- L Q Choo
- G Spagliardi
- M Malinsky
- K T C A Peijnenburg
Little is known about when and how planktonic species arise and persist in the open ocean without apparent dispersal barriers. Pteropods are planktonic snails with thin shells susceptible to dissolution that are used as bio-indicators of ocean acidification. However, distinct evolutionary units respond to acidification differently and defining species boundaries is therefore crucial for predicting the impact of changing ocean conditions. In this global population genomic study of the shelled pteropod Limacina bulimoides, we combined genetic (759,000 single nucleotide polymorphisms) and morphometric data from 161 individuals, revealing three major genetic lineages (FST = 0.29 to 0.41): an 'Atlantic lineage' sampled across the Atlantic, an 'Indo-Pacific lineage' sampled in the North Pacific and Indian Ocean, and a 'Pacific lineage' sampled in the North and South Pacific. A time-calibrated phylogeny suggests that the lineages diverged about one million years ago, with estimated effective population size remaining high (~10 million) throughout Pleistocene glacial cycles. We do not observe any signatures of recent hybridisation, even in areas of sympatry in the North Pacific. While the lineages are reproductively isolated, they are morphologically cryptic, with overlapping shell shape and shell colour distributions. Despite showing that the circumglobal L. bulimoides consists of multiple species with smaller ranges than initially thought, we found that these pteropods still possess high levels of genetic variability. Our study adds to the growing evidence that speciation is often overlooked in the open ocean, and suggests the presence of distinct biological species within many other currently defined circumglobal planktonic species.
Mitochondria originated from an ancient bacterial endosymbiont that underwent reductive evolution by gene loss and endosymbiont gene transfer to the nuclear genome. The diversity of mitochondrial genomes published to date has revealed that gene loss and transfer processes are ongoing in many lineages. Most well-studied eukaryotic lineages are represented in mitochondrial genome databases, except for the superphylum Retaria-the lineage comprising Foraminifera and Radiolaria. Using single-cell approaches, we determined two complete mitochondrial genomes of Foraminifera and two nearly complete mitochondrial genomes of radiolarians. We report the complete coding content of an additional 14 foram species. We show that foraminiferan and radiolarian mitochondrial genomes contain a nearly fully overlapping but reduced mitochondrial gene complement compared to other sequenced rhizarians. In contrast to animals and fungi, many protists encode a diverse set of proteins on their mitochondrial genomes, including several ribosomal genes; however, some aerobic eukaryotic lineages (euglenids, myzozoans, and chlamydomonas-like algae) have reduced mitochondrial gene content and lack all ribosomal genes. Similar to these reduced outliers, we show that retarian mitochondrial genomes lack ribosomal protein and tRNA genes, contain truncated and divergent small and large rRNA genes, and contain only 14 or 15 protein-coding genes, including nad1, -3, -4, -4L, -5, and -7, cob, cox1, -2, and -3, and atp1, -6, and -9, with forams and radiolarians additionally carrying nad2 and nad6, respectively. In radiolarian mitogenomes, a noncanonical genetic code was identified in which all three stop codons encode amino acids. Collectively, these results add to our understanding of mitochondrial genome evolution and fill in one of the last major gaps in mitochondrial sequence databases. IMPORTANCE We present the reduced mitochondrial genomes of Retaria, the rhizarian lineage comprising the phyla Foraminifera and Radiolaria. By applying single-cell genomic approaches, we found that foraminiferan and radiolarian mitochondrial genomes contain an overlapping but reduced mitochondrial gene complement compared to other sequenced rhizarians. An alternative genetic code was identified in radiolarian mitogenomes in which all three stop codons encode amino acids. Collectively, these results shed light on the divergent nature of the mitochondrial genomes from an ecologically important group, warranting further questions into the biological underpinnings of gene content variability and genetic code variation between mitochondrial genomes.
Orchidaceae show remarkable diversity in pollination strategies, but how these strategies vary globally is not entirely clear. To identify regions and taxa that are data-rich and lend themselves to rigorous analyses or are data-poor and need attention, we introduce a global database of orchid reproductive biology. Our database contains > 2900 species representing all orchid subfamilies and 23 of 24 tribes. We tabulated information on habit, breeding systems, means of pollinator attraction and the identity of pollinators. Patterns of reproductive biology by habit, geography and taxonomy are presented graphically and analysed statistically. On the basis of our database, most orchid species sampled are pollinator dependent (76%) and self-compatible (88%). Pollinator attraction based on rewards occurs in 54% of the species, whereas 46% use some means of deceit. Orchids generally have highly specific pollinator interactions (median number of pollinator species = 1). Nonetheless, on average, specificity is lower for species offering rewards, occurring in multiple continental regions or Northern America (as defined by the Taxonomic Database Working Group Level 1 regions). Although our database reveals impressive knowledge gains, extensive gaps in basic observations of orchid reproductive biology exist, particularly in tropical regions and diverse lineages of fly-pollinated species. The database is expected to facilitate targeted studies, further elucidating the ecological and evolutionary drivers of orchid diversity.
Islands have long been recognized as distinctive evolutionary arenas leading to morphologically divergent species, such as dwarfs and giants. We assessed how body size evolution in island mammals may have exacerbated their vulnerability, as well as how human arrival has contributed to their past and ongoing extinctions, by integrating data on 1231 extant and 350 extinct species from islands and paleo islands worldwide spanning the past 23 million years. We found that the likelihood of extinction and of endangerment are highest in the most extreme island dwarfs and giants. Extinction risk of insular mammals was compounded by the arrival of modern humans, which accelerated extinction rates more than 10-fold, resulting in an almost complete demise of these iconic marvels of island evolution.
Summary.—Mexican Woodnymph Thalurania ridgwayi was long included in thegenus Thalurania. A previously published molecular phylogenetic study found thatthis species is in fact sister to the genus Eupherusa. We discuss whether ridgwayi isbetter lumped with Eupherusa or placed in a different genus, and consider that the latter arrangement best reflects the multiple morphological differences between ridgwayi and Eupherusa. Consequently, we describe a new genus for ridgwayi. (PDF) A new genus for Thalurania ridgwayi (Trochilidae). Available from: https://www.researchgate.net/publication/369038877_A_new_genus_for_Thalurania_ridgwayi_Trochilidae [accessed Mar 07 2023].
Based on recent achievements in phylogenetic studies of the Brassicaceae, a novel infrafamilial classification is proposed that includes major improvements at the subfamilial and supertribal levels. Herein, the family is subdivided into two subfamilies, Aethionemoideae (subfam. nov.) and Brassicoideae. The Bras-sicoideae, with 57 of the 58 tribes of Brassicaceae, are further partitioned into five supertribes, including the previously recognized Brassicodae and the newly established Arabodae, Camelinodae, Heliophilo-dae, and Hesperodae. Additional tribus-level contributions include descriptions of the newly recognized Arabidopsideae, Asperuginoideae, Hemilophieae, Schrenkielleae, and resurrection of the Chamireae and Subularieae. Further detailed comments on 17 tribes in need of clarifications are provided.
Until recently, and when compared with diurnal birds that use contrasting plumage patches and complex feather structures to convey visual information, communication in nocturnal and crepuscular species was considered to follow acoustic and chemical channels. However, many birds that are active in low-light environments have evolved intensely white plumage patches within otherwise inconspicuous plumages. We used spectrophotometry, electron microscopy, and optical modelling to explain the mechanisms producing bright white tail feather tips of the Eurasian woodcock Scolopax rusticola. Their diffuse reflectance was approximately 30% higher than any previously measured feather. This intense reflectance is the result of incoherent light scattering from a disordered nanostructure composed of keratin and air within the barb rami. In addition, the flattening, thickening and arrangement of those barbs create a Venetian-blind-like macrostructure that enhances the surface area for light reflection. We suggest that the woodcocks have evolved these bright white feather patches for long-range visual communication in dimly lit environments.
The emergence of several bat coronavirus-related disease outbreaks in human and domestic animals has fueled surveillance of coronaviruses in bats worldwide. However, little is known about how these viruses interact with their natural hosts. We demonstrate a Betacoronavirus (subgenus Merbecovirus), PN-βCoV, in the intestine of its natural host, Nathusius's Pipistrelle Bat (Pipistrellus nathusii), by combining molecular and microscopy techniques. Eighty-eight P. nathusii bat carcasses were tested for PN-βCoV RNA by RT-qPCR, of which 25 bats (28%) tested positive. PN-βCoV RNA was more often detected in samples of the intestinal tract than in other sample types. In addition, viral RNA loads were higher in intestinal samples compared to other sample types, both on average and in each individual bat. In one bat, we demonstrated Merbecovirus antigen and PN-βCoV RNA expression in intestinal epithelium and the underlying connective tissue using immunohistochemistry and in situ hybridization, respectively. These results indicate that PN-βCoV has a tropism for the intestinal epithelium of its natural host, Nathusius's Pipistrelle Bat, and imply that the fecal-oral route is a possible route of transmission. IMPORTANCE Virtually all mammal species circulate coronaviruses. Most of these viruses will infect one host species; however, coronaviruses are known to include species that can infect multiple hosts, for example the well-known virus that caused a pandemic, SARS-CoV-2. Chiroptera (bats) include over 1,400 different species, which are expected to harbor a great variety of coronaviruses. However, we know very little about how any of these coronaviruses interact with their bat hosts; for example, we do not know their modes of transmissions, or which cells they infect. Thus, we have a limited understanding of coronavirus infections in this important host group. The significance of our study is that we learned that a bat coronavirus that occurs in a common bat species in Europe has a tropism for the intestines. This implies the fecal-oral route is a likely transmission route.
A recurring feature of oceanic archipelagos is the presence of adaptive radiations that generate endemic, species-rich clades that can offer outstanding insight into the links between ecology and evolution. Recent developments in evolutionary genomics have contributed towards solving long-standing questions at this interface. Using a comprehensive literature search, we identify studies spanning 19 oceanic archipelagos and 110 putative adaptive radiations, but find that most of these radiations have not yet been investigated from an evolutionary genomics perspective. Our review reveals different gaps in knowledge related to the lack of implementation of genomic approaches, as well as undersampled taxonomic and geographic areas. Filling those gaps with the required data will help to deepen our understanding of adaptation, speciation, and other evolutionary processes.
Nanomaterials are widespread in the human environment as pollutants, and are being actively developed for use in human medicine. We have investigated how the size and dose of polystyrene nanoparticles affects malformations in chicken embryos, and have characterized the mechanisms by which they interfere with normal development. We find that nanoplastics can cross the embryonic gut wall. When injected into the vitelline vein, nanoplastics become distributed in the circulation to multiple organs. We find that the exposure of embryos to polystyrene nanoparticles produces malformations that are far more serious and extensive than has been previously reported. These malformations include major congenital heart defects that impair cardiac function. We show that the mechanism of toxicity is the selective binding of polystyrene nanoplastics nanoparticles to neural crest cells, leading to the death and impaired migration of those cells. Consistent with our new model, most of the malformations seen in this study are in organs that depend for their normal development on neural crest cells. These results are a matter of concern given the large and growing burden of nanoplastics in the environment. Our findings suggest that nanoplastics may pose a health risk to the developing embryo.
Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macroecological studies and applied freshwater research is missing. We aim to fill this gap and present the Global EPTO Database, which includes worldwide geo‐referenced aquatic insect occurrence records for four major taxa groups: Ephemeroptera, Plecoptera, Trichoptera and Odonata (EPTO). A total of 8,368,467 occurrence records globally, of which 8,319,689 (99%) are publicly available. The records are attributed to the corresponding drainage basin and sub‐catchment based on the Hydrography90m dataset and are accompanied by the elevation value, the freshwater ecoregion and the protection status of their location. The database covers the global extent, with 86% of the observation records having coordinates with at least four decimal digits (11.1 m precision at the equator) in the World Geodetic System 1984 (WGS84) coordinate reference system. Sampling years span from 1951 to 2021. Ninety‐nine percent of the records have information on the year of the observation, 95% on the year and month, while 94% have a complete date. In the case of seven sub‐datasets, exact dates can be retrieved upon communication with the data contributors. Ephemeroptera, Plecoptera, Trichoptera and Odonata, standardized at the genus taxonomic level. We provide species names for 7,727,980 (93%) records without further taxonomic verification. The entire tab‐separated value (.csv) database can be downloaded and visualized at https://glowabio.org/project/epto_database/. Fifty individual datasets are also available at https://fred.igb‐berlin.de, while six datasets have restricted access. For the latter, we share metadata and the contact details of the authors.
There has been a spate of recent cases of human alveolar echinococcosis (AE) in Alberta, Canada. Alveolar echinococcosis is caused by Echinococcus multilocularis, which is prevalent among coyote populations and present in domestic dogs in Alberta. Using qPCR, we estimated the seasonal fecal prevalence of E. multilocularis in coyotes and dogs in a multiuse recreation area close to Edmonton, Alberta, where we also setup remote cameras to model seasonal changes in the overlap in temporal activity and the spatial intensity of use among coyotes, humans, and dogs, as a proxy of potential transmission. We detected E. multilocularis in 18 of 137 wild canid feces and none in 44 dog feces. After correcting for the qPCR test’s sensitivity and specificity, we estimated at 15.7% (9.7-22.7%, 95% CrI) the true fecal prevalence for coyotes. Temporal overlap between coyotes and both humans and dogs increased in the fall and winter relative to the spring and summer. Coyote intensity of use showed seasonal variations and was higher on maintained trails and locations closer to visitor parking and at sites with high intensity of dog use. Our results reinforce the need of an integrated approach, typical of both One-Health and Eco-Health, to park management for minimizing the likelihood of transmission where human and dog activity results in significant overlap with the one of the natural definitive hosts of zoonotic parasites.
A dead individual of Metamasius hemipterus (Linnaeus, 1758) was collected by a citizen scientist in Athens, Greece from a hand of imported bananas. The equatorial origin of the fruit as well as the extensive growth of a fungus on the specimen, both suggest an unintentional introduction as a contaminant. Nevertheless, this record highlights the valuable contribution of citizen scientists in the study of alien species. Although the species is not presently considered as established in the country, citizen-science initiatives in order to raise awareness and monitor its presence are ongoing.
Stigmella naturnella (Klimesch, 1936), a leafminer of Betula , is here recorded as new for France, Croatia, Ukraine, Belgium, and the Netherlands, Since 2018, it has expanded its range into the last two countries, partly based on numerous online observations. Its distribution history is reviewed, the species is diagnosed and its life history is described. A lectotype is designated for Nepticula naturnella Klimesch, 1936. The species is widespread in the Palearctic, from Japan to the North Sea, with a maximum of 1.63% variation in its DNA barcode. Legacy leafmine records for Germany are reviewed, resulting in the confirmation of its occurrence in Baden-Württemberg already in 1935, but other old records are rejected. It is one of the few Nepticulidae species that hibernate as adult, a possible contributing factor to its expansion. As the leafmines may be confused with other Betula mining species, a revised key to the leafmines of European Stigmella species on Betula is provided. Stigmella glutinosae (Stainton, 1858) and S. alnetella (Stainton, 1856), usually feeding in Alnus , are both recorded to occur occasionally on Betula and are included in the key.
The availability of public genomic resources can greatly assist biodiversity assessment, conservation, and restoration efforts by providing evidence for scientifically informed management decisions. Here we survey the main approaches and applications in biodiversity and conservation genomics, considering practical factors, such as cost, time, prerequisite skills, and current shortcomings of applications. Most approaches perform best in combination with reference genomes from the target species or closely related species. We review case studies to illustrate how reference genomes can facilitate biodiversity research and conservation across the tree of life. We conclude that the time is ripe to view reference genomes as fundamental resources and to integrate their use as a best practice in conservation genomics.
In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics.
Trace elements are chemical contaminants spread in the environment by anthropogenic activities and threaten wildlife and human health. Many studies have investigated this contamination in apex raptors as sentinel birds. However, there is limited data for long-term biomonitoring of multiple trace elements in raptors. In the present study, we measured the concentrations of 14 essential and non-essential trace elements in the livers of the common buzzard (Buteo buteo) collected in the United Kingdom from 2001 to 2019 and investigated whether concentrations have changed during this period. In addition, we estimated the importance of selected variables for modelling element accumulations in tissues. Except for cadmium, hepatic concentrations of harmful elements in most buzzards were lower than the biological significance level of each element. Hepatic concentrations of certain elements, including lead, cadmium, and arsenic, varied markedly seasonally within years. Their peak was in late winter and trough in late summer, except copper which showed an opposite seasonal pattern. In addition, lead in the liver consistently increased over time, whereas strontium showed a decreasing trend. Hepatic concentrations of cadmium, mercury, and chromium increased with age, whereas selenium and chromium were influenced by sex. Hepatic concentrations of arsenic and chromium also differed between different regions. Overall, our samples showed a low risk of harmful effects of most elements compared to the thresholds reported in the literature. Seasonal fluctuation was an important descriptor of exposure, which might be related to the diet of the buzzard, the ecology of their prey, and human activities such as the use of lead shot for hunting. However, the reason for these observed trends needs further examination, and biomonitoring studies exploring the effects of variables such as age, sex, and seasonality are required.
Premise: Species in Thismiaceae can no longer photosynthesize, and instead obtain carbon from soil fungi. Here we infer Thismiaceae phylogeny using plastid genome data, and also characterize the molecular evolution of this genome. Methods: We assembled five Thismiaceae plastid genomes from genome skimming data, adding to previously published data for phylogenomic inference. We investigated plastid-genome structural changes, considering locally colinear blocks (LCBs). We also characterized possible shifts in selection pressure in retained genes by considering changes in ω, the ratio of non-synonymous to synonymous changes. Key results: Thismiaceae experienced two major pulses of gene loss around the early diversification of the family, with subsequent scattered gene losses across descendent lineages. In addition to massive size reduction, Thismiaceae plastid genomes experienced occasional inversions, and there likely were two independent losses of the plastid inverted repeat (IR) region. Retained plastid genes remain under generally strong purifying selection (ω << 1), with significant and sporadic weakening or strengthening in several instances. The bifunctional trnE-UUC gene of Thismia huangii likely retains a secondary role in heme biosynthesis, despite a probable loss of functionality in protein translation. Several cis-spliced group IIA introns are retained, despite the loss of the plastid intron maturase, matK. Conclusions: We infer that most gene losses in Thismiaceae occurred early and rapidly, following the initial loss of photosynthesis in its stem lineage. As a species-rich, fully mycoheterotrophic lineage, Thismiaceae provides a model system for uncovering the unique and divergent ways in which plastid genomes evolve in heterotrophic plants. This article is protected by copyright. All rights reserved.
Calcareous sponges are an often overlooked element of sponge communities. In contrast to most other sponges, calcareous sponges produce calcium carbonate spicules, as opposed to the siliceous spicules of most sponges. Here, we investigated bacterial communities of 17 sponge species, including type and paratype specimens of recently described calcareous species, sampled off the remote island of Rodrigues, in the Indian Ocean. The main axis of variation in a PCO analysis of all samples separated non-calcareous sponge species including Axinyssa aplysinoides, Cinachyrella aff. australiensis, Petrosia seychellensis, Ircinia aff. variabilis, Spongia ceylonensis, Plakinastrella aff. clipptertonensis, Agelas aff. ceylonesis, Agelas aff. Mauritiana, and Hyrtios erectus from calcareous sponges, the non-calcareous Biemna tubulata, sediment and seawater. Overall, the bacterial communities of calcareous sponges revealed unique prokaryotic profiles with low abundances of several bacterial phyla, and relatively high abundances of other taxa e.g. the phyla Fibrobacterota, Proteobacteria, and SAR324 clade, the class Alphaproteobacteria and orders Cytophagales and Cyanobacteriales, although there was considerable variation among species. Calcareous sponges also had a high dominance of unknown bacterial operational taxonomic units (OTUs). Considering the unique nature of these communities, further studies are needed to better understand the environmental and ecological drivers of calcareous sponge-associated bacterial communities and their relevance as potential sources of novel microbes of biotechnological interest.
The eresid spider genus Loureedia (Miller et al., 2012) was described a decade ago, despite its type species being described in the mid-19th century, which illuminates the difficulties in obtaining specimens. The genus was initially described as monotypic. Ever since, four other species have been assigned to Loureedia, including three newly discovered ones. Primarily due to the extravagant appearance of the males, stories about the discovery of species of Loureedia have been the subject of relatively wide media coverage over the years, leading to numerous new populations and putative undescribed species being documented by naturalists and citizen scientists. These species, although bearing distinct differences in their coloration patterns, typically vary only slightly in the structure of their copulatory organs, the primary traits used in spider systematics. This highlights an important taxonomic problem: while it is easy to diagnose the genus or recognize the species that belong to it, it is challenging to differentiate the species from one another, particularly when using only a single line of evidence. In this paper, we have tackled this issue using an integrative approach, i.e., a combination of molecular markers (the mitochondrial COI) and traditional morphological characters. The effects of different observational angles on the perceived shape of the conductor are discussed. Except for one species, we obtained DNA data of all members of the genus. Based on these data, the first phylogeny for Loureedia is presented, and two North African species, Loureedia maroccana (Gál et al., 2017) and Loureedia jerbae (El-Hennawy, 2005), are revalidated from synonymy. The distribution records of all described species are mapped.
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