Ecological expansion of Idioprioniodus (Conodonta) controlled by paleoenvironmental changes in Bashkirian-Moscovian epicontinental sea in Western Gondwana: Evidence from the Amazonas Basin

Assessment frameworks do not capture the complexity of the social-ecological dynamics of small-scale fisheries (SSF), which support millions of livelihoods yet face persistent sustainability challenges. Reciprocal feedbacks between fish populations and fishers that are central to sustainability remain insufficiently integrated into assessment approaches because conventional fisheries management emphasizes population dynamics, whereas social-ecological systems research focuses on social drivers and faces operational challenges. We propose an integrative diagnostic approach that explicitly links fish population dynamics with theories of fisher behavior and governance. We illustrate its application using co-managed arapaima fisheries in the Amazon Basin, where sustainability emerges from multi-scalar social and ecological interactions. By capturing these feedbacks, the approach bridges ecological and social dimensions to identify key drivers of sustainability. It provides a replicable, interdisciplinary framework for diagnosing SSF sustainability and identifying leverage points to support adaptive governance across diverse contexts.

SUMMARYJorge Lobo's disease (JLD) is a chronic cutaneous and subcutaneous mycosis endemic to the Amazon Basin and tropical rainforests of Latin America. Despite more than a century of study, the disease remains underrecognized, poses significant diagnostic challenges, and is often therapeutically refractory. Here, we synthesize historical, clinical, and ecoepidemiological evidence; provide a practical diagnostic approach; and highlight unresolved questions. Clinically, JLD presents as slowly progressive keloid-like nodules and plaques on exposed areas. Diagnosis relies on direct microscopy and histopathology showing chains of thick-walled yeast-like cells connected by narrow-neck budding; culture is not feasible, and molecular assays are rarely available outside reference centers. We contrast JLD with key mimickers (cutaneous leishmaniasis, chromoblastomycosis, leprosy, atypical mycobacterioses, and non-infectious lesions such as keloid scars) and summarize current management options, emphasizing when surgery alone suffices and when prolonged azole therapy should be considered. From an ecoepidemiological perspective, historical settlement patterns, occupational exposures, and environmental disturbance in humid forest biomes appear to have amplified human contact with putative environmental reservoirs. New phylogenomic data position Paracoccidioides lobogeorgii as an early-diverging lineage within Paracoccidioides, refining prior MLST-based inferences. We outline practical surveillance steps to address under-ascertainment, standardized case definitions, sentinel reporting, and laboratory quality assurance and propose research priorities spanning environmental detection, host-pathogen interactions, and therapeutic evaluation. We contextualize the disease within broader frameworks of fungal emergence, structural neglect, and environmental disruption, arguing that revisiting JLD is not merely retrospective but a necessary scientific and ethical priority.

ABSTRACTCatfishes of the genus Hypancistrus are among the most emblematic endemic species of the Xingu River rapids, a biodiversity hotspot of the Amazon Basin. In the unique Volta Grande region, the distribution of Hypancistrus zebra, Hypancistrus seideli, and Hypancistrus yudja overlap, creating a potential zone of biological interaction, and previous morphological analyses suggest the occurrence of hybridization between H. seideli and H. yudja. We investigated maternal inheritance and phylogenetic relationships among the three species and hybrids using complete mitochondrial genomes and nuclear genome size estimates. Phylogenetic analyses revealed that hybrids carried maternal lineages exclusively from H. zebra and H. seideli, with no evidence of contribution from H. yudja. Nuclear genome size analyses support this pattern, with hybrids exhibiting intermediate values consistent with additive inheritance. Divergence time estimates indicated a very recent evolutionary radiation (< 0.5 Ma), explaining the persistence of reproductive compatibility among the species. These findings raise conservation concerns, particularly for the zebra pleco H. zebra, a critically endangered species at risk of genetic introgression. Our study provides the first complete mitochondrial genome data for these species and emphasizes the importance of integrating morphological and genomic approaches to understand hybridization dynamics and guide conservation strategies in the Xingu River.

Stable oxygen isotopes (δ18O) in wood provide integrative records of plant water use and regional hydroclimatic processes, offering a powerful framework for spatial ecological analysis in tropical forests. Here, we present the first regional-scale δ18O isoscapes for Amazonian wood based on 387 trees sampled across 25 sites. After α-cellulose extraction, δ18O values were modeled using multiple linear regression (MLR) and Random Forest (RF) approaches. A Moran’s I test revealed no significant spatial autocorrelation (p = 0.73), indicating that geostatistical interpolation methods such as kriging were not appropriate for this dataset. The MLR model based on site-average data achieved an R2 of 0.70, with a mean absolute error (MAE) of 0.56‰ and root mean square error (RMSE) of 0.68‰. The RF model showed comparable performance (R2 = 0.67; MAE = 0.64‰; RMSE = 0.77‰). Both approaches reproduced a coherent southeast-to-northwest gradient, with lower δ18O values in the western Amazon and higher values in the east, consistent with regional patterns in precipitation isotopic composition and evapotranspiration. These findings demonstrate that climate-driven statistical modeling effectively captures large-scale isotopic structure across the Amazon basin, providing a robust spatial representation of δ18O variability in tropical forest wood.

Humanity is putting unprecedented pressures on the Amazon forest system through global warming and landuse changes1,2. As the Amazon forest may undergo self-reinforcing transitions, these pressures could lead to system-wide changes across major parts of Amazonian ecosystems1-4. Here we apply a dynamical systems model to assess the local and far-reaching cascading transition risks towards degraded ecosystems in the Amazon biome under different Shared Socioeconomic Pathways. For these emission scenarios, we constructed how moisture is transported through the atmosphere within the Amazon basin using an established atmospheric moisture-tracking model5. Without accounting for deforestation, we find a critical global warming threshold of 3.7-4.0 °C, beyond which up to a third of the Amazon forest risks losing stability. However, when considering deforestation, we find a near system-wide transition of the Amazon forest (62-77% of the area) under the combination of a lower threshold range of global warming of 1.5-1.9 °C and deforestation of 22-28%. The large majority of the simulated transitions is caused by spatial knock-on effects from increasing drought intensities, leading to long-ranging and self-propelling cascades on scales of hundreds to thousands of kilometres. Overall, our results reinforce the need to keep global warming levels below 1.5 °C and halt deforestation, as well as ecologically restore degraded forests to avoid high transition risks across the Amazon forest system.

Annual increases in atmospheric methane have reached record highs over the past five years, yet the underlying processes and regional sources remain uncertain. Here we quantify the average 2019-2021 global methane budget using Bayesian 4D-Var inversions that assimilate satellite methane retrievals and in-situ δ13C-CH4 and δD-CH4 measurements. The methane-isotopic inversion yields total emissions of 623 [585-643] Tg/y, slightly higher than the methane-only inversion. Incorporating isotopic constraints leads to a redistribution of emissions in tropical and subtropical regions. Compared with the methane-only inversion, the methane-isotopic inversion indicates that emission estimates increase by 26 [-3-27] Tg/y in East Asia (primarily China), 7 [-1-8] Tg/y in South Asia (primarily India), and 5 [-3-10] Tg/y in central Africa, while decreasing by 5 [-6-7] Tg/y in Amazon Basin and 12 [-14-20] Tg/y elsewhere. This points to a stronger anthropogenic contribution to the post-2019 methane budget, including higher fossil emissions in China and slightly less wetland emissions in the Amazon Basin. The methane-isotopic inversion also alters inferred emission seasonality, showing less seasonality in China compared with the methane-only inversion, weaker coal-mine phase-out signals, and a delayed summer peak in Southeast Asia, pointing to sources missing from current inventories.

ABSTRACT The family Euryrhynchidae comprises freshwater shrimps with a disjunct distribution, occurring mainly in the Amazon basin. Basic biological information for this group, which is comparatively recent in evolutionary terms, is still lacking. The present study provides the first morphometric and biological data for Euryrhynchus amazoniensis and E. burchelli, analysing relative growth, sexual dimorphism and patterns of heterochely and handedness in both sexes. Specimens were collected from floodplain areas of two rivers in Manaus, northern Brazil. Individuals were measured for carapace length and for the articles of the chelipeds. In both species, males were larger than females and exhibited proportionally more developed chelipeds. No significant handedness pattern was observed, indicating that the larger cheliped may occur on either side of the body. In E. amazoniensis, relative growth analyses revealed strong sexual dimorphism, with males allocating more energy to cheliped development. Furthermore, the morphological analyses and evidence indicate the presence of different male morphotypes in this species, a pattern commonly reported for other freshwater carideans, but previously unrecorded for Euryrhynchidae. Overall, the results indicate that E. amazoniensis and E. burchelli share morphological patterns typical of other freshwater shrimps but also exhibit evolutionary particularities reflecting unique reproductive and ecological strategies, thereby expanding current knowledge of the biology of Euryrhynchidae.

Current understanding of potential anthropogenic/environmental drivers and ecotoxicological risks of emerging contaminants in the Amazon Basin, particularly organic flame retardants and plasticisers, is limited. We collected sediment samples from Amazonian Rivers near Manaus city/Amazonas State, Brazil, and measured concentrations of 39 organic flame retardants and plasticisers, namely: polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), dechlorane plus (DP), hexabromocyclododecane (HBCDD), organophosphate esters (OPEs), and polychlorinated biphenyls (PCBs). Concentrations of Σ9PBDEs, Σ9NBFRs, Σ2DPs, Σ3HBCDDs, Σ7OPEs, and Σ9PCBs ranged between <0.26 and 5.1, 2.0 - 18, <0.075 - 290, <0.0014 - 0.29, 2.2 - 15, and 0.18 - 3.0ng/g dw in sediments, respectively. Distribution of legacy BFRs (PBDEs and HBCDD), DPs, and OPEs in sediments was primarily driven by domestic sources; distribution of NBFRs was mainly driven by industrial sources; while distribution of PCBs was primarily modulated by organic matter. We also measured PBDEs in paired surface water samples collected from the Amazon basin near Manaus, with concentrations of Σ9PBDEs ranging between 0.18 and 3.4ng/L. In contrast to sediments, PBDE concentrations in water were primarily controlled by short-term aggregation and sedimentation enhanced by organic matter. Comparisons of our observations with PNEC (predicted no-effect concentration) values imply high ecotoxicological risks presented by DP, bis(2-ethyl hexyl) tetrabromophthalate (BEH-TEBP), PCB-11, and tris(1-chloro-2-propyl) phosphate (TCIPP) in sediments, and low to medium risks by other pollutants. This is especially striking for DP for which the maximum RQ (Risk Quotient) value was 24.7at sampling point 1, possibly due to the impact of domestic waste disposal and intensive boat traffic.

Oropouche virus: transmission, epidemiology, genetic diversity, and public health implications.

Abstract Increasing fire within the Amazon rainforest is a significant disturbance that has the potential to alter flow regimes and subsequently impact local ecology and ecosystem services. While previous studies have examined the impact of land cover change on streamflow, the specific effects of fire on the hydrology of Amazonian forested catchments remain uncertain, especially in previously undisturbed forests. This study investigates the impacts of fire on hydrology in the Amazon using a before‐after control‐impact (BACI) paired‐watershed approach. Our analysis tested for post‐fire changes in the magnitude and variability of the streamflow regimes of five watersheds in the southeastern Brazilian Amazon. Flow regime magnitude and variability were quantified using monthly basin yield and coefficient of variation, number of reversals, and average rise rate. Differences in metrics before and after fire disturbance were assessed relative to nearby reference watersheds. Following fire disturbance, three of five watersheds showed increases in magnitude and four watersheds showed increases in variability. Fire effect size ranged from 6.01% to 7.98% for streamflow magnitude and from 10.9% to 70.3% for variability. Our findings confirm that fire affects streamflow in the Amazon, with the primary impacts being increases in streamflow variability. Overall, this study provides insights into the impact of fire on Amazonian catchment hydrology and highlights the importance of considering fire as a factor in managing and protecting tropical forest ecosystems.

The North Channel of the Amazon River is a vital navigational gateway to the Amazon Basin. This paper analyzes the geomorphological evolution of the channel between 2011 and 2024, and assesses the observed morphodynamic processes, while also quantifying the differential uncertainty of the different sources of data. This analysis was based on a rigorous standardization process, which reprojected the multibeam survey data (2011) and digitized the nautical chart data (2024) to the SIRGAS 2000 metric system/UTM Zone 22S. This approach used ordinary kriging interpolation with individually fitted Gaussian models. The cross-validation of the results provided a measure of the disparity in the precision between the sources, revealing a low Root Mean Square Error (RMSE) of only 1.16 m for the 2011 model and a moderate, well-characterized error of 5.25 m for the 2024 model. The geomorphological analysis indicated a marked trend of silting, with mean depth decreasing from 26 m to 22 m, and the migration of the channel toward the east-northeast. These findings indicate that the safe management channel depends on an integrated approach that incorporates an accurate measure of this uncertainty. This analysis reinforces the need for continuous bathymetric monitoring, and supports the need to adopt adaptive navigational strategies, such as dynamic draft, to ensure operational safety in this complex fluvial system.

Hunter ants are among top invertebrate predators in tropical forests and play a key role in regulating invertebrate populations. This study documents new records of Ectatomminae and Ponerinae ants in the Colombian Amazon Basin. We provide the first country record of the genus and species Corrieopone nouragues, as well as new country records for ten other species: Alfaria simulans, Poneracantha mediatrix, Odontomachus allolabis, O. chicomendesi, O. davidsoni, O. ruginodis (sensu França et al. 2024), O. spissus, Pachycondyla procidua, Typhlomyrmex meire, and Simopelta anomma. Taxonomic notes are included for five species: Holcoponera auricula, H. dichotoma, Typhlomyrmex major, Odontomachus bauri, and O. ruginodis. An updated modified key is provided for species of Typhlomyrmex, along with the first photographs of the types of H. auricula and H. dichotoma, as well as the description of the queen of O. mormo.

The rediscovery of Lophophytum weddellii Hook. f. (Balanophoraceae) in Colombia is documented 135 years after its last record. Three individuals were found in Segovia, Antioquia, parasitizing Inga umbellifera (Vahl) Steud. (Fabaceae), representing the first confirmed host and photographic record for the country. Morphological data, pollen description, and floral visitors are reported. Historical notes on William Purdie&amp;rsquo;s 1845 collections and the biogeographic context of the Nech&amp;iacute; Refuge highlight the relevance of this finding for understanding the disjunct distribution of the species between the Magdalena Valley and the Amazon Basin.

ABSTRACT Climate change and habitat loss represent major threats to biodiversity worldwide, especially for species with narrow distributions and specific ecological requirements. Atelocynus microtis (Sclater, 1882) (Carnivora, Canidae), a forest‐dependent canid endemic to the Amazon Basin, is highly sensitive to environmental disturbances, making it particularly vulnerable to ongoing climatic and land‐use changes. In this study, we used species distribution models (SDMs) to evaluate the potential impacts of future climate scenarios on the distribution of A. microtis , and to assess the effectiveness of protected areas (PAs) in maintaining suitable habitats for the species. We compiled and filtered occurrence records, applied environmental and spatial thinning, and developed ensemble models using six algorithms under baseline and future climate scenarios (SSP2–4.5 and SSP5–8.5, 2061–2080). SDMs were constrained by vegetation cover and masked to the Amazon biome. Our results indicate a potential loss of 21% to 53% in suitable habitat under future climate conditions. However, despite this projected decline, approximately 53% of suitable range remains within PAs across all scenarios, far exceeding the minimum conservation target of 10% for wide‐ranging species. This underscores the critical role of PAs, particularly Indigenous lands, in safeguarding Amazonian biodiversity under accelerating anthropogenic pressure. These findings reinforce the need to strengthen and maintain the integrity of conservation networks, especially in regions like the southern Amazon where projected habitat losses are most severe. Our results highlight the importance of integrating climate resilience into conservation planning to ensure long‐term species survival.

Flaviviruses (genus Orthoflavivirus, family Flaviviridae) are positive-sense RNA viruses able to infect a wide range of hosts and are associated with disease in humans, domestic animals and wildlife; thus, they are considered a major global health concern. The sylvatic cycle is potentially linked with human outbreaks; therefore, it is essential to monitor and understand flavivirus infections in wildlife. Little is known about flaviviruses in cetaceans. To fill part of this knowledge gap, we surveyed for the presence of flavivirus RNA in tissues (brain, spleen, lung, kidney, lymph node, liver, and adrenal gland) and serum samples of 151 cetaceans of 22 species that were found stranded, bycaught, or live captured in scientific expeditions in Brazil in two different biomes (marine and Amazon basin). Total RNA was extracted from 589 samples (523 tissues and 66 sera) using commercial kits; subsequently, a broad-range real-time PCR targeting the Orthoflavivirus genus was performed. All individuals were negative for flavivirus RNA (95% confidence interval, 0-1.96%). These results potentially indicate that the known flaviviruses, if present, have limited circulation in wild cetaceans, likely accidental hosts. Future studies are warranted to understand the epidemiology of flaviviruses within the genus Orthoflavivirus in cetaceans.

In March 2024, Brazil reported an unprecedented Oropouche fever outbreak, driven by the emergence of a reassortant lineage of the Oropouche virus (OROV) expanding beyond the Amazon Basin. To investigate the expansion dynamics of OROV, we implemented complementary phylogeographic and ecological niche modelling approaches that aimed to characterize the environmental factors associated with the range expansion and the risk of local circulation, respectively. Our analyses reveal a multiscale expansion process with both short- and long-distance dispersal events and diffusion velocities in line with air traffic-mediated jumps. We identify banana and cocoa cultivation, temperature, the predicted suitability of the primary vector Culicoides paraensis and human population density as key environmental factors associated with OROV range expansion in new areas. We further show that OROV circulated in areas of enhanced ecological suitability immediately preceding its explosive epidemic expansion in the Amazon. Our study provides valuable insights into the dispersal and ecological dynamics of OROV, highlighting the probable role of human mobility in the long-distance colonization of new areas and raising concern over high viral suitability along the Brazilian coast.

A new species of the genus Tympanopleura is described from the Iquiri River, a tributary of the Ituxi River, a right-bank tributary to the Purus River, Amazon River, northern Brazil. The new species is distinguished from all its congeners by a combination of features, such as the presence of an intensely pigmented square-shaped blotch on the supraoccipital, a semicircular dark blotch above each eye and an inconspicuous vertical bar on the caudal-fin base (except Tympanopleura piperata), and by a combination of meristic and morphometric character states. Preliminary molecular analyses demonstrate genetic distance values of 2.4% of cytochrome oxidase, subunit I, divergence between the new species and T. piperata and 8.0%-13.0% between the new species and the other congeners. The new species shows several reproductive adaptations to copulation and internal insemination. Considering the period during which prenuptial and nuptial specimens were available, we can presume that its reproductive period occurs when the water level increases. In addition, an identification key for the species of Tympanopleura is provided.

Peru is a megadiverse country, home to some of the world's most important biodiversity hotspots. This paper systematically reviews published studies on the phylum Rotifera in Peru, aiming to identify key features, knowledge gaps, and research challenges, thereby contributing to the conservation of rotifers. A brief history of rotifer studies is presented, and the first annotated checklist is provided of all rotifer taxa recorded according to their most recent taxonomic status, valid nomenclature, and department distribution. The number of studies on Peruvian rotifer fauna is limited, with only 35 publications. These papers are primarily in the Spanish language and are published in national journals. Ecological studies, often conducted on a short-term basis, frequently dominate classical taxonomic works. Additionally, many departments and types of freshwater environments in the country remain understudied. To date, 203 valid rotifer species have been recorded. This number is unrepresentative, as more than half of the departments lack documented records. Most recorded rotifer species in Peru are from freshwater habitats in the eastern of the country, particularly near the Amazon Basin. Several important gaps are highlighted, including the need for precise revision of existing records, promoting taxonomic harmonization, and enhancing sampling efforts.

ABSTRACT The Amazon Basin is home to the world's greatest terrestrial biodiversity, but many plant groups remain poorly studied. One example is the mycoheterotrophic genus Thismia (Thismiaceae), which is notable for its highly specialized floral morphology and ephemeral life cycles, making it difficult to detect in the field and limiting its representation in scientific collections. Here, we report the first confirmed record of Thismia pseudomelanomitra in the Ecuadorian Amazon and expand its known distribution to the Brazilian State of Acre. Our study is based on a comprehensive review of herbarium specimens (AAU, RB, UFACPZ) and photographic records from iNaturalist.org . We also provide the first morphological description of its fruits and seeds, a distribution map, and an identification key for Ecuadorian species. Morphological comparisons reveal significant differences from related taxa, particularly T. melanomitra and specimens previously assigned to T. singeri . These findings highlight the role of citizen science and integrative approaches in documenting rare taxa and advancing conservation strategies.