Identification and Spread of the Ghost Silverfish (Ctenolepisma calvum) among Museums and Homes in Europe.

Ctenolepisma calvum was first described in Sri Lanka (Ceylon) in 1910, and this island is probably the origin of this species. Later, it was also found in the Caribbean (Cuba and Trinidad and Tobago). Up until the present, it has only been identified within buildings (a synanthropic species), and its natural habitat is unknown. In 2007, it was discovered in Germany and was considered a neobiotic species of Lepismatidae in Europe. It has rapidly spread throughout Europe and beyond in recent years. This led us to analyze the available data of the first occurrences in Germany, Austria, and other European countries. Furthermore, we compared the spread inside of museums in Vienna (Austria) and Berlin (Germany). These museums have been monitored for a long period with sticky traps, representing the best source of information on the dispersion dynamics of Ctenolepisma calvum. We found a scattered occurrence of this species in 18 countries in Europe (including Russia and Ukraine). The first record for Poland has not previously been published; however, this species has been present there since 2014. Surprisingly, it was found in Hungary in 2003, but a record was only published online in 2021. Additionally, in Germany and Austria, where most data are available, the spread of the species does not follow any clear pattern. In museums in Berlin, the species has only been found in one location. In contrast, the species rapidly spread in museums in Vienna between 2014 and 2021, from four to 30 locations, and it is now a well-established species with occasional high abundance. We examined the spread of the species at three spatial scales: (i) Europe, (ii) national, and (iii) regional. Our observations indicate that it is possibly distributed with materials (packaging material, hygiene articles, paper, cardboard, and collection items). Little is yet known about the biology of this introduced pest. We describe its preferred habitat within buildings, its climate requirements, and its potential to act as a new museum pest in Central Europe. This species seems to thrive at room temperature in buildings. Further impact on the species due to climate change in the future is also discussed. We offer a simple morphological key and a detailed identification table to help correct species identification.

First Record of Trichobilharzia physellae (Talbot, 1936) in Europe, a Possible Causative Agent of Cercarial Dermatitis.

Several species of avian schistosomes are known to cause dermatitis in humans worldwide. In Europe, this applies above all to species of the genus Trichobilharzia. For Austria, a lot of data are available on cercarial dermatitis and on the occurrence of Trichobilharzia, yet species identification of trematodes in most cases is doubtful due to the challenging morphological determination of cercariae. During a survey of trematodes in freshwater snails, we were able to detect a species in the snail Physella acuta (Draparnaud, 1805) hitherto unknown for Austria, Trichobilharzia physellae; this is also the first time this species has been reported in Europe. Species identification was performed by integrative taxonomy combining morphological investigations with molecular genetic analyses. The results show a very close relationship between the parasite found in Austria and North American specimens (similarity found in CO1 ≥99.57%). Therefore, a recent introduction of T. physellae into Europe can be assumed.

First confirmed record of Trichobilharzia franki Müller & Kimmig, 1994, from Radix auricularia (Linnaeus, 1758) for Austria.

Avian schistosomes are of medical and veterinary importance as they are responsible for the annually occurring cercarial dermatitis outbreaks. For Austria, so far, only Trichobilharzia szidati Neuhaus 1952 was confirmed on species level as causative agent of cercarial dermatitis. Here we present the first record of Trichobilharzia franki Müller & Kimmig 1994 in Austria. The species was detected during a survey of digenean trematodes in Upper Austrian water bodies. Furthermore, we provide DNA barcodes of T. franki as well as measurements of several parasite individuals to indicate the intraspecific diversity. We also recommend the usage of an alternative primer pair, since the "standard COI primer pair" previously used for Schistosomatidae amplified an aberrant fragment in the sequence of T. franki. Overall, our study shows how limited our knowledge about occurrence and distribution of avian schistosomes in Austria is and how important it is to acquire such a knowledge to estimate ecological and epidemiological risks in the future.

Four myriapod relatives - but who are sisters? No end to debates on relationships among the four major myriapod subgroups.

BACKGROUND: Phylogenetic relationships among the myriapod subgroups Chilopoda, Diplopoda, Symphyla and Pauropoda are still not robustly resolved. The first phylogenomic study covering all subgroups resolved phylogenetic relationships congruently to morphological evidence but is in conflict with most previously published phylogenetic trees based on diverse molecular data. Outgroup choice and long-branch attraction effects were stated as possible explanations for these incongruencies. In this study, we addressed these issues by extending the myriapod and outgroup taxon sampling using transcriptome data. RESULTS: We generated new transcriptome data of 42 panarthropod species, including all four myriapod subgroups and additional outgroup taxa. Our taxon sampling was complemented by published transcriptome and genome data resulting in a supermatrix covering 59 species. We compiled two data sets, the first with a full coverage of genes per species (292 single-copy protein-coding genes), the second with a less stringent coverage (988 genes). We inferred phylogenetic relationships among myriapods using different data types, tree inference, and quartet computation approaches. Our results unambiguously support monophyletic Mandibulata and Myriapoda. Our analyses clearly showed that there is strong signal for a single unrooted topology, but a sensitivity of the position of the internal root on the choice of outgroups. However, we observe strong evidence for a clade Pauropoda+Symphyla, as well as for a clade Chilopoda+Diplopoda. CONCLUSIONS: Our best quartet topology is incongruent with current morphological phylogenies which were supported in another phylogenomic study. AU tests and quartet mapping reject the quartet topology congruent to trees inferred with morphological characters. Moreover, quartet mapping shows that confounding signal present in the data set is sufficient to explain the weak signal for the quartet topology derived from morphological characters. Although outgroup choice affects results, our study could narrow possible trees to derivatives of a single quartet topology. For highly disputed relationships, we propose to apply a series of tests (AU and quartet mapping), since results of such tests allow to narrow down possible relationships and to rule out confounding signal.

The Genome of the Blind Soil-Dwelling and Ancestrally Wingless Dipluran Campodea augens: A Key Reference Hexapod for Studying the Emergence of Insect Innovations.

The dipluran two-pronged bristletail Campodea augens is a blind ancestrally wingless hexapod with the remarkable capacity to regenerate lost body appendages such as its long antennae. As sister group to Insecta (sensu stricto), Diplura are key to understanding the early evolution of hexapods and the origin and evolution of insects. Here we report the 1.2-Gb draft genome of C. augens and results from comparative genomic analyses with other arthropods. In C. augens, we uncovered the largest chemosensory gene repertoire of ionotropic receptors in the animal kingdom, a massive expansion that might compensate for the loss of vision. We found a paucity of photoreceptor genes mirroring at the genomic level the secondary loss of an ancestral external photoreceptor organ. Expansions of detoxification and carbohydrate metabolism gene families might reflect adaptations for foraging behavior, and duplicated apoptotic genes might underlie its high regenerative potential. The C. augens genome represents one of the key references for studying the emergence of genomic innovations in insects, the most diverse animal group, and opens up novel opportunities to study the under-explored biology of diplurans.

DNA barcode reference libraries for the monitoring of aquatic biota in Europe: Gap-analysis and recommendations for future work.

Effective identification of species using short DNA fragments (DNA barcoding and DNA metabarcoding) requires reliable sequence reference libraries of known taxa. Both taxonomically comprehensive coverage and content quality are important for sufficient accuracy. For aquatic ecosystems in Europe, reliable barcode reference libraries are particularly important if molecular identification tools are to be implemented in biomonitoring and reports in the context of the EU Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD). We analysed gaps in the two most important reference databases, Barcode of Life Data Systems (BOLD) and NCBI GenBank, with a focus on the taxa most frequently used in WFD and MSFD. Our analyses show that coverage varies strongly among taxonomic groups, and among geographic regions. In general, groups that were actively targeted in barcode projects (e.g. fish, true bugs, caddisflies and vascular plants) are well represented in the barcode libraries, while others have fewer records (e.g. marine molluscs, ascidians, and freshwater diatoms). We also found that species monitored in several countries often are represented by barcodes in reference libraries, while species monitored in a single country frequently lack sequence records. A large proportion of species (up to 50%) in several taxonomic groups are only represented by private data in BOLD. Our results have implications for the future strategy to fill existing gaps in barcode libraries, especially if DNA metabarcoding is to be used in the monitoring of European aquatic biota under the WFD and MSFD. For example, missing species relevant to monitoring in multiple countries should be prioritized for future collaborative programs. We also discuss why a strategy for quality control and quality assurance of barcode reference libraries is needed and recommend future steps to ensure full utilisation of metabarcoding in aquatic biomonitoring.

Morphological and Genetic Analysis of the Acerentomon doderoi Group (Protura: Acerentomidae) with Description of A. christiani sp. nov.

Acerentomon christiani sp. nov. is described from Vienna, Austria. The new species is a member of the "doderoi" group, characterized by the presence of seta x on tergite VII. It is most similar to A. gallicum, A. brevisetosum and A. tenuisetosum, but differs from these species in the length of foretarsal sensillum c and certain other chaetotaxic measurements and indices. In addition to the morphological description, the DNA barcoding region of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) and the 28S ribosomal RNA of the new species are provided. The morphological characters and the barcode of the new species are discussed in comparison to those of other Acerentomon species. An identification key to all known Acerentomon spp. of the "doderoi" group is given.

Where taxonomy based on subtle morphological differences is perfectly mirrored by huge genetic distances: DNA barcoding in Protura (Hexapoda).

BACKGROUND: Protura is a group of tiny, primarily wingless hexapods living in soil habitats. Presently about 800 valid species are known. Diagnostic characters are very inconspicuous and difficult to recognize. Therefore taxonomic work constitutes an extraordinary challenge which requires special skills and experience. Aim of the present pilot project was to examine if DNA barcoding can be a useful additional approach for delimiting and determining proturan species. METHODOLOGY AND PRINCIPAL FINDINGS: The study was performed on 103 proturan specimens, collected primarily in Austria, with additional samples from China and Japan. The animals were examined with two markers, the DNA barcoding region of the mitochondrial COI gene and a fragment of the nuclear 28S rDNA (Divergent Domain 2 and 3). Due to the minuteness of Protura a modified non-destructive DNA-extraction method was used which enables subsequent species determination. Both markers separated the examined proturans into highly congruent well supported clusters. Species determination was performed without knowledge of the results of the molecular analyses. The investigated specimens comprise a total of 16 species belonging to 8 genera. Remarkably, morphological determination in all species exactly mirrors molecular clusters. The investigation revealed unusually huge genetic COI distances among the investigated proturans, both maximal intraspecific distances (0-21.3%), as well as maximal congeneric interspecifical distances (up to 44.7%). CONCLUSIONS: The study clearly demonstrates that the tricky morphological taxonomy in Protura has a solid biological background and that accurate species delimitation is possible using both markers, COI and 28S rDNA. The fact that both molecular and morphological analyses can be performed on the same individual will be of great importance for the description of new species and offers a valuable new tool for biological and ecological studies, in which proturans have generally remained undetermined at species level.

Decisive data sets in phylogenomics: lessons from studies on the phylogenetic relationships of primarily wingless insects.

Phylogenetic relationships of the primarily wingless insects are still considered unresolved. Even the most comprehensive phylogenomic studies that addressed this question did not yield congruent results. To get a grip on these problems, we here analyzed the sources of incongruence in these phylogenomic studies by using an extended transcriptome data set. Our analyses showed that unevenly distributed missing data can be severely misleading by inflating node support despite the absence of phylogenetic signal. In consequence, only decisive data sets should be used which exclusively comprise data blocks containing all taxa whose relationships are addressed. Additionally, we used Four-cluster Likelihood Mapping (FcLM) to measure the degree of congruence among genes of a data set, as a measure of support alternative to bootstrap. FcLM showed incongruent signal among genes, which in our case is correlated neither with functional class assignment of these genes nor with model misspecification due to unpartitioned analyses. The herein analyzed data set is the currently largest data set covering primarily wingless insects, but failed to elucidate their interordinal phylogenetic relationships. Although this is unsatisfying from a phylogenetic perspective, we try to show that the analyses of structure and signal within phylogenomic data can protect us from biased phylogenetic inferences due to analytical artifacts.

Brain anatomy in Diplura (Hexapoda).

BACKGROUND: In the past decade neuroanatomy has proved to be a valuable source of character systems that provide insights into arthropod relationships. Since the most detailed description of dipluran brain anatomy dates back to Hanström (1940) we re-investigated the brains of Campodea augens and Catajapyx aquilonaris with modern neuroanatomical techniques. The analyses are based on antibody staining and 3D reconstruction of the major neuropils and tracts from semi-thin section series. RESULTS: Remarkable features of the investigated dipluran brains are a large central body, which is organized in nine columns and three layers, and well developed mushroom bodies with calyces receiving input from spheroidal olfactory glomeruli in the deutocerebrum. Antibody staining against a catalytic subunit of protein kinase A (DC0) was used to further characterize the mushroom bodies. The japygid Catajapyx aquilonaris possesses mushroom bodies which are connected across the midline, a unique condition within hexapods. CONCLUSIONS: Mushroom body and central body structure shows a high correspondence between japygids and campodeids. Some unique features indicate that neuroanatomy further supports the monophyly of Diplura. In a broader phylogenetic context, however, the polarization of brain characters becomes ambiguous. The mushroom bodies and the central body of Diplura in several aspects resemble those of Dicondylia, suggesting homology. In contrast, Archaeognatha completely lack mushroom bodies and exhibit a central body organization reminiscent of certain malacostracan crustaceans. Several hypotheses of brain evolution at the base of the hexapod tree are discussed.

Adaptations for nectar-feeding in the mouthparts of long-proboscid flies (Nemestrinidae: Prosoeca).

The insects with the longest proboscis in relation to body length are the nectar-feeding Nemestrinidae. These flies represent important pollinators of the South African flora and feature adaptations to particularly long-tubed flowers. The present study examined the morphology of the extremely long and slender mouthparts of Nemestrinidae for the first time. The heavily sclerotized tubular proboscis of flies from the genus Prosoeca is highly variable in length. It measures 20-47 mm in length and may exceed double the body length in some individuals. Proximally, the proboscis consists of the labrum-epipharynx unit, the laciniae, the hypopharynx, and the labium. The distal half is composed of the prementum of the labium, which solely forms the food tube. In adaptation to long-tubed and narrow flowers, the prementum is extremely elongated, bearing the short apical labella that appear only to be able to spread apart slightly during nectar uptake. Moving the proboscis from resting position under the body to a vertical feeding position is accomplished in particular by the movements of the laciniae, which function as a lever arm. Comparisons with the mouthparts of other flower visiting flies provide insights into adaptations to nectar-feeding from long-tubed flowers.

The mouthparts of Scutigerella immaculata: Correspondences and variation among serially homologous head appendages.

Descriptions of the skeletomuscular system of the symphylan head are characterized by a high number of incongruencies among authors. The increased accuracy and transparency of 3D-reconstruction methods allows for an allocation of some of the incongruencies to (i) misinterpretations of literature descriptions, or (ii) different views of what constitutes a separate muscle. A structural comparison allows to homologize muscles among the serially arranged mouthparts of Symphyla.

Can comprehensive background knowledge be incorporated into substitution models to improve phylogenetic analyses? A case study on major arthropod relationships.

BACKGROUND: Whenever different data sets arrive at conflicting phylogenetic hypotheses, only testable causal explanations of sources of errors in at least one of the data sets allow us to critically choose among the conflicting hypotheses of relationships. The large (28S) and small (18S) subunit rRNAs are among the most popular markers for studies of deep phylogenies. However, some nodes supported by this data are suspected of being artifacts caused by peculiarities of the evolution of these molecules. Arthropod phylogeny is an especially controversial subject dotted with conflicting hypotheses which are dependent on data set and method of reconstruction. We assume that phylogenetic analyses based on these genes can be improved further i) by enlarging the taxon sample and ii) employing more realistic models of sequence evolution incorporating non-stationary substitution processes and iii) considering covariation and pairing of sites in rRNA-genes. RESULTS: We analyzed a large set of arthropod sequences, applied new tools for quality control of data prior to tree reconstruction, and increased the biological realism of substitution models. Although the split-decomposition network indicated a high noise content in the data set, our measures were able to both improve the analyses and give causal explanations for some incongruities mentioned from analyses of rRNA sequences. However, misleading effects did not completely disappear. CONCLUSION: Analyses of data sets that result in ambiguous phylogenetic hypotheses demand for methods, which do not only filter stochastic noise, but likewise allow to differentiate phylogenetic signal from systematic biases. Such methods can only rely on our findings regarding the evolution of the analyzed data. Analyses on independent data sets then are crucial to test the plausibility of the results. Our approach can easily be extended to genomic data, as well, whereby layers of quality assessment are set up applicable to phylogenetic reconstructions in general.