Common Taxa Research Articles

Age‐prevalence curves in a multi‐species parasite community

Abstract The relationship between infection prevalence and host age is informative because it can reveal processes underlying disease dynamics. Most prior work has assumed that age‐prevalence curves are shaped by infection rates, host immunity and/or infection‐induced mortality. Interactions between parasites within a host have largely been overlooked as a source of variation in age‐prevalence curves. We used field survey data and models to examine the role of interspecific interactions between parasites in shaping age‐prevalence curves. The empirical dataset included quantification of parasite infection prevalence for eight co‐occurring trematodes in over 15,000 snail hosts. We characterized age‐prevalence curves for each taxon, examined how they changed over space in relation to co‐occurring trematodes and tested whether the shape of the curves aligned with expectations for the frequencies of coinfections by two taxa in the same host. The models explored scenarios that included negative interspecific interactions between parasites, variation in the force‐of‐infection (FOI) and infection‐induced mortality that varied with host age, which were mechanisms hypothesized to be important in the empirical dataset. In the empirical dataset, four trematode parasites had monotonic increasing age‐prevalence curves and four had unimodal age‐prevalence curves. Some of the curves remained consistent in shape in relation to the prevalence of other potentially interacting trematodes, while some shifted from unimodal to monotonic increasing, suggesting release from negative interspecific interactions. The most common taxa with monotonic increasing curves had lower co‐infection frequencies than expected, suggesting they were competitively dominant. Taxa with unimodal curves had coinfection frequencies that were closer to those expected by chance. The model showed that negative interspecific interactions between parasites can cause a unimodal age‐prevalence curve in the subordinate taxon. Increases in the FOI and/or infection‐induced mortality of the dominant taxon cause shifts in the peak prevalence of the subordinate taxon to a younger host age. Infection‐induced mortality that increased with host age was the only scenario that caused a unimodal curve in the dominant taxon. Results indicated that negative interspecific interactions between parasites contributed to variation in the shape of age‐prevalence curves across parasite taxa and support the growing importance of incorporating interactions between parasites in explaining population‐level patterns of host infection over space and time. Read the free Plain Language Summary for this article on the Journal blog.

Microbial Community Analysis Offers Insight into the Complex Origins of Plant Disease in a Smallholder Farm Context

Classical approaches to plant disease diagnosis assume a single pathogen/single disease paradigm. Here, we revisit the presumed role of Fusarium oxysporum as the causal agent of wilting and yellowing of chickpea plants on smallholder farms in Ethiopia. Contrary to expectations, detection of Fusarium DNA using conserved PCR primers failed to associate the pathogen with symptomatic plants. Instead, culture-independent sequencing of microbial communities nominated unexpected pathogens and revealed patchiness in the assembly of common microbial consortia. Surprisingly, tests of differential enrichment identified Phytophthora as the most common disease-associated taxon. More generally, across all field sites, multilevel pattern analysis identified indicator taxa whose patterns of co-occurrence demarcate discrete microbial communities and are consistent with a range of specific interactions, including mutualism and antagonism. Taken together, these data indicate that soilborne chickpea disease in Ethiopia has heterogeneous origins and that despite decades of emphasis and disease resistance breeding, the role of Fusarium as the frequent agent of chickpea disease in Ethiopia remains enigmatic.

Calcareous nannoplankton fluctuation within the Albian-Cenomanian Boundary Event of the Tethyan Himalaya

A hemipelagic succession 29m thick, situated in South Tibet within the Tethyan Himalaya tectonic unit, has been investigated for its calcareous nannofossil content. A total of 17 samples were subject to qualitative and semi-quantitative analysis. The studied interval belongs to the upper Albian-lowermost Cenomanian and extends into the UC0 nannofossil zone; based on the last occurrence of Hayesites albiensis, the UC0a and UC0b-c subzones were recognized. The most abundant nannofossil of the Youxia section is Watznaueria barnesiae. Other common taxa are Eiffellithus turriseiffelii, Eprolithus floralis, Rhagodiscus spp., and Zeugrhabdotus spp. In the lowermost part of the studied section, below the beginning of the Albian-Cenomanian Boundary Event (ACBE), i.e., prior to the δ13C positive excursion related to OAE1d, the nannofossils confined to high paleolatitudes, namely Repagulum parvidentatum, Seribiscutum primitivum, and Sollasites horticus, are present with a low abundance. This occurrence is believed to be evidence of a short episode of cooler surface waters linked to a transgressive event. The nannofossil abundance and diversity, along with the fluctuation patterns of the nutrient and temperature indices throughout the section, reflects a primary signal of mesotrophic to eutrophic conditions from the base of the succession up to the two oldest δ13C peaks of ACBE, both late Albian in age and within the OAE1d. By contrast, the dominance of Watznaueria barnesiae, representing more than 80% of the total assemblages, along with the significant drop in abundance and diversity shown by nannofossils within late phases of ACBE, are interpreted as a diagenetic signal. Mesotrophic to eutrophic conditions returned towards the top of the studied succession, where Biscutum constans and Zeugrhabdotus erectus again show a higher abundance.

Postharvest blown-arc plasma treatment did not reduce Fusarium graminearum or its mycotoxins in field-infested wheat grain

The increasing prevalence of Fusarium graminearum, a major causative pathogen of Fusarium head blight in cereal crops, leads to contamination of grain with mycotoxins, which necessitates the development of effective management strategies. This study investigated whether postharvest Blown-Arc plasma treatment could reduce F. graminearum and associated mycotoxins in field-infested grain. Postharvest Blown-Arc plasma treatment for 60 or 180 s was trialled to reduce Fusarium graminearum and deoxynivalenol (DON) mycotoxins in field-infested wheat grain. Changes in fungal components of the grain microbiome following the treatment were assessed using metabarcoding analysis of the nuclear ribosomal internal transcribed spacer gene region, and liquid chromatography mass spectrophotometry was used to measure changes in concentrations of the mycotoxins deoxynivalenol (DON), DON-3-glucoside (DON3-G) and 3-acetyl-DON (3-ADON). Fusarium spp. were the most common taxa in the grain over two seasons, with the relative abundance being higher in 2020 (72%) compared to 2021 (45%). Postharvest plasma treatment of field-infested grain for 60 or 180 s did not significantly lower Fusarium abundance. Alpha and beta diversity of the natural mycobiota in the grain were also unaffected. The concentrations of mycotoxins were not significantly different after the treatments, except that in the 2021 trial, the 180 s treatment caused a significant increase in DON concentration. We concluded that the postharvest plasma treatment used in this study did not reduce Fusarium contamination or the concentration of mycotoxins, DON, DON3-G and 3-ADON in field-infested grain. The results highlight the importance of using field-infested grain in experiments, as opposed to grain inoculated under laboratory conditions, which provides only superficial infection. This approach is crucial for accurately understanding the dynamics of treatment efficacy.

First record of Aegyptobatus (Hybodontiformes: Distobatidae) in the Cretaceous Alcântara formation (?Albian-Cenomanian) of Maranhão, Northeastern Brazil

ABSTRACT Hybodontiformes are considered the closest relatives of modern sharks and were the dominant shark group throughout most of the Mesozoic. Although, originally a marine group, during their long temporal range, they conquered the freshwater environment. This is the case of numerous taxa known in northern Gondwana. Here, we report the presence of the hybodontiform Aegyptobatus in the Albian-Cenomanian Alcântara Formation of the São Luis Basin, Northeastern Brazil. A comparison made with other hybodontiform teeth from the Northern Gondwana suggests that the teeth from the Alcântara Formation is noticeably the same species found in the late Cenomanian Bahariya Formation of Egypt, A. kuehnei. Although probably restricted to freshwater, the new discovery increases the geographic range of this taxon, adds one more common taxon between the Brazilian Alcântara Formation and Cretaceous units of North Africa, and extends the temporal range of this taxon down into the Albian-Cenomanian.

Understanding spatiotemporal effects of food supplementation on host-parasite interactions using community-based science.

Supplemental feeding can increase the overall health of animals but also can have variable effects on how animals defend themselves against parasites. However, the spatiotemporal effects of food supplementation on host-parasite interactions remain poorly understood, likely because large-scale, coordinated efforts to investigate them are difficult. Here, we introduce the Nest Parasite Community Science Project, which is a community-based science project that coordinates studies with bird nest box 'stewards' from the public and scientific community. This project was established to understand broad ecological patterns between hosts and their parasites. The goal of this study was to determine the effect of food supplementation on eastern bluebirds (Sialia sialis) and their nest parasite community across the geographic range of the bluebirds from 2018 to 2021. We received 674 nests from 69 stewards in 26 states in the eastern United States. Nest box stewards reported whether or not they provided mealworms or suet near nesting bluebirds, then they followed the nesting success of the birds (number of eggs laid and hatched, proportion that hatched, number and proportion of nestlings that successfully fledged). We then identified and quantified parasites in the nests. Overall, we found that food supplementation increased fledging success. The most common nest parasite taxon was the parasitic blow fly (Protocalliphora sialia), but a few nests contained fleas (Ceratophyllus idius, C. gallinae and Orchopeas leucopus) and mites (Dermanyssus spp. and Ornithonyssus spp.). Blow flies were primarily found at northern latitudes, where food supplementation affected blow fly prevalence. However, the direction of this effect varied substantially in direction and magnitude across years. More stewards fed bluebirds at southern latitudes than at northern latitudes, which contradicts the findings of other community-based science projects. Overall, food supplementation of birds was associated with increased host fitness but did not appear to play a consistent role in defence against these parasites across all years. Our study demonstrates the importance of coordinated studies across years and locations to understand the effects of environmental heterogeneity, including human-based food supplementation, on host-parasite dynamics.

O-277 Exploring the relationship between the vaginal microbiota and vaginal symptoms

Abstract Study question What is the relationship between self-reported vaginal symptoms and the composition of the vaginal microbiome? Summary answer Our study reveals a complex and multifactorial relationship between vaginal symptoms and the composition of the vaginal microbiome. What is known already Vaginal dysbiosis (VD) is a microbial condition characterized by the absence of beneficial lactobacilli and the presence of pathogenic bacteria in the vagina. VD is associated with elevated risks of sexually transmitted infections, preterm birth, pregnancy loss, infertility, and suboptimal outcomes in in vitro fertilization. Clinical manifestations often include increased vaginal discharge and malodour, although it’s noteworthy that a substantial proportion of women with VD remain asymptomatic, which makes diagnosing these women challenging. Study design, size, duration Our study was conducted as part of a Double-Blinded Randomized Controlled Trial (RCT) evaluating Vaginal Microbiota Transplantation (VMT) as a novel approach for treating vaginal dysbiosis without antibiotics. This study included 263 women aged 18-40 years. Participants/materials, setting, methods We employed shotgun metagenomic sequencing to analyse the vaginal microbiome on cycle day 10+/-2 days. Moreover, we collected data on vaginal symptoms, hormonal contraceptive use, and sexual behaviour. Main results and the role of chance Among the 263 participants, 65% exhibited eubiotic microbiomes, 23% had dysbiotic microbiomes, and 12% had intermediate microbiomes. Vaginal symptoms were reported by 33%, while 63% remained symptom-free. In terms of dominance, L. crispatus dominated in 40% of samples, followed by L. iners (30%) and G. vaginalis (9.1%). In symptomatic women, L. iners (22%) and L. crispatus (21%) were common taxa, while asymptomatic women showed higher prevalence of these taxa: L. crispatus (50%) and L. iners (34%). Symptoms analysis showed two significant clusters dominated by L. crispatus or L. iners, along with smaller dysbiotic clusters led by G. vaginalis and F. vaginae. Dysbiotic samples exhibited higher rates of increased discharge and malodor, while stinging and itching were more prevalent in eubiotic samples. Positive associations were noted between specific microbial taxa and distinct symptoms. Exploring external factors, contraceptive use revealed weak associations with microbial changes. Sexual behavior patterns also influenced microbial composition, notably in women with varying numbers of male sexual partners within the last 3 months. These findings provide valuable insights into the intricate interactions between vaginal microbiota, symptoms, and external factors, shedding light on the complex landscape of vaginal dysbiosis. Limitations, reasons for caution Our study is limited by the cross-sectional design, and causality cannot be inferred. Self-reporting of symptoms may introduce bias. Additionally, our findings may not be generalizable to all populations sin the majority of the women in our cohort are younger and likely to have higher education Wider implications of the findings Our findings highlight the complexity of VD symptomatology and underscore the need for further research into the relationship between vaginal symptoms, microbiota and clinical outcomes. Trial registration number NCT04855006

Spatiotemporal diversity of wild bee communities (Hymenoptera, Apoidea) in grassland ecosystems in semi-arid climate of North Africa (Algeria)

ABSTRACT In order to improve our knowledge on the biodiversity of wild bee communities in Algerian grasslands, two stations (El-Kouif and Gourigueur) belonging to Tebessa region were chosen. The current study provides data on the diversity and the structure of this taxonomic group in a semi-arid steppe in Northeastern Algeria. Wild bee alpha and beta diversity were investigated through the utilisation of diverse parameters such as species richness, occurrence, diversity indices, rarefaction curves, similarity indices. In total, 411 individuals of 14 genera and 46 species were collected. The most abundant species was Eucera nigrilabris (Apidae) with 69 individuals (16.79% of the total). The collected species were dominated by common taxa (17 species, 36.95% of the total). The GLM tests showed that the temporal variations of the abundance values (N) and the species richness (S) of wild bees were statistically significant. Overall, the most visited plant species was Eruca vesicaria (Brassicaceae) (N = 168, S = 24). Two types of species were distinguished in the present study, species foraged a wide range of plant and species foraged only one plant species. The wild bee communities showed high taxonomic diversity in grasslands situated in semi-arid steppe.

Middle Stone Age fauna from the RS sub-member (MSA I) at Cave 1B, Klasies River Main site, South Africa

Klasies River is an important site for the study of the evolution of Homo sapiens, understanding modern behaviour and human interaction with the environment during the Middle Stone Age. The faunal sample from the RS sub-member in Cave 1B (MSA I), dating to ca. 115 000 years ago and older, was recently analysed. The results indicate that humans were hunting a variety of prey. The most common taxa in the sample are indeterminate medium birds, indeterminate small mammals, rock hyraxes, and indeterminate medium mammals. Based on multiple lines of evidence including the presence of: cultural artefacts, shellfish, tortoises, large mammals, butchery marks, and burnt specimens; and, a lack of carnivore taxa compared to ungulates (as reflected in the low carnivore-ungulate ratio), hyena coprolites and beak damage, coupled with infrequent baboons and the absence of leopards (as reflected in the low leopard index), it is apparent that humans were the main agent of accumulation of the fauna. However, other agents of accumulation such as brown hyenas, leopards and raptors likely contributed some faunal remains, especially of smaller taxa.

The Taxonomic Circumscription and Nomenclatural History of Pilosella suecica (Asteraceae): A Special Case of Grey Literature in Taxonomic Botany.

The taxonomic history, nomenclature and application of the oldest species names available for the common hybrids between Pilosella caespitosa and P. lactucella are reviewed. Elias Fries created a nomenclatural and bibliographical collision when he replaced a printed label of his exsiccata Herbarium normale with its second version, distributed at a later date, in which the protologue of Hieracium suecicum had appeared. In this protologue, the new species name was validly published with a mere reference to the original description of H. auricula var. majus, thus being based on the type of the latter. In a later fascicle of the same exsiccata, Fries excluded this synonym and distributed a different morphotype of H. suecicum, which caused taxonomic confusion and re-description of the same taxon under the name H. fennicum. The surviving original material of H. auricula var. majus is rejected, and its neotype is designated, making H. suecicum the correct name for the hybrids strictly intermediate between P. lactucella and P. caespitosa. Such hybrids constitute the most common hybridogenous taxon of Pilosella in Scandinavia, Finland and neighbouring Russia, with many synonyms described from this area and partly typified here. Another hybridogenous taxon of the same origin, more similar to P. lactucella and previously known as P. cochlearis, is correctly named P. stipitiflora comb. nov. The nomenclatural value and bibliographic complexity of exsiccata, a commonly underestimated kind of grey literature in taxonomic botany, are further highlighted.

Policy-making for peri-urban landscapes as arenas of human-wildlife interactions

Peri-urban landscapes are transitional areas between urban and rural areas that are constantly changing. They are characterised by land use mixes and land cover changes, leading to significant changes in wildlife habitats. These changes, combined with an increasing anthropogenic presence, turn peri-urban landscapes into arenas of intensified human-wildlife interactions. In many scientifically documented cases, scientists are focusing on negative interactions. Furthermore, research about appropriate policy instruments for managing human-wildlife interactions is rare. This study focused on case studies and their characteristics from around the world on positive, neutral, or negative interactions between humans and wildlife at local level. In addition, influencing factors of human-wildlife interactions and policy instruments for managing human-wildlife interactions in peri-urban landscapes were addressed. A survey was conducted with an international group of scientists and practitioners working in this field. The results showed that various species were involved in human-wildlife interactions in peri-urban landscapes worldwide, with mammals as being the most common taxon. Contemporary changes in land use and land cover could be identified as a significant factor for increasing human-wildlife interactions in peri-urban landscapes. It can be highlighted that a policy mix consisting mainly of social and cultural instruments in combination with legal and regulatory instruments could be most suitable to address this situation.

The fauna from Mughr el-Hamamah, Jordan: Insights on human hunting behavior during the Early Upper Paleolithic

As a corridor for population movement out of Africa, the southern Levant is a natural laboratory for research exploring the dynamics of the Middle-to-Upper Paleolithic transition. Yet, the number of well-preserved sites dating to the initial millennia of the Early Upper Paleolithic (EUP; ∼45–30 ka) remains limited, restricting the resolution at which we can study the biocultural and techno-typological changes evidenced across the transition. With EUP deposits dating to 45–39 ka cal BP, Mughr el-Hamamah, Jordan, offers a key opportunity to expand our understanding of EUP lifeways in the southern Levant. Mughr el-Hamamah is particularly noteworthy for its large faunal assemblage, representing the first such assemblage from the Jordan Valley. In this paper, we present results from taxonomic and taphonomic analyses of the EUP fauna from Mughr el-Hamamah. Given broader debates about shifts in human subsistence across the Middle-to-Upper Paleolithic transition, we also assess evidence for subsistence intensification, focusing especially on the exploitation of gazelle and the use of small game. Taphonomic data suggest that the fauna was primarily accumulated by human activity. Ungulates dominate the assemblage; gazelle (Gazella sp.) is the most common taxa, followed by fallow deer (Dama mesopotamica) and goat (Capra sp.). Among the gazelle, juveniles account for roughly one-third of the sample. While the focus on gazelle and the frequency of juveniles are consistent with broader regional trends, evidence for the regular exploitation of marrow from gazelle phalanges suggests that the EUP occupants of Mughr el-Hamamah processed gazelle carcasses quite intensively. Yet, the overall degree of dietary intensification appears low—small game is rare and evidence for human capture of this game is more equivocal. As a whole, our results support a growing body of data showing gradual shifts in animal exploitation strategies across the Middle-to-Upper Paleolithic transition in the southern Levant.

The taxonomy and distribution of algae in the thermal springs of Türkiye

The algal flora and physio-chemical parameters of seven thermal springs in Denizli were studied for the first time. Samples for algal analyses were taken monthly between May 2013 and June 2014, while the physio-chemical parameters were measured seasonally. The mean pH value of the thermal springs was 6.3, and temperatures varied between 34-60 °C. The significant differences (P < 0.001) among the thermal springs were in their temperature and pH, as well as concentration of Cl^- , Fe^2+ , K^+ , Mg^+ , Na^+ , Li^+ , Ca^+ , HCO3^ - , and SO4^2- ions. A total of 43 Cyanobacteria and three Bacillariophyta taxa were determined.The most common taxon was Spirulina subsalsa Oersted ex Gomont, sampled from five sampling sites. According to the principal component analysis (PCA), the most important determining factor for the algae was temperature, followed by concentration of K^+ and Cl^- ions.

Bone diseases in a Pleistocene South American native ungulate species: the case of Toxodon platensis Owen, 1837 (Mammalia, Notoungulata, Toxodontidae)

ABSTRACTKnowledge of bone pathologies in South American native ungulates is very scarce, which contrasts with other groups of megamammals such as xenarthrans and proboscideans. In this paper, based on morphological and histological analysis, we describe different bone pathologies in two specimens of Toxodon platensis Owen (Notoungulata), one of the most common taxa in the Late Pleistocene faunistic associations of northeastern Argentina. Subchondral erosions on the metacarpus and magnum, non‐marginal syndesmophytes and enthesitis on the vertebral body, the neural column and the zygapophyseal joint of the lumbar vertebrae, as well as a particular periosteal reaction on the ribs, have been interpreted as manifestations of spondyloarthropathies in one of the analyzed individuals. In the same individual, a process of fusion and bone neoformation is observed in the caudal vertebrae, which seems to correspond both to the aforementioned spondyloarthropathy and to an infectious process. A lesion on the fourth metatarsus of a second individual with an evident cloaca is suggestive of osteomyelitis; this is the first report of this pathology in notoungulates. It seems possible that some of these pathologies may have been facilitated by factors such as body mass, mode of locomotion and/or environment. These findings provide insight into some aspects of the ecology of this particular group of extinct South American megamammals.

Benthic graptolites (Graptolithina, Pterobranchia) in the Miaolingian (Cambrian Series 3)

Benthic graptolites (Graptolithina) were surprisingly common and diverse in the Miaolingian (Cambrian), but have rarely been described in detail. Encrusting and erect growing colonies already evolved and can be differentiated in early Miaolingian faunas. The Rhabdopleuridae with their encrusting colonies provide few fossils, but members of the erect growing, bushy colonies of the Dithecodendridae are more common, at least as fragments indicating considerable fragmentation and transport. In the Wuliuan, the benthic graptolites reached a considerable diversity at the genus level with at least 6 genera appearing in this interval. The most common taxon is the encrusting genus Sphenoecium with its robust colonies, showing a worldwide distribution. Most taxa, however, are known from few records and their biostratigraphical and palaeogeographical distribution cannot be established yet. Erroneously, the widely distributed Tarnagraptus with its conical thecae has often been misidentified as the Ordovician Mastigograptus, but differs considerably in its tubarium construction and both might not be closely related.

Combining Air Sampling and DNA Metabarcoding to Monitor Plant Pathogens

Monitoring the air for airborne plant pathogens is an increasingly common method for the management of economically important plant diseases. In Alberta, Canada, several commodity clusters, including dry bean, canola, potato, and wheat, currently support air monitoring research programs for airborne pathogens of interest. In this study, we assessed the feasibility of monitoring for these, and more, plant fungal pathogens simultaneously using two different sampler types (cyclone versus rotation impaction) and by metabarcoding the ITS1 region using the Illumina sequencing platform. We collected air samples from four geographically distant sites across Alberta and monitored four crop types in southern Alberta. Overall, we found weak, but statistically significant, effects of geographic location and crop type on the aeromycobiota community composition. A few common taxa, such as Ramularia, Alternaria, and Epicoccum, constituted the vast majority of reads across all samples. Nevertheless, in each sample, we identified many plant pathogens of interest and organisms that previous research has found antagonistic to those pathogens, highlighting the utility of these approaches in understanding the pathobiome. In assessing the real-world implications of read counts, we discovered that they were only weakly correlated with spore counts quantified by qPCR. The two types of samplers collected different community profiles, reinforcing the importance of carefully considering which sampler type to use in monitoring programs. Taken together, our results show promise for the future of monitoring the air pathobiome, although much more work is required to understand the relationship of airborne communities to their in-field impact on disease development. [Formula: see text] Copyright © 2023 His Majesty the King in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada. This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Early eukaryotic microfossils of the late Palaeoproterozoic Limbunya Group, Birrindudu Basin, northern Australia

AbstractFine‐grained, siliciclastic units of the >1642 ± 3.9 Ma late Palaeoproterozoic Limbunya Group, Birrindudu Basin host rich, well‐preserved organic‐walled microfossil assemblages that include members of total‐group eukaryotes. These assemblages include taxa characteristic of this interval such asTappania planaandSatka favosa, as well as less common taxa such asGigantosphaeridium fibratum,Gigantosphaeridium floccosum,Kamolineata elongata(= Valeria elongata; new combination), and four new species. The new taxa includeLimbunyasphaera operculatagen et sp. nov., the oldest known operculate taxon; the large septate filaments ofSiphonoseptum bombycinumgen. et sp. nov.; the platy tubular formBirrindudutuba brigandiniagen. et sp. nov.; andFilinexum torsivumgen. et sp. nov., which bears a spirally twisted wall constructed of bound fibres. Our data show that eukaryotic fossils are particularly abundant in marginal marine environments such as tidal flats and back‐barrier lagoonal settings. This is exemplified by the Blue Hole Formation, which features an especially diverse and complex assemblage. We also present a new within‐formation eukaryotic species richness estimate for the Palaeoproterozoic to Tonian. This estimate indicates that the oldest eukaryote‐bearing units already show species richness levels similar to those of the much younger and more heavily sampled Tonian period. Additionally, these oldest eukaryotic assemblages show significant morphological disparity, particularly in vesicle construction. These high levels of eukaryotic species richness and morphological disparity suggest that although late Palaeoproterozoic units preserve our oldest record of eukaryotes, the eukaryotic clade has a much deeper history.

Гіллястовусі раки Львівщини (Crustacea: Cladocera) у гідробіологічних дослідженнях Б. Дибовського та М. Гроховського (за матеріалами круглого столу екологічної комісії наукового товариства ім. Шевченка)

49 taxa of Cladocera were registered in the reservoirs of Lviv region according to the materials of B. Dybovskyi and M. Grohovskyi. From the point of view of faunal diversity, the studied locations can be divided into two groups. The first group of locations (registered 10 or more taxa each): Pelchynsky pond, Yanivsky pond, Big Golosko. The second group of locations (up to 5 taxa are registered): Kilinsky Park, Sobka pond, Small Golosko, Zboishcha, Snopkiv, Horodok, Zhydachiv. The largest number of Cladocera taxa was registered in the Janivsky pond (21 taxa). The smallest number (1 taxon) was registered in the location Zboyishcha. Taking into account the frequency of occurrence, 4 groups of taxa were distinguished. The first group has a frequency of 10 % (34 taxa), the second – 21 % (10 taxa), the third – 30 % (4 taxa), the fourth – 50 % (1 taxa). The most common taxa with a frequency of 30 % include Alona affinis, Leydig., Ceriodaphnia polonica, nob., Peracantha truncata, O. Fr. Müll., Sida crystallina, O. Fr. Müll. The frequency of occurrence of 50 % is characteristic of Simocephalus vetulus, O. F. Müll. The measure of pairwise similarity of the Cladocera fauna of reservoirs of various locations, calculated by the Jaccard index and the Sørensen index, has the same trends. 23 pairs of water bodies do not have common species. For them, the Jaccard index and the Sørensen index are equal to zero. The highest coefficient of similarity of fauna between the reservoirs of the locations Kilinsky Park and Zboiyshche (Jaccard’s index – 33 %, Sørensen’s index – 50 %). The lowest rate was registered for the locations Yaniv – Zhidachiv and Small Golosko – Yaniv (Jaccard’s index – 4 %, Sørensen’s index – 8 %). The Jaccard index is characterized by a larger amplitude of the calculated indicators and gives better differentiation at high and average indicators of similarity. With low indicators of similarity, the Sørensen index is preferred. The conducted research is of particular interest in view of the faunal analysis of Cladocera groups and the comparative characteristics of indicators identifying long periods of time. Such materials are one of the key aspects on which the issue of hydroecological monitoring is based.

Survival Strategies of High GC-Content Microorganisms in Oligotrophic Deep Groundwater

Deep groundwaters are among the most energy and nutrient-limited ecosystems on the planet. The limited resources are mainly due to the absence of photosynthesis-driven primary production (Kadnikov et al. 2020). These ecosystems do however host phylogenetically diverse and metabolically active microorganisms from all domains of life plus viruses (Holmfeldt et al. 2021, Mehrshad et al. 2021). In this study, we used a large metagenomic dataset generated over the last eight years from the Äspö Hard Rock Laboratory (Äspö HRL) in Sweden and drill holes in Olkiluoto Island, Finland. This dataset, termed the “Fennoscandian Shield Genomic Dataset” (FSGD), contains metagenome-assembled genomes (MAGs) and single-cell amplified genomes (SAGs). Previous studies on this dataset have shown that reciprocal symbiotic partnerships and efficiency of energy metabolism define the core microbiome of these deep groundwaters (Mehrshad et al. 2021). Studies on different marine and freshwater ecosystems show that oligotrophic environments host streamlined genomes with lower GC content. However, it is not known how the low carbon and energy availability in deep groundwaters affect the microbial community regarding their genome size and GC content. To address this, we used the FSDG to study the distribution of genome size and GC content among bacterial and archaeal genomes in Fennoscandian Shield deep groundwaters. We further disentangled the prevalent metabolic strategies in these genomes that is being used to support their carbon and nitrogen demands for replication and survival. A total of 1990 MAGs/SAGs with a completeness of ≥50% and <5% contamination were recovered from 43 metagenomic datasets. The taxonomy of the MAGs/SAGs was assigned using the GTDB-tk (Chaumeil et al. 2022) and the GC content and genome size of MAGs/SAGs were calculated. MAGs/SAGs were also functionally annotated to investigate the genome-encoded functional potential. To survey the preference for different metabolic pathways and metabolic cross-feeding, the C-fixation pathways were subdivided into 82 routes that lead to the production of intermediate compounds (e.g., formate, pyruvate, oxaloacetate, etc.). A similar analysis for nitrogen acquisition pathways and CO2-capturing enzymes was performed and the presence/absence of these metabolic modules was investigated in representative MAGs/SAGs from various deep groundwater types to explore the microbial community’s metabolic interaction. The GC content and estimated genome size (EGS) of the recovered MAGs/SAGs were linearly correlated, suggesting that higher genome-level GC content is associated with larger genome size. The most common taxa among high GC (≥50%) content MAGs/SAGs were affiliated with the phyla Proteobacteria, Desulfobacterota, Actinobacteriota, Chloroflexota, and Patescibacteria. Analysis of metabolic modules in the environmental context revealed that high GC content MAGs constituted the main primary producers in all investigated groundwaters. Among the seven investigated C-fixation pathways, routes leading to the production of intermediates of reductive tricarboxylic acid (rTCA) were significantly enriched in high GC-content genomes. Both carboxylation/reduction first CO2-capturing enzymes were significantly enriched in MAGs with high GC contents. Of the various carbon fixation strategies, rGly and rTCA are the most energy-efficient and consume one and three ATP molecules, respectively (Bar-Even et al. 2011), matching the high prevalence of rTCA in oligotrophic deep groundwater. High GC content genomes featured metabolic pathways to generate key precursors for synthesizing purine/pyrimidine and amino acids. As GC base-pairs require one more nitrogen than AT base-pairs, prokaryotes with a higher GC content need proportionally more nitrogen for genome replication. In agreement with this, high GC content MAGs/SAGs from the FSGD feature additional nitrogen uptake systems including ammonium permease and N-fixation genes. High GC content MAGs/SAGs appear to be metabolically versatile and capable of acquiring nutrients via different carbon and nitrogen fixation pathways along with various C-scavenging strategies for substrate uptake to acquire energy and survive in oligotrophic conditions. Although their larger genome size and higher GC content entail higher expenses for replication and maintenance, their presence within the community of deep groundwater is supported by the “Black Queen Theory”. According to this theory, a cell containing an expensive metabolic pathway is maintained within the community as it provides a service that other members cannot.

Notes on sorediate Parmelia species in North America with the first records of P. asiatica and P. barrenoae

The first record of Parmelia asiatica from North America is presented. The species differs from other sorediate Parmelia taxa in having narrow, sublinear lobes with circular or semicircular, terminal or marginal soralia. New records and earlier data together suggest that P. asiatica may be a more common taxon in the Northern Hemisphere than previously reported. Additionally, the first record of P. barrenoae from Canada and the central states of the USA is presented. Notes on similar sorediate species of the genus Parmelia are provided with information about secondary chemistry checked by thin-layer chromatography methods in solvents A and C.