations is challenging using conventional frequentist statistics. Our study used Bayesian latent models to estimate DBM prevalence at the individual-level in small populations located in remote towns and rural communities in the Brazilian Amazon. Methods:We employed a cross-sectional survey of urban and rural children aged 6-59 months, considering DBM as the coexistence of stunting and overweight in the same individual. We evaluated four river-dependent municipalities, sampling children in randomly selected households in each town and a total of 60 riverine forest-proximate communities. Through Bayesian modeling we estimated the latent double burden of malnutrition (LDBM) and credible intervals (CI). Results:The exceedance probability of LDBM was used to quantify this form of malnutrition at the population level. Rural prevalence of LDBM was significantly higher in Jutai (3.3%; CI: 1.5% to 6.7%) compared to Maues and Caapiranga. The likelihood that LDBM rural prevalence exceeded 1% was very high in Jutai (99.7%), and Ipixuna (63.2%), and very low (< 2%) in rural communities elsewhere. Exceedance probabilities (at 1%) also varied widely among urban sub-populations, from 6.7% in Maues to 41.2% in Caapiranga. The exceedance probability of LDBM prevalence being above 3.0% was high in rural Jutai (59.7%). Discussion:Our results have important implications for assessing DBM in vulnerable and marginalized populations, where health and nutritional status are often poorest, and public health efforts remain focused on undernutrition. Our analytical approach could enable more accurate estimation of low prevalence health outcomes, and strengthen DBM monitoring of hard-to-reach populations.

Demands for territorial recognition are foundational to the claiming of rights by forest-proximate people who attempt to conserve their forests. The rights of these often-marginalized populations have been largely overlooked by conservationists, yet they are central to achieving people-centered conservation. We further developed the concept of forest citizenship as a normative framework and analytical tool based on Brazilian social environmentalism (socioambientalismo), florestania (a former political project in Acre state), Latin American scholarship on ecological citizenship, and Eurocentric political philosophy. Decades of struggle for territorial recognition and social inclusion have solidified the right to have rights for Amazonia's forest citizens. Hence, forest citizens are people who have become so through the sociopolitical dynamics of their rights claims. Forest citizenship is built on community mobilization to create legally recognized territories with participatory governance but becomes tangible only if individuals and communities can successfully claim other rights from institutions through everyday practices of citizenship. We also assessed the current number and distribution of forest citizens across Brazilian Amazonia based on gridded population data and spatial analyses to calculate the resident population in four territorial categories that meet these democratic preconditions: Indigenous lands, extractive reserves, sustainable development reserves, ecological settlement projects, and Afro-descendent Quilombola territories. The territories covered 31% of the Legal Amazon, were home to 1.05 million forest citizens, and had diverse primary policy objectives but shared goals of empowering communities and conserving forests. To be emancipatory, forest citizenship must be bottom-up, socially inclusive, and improve people's lives. We suggest that conservationists pay greater attention to power relations and decision-making structures related to forest territories. Territory-based forest citizenship may be relevant for other countries where environmentalism has intersected with struggles for land rights and democracy.

The relationship between tropical deforestation and human development is unclear and contested. We evaluated the boom-bust hypothesis across agricultural frontiers in the Brazilian Caatinga dry forest, one of the largest dry forests in the world and home to 28 million people. We used panel data (1991, 2000 and 2010), and crosssectional data (2010) from 1207 municipalities to assess how development indicators are linked to deforestation through a quasi-experimental approach. Our main finding is that deforestation in the Caatinga is associated with a boom-bust development pattern or at least to a stagnation in development in highly deforested municipalities. Municipalities at the advanced stage of deforestation (<33 % of forest cover remaining) in 1991 generally had higher development indicators than the initial stage (>66 % remaining), but differences between these groups disappeared by 2010. Intermediate stage municipalities (33-66 % remaining) consistently outperformed initial and/or advanced stage municipalities in four out of six development indicators (longevity, monetary income, extreme poverty prevalence, and child mortality), indicating a temporary 'boom' during frontier advance, followed by a stagnation. Evidence of a boom-bust was supported by cross-sectional analysis of 2010 data using propensity score weighting and a spatial autoregressive model. Overall, our findings contribute to on-going debate and strengthen the boom-bust hypothesis. By implication, the mere consumption of natural resources is inadequate to ensure sustained development progress. Achieving sustainability in Brazil's agricultural frontiers necessitates more than apolitical technical solutions; it requires active engagement by the state, non-state institutions, and society as a whole to address the country's deep-seated inequalities and imbalanced power dynamics.

Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, Timorebestia koprii gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to Amiskwia sagittiformis . Amiskwia has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that T. koprii shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in T. koprii suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today.

The documentation of cuticular micro-ornament is vital for the taxonomic assignment of palaeoscolecids: vermiform lower Palaeozoic ecdysozoans interpreted as stem-group priapulans or early diverging panarthropods. This is due to the absence of the character-rich proboscis and tail hooks in palaeoscolecid material not from Burgess Shale-type Konservat-Lagerst & auml;tten. Here, the cuticular micro-ornamentation of palaeoscolecids from the upper Silurian (Ludlow) fauna of Leintwardine (Herefordshire, England), is described using scanning electron microscopy and reflectance transformation imaging. This material is taxonomically unstable because it was included in an effective wastebasket genus (Protoscolex) long before these imaging techniques were developed. The Leintwardine material is shown to be most closely comparable to a palaeoscolecid from the Darriwilian (Middle Ordovician) of the Builth-Llandrindod inlier, Powys, Wales, and is transferred accordingly to Radnorscolex Botting et al. as Radnorscolex latus (Bather). The Leintwardine fauna represents the uppermost stratigraphic occurrence of palaeoscolecids, constrained to the Saetograptus leintwardinensis Zone (lower Ludfordian), and the comparatively sparse Silurian palaeoscolecid record is subsequently discussed. It is hypothesized that palaeoscolecids may have become extinct during the mid-Ludfordian Lau Event, the onset of which is recorded in the biozone immediately above the Leintwardine fauna (Bohemograptus Zone). Finally, the British palaeoscolecid fauna is summarized, including a new record from the Dapingian (Middle Ordovician) of Carmarthenshire, South Wales.

The "short-great-appendage" arthropods (Megacheira), such as Leanchoilia, have featured heavily in discussions of arthropod evolution, particularly related to the head and its appendages.1,2,3,4 Megacheirans are subject to competing interpretations, either as a clade4 or a grade,5 in the stem group of Euarthropoda6 or, alternatively, Chelicerata.4 They are most diverse in Cambrian Burgess-Shale-type deposits, where the family Leanchoiliidae is represented by six genera,7,8,9,10,11,12 characterized by the presence of three distal flagella on the great appendage with a presumed sensory function. We describe the first post-Cambrian member of this family, Lomankus edgecombei gen. et sp. nov, from the Upper Ordovician (Katian) Beecher's Trilobite Bed site of New York State-the first post-Cambrian megacheiran with the exception of the Silurian and Devonian Enaliktidae. Micro-computed tomography (micro-CT) scanning reveals the morphology of the short great appendage with elongate flagella, four biramous cephalic limbs, 11 trunk segments with biramous limbs and dorsal tergites, and an elongate telson unique within Leanchoiliidae. The great appendage is also unique: the long endites that bear the flagella in other leanchoiliids are absent (or at least greatly reduced) and each flagellum appears to attach directly to an individual podomere, suggesting a sensory rather than a raptorial function. The remarkable preservation of a well-developed ventral plate (epistome-labrum complex) anterior of the mouth reinforces a deutocerebral origin2,13 of the short great appendages. Lomankus edgecombei unveils the three-dimensional (3D) head morphology of leanchoiliids in unparalleled detail and demonstrates that these iconic fossil arthropods ranged into dysaerobic environments in the Ordovician, where Lomankus occupied a deposit-feeding niche.

Mollusks encompass enormous disparity, including familiar clams and snails alongside less familiar aculiferans (chitons and vermiform aplacophorans) with complex multicomponent skeletons. Paleozoic fossils trace crown mollusks to forms exhibiting a combination of biomineralized shells and sclerites (e.g., scales, spines, and spicules). We describe a shell-less, Cambrian stem mollusk, Shishania aculeata gen. et sp. nov., with conical, hollow chitinous sclerites and a smooth girdle, broad foot, and mantle cavity. The sclerites have a microstructure of narrow canals consistent with the impressions of chaetal microvilli found in annelids and brachiopods. Shishania sclerites provide a morphological stepping stone between typical chaetae (chitinous bristles) and the external organic part of aculiferan sclerites that encloses a mineralized body. This discovery reinforces a common origin of lophotrochozoan chaetae and the biomineralized aculiferan sclerites, suggesting that the mollusk ancestor was densely covered with hollow chitinous chaetae.

Ecosystem engineers can radically reshape ecosystems by modulating the availability of resources to other organisms through modifying either physical or biological aspects of the environment. The introduction or removal of ecosystem engineers from otherwise stable ecosystems can impact the diversity of co-occurring species, such as driving local extinctions of native taxa. While these impacts are well established over ecological timescales for a wealth of taxa, the macroevolutionary implications of the onset of ecosystem engineering behaviours are less clear. Despite this uncertainty, ecosystem engineering has been implicated in several major transitions in Earth history including the appearance of extensive bioturbation during the Cambrian substrate revolution and associated Ediacaran-Cambrian turnover, and the Great Oxygenation Event. Whether ecosystem engineers are frequently associated with turnover and extinction in deep time is not known. Here we investigate this with an eco-evolutionary simulation framework in which we assign lineages the ability to impact the fitness of co-occurring taxa through phenotype-environment feedback. We explore numerous conditions, including how frequently such feedback occurs, and whether ecosystem engineers modify or create niches. We show that there is no general expected outcome from the introduction of ecosystem engineers. In a minority of runs, ecosystem engineering lineages completely dominate, rendering all others extinct, but in others they persist (but do not dominate), or die out. We suggest that ecosystem engineers have complex impacts, but possess the capacity to profoundly shape diversity, and it is appropriate to consider them alongside other exogenous extinction drivers in deep time.

Governments continue to narrowly equate improved well-being with economic growth, contrary to decades of development scholarship. The capabilities approach, instead, emphasizes freedom and what individuals are able to do and to be within society. However, it underplays structural determinants of social inequities and says little about violence, a dominant problem in metropolitan areas of Latin America. Framing our analysis around capabilities and theorizing on disadvantage, we examine experiences of inequity and violence in Manaus, a metropolis in the Brazilian Amazon. We show how the threat of physical violence is highly corrosive because it underpins a cluster of disadvantage that profoundly impacts central capabilities, including emotions, bodily integrity, and affiliation. Social isolation is commonplace because interactions are perceived as risks rather than pathways to mutual recognition. Violence begets violence in low-income neighborhoods and this constrains capabilities, causes shame and indignity, and limits potential for self-realization. Policy makers should address how disadvantaged people feel about themselves, relate to others, and are able to decide how to conduct their daily lives.

Machaeridians are armoured annelids that were morphologically diverse during the Palaeozoic. The scleritome developed from fleshy protrusions at the base of each parapodium, with alternating segments giving rise to differentiated inner and outer shell plates. The elytra-like anatomy of the shell-bearing soft tissues and distinctive jaw apparatus support an affinity of machaeridians with aphroditacean scaleworms. While frequently found as disarticulated remains, whole scleritomes of machaeridians are rare. Only a few species are represented by multiple articulated individuals, rendering many aspects of our knowledge of scleritome construction and growth uncertain. Here we describe a collection of articulated scleritomes of the plumulitid machaeridian Plumulites tafennaensis Chauvel from the Upper Ordovician (Katian) Upper Tiouririne Formation of Morocco that includes individuals representing both adult and juvenile stages. These scleritomes shed light on the morphology of the anterior region in plumulitids and show an increase in the number of shell plates with increasing size, suggesting that unlike some derived lepidocoleids, at least some plumulitids added segments repeatedly during ontogeny. Shell plates with a distinctive umbo have previously been assigned exclusively to the anterior region, but our material shows that they are present along the scleritome, with corresponding sclerites on the opposite side of the skeleton showing normal morphologies. We suggest that these plates are abnormal and best explained as healed injuries, replacing plates that had been previously removed from the body, demonstrating the capacity for machaeridians to regenerate lost body parts, a feature that is widespread in living annelids.

Inner phenomena, such as personal motivations for pursuing sustainability, may be critical levers for improving conservation outcomes. Most conservation research and policies, however, focus on external phenomena (e.g., ecological change or economic processes). We explored the factors shaping 9 conservation attitudes toward forest and wildlife protection among colonist farmers around an Amazonian deforestation frontier. Our data comprised 241 face‐to‐face quantitative surveys, complemented with qualitative insights from open‐ended questionnaire responses and opportunistic semistructured interviews. To account for the full spectrum of possible inner motivations, we employed measures of nature connection (indicating biospheric motivation) and personal values organized around the traditionalism (traditionalist through to high openness to change) and universalism dimensions (egoistic through to altruistic motivations). We used averaged beta‐binomial generalized linear models to assess the role of external factors (socioeconomic, sociodemographic, and environmental) and personal (inner) motivations on the variation in attitudes. Each attitude was modeled separately. The relative importance of each predictor was judged by the proportion of models where it appeared as significant. Proconservation views were expressed by the majority (at least 65%) of the respondents in 7 out of the 9 attitude models. The most consistent predictors were emotional nature connection and personal values (significant in 4–6 out of 9 models), rather than external phenomena (significant in 0–5 models). However, the poorest farmers had lower scores on the agreement with prioritizing nature over development (𝛽 = –0.52, 95% CI: –0.96 to –0.07). Qualitative data also indicated that economic barriers hinder forest conservation on farms. These results suggest that biospheric, traditionalistic, and altruistic motivations promote people's proconservation attitudes, but nurturing these latent motivations is unlikely to improve conservation outcomes if material poverty remains unaddressed. Integrating the inner–outer perspective into conservation thinking and practical interventions could foster environmental stewardship and increase human well‐being.

We examine ways in which the role of wild animals in the Amazonian food system may be socially differentiated and species-specific. We combine a hybrid framework of food choice preferences and theorizing on access to natural resources with fieldwork in Brazilian Amazon, where social and environmental challenges coalesce around the role of wildlife in feeding a growing urban population. Based on 798 household surveys across four towns, we found that consumption of, and taste preferences for, selected species of mammals, fishes, birds, and reptiles are related to variation in means of access (e.g., level of social trust -the basis of reciprocity and informal urban safety nets), and having rural cultural origins (marginal to migrants' other socioeconomic differences). The likelihood of eating particular species was associated with taste preferences and household experiences of food insecurity. Hunting and fishing households consumed many wild species; it is unclear if they depend heavily on any in particular. Vulnerable species, including manatee, tortoise, and river turtle, were eaten mainly by relatively privileged households, and less so by other households (e.g., rural-urban migrants). Rural origins increased by 90% the likelihood of a strong wild meat preference, compared to other households. Evidently, wildlife consumption is a rural tradition that influences migrants' dietary practices in towns, through the interplay of preferences, means of access, and context. Finally, severe and moderate food insecurity was associated with eating howler monkey and catfishes (barred and redtail) and not eating manatee and turtle. Hence, urban consumption of some, but not all, wild species is associated with household disadvantage and food insecurity. Amazonian town-dwellers consume many wild species, drawing on diverse means of access, which are species-specific and reflect social inequalities. Species-specific governance of wildlife consumption may help balance the risks of overharvesting against the well-being of Amazonia's vulnerable town-dwellers.

Fossil material assigned to Nenoxites from the late Ediacaran Khatyspyt Formation of Arctic Siberia (550-544 Ma) has been presented as evidence for bioturbation prior to the basal Cambrian boundary. However, that ichnological interpretation has been challenged, and descriptions of similar material from other global localities support a body fossil origin. Here we combine x-ray computed tomography, scanning electron microscopy and petrographic methods to evaluate the body or trace fossil nature of Nenoxites from the Khatyspyt Formation. The fossilized structures consist of densely packed chains of three-dimensionally preserved silicic, bowl-shaped elements surrounded by distinct sedimentary halos, in a dolomitized matrix. Individual bowl-shaped elements can exhibit diffuse mineralogical boundaries and bridging connections between elements, both considered here to result from silicification and dolomitization during diagenesis. This new morphological and petrological evidence, in conjunction with recent studies of the late Ediacaran tubular taxa Ordinilunulatus and Shaanxilithes from China, suggest that the Khatyspyt specimens most probably reflect a coquina deposit of Shaanxilithes-like body fossils. Our data support the possibility of Shaanxilithes-like organisms representing total group eumetazoans.

Time-scaled phylogenies underpin the interrogation of evolutionary processes across deep timescales, as well as attempts to link these to Earth’s history. By inferring the placement of fossils and using their ages as temporal constraints, tip dating under the fossilised-birth death (FBD) process provides a coherent prior on divergence times. At the same time, it also links topological and temporal accuracy, as incorrectly placed fossil terminals should misinform divergence times. This could pose serious issues for obtaining accurate node ages, yet the interaction between topological and temporal error has not been thoroughly explored. We simulate phylogenies and associated morphological datasets using methodologies that incorporate evolution under selection, and are benchmarked against empirical datasets. We find that datasets of moderate sizes (300 characters) and realistic levels of missing data generally succeed in inferring the correct placement of fossils on a constrained extant backbone topology, and that true node ages are usually contained within Bayesian posterior distributions. While increased fossil sampling improves the accuracy of inferred ages, topological and temporal errors do not seem to be linked: analyses in which fossils resolve less accurately do not exhibit elevated errors in node age estimates. At the same time, divergence times are systematically biased, a pattern that stems from a mismatch between the FBD prior and the shape of our simulated trees. While these results are encouraging, suggesting even fossils with uncertain affinities can provide useful temporal information, they also emphasise that paleontological information cannot overturn discrepancies between model priors and the true diversification history.

The lives of the urban poor in the majority world are unfree: blighted by social injustice in its manifold forms, from violence and ill-health to absent economic opportunities. We explore the pursuit of freedom through migration away from the metropole to ramais (colonisation tracks) at the rainforest frontier. Drawing on a case study in Brazilian Amazonia, we reveal urban-rural migration as a frontier dynamic driven by the search for a good life. We theorize freedom and the good life using the capabilities approach, starting from the observation that people in the ramais reported feeling better, and asking why that is. We find that frontiers provide a safer environment, which fosters individual and collective capabilities. A lower risk of violence reduces fears around bodily integrity, pervasive in Latin American cities. This safety fosters freedom and dignity by reducing worries and anxieties, leading to improvements in emotional well-being. We understand this increased sense of freedom as enhanced agency, that is, empowerment. In addition to new forms of political activity and subjectivity, we report a flourishing of senses, imagination and affiliation with others. Inequalities are reduced, positively influencing dignity and self-worth. These new freedoms are threatened by lack of rights provisioning by the State, however. We recommend that the Brazilian state should address social and environmental dimensions of these new forest frontiers. The state should recognize and support these settlements as valid forms of development, because they so clearly contribute to human wellbeing and flourishing. The state should guide and assist livelihood and landscape management toward more ecological approaches such as agroecology and agroforestry, to mitigate deforestation risks typical of forest frontiers.

Exoskeletal dwelling tubes are widespread among extant animals and early fossil assemblages. Exceptional fossils from the Cambrian reveal independent origins of tube dwelling by several clades including cnidarians, lophophorates, annelids, scalidophorans, panarthropods and ambulacrarians. However, most fossil tubes lack preservation of soft parts, making it difficult to understand their affinities and evolutionary significance. Gangtoucunia aspera (Wulongqing Formation, Cambrian Stage 4) was an annulated, gradually expanding phosphatic tube, with occasional attachments of multiple, smaller juveniles and has previously been interpreted as the dwelling tube of a ‘worm’ (e.g. a scalidophoran), lophophorate or problematicum. Here, we report the first soft tissues from Gangtoucunia that reveal a smooth body with circumoral tentacles and a blind, spacious gut that is partitioned by septa. This is consistent with cnidarian polyps and phylogenetic analysis resolves Gangtoucunia as a total group medusozoan. The tube of Gangtoucunia is phenotypically similar to problematic annulated tubular fossils (e.g. Sphenothallus, Byronia, hyolithelminths), which have been compared to both cnidarians and annelids, and are among the oldest assemblages of skeletal fossils. The cnidarian characters of G. aspera suggest that these early tubular taxa are best interpreted as cnidarians rather than sessile bilaterians in the absence of contrary soft tissue evidence.

Among extant animals, Lophotrochozoa accounts for the majority of phyla.1 This bilaterian clade radiated rapidly during the Cambrian explosion, obfuscating its phylogenetic relationships and rendering many aspects of its early evolution uncertain. Many early lophotrochozoans are known only from isolated skeletal microfossils, "small shelly fossils," often derived from larger animals with complex multi-element skeletons.2 The discovery of articulated fossils has revealed surprising insights into the animals from which these skeletal pieces were derived, such as paired shells in the mollusc Halkieria.3 Tommotiids are a key group of phosphatic early skeletal fossils that first appear in the late early Cambrian.4,5 Although their affinities were previously obscure, discoveries of partial scleritomes and investigations of growth and microstructure6 provide links with Brachiopoda7,8 and Phoronida,9 two of the lophophorate phyla. By contrast, the body plan of camenellan tommotiids remains a palaeontological mystery, with hypothetical reconstructions representing motile, benthic, dorsally armored worms.4,10 Here, we describe an articulated camenellan (Wufengella bengtsoni gen. et sp. nov.) from the Cambrian Chengjiang Biota, China, revealing the morphology of the scleritome and the first soft tissues from an adult tommotiid. Wufengella carries two dorsal rows of sclerites in a highly asymmetric arrangement, flanked by smaller, cap-shaped sclerites. The scleritome was fringed by iterated fascicles of chaetae and two layers of flattened lobes. Phylogenetic analysis confirms that camenellans occupy a deep branch in lophophorate phylogeny, prior to the acquisition of a sessile lifestyle. Wufengella reveals direct evidence for a metameric body plan reminiscent of annelids early in the evolutionary history of lophophorates.11,12.