The genus Pterotiltus, first established in 1893, has long been a taxonomic headache. Its twelve previously known species live exclusively in the wet forests of West and Central Africa, stretching from Ghana through Cameroon and the Congo Basin into Central Uganda. Yet museum drawers hold remarkably few specimens. The insects inhabit dense forest understory that is difficult to penetrate, and their populations are scattered across an enormous altitudinal range, from sea level up to more than 2,000 meters. As far back as 1972, the French entomologist Marc Descamps flagged Pterotiltus as an African genus urgently requiring revision, a call that has gone largely unanswered until now.

The new work, led by entomologist Oumarou Ngoute C., is based on specimens collected across six localities in Cameroon’s lowland and highland rainforests, including Campo National Park on the coast and Nki National Park in the country’s remote southeast. In the southern lowlands, the team encountered two striking new species. Pterotiltus ngoylaensis, found at around 500 meters in Nki National Park, is predominantly green with black and yellow markings and sports eyes that are conspicuously violet in life, a trait unique within the entire genus. Pterotiltus campoensis, discovered near sea level in Campo National Park, breaks the mold in a different way: it is the only known member of the genus dominated by vivid red and blue-black coloration rather than green.

Both lowland species share the hallmark adaptations that led one reviewer to describe Pterotiltus as the culmination of adaptation to forest life among its subfamily, the Oxyinae. All species in the group are flightless, their wings reduced to tiny ridges or minute flaps that never extend beyond the thorax. Their ovipositors have evolved smooth, rod-like valves, an adaptation for laying eggs in highly specialized sites, and researchers have previously documented one species gluing its eggs directly onto the leaves of its food plants. These are insects that have traded the open grasslands of their relatives for a life spent clambering through the herb layer of the forest floor.

The real surprise came from the highlands of western Cameroon. There, at elevations between roughly 1,300 and 2,400 meters, the team collected grasshoppers that outwardly resembled Pterotiltus but carried a suite of anatomical differences too substantial to ignore. The males averaged just 12 to 14 millimeters in length, notably smaller than their lowland cousins. Their forewings, though tiny, were actually present and sometimes brightly colored, rather than almost entirely lost. Most tellingly, the fine structures of the reproductive system told a different evolutionary story in both sexes.

Male grasshoppers in this group are classified largely by the architecture of the epiphallus, a sclerotized structure at the top of the phallic complex, and the valvular plate that covers the aedeagus. In lowland Pterotiltus, the outer lophi of the epiphallus are long, slender, blade-like, and curved forward, while the valvular plate is foliose, elaborately ornamented with cuticular folds that often take species-specific forms. In the highland insects, the lophi curve upward and inward instead, ending in horn-like points or bifid tips, and the valvular plate is simple and unadorned. The females clinched the case: their subgenital plates bear two robust, rearward-directed projections that are completely absent in Pterotiltus.

On the strength of these differences, the researchers erected a new genus, Parapterotiltus, with the previously enigmatic species Pterotiltus minimus, described from a single male back in 1929, as its type. The study also finally describes the female of that species for the first time, nearly a century after the male was named. Two additional new species join the genus: Parapterotiltus minimoides, so named because it is almost indistinguishable from P. minimus in outward appearance, and Parapterotiltus bamboutos, a black-bodied species known only from the slopes of Mount Bamboutos. Remarkably, the two lookalike species occur together at some of the same sites between 1,000 and 1,600 meters, separated not by geography but by anatomy that only becomes obvious under the microscope.

The taxonomic detective work involved meticulous measurement. The team quantified body proportions, tarsal segment lengths, tibial spine counts, and ratios of sexual dimorphism, normalizing measurements against pronotum length so that species of different sizes could be compared fairly. Dissections of genitalia required relaxing pinned specimens, macerating tissue in potassium hydroxide, and staining structures with acid fuchsin, a reminder that species boundaries in this group rest on anatomy invisible to anyone walking through the forest. The researchers are now preparing a full revision of Pterotiltus, with the current paper serving as its foundation.

There is an urgent conservation dimension to the discovery. Parapterotiltus bamboutos is known from a single, very small population on Mount Bamboutos, one of the most degraded mountains in Cameroon, where human activity has destroyed nearly all remaining forest pockets and replaced them with crops. The authors warn that conservation measures are needed urgently, though a 2010 photograph from nearby Mount Kupe hints the species may survive elsewhere along Cameroon’s volcanic line. The lowland species fare somewhat better, since both Nki and Campo Ma’an National Parks offer protected habitat, but deforestation across southern Cameroon continues at an accelerating pace, and these strictly forest-dependent insects have nowhere else to go.

The study also carries a broader lesson for how biodiversity is catalogued in the tropics. Because external appearance in these grasshoppers is so uniform, species have historically been defined by subtle differences in size and color, and ecologists working with incomplete identifications have faced an unenviable choice between excluding uncertain records or risking inaccuracy. The new work shows that the real diversity is written in the genitalia, structures so varied between species that they can even justify splitting a genus in two. As the authors note, the poorly surveyed highlands of western Cameroon may hold more undescribed taxa still, provided the forests they depend on last long enough for anyone to find them.

Subject of Research: Taxonomic description of new flightless grasshopper species and a new genus from Cameroon's rainforests

Article Title: New species of Pterotiltus from Cameroon, and a new genus, Parapterotiltus ( Orthoptera , Acrididae , Oxyinae )

Article References: Oumarou Ngoute, C., & Rowell, C. H. F. (2024). New species of Pterotiltus from Cameroon, and a new genus, Parapterotiltus (Orthoptera, Acrididae, Oxyinae). Journal of Orthoptera Research, 33(1), 127-146. https://doi.org/10.3897/jor.33.96043

Image Credits: AI Generated

DOI: 10.3897/jor.33.96043

Keywords: grasshoppers, Cameroon, new species, Orthoptera, taxonomy, biodiversity, rainforest, Parapterotiltus, Pterotiltus, entomology, conservation, Africa

The stakes are considerable. The GBMWHA, inscribed by UNESCO in 2000, protects over one million hectares of vegetation celebrated for its Outstanding Universal Values, including ancient Gondwanan plant lineages found nowhere else on Earth. Yet rainforest represents only about one percent of the currently mapped vegetation in the reserve. When vegetation mapping fails to match what grows on the ground, management decisions such as prescribed burning, conservation prioritisation and threat mitigation are built on a distorted picture of where significant biodiversity actually resides. For fire-sensitive rainforest pockets embedded within flammable eucalypt forest, that distortion can be lethal.

The research team set out to validate the regulatory vegetation map units, known as Plant Community Types (PCTs), across the Hawkesbury subsection of the GBMWHA, an area bounded by the Colo, Nepean-Hawkesbury and Grose rivers and the township of Bilpin. The PCT classification is a major numerical undertaking: it was built from more than 90,000 floristic plots spanning 23.5 million hectares of eastern New South Wales, standardised to a modified six-point Braun-Blanquet cover-abundance scale, and embedded within the NSW State Vegetation Type Map (SVTM) that now underpins environmental regulation. Preliminary field survey, however, had hinted at large-scale mapping errors in the region’s remote gullies, where deep sheltered terrain and the moisture-rich Burralow Formation sediments create conditions favourable to rainforest.

To test whether the vegetation in these largely unsurveyed areas could be reliably matched to existing PCTs, the researchers deployed 55 plots across two complementary survey campaigns. Forty-six plots followed the standard NSW government technique for assessing cover and abundance within 20 by 20 metre quadrats, while nine larger circular plots of roughly 700 square metres quantified structural elements such as size class distributions and growth stages, with allometric equations scaling projected foliage area against stem diameter. Sites were stratified along an aridity gradient and split between two topographic positions: ‘Gully’ sites in deep sheltered locations near creeks, and ‘Bench’ sites at more elevated positions at the base of escarpments or on upper slopes. Crucially, the team also recorded bryophytes, the mosses, liverworts and hornworts typically overlooked in vegetation classification, through 15-minute active searches at 26 plots.

The statistical verdict was unambiguous. Using non-metric multidimensional scaling ordinations built on Bray-Curtis dissimilarity, the metric emulating the NSW PCT classification approach, the team found that their field plots occupied vacant ordination space defined by the established PCTs. Permutational multivariate analysis of variance (PERMANOVA) confirmed that the two putative communities differed significantly in floristic composition from all locally mapped PCTs and from all plausible regional rainforest PCTs, with all p-values at or below 0.038 after false discovery rate correction. The results held under both Bray-Curtis and Gower dissimilarity indices, which treat Braun-Blanquet classes differently, demonstrating that the findings were not an artefact of metric choice. Permutational analysis of multivariate dispersion showed the new communities ranked among the tightest groups in ordination space, meaning their distinctiveness was not inflated by internal spread.

The team then ran their data through the NSW government’s Eastern NSW Plot to PCT Assignment Tool, the formal instrument used to meet regulatory obligations. The Tool returned best matches scattered across as many as eight different PCTs for the Gully plots and five for the Bench plots, with no coherent geographic or environmental story. The authors argue that such inconsistency, even when matches fall within the Tool’s statistical threshold of 0.695 distance-to-centroid, indicates a habitat the existing classification does not adequately capture. The 0.695 threshold, they note, represents the 95th percentile of distances for well-sampled PCTs and is designed to test statistical stability, not ecological distinctiveness. Floristically, the new communities sat closest to coastal rainforest types from the Illawarra and Central Coast regions, hundreds of kilometres away, rather than to any locally mapped rainforest.

Bryophyte data added an unexpected layer of discrimination. The 34 bryophyte species recorded separated the Gully and Bench communities in ordination space, with non-overlapping 95 percent confidence intervals around group centroids and a marginally significant PERMANOVA result. The moss Papillaria flavolimbata, which festoons tree branches in Bench rainforest, was never observed doing so in Gully rainforest, while several liverworts and hornworts such as Symphyogyna podophylla and Bazzania adnexa were restricted to creekside Gully sites. The authors suggest that integrating non-vascular plant data into community analysis could become a useful tool for Australian vegetation classification, though they caution that bryophytes varied more within communities than between them, likely reflecting fine-scale responses to moisture, substrate and light.

Spatial mapping revealed the true scale of the discrepancy. Using high-resolution aerial imagery, canopy height modelling and terrain analysis to isolate gullies and benches, then ground-truthing the output across two field campaigns, the team estimated a conservative minimum extent of 2,086 hectares of rainforest in the study area, against just 645 hectares documented in the SVTM. The overlap between the two mapping products was a mere 12 percent, implying the SVTM may carry a false positive rate exceeding 40 percent, which would push the actual increase in rainforest extent closer to seven or eight times the official figure. The team mapped over 40 distinct patches of Bench rainforest ranging from 1 to more than 30 hectares, and proposed two new vegetation types for inclusion in the PCT classification: ‘Hawkesbury Warm Sheltered Gully Rainforest’ and ‘Hawkesbury Subtropical-Dry Bench Rainforest’, intermediate forms bridging warm temperate, subtropical and dry rainforest.

The botanical significance of these communities is striking. Bench rainforest ranked highest in mean species richness among all regional rainforest PCTs with more than one reference site, and Gully rainforest ranked third. The communities harbour regionally rare species and notable range extensions, including the white cedar relative Dendrocnide photinophylla, apparently restricted to a single location with fewer than fifty living trees more than 100 kilometres from its nearest known population, and several hundred individuals of the Critically Endangered tree Rhodamnia rubescens across at least five populations. The team also recorded species such as Gmelina leichhardtii, Ficus henneana, Diospyros pentamera and Calanthe triplicata, many documented decades ago in botanical surveys of the Wheeny Creek area by ecologist Rosemary Floyd, whose historical records the authors argue were overlooked during the development of contemporary mapping.

The refugial story behind these rainforests is one of the study’s most compelling threads. As Australia drifted north and aridified from the Late Eocene, rainforest contracted under fire regimes favouring sclerophyllous species, persisting in pockets where conditions remained suitable. The Hawkesbury landscape, with mountain peaks receiving 1,200 to 1,300 millimetres of annual precipitation, deeply incised gorges and the semi-impermeable clay layers of the Burralow Formation acting as aquitards, appears to have buffered these assemblages from long-term climate drying and fire. The authors speculate that under past climates, more extensive rainforest links once existed between the Illawarra, Hawkesbury and Central Coast regions, dispersed along the hydrological conduit of the Hawkesbury-Nepean River and the movements of fruit-eating fauna.

That refugial buffering is now under threat. By 2090, the study region is predicted to warm by up to 3.4 degrees Celsius, lose up to 10 percent of annual rainfall and suffer more severe fire weather days. The Gully and Bench rainforests cover less than 1,000 hectares across four small subcatchments, making them acutely vulnerable to wildfires like those of 2019-2020, which affected hundreds of thousands of hectares. The researchers observed evidence that some rainforest patches within historical fire perimeters had been transformed into perpetual vine thickets with few large trees. Myrtle rust, the introduced pathogen Austropuccinia psidii, was consistently observed on Rhodamnia rubescens and other species, while invasive plants including Ochna serrulata and Lantana camara compete with threatened populations. Illegal four-wheel drive and mountain bike activity in the ridgetops of the Burralow, Wheeny and Gospers Creek catchments risks igniting unplanned fires and transporting weeds and pathogens into undisturbed areas.

The authors urge rapid revision of the PCT mapping and targeted measures to protect the remaining patches, warning that fires and urban development pressures will likely threaten the integrity of these rainforests in future. Prescribed burning is implemented across the region to reduce wildfire risk to lives and property, and rapid urban expansion is converting former rural lands to housing at the bushland interface, raising the probability of unplanned ignitions. Because 65 percent of the surveyed rainforest sites are officially mapped as sclerophyll forest, there is a material risk of off-target impacts from fire management activities within the World Heritage Area. The new community descriptions, diagnostic species lists and revised mapping provide land managers with the tools to plan burns around rainforest boundaries and to conserve what the authors describe as remnants that hold the stories of plant evolution over geological time, contributing more to the Outstanding Universal Values of the World Heritage Area than has previously been ascribed.

Subject of Research: Identification of distinctive new rainforest communities in the Greater Blue Mountains World Heritage Area, Australia

Article Title: Identification of distinctive new rainforest communities in the Greater Blue Mountains World Heritage Area, Australia

Article References: Bendall, E. R., Wong, V., Bell, S. A. J., & Gallagher, R. V. (2026). Identification of distinctive new rainforest communities in the Greater Blue Mountains World Heritage Area, Australia. Vegetation Classification and Survey, 7, 103-125. https://doi.org/10.3897/vcs.186732

Image Credits: AI Generated

DOI: 10.3897/VCS.186732

Keywords: Identification, distinctive, rainforest, communities, Greater, Blue, Mountains, World, Heritage, Area, Australia, scientific research

Biscogniauxia belongs to the family Graphostromataceae within the order Xylariales, a group of ascomycete fungi known for their dark, carbonaceous fruiting bodies called stromata. The genus was established in 1891 with Biscogniauxia nummularia as its type species and is characterized by corticolous, bipartite stromata that develop beneath the bark of host trees and break open when mature. These fungi produce unitunicate asci with an amyloid apical apparatus and ellipsoid brown ascospores bearing germ slits, usually without slimy sheaths or appendages. For decades the genus was assigned to the family Xylariaceae based purely on morphology, but multigene phylogenetic analyses by Wendt and colleagues in 2018 segregated it into Graphostromataceae alongside genera such as Graphostroma, Camillea, Obolarina and Vivantia.

Today Biscogniauxia is the largest genus in Graphostromataceae, with more than 65 widely accepted species recorded across North America, Africa, Europe, Asia and Oceania. Most species are saprobes that decompose dead wood, but some are plant pathogens capable of causing diseases in a wide range of dicotyledonous angiosperm trees, including hosts as diverse as Eucalyptus, Quercus, Prunus, Fagus and Acer. Others live as endophytes inside healthy plant tissues, waiting until their hosts become old or stressed before turning pathogenic. Some species are also notable producers of novel bioactive compounds and secondary metabolites, making the genus of considerable ecological and economic interest.

Despite this broad distribution, the species diversity of Graphostromataceae in tropical regions remains poorly understood. China has documented 17 species and 4 varieties of Biscogniauxia, but collections from the country’s tropical areas are few, and many undescribed novel species are expected to exist. The Hainan Tropical Rainforest National Park, located in south-central Hainan Province between roughly 18°33’N and 19°14’N, harbours 4,367 higher plant species across 1,368 genera and 289 families under a tropical monsoon climate. Only three species of Graphostromataceae had previously been documented from the entire island, underscoring how little explored this fungal lineage is in tropical China.

The research team collected dead branches bearing fungal stromata from the park and deposited the dried specimens in the Fungarium of the Institute of Tropical Bioscience and Biotechnology at the Chinese Academy of Tropical Agricultural Sciences. Macroscopic features were documented with field photographs and examined under a Keyence VHX-6000 3D microscope, while microscopic structures were observed with an Olympus IX73 inverted fluorescence microscope using a 100x oil immersion objective. Sections were mounted in water, Melzer’s reagent and potassium hydroxide to reveal diagnostic characters. At least 30 asci and 50 ascospores from each specimen were measured randomly, with 5 percent of measurements excluded from each end of the reported size ranges to reflect natural variation.

For the molecular work, genomic DNA was extracted from the dried specimens and three genetic loci were amplified: the internal transcribed spacer region of nuclear ribosomal DNA, a portion of the beta-tubulin gene, and a segment of the RNA polymerase II second largest subunit gene. These three markers, abbreviated ITS, TUB2 and RPB2, are standard tools in fungal systematics because they evolve at different rates and together provide enough resolution to distinguish closely related species. The newly generated sequences were uploaded to NCBI GenBank and combined with publicly available data from 61 strains representing 43 species, including relatives in Camillea, Cryptostroma, Graphostroma and Obolarina, with Jackrogersella cohaerens and Hypoxylon rubiginosum serving as outgroups.

The combined dataset contained 3,233 aligned characters, of which 1,683 were constant, 1,326 were phylogenetically informative and 224 were variable but uninformative. Maximum likelihood analysis using the RAxML GUI software with the GTRGAMMA model and 1,000 rapid bootstrap replicates, along with Bayesian inference using MrBayes with jModelTest-selected substitution models run for 3,000,000 generations, produced highly similar tree topologies. The results confirmed that both new species belong to Biscogniauxia but occupy clearly separate positions within the genus. Biscogniauxia jianfengensis grouped with Biscogniauxia philippinensis var. microspora with maximum support, while Biscogniauxia diaoluoshanensis resolved as a basal lineage of the other Biscogniauxia taxa included in the study.

Morphologically, the two species are readily distinguishable. Biscogniauxia diaoluoshanensis produces applanate, orbicular to irregularly lobed stromata measuring 4 to 12 centimetres across, with shiny black surfaces and conspicuous depressions. Its perithecia are ovoid to pyriform, frequently flattened laterally and basally, and its ascospores are light brown to brown, ellipsoid and almost equilateral, with a conspicuous straight germ slit that runs almost the full length of the spore. Biscogniauxia jianfengensis, by contrast, forms applanate to slightly pulvinate stromata that coalesce into widely effused compound structures with dull black, matte surfaces. Its perithecia are tubular to short-tubular, and its dark brown to blackish brown ascospores are inequilateral, bearing an inconspicuous unilateral germ slit on the most convex side and, remarkably, an opaque thick-walled cellular appendage on one side, a feature that sets it apart from most of its congeners.

Sequence divergence comparisons further reinforced the distinctness of the new species. Biscogniauxia nummularia, the type species of the genus, differs from B. diaoluoshanensis by 168 base pairs in the TUB2 alignment, representing 11.52 percent of the aligned region, while strain CBS 969.70 of the same species shows 95- and 164-base-pair divergences in RPB2 and TUB2 respectively. Biscogniauxia capnodes differs by 83 base pairs in RPB2, and for other congeneric species sequence similarity to the new taxon falls below 91 percent for both RPB2 and TUB2, with ITS similarity below 86 percent for all previously known species. Unfortunately, no molecular sequences are available for Biscogniauxia philippinensis, so nucleotide comparisons with that tropical relative could not be performed, though its larger ascospores of 22 to 27 by 11.5 to 13 micrometres distinguish it morphologically from B. jianfengensis.

The phylogenetic analyses also confirmed that Biscogniauxia is polyphyletic, consistent with several previous studies, with species distributed across six separate clades and Camillea species nesting within the Biscogniauxia clade. This finding suggests that the generic classification remains ambiguous and that further studies with expanded sampling across broader geographic regions are needed. The researchers also proposed a dichotomous identification key to the Biscogniauxia taxa known from China, incorporating the two new species. Given how sparse records of Graphostromataceae remain across tropical Asia, the team expects that continued surveys across the diverse forest types of Hainan will yield additional new species, adding to a growing catalogue of fungal life emerging from one of China’s richest tropical ecosystems.

Subject of Research: Two new Biscogniauxia fungal species from Hainan Tropical Rainforest National Park are described using morphology and ITS, RPB2 and TUB2 phylogenetics.

Article Title: Phylogenetic analyses and morphological studies reveal two new species of Biscogniauxia ( Xylariales , Ascomycota ) from Hainan Tropical Rainforest National Park, China

Article References: Ma, S.-Y., Liu, S., Qu, Z., Jiang, H., Zhu, A.-H., & Ma, H.-X. (2026). Phylogenetic analyses and morphological studies reveal two new species of Biscogniauxia (Xylariales, Ascomycota) from Hainan Tropical Rainforest National Park, China. MycoKeys, 140, 241-259. https://doi.org/10.3897/mycokeys.140.206566

Image Credits: AI Generated

DOI: 10.3897/mycokeys.140.206566

Keywords: Phylogenetic, analyses, morphological, studies, reveal, species, Biscogniauxia, Xylariales, Ascomycota, Hainan, Tropical, Rainforest

The central finding is stark: in the absence of human ignition, Amazonian forest fires rarely, if ever, start and spread on their own. Before people arrived in South America during the late Pleistocene, paleoecological records show little to no fire. Sediment cores from Serra Sul dos Carajás in drier eastern Amazonia lacked fire at some sites until the deglacial period and the onset of the Holocene, and where glacial-age fire did occur, charcoal abundances were far lower than in the last 10,000 years. Even fire-prone settings tell the same story. Lakes on the rainforest-savanna ecotone in Bolivia show very low and infrequent fire during the glacial period, high Andean lake sediments contain only minuscule pre-human charcoal, and a sediment core from 2,700 meters on the eastern Andean slopes of Ecuador recorded an absence of fire for 30,000 years until human activity began around 4,500 calibrated years before present.

To build the new reconstruction, the researchers compiled 1,361 accelerator mass spectrometry radiocarbon dates from 303 sites, discarding 32 modern post-1950 dates and analyzing the remaining 1,329 individually calibrated ages, which span the last 12,000 years. The dataset combined 815 dates from archaeological sites where the dated material was explicitly described as charcoal or charred, and 546 dates from charcoal fragments retrieved from soil cores, including 31 new fragments the team submitted from eight soil sites across three regions of northwestern and southwestern Amazonia. Each date was calibrated with the IntCal20 or SHCal20 curve, and the team used summed probability distributions alongside composite kernel density estimations, repeated 1,000 times on random draws of the data, to guard against overinterpreting noise and calibration-curve artifacts.

The results reveal a clear geographic trajectory for fire in the basin. The earliest fires cluster in peripheral areas and along the main Amazon River channel, mirroring the earliest archaeological sites in the region. Fire activity increased across most regions between roughly 6,000 and 4,000 years ago, a period that also saw a rise in dated occupation sites across South America and coincides with the earliest documented maize cultivation in northwestern and southwestern Amazonia. From there, human-ignited fire spread geographically, and by about 2,000 years ago it appears across all regions and deep into the interior of the forests, a timing consistent with many Amazonian societies transitioning to sedentary lifestyles reliant on cultivation and plant domestication.

Not every region followed the same script. Random mark permutation tests, which compared each region’s summed probability distribution against the basin-wide pattern 1,000 times, showed that central Amazonia lagged behind the rest of the basin, with significantly lower fire activity for most of the period from 7,000 to 2,000 years ago and only exceeding other regions in the last 1,500 years. Northwestern Amazonia showed higher activity than other regions around 4,000 to 2,000 years ago but lower activity during the last 800 years. The southwestern and central regions were even antiphased between about 1,500 and 500 years ago, with one rising as the other fell, underscoring that fire histories were not regionally synchronous.

The most striking pattern, however, emerges in the last millennium. Overall fire frequency peaked between 1,300 and 500 calibrated years before present, corresponding to roughly A.D. 700 to 1450, and then declined in a two-phase pattern. The first decline began around 700 to 500 years before present, several centuries before Europeans first traveled down the Amazon River in A.D. 1541, and appeared in every region of the basin, though not synchronously. A second wave of decline in the frequency and density of dated material followed after European arrival. The authors argue that these two waves support two distinct demographic hypotheses: an ‘early abandonment’ or major land-use change preceding contact, and the ‘Great Dying’ — the catastrophic collapse of Indigenous populations estimated at 90 to 95 percent through enslavement, disease, and warfare following colonization.

The pre-contact decline is particularly significant because it has been contested. An estimated 5 to 20 million Indigenous people lived in Amazonia before European arrival, and the Great Dying has been hypothesized to have driven large-scale site abandonment and even a measurable dip in atmospheric carbon dioxide as forests regrew and sequestered carbon. Yet a previous synthesis of lake sediment records found no signal of widespread abandonment and reforestation at the moment of European contact; instead, it documented larger changes in fire and vegetation several hundred years earlier. The new soil and archaeological dataset, with its much broader spatial coverage than lake records alone, independently confirms that the earlier signal is real, while the larger sample size now also reveals the subsequent post-contact decline. The reason for the initial pre-European abandonment or land-use change remains unknown.

Why does fire matter so much in this forest? Because Amazonian plants evolved for millions of years in landscapes where fire was essentially absent, most species lack any adaptation to survive burning. A single fire can trigger significant species turnover, and repeated burns can produce complete turnover, favoring the few lineages with some fire tolerance, such as certain palms. A recent synthesis of Holocene charcoal and pollen from lake sediments showed that vegetation responses to human activities were slow and gradual until the last 2,000 years, then accelerated sharply. The new radiocarbon synthesis captures that same acceleration, showing fire spreading across all regions during the final two millennia of the pre-Columbian era.

The scale of that transformation leads the authors to a provocative conclusion: the restructuring of Amazonian pyrogeography over the last 2,000 years has likely induced rates and magnitudes of vegetation change comparable to, or exceeding, major climatic events such as deglaciation or ecological upheavals like the extinction of Pleistocene megafauna. Because the pool of species able to return after fire remained biogeographically and evolutionarily Amazonian and essentially fire-sensitive, the overall impact on plant assemblages has been subtle — shifting the balance toward species that were already present but tolerated fire best — yet the fingerprint of millennia of human fire management is now understood to be embedded in the structure of the forests standing today.

The study also demonstrates the power of newly curated databases. The Neotoma Database houses paleoecological data from lake sediments, the Latin American Pollen Database catalogs published records, and the recently launched AmazonArch database documents more than 6,000 archaeological sites with locations and radiocarbon dates. By integrating these compilations with new soil-charcoal dates, the researchers show that the modern Amazon is not a pristine wilderness untouched by fire, but a landscape whose fire regime — and therefore whose forest composition — was shaped by Indigenous societies for millennia, then reshaped again by their demographic collapse. As modern fires increasingly penetrate standing rainforest, understanding this deep history of human-fire interaction becomes essential context for conserving what remains.

Subject of Research: Holocene fire history and human-driven pyrogeography of the Amazon basin reconstructed from radiocarbon-dated charcoal and archaeological material

Article Title: The pyrogeography of Amazonia: a Holocene perspective

Article References: McMichael, C. N. H., Heijink, B. M., Witteveen, N. H., Zwarts, A., & Bush, M. B. (2026). The pyrogeography of Amazonia: a Holocene perspective. Frontiers of Biogeography, 19, Article e169863. https://doi.org/10.21425/fob.19.169863

Image Credits: AI Generated

DOI: 10.21425/fob.19.169863

Keywords: Amazonia, pyrogeography, radiocarbon dating, charcoal, Holocene, Indigenous populations, Great Dying, early abandonment, paleoecology, fire history, archaeology, rainforest

Tomocyrba is a genus of jumping spiders in the family Salticidae, subfamily Hisponinae, endemic to Madagascar. It was first described by the famed French arachnologist Eugène Simon in 1900, based on specimens collected near Antongil in northeastern Madagascar. Despite its early recognition, the genus has received remarkably little taxonomic attention since then. In fact, until now, only a single contribution to its taxonomy had been made in the last 120 years: a 2009 revision by Tamás Szűts and Nikolaj Scharff, which expanded the genus to six species, four of which were newly described at that time. All previously known material was based on historic type specimens more than a century old, leaving researchers with little understanding of the spiders’ ecology, variation, or true diversity.

The new study stems from two recent expeditions to northern Madagascar organized by the Biodiversity Inventory for Conservation (BINCO) and collaborators. One expedition targeted the Mahimborondro protected area in the far north of the island, while the other explored Makira Natural Park near the town of Maroantsetra, close to Antongil Bay. These surveys yielded a small but scientifically precious collection of adult Tomocyrba specimens, allowing lead author Brogan L. Pett to describe one species new to science and to provide a supplementary redescription of the type species, Tomocyrba decollata Simon, 1900, based on the first newly collected material in over a century.

The new species, named Tomocyrba ankihiberta sp. nov., was found in the Mahimborondro protected area at an elevation of 1,500 meters in tropical rainforest. The name derives from the Malagasy word ankihibe, meaning thumb, combined with RTA, the abbreviation for retrolateral tibial apophysis, a key anatomical feature of the male pedipalp. This thumb-like structure is one of the distinctive traits that sets the new species apart from its relatives. Both a male holotype and a female paratype were collected between late January and mid-February 2019 and are now deposited in the Royal Museum for Central Africa in Tervuren, Belgium.

Diagnosing a new spider species relies heavily on the intricate architecture of reproductive structures, which are often species-specific and act like evolutionary fingerprints. In male T. ankihiberta, the embolus, the slender sperm-transferring structure at the tip of the pedipalp, is barbed, slightly bent, and tapers to a sharp point, projecting prolaterally along its entire length. This distinguishes it most clearly from its closest relative, T. barbata, whose embolus is curved retrolaterally in its basal half, broad, and lacks a tapered point. The retrolateral tibial apophysis in the new species is short, rounded, and thumb-like, whereas in T. barbata it projects a short distance before curving back toward the palp with a thin sharp point. Females of the new species share long, mostly straight copulatory ducts with T. berniae, but differ in having two copulatory openings rather than one, and in possessing paddle-shaped, chambered spermathecal walls rather than undulating, tube-like ones.

The rediscovery of Tomocyrba decollata is equally significant. The species was originally described from specimens collected at Antongil, likely corresponding to the port city of Maroantsetra adjacent to Antongil Bay. The 2009 redescription relied on syntype material more than 120 years old, with specimens so bleached that the female’s internal genitalia could only be examined by temporarily clearing the abdomen with methyl salicylate, a technique that left the vulva unprepared for detailed study. The new material, consisting of two males and one female collected in Makira Natural Park in September 2023, represents the first records of this species in 120 years and provides the first-ever illustration of the internal structure of the female epigyne. Remarkably, the new collection site lies possibly only around 30 kilometers from the original type locality.

The fresh specimens allowed for a thorough redescription of T. decollata, revealing details that had been obscured by the degraded condition of the historic types. Males are easily recognized by a very short, undulating embolus and a broad, evenly rounded retrolateral tibial apophysis. Females are distinguished by an epigyne that is much broader than long, with short copulatory ducts running posteriorly from the copulatory openings. The redescription also documented previously unrecorded details, including the arrangement of teeth on the chelicerae: the promargin bears nine teeth, with the distal two and the second from the base much larger than the others, while teeth three through five are reduced to small denticles. The retromargin carries a single comb-like tooth with seven small denticles in males and eight in females.

Understanding where Tomocyrba sits on the spider family tree adds another layer of intrigue. The subfamily Hisponinae, to which the genus belongs, is well supported by both molecular and morphological evidence. It is diagnosed by a distinctive constriction in the carapace just behind the posterior median eyes, first noticed by Simon in 1901, along with a first metatarsus bearing no more than one pair of spines. More recently, researchers discovered that hisponines possess dual copulatory ducts in the epigyne, a trait that appears to be a shared derived feature of the subfamily. Phylogenetically, hisponines are enigmatic: they sit as the sister group to the Salticinae, the subfamily that dominates jumping spider diversity across the globe, yet they are relatively common in Baltic Amber fossils, suggesting a much wider historical distribution than their current, largely restricted range.

The fieldwork methods behind the discovery highlight the practical challenges of documenting rare arthropods in tropical forests. Mahimborondro specimens were collected opportunistically using small plastic pots filled with diluted ethanol, while Makira specimens were obtained through dedicated active searches on shrubbery and leaf litter, or with beating sheets. In the laboratory, male pedipalps and female epigynes were carefully dissected and cleared in warm potassium hydroxide solution before examination under compound and stereo microscopes. High-resolution habitus and genitalia images were captured using digital imaging systems and z-stacked photomontage software, producing the detailed figures that accompany the taxonomic descriptions.

Madagascar is renowned as a global biodiversity hotspot, with an extraordinary proportion of its flora and fauna found nowhere else on Earth. Yet its rainforests continue to face intense pressure from deforestation, fragmentation, and climate change. The fact that a genus as distinctive as Tomocyrba went essentially unstudied for 120 years, and that its type species could be rediscovered just tens of kilometers from where it was first collected, speaks both to the resilience of these forest ecosystems and to how much remains undocumented. Each new species description and each rediscovery strengthens the case for protecting Madagascar’s remaining rainforest corridors, not only for charismatic vertebrates but for the countless small, cryptic organisms that make up the bulk of the island’s evolutionary heritage. For now, T. ankihiberta joins the ranks of Madagascar’s endemic jumping spiders, and T. decollata emerges from more than a century of obscurity with its anatomy finally brought into sharp, modern focus.

Subject of Research: Taxonomy and rediscovery of jumping spiders in the genus Tomocyrba from northern Madagascan rainforests

Article Title: Discovery of a new Tomocyrba ( Araneae , Salticidae , Hisponinae ) and rediscovery of the type species from rainforests in northern Madagascar

Article References: Pett, B. L., & Murray, K. I. (2026). Discovery of a new Tomocyrba (Araneae, Salticidae, Hisponinae) and rediscovery of the type species from rainforests in northern Madagascar. African Invertebrates, 67(1), 37-46. https://doi.org/10.3897/afrinvertebr.67.183477

Image Credits: AI Generated

DOI: 10.3897/AfrInvertebr.67.183477

Keywords: Tomocyrba, Salticidae, Hisponinae, Madagascar, jumping spiders, new species, taxonomy, rainforest, biodiversity, rediscovery, Mahimborondro, Makira

Researchers from Southern Cross University, together with a colleague from NASA’s Goddard Space Flight Center and the University of Maryland, carried out four field campaigns in a subtropical Australian rainforest, measuring methane fluxes from both tree stems and forest soils. Their study plots were deliberately positioned along a moisture gradient: a valley floor plot where water lingers, a lower slope plot, and an upper slope plot where the ground drains freely. This design allowed the team to isolate one of the most important controls on methane cycling in any landscape, the availability of oxygen in the soil.

The underlying science is a contest between two microbial communities. In aerated soils, methanotrophic bacteria consume methane from the atmosphere, oxidizing it for energy and acting as a biological filter that removes this potent greenhouse gas before it can accumulate. But when soils become saturated, oxygen disappears, and a different group of microbes, the methanogenic archaea, takes over, producing methane as a byproduct of anaerobic decomposition. Whether a forest soil is a net sink or a net source of methane depends on which of these processes dominates, and that, in turn, depends heavily on soil moisture.

The study’s findings show that this dominance can flip with the seasons. On the valley floor, the researchers documented a remarkable transition: at the end of the dry season, the soil absorbed methane at a rate of about 151 micromoles per square meter per day, acting as a modest sink. But by the end of the wet season, the same soil had transformed into a powerful methane source, emitting around 830 micromoles per square meter per day. That is a swing of nearly a thousand micromoles per square meter per day driven almost entirely by changing water conditions, a magnitude of seasonal variability that underscores how misleading single-visit field measurements can be when estimating a landscape’s true greenhouse gas budget.

The sloped plots told a steadier story. On the lower slope, soils absorbed methane at an average rate of 135 micromoles per square meter per day, while the upper slope soils absorbed slightly more, at 156 micromoles per square meter per day. Crucially, these drier positions maintained their methane-consuming function throughout the year, remaining reliable sinks regardless of season. Because upland forests cover vast areas of the planet, this finding reinforces the significance of well-drained forest soils as one of the biological world’s most important natural defenses against methane accumulation in the atmosphere.

But the soil was only half the investigation. In recent years, scientists have increasingly recognized that trees themselves can act as conduits for methane, drawing dissolved gas up from waterlogged soils through their vascular systems and venting it from their stems, or hosting methane-producing microbes within their own tissues. Whether these stem emissions are significant enough to undermine the methane-removal service provided by upland forest soils has remained one of the field’s most pressing open questions.

Across most of the study site, the answer was reassuring. In the sloped plots, tree stems emitted negligible amounts of methane, and their tiny emissions offset less than one percent of the methane being consumed by the surrounding soils. In other words, the upland rainforest kept its carbon credentials intact: soils continued to scrub methane from the atmosphere, and the trees did little to undo that work. This is an important benchmark for global models, which must decide how much attention to give tree stem fluxes in dry upland settings, and it suggests that in such environments the soil sink comfortably dominates.

The valley floor was another matter. At the end of the wet season, when the saturated soil was already releasing methane in earnest, the trees added substantially to the problem. Stem emissions there contributed an extra 27 percent on top of the soil source, effectively amplifying an already large methane flux. The mechanism is intuitive: when soil air spaces fill with water, methane produced below ground can escape upward more readily through the aerenchyma and transport tissues of trees than through the waterlogged soil itself, making trees the path of least resistance for gas trying to reach the atmosphere.

Among the more striking discoveries were two individual trees that the researchers describe as high emitters. These outliers vented methane at rates two hundred and three hundred times higher than neighboring trees of comparable size on the same plots. Such extreme individual variability has been noted in other forest systems, but documenting it in a subtropical rainforest highlights a persistent challenge for field scientists and modelers alike: a small number of anomalous trees can disproportionately influence plot-level emissions estimates, particularly if they cluster in wetter microsites. Understanding what makes certain trees such efficient methane conduits, whether it is their rooting depth, stem anatomy, associated microbial communities, or proximity to methane-rich soil layers, is now a priority for follow-up work.

Statistically, the study found that both tree stem and soil methane fluxes correlated significantly and positively with soil moisture, confirming the moisture gradient as the master variable governing methane exchange in this ecosystem. This relationship has implications well beyond one Australian forest. As climate change alters rainfall patterns, intensifying both droughts and deluges in many subtropical regions, the moisture status of forest soils will shift accordingly, and with it the delicate balance between methane consumption and production. Periods of unusual wetness could temporarily convert upland landscapes that normally function as methane sinks into net emitters, while prolonged drying could expand the spatial footprint of the sink.

The research also carries lessons for how greenhouse gas inventories should be constructed. Because the valley floor transitioned between sink and source within a single year, any sampling campaign that visits a site only once, in either the wet or the dry season, risks capturing a snapshot that badly misrepresents the annual picture. The authors emphasize the high spatial and temporal heterogeneity of tree and soil methane fluxes in upland forests, a heterogeneity that demands repeated, seasonally distributed measurements across topographic gradients if regional and global methane budgets are to be trustworthy.

For the broader public, the takeaway is both sobering and hopeful. Sobering, because even pristine rainforests are not immune to climate feedbacks: wetter soils and methane-venting trees can tip natural ecosystems into contributing to the very problem they help mitigate. Hopeful, because the study confirms that the drier, extensive portions of subtropical rainforest landscapes remain steadfast methane sinks year-round, quietly removing a powerful greenhouse gas from the air at rates that matter globally. Protecting these forests, and the complex moisture gradients within them, preserves not only biodiversity and carbon storage but also this often-overlooked methane-scrubbing service.

The work, conducted with support from the Australian Research Council, the Hermon Slade Foundation, and other funders, adds a valuable subtropical data point to a global dataset still dominated by temperate and boreal measurements. As the search intensifies for natural systems that help regulate atmospheric methane, this study makes clear that the answer lies in the ground as much as in the canopy, and that the ground’s verdict changes with the weather.

Subject of Research: Seasonal methane fluxes from tree stems and soils along a soil moisture gradient in a subtropical Australian rainforest

Article Title: Seasonal changes in tree stem and soil methane fluxes along a soil moisture gradient in a subtropical Australian rainforest

Article References: Dittmann, J., Maher, D. T., Johnston, S. G., Das, A., Padilla-Montalvo, J. A., Stovall, A. E. L., & Jeffrey, L. C. (2026). Seasonal changes in tree stem and soil methane fluxes along a soil moisture gradient in a subtropical Australian rainforest. Biogeochemistry. https://doi.org/10.1007/s10533-026-01371-7

Image Credits: AI Generated

DOI: 10.1007/s10533-026-01371-7

Keywords: methane flux, rainforest, soil moisture, tree stems, greenhouse gases, methanotrophs, methanogenesis, soil sink, biogeochemistry, subtropical forest, seasonal variation, climate change