including remarks on evolution and phylogeny

In meiner Dissertation befasse ich mich mit der Morphologie und der Evolution des Thorax der Libellen (Odonata). Das Hauptaugenmerk liegt auf der Morphologie der Muskulatur und auf der Homologisierung der Libellenmuskeln mit einem generalisierten Grundbauplan der neopteren Insekten (vereinfacht – alle anderen geflügelten Insekten). Zudem wurden die Skelettelemente der Odonata eingehend behandelt und die bestehenden Homologiehypothesen wurden erweitert und gestützt. Darüber hinaus habe ich mich mit der Morphologie, Genetik, Biogeografie und der damit zusammenhängenden Verwandtschaft sehr seltener asiatischer Libellen (Epiophlebia) auseinander gesetzt. Letztere Gruppe von asiatischen Libellen nimmt eine Sonderstellung innerhalb der Odonata ein. Die Gruppe Epiophlebia ist in einem gut begründeten Schwestergruppenverhältnis mit den Großlibellen positioniert (Epiprocta) und stellt somit die einzige Libellengruppe dar, die nicht zu den Groß- oder Kleinlibellen gruppiert werden kann. Die vier bekannten Arten von Epiophlebia sind an einen extremen Lebensraum angepasst. Sie bevorzugen kalte, schnell fließende Gebirgsbäche in Höhen von 1000-3500 Meter ü. NHN (Stenökie), sind aber auch an einen solchen Lebensraum gebunden. Die vier Arten kommen räumlich weit voneinander getrennt (disjunkte Verbreitung) auf dem asiatischen Kontinent vor. Ihre jeweiligen Verbreitungsgebiete haben heutzutage keinen Überlappungsbereich, was für eine Artaufspaltung durch räumliche Isolation (Separation) spricht. Daher sind die genetischen Ergebnisse von drei der vier Arten, die eine hohe Homogenität der einzelnen DNA Abschnitte (Sequenzen) aufzeigen, sehr überraschend. Diese Ergebnisse führen zu der Annahme eines biogeographischen Szenarios, welches einen gemeinsamen Lebensraum von Epiophlebia in der Würm-Eiszeit (vor ungefähr 20.000 Jahren) annimmt. Bei Rückgang der Eismassen wurde die Epiophlebia-Population durch ihre starke Stenökie in getrennte Populationen in Glazialrefugien – vereinfacht gesprochen kalt gebliebene Rückzugsgebiete – zurück gedrängt, in denen sie heute noch vorkommt. Dieser für evolutive Prozesse kurze Zeitraum kann die genetische Homogenität erklären. Dennoch bleibt die Frage nach dem Artstatus der vier Epiophlebia-Arten o!en: Sind sie eine einzige Art? Dies würde bedeuten, dass sie eine voneinander räumlich getrennte Population darstellen. In diesem Fall wäre die Art Epiophlebia superstes Sélys, 1889. Oder sind sie wirklich vier getrennte Arten, so wie es der derzeitige Stand der Forschung annimmt. Die Frage nach dem Artstatus konnte zumindest für eine zweite Art Epiophlebia laidlawi Tillard, 1921 in einer darauf folgenden morphologischen Studie positiv beantwortet werden, so dass zwei Arten angenommen werden können. Eine weitere Studie, die sich aus der genetischen Untersuchung von Epiophlebia ergeben hat, umfasst eine genetische Sequenz (S4-Region des 28s rRNA Gens), die für ein universelles Verfahren zur Art-Identifikation bei Insekten geeignet ist. Hierbei wurden die meisten aller Insektengruppen erfolgreich auf die Art identifiziert. Unsere Untersuchung umfasst 85 Proben aus 65 Insektenarten – mindestens eine Art aus jeder Großgruppe, die früher als Gattungen geführte wurde. Bei diesem sogenannten Barcoding, also dem Identifizieren von Arten mit Hilfe einer genetischen Analyse, kommt es häufig zu Schwierigkeiten. Wirhaben gezeigt, dass unser System große Vorteile gegenüber bereits bestehenden Systemen (z.B. COI) hat. Sie liegen vor allem in der universellen Anwendbarkeit sowie der hohen Funktionalität, da dieses Analyseverfahren auch bei stark degradierter DNA (z.B. durch Alterung, Verwitterung oder chemische Beeinflussung verursacht) anwendbar ist. Die Untersuchungen zum Libellenthorax umfassen zwei Studien über adulte Kleinlibellen (Zygoptera). Hier wurden in einer Studie sowohl die Skelettelemente als auch die Muskulatur des Flugapparates untersucht. Eine weitere Studie umfasste die gesamte Muskulatur des Thorax bei Großlibellennymphen (Anisoptera-). Ziel war es, den wenig untersuchten Thorax der Zygoptera und der Libellen-Nymphen grundsätzlich besser zu verstehen und deren morphologische Eigenheiten aufzuzeigen, um diese Daten zu nutzen und um sie nach homologen Merkmalen zu untersuchen. Für die Analyse wurden traditionelle morphologische Verfahren, welches das Sezieren der Tiere und darau!olgendes Zeichnen beinhalten, mit modernen röntgentomographischen Verfahren (SR"CT), inklusive 3D-Rekonstruktion, kombiniert, um ein bestmögliches Ergebnis zu erhalten. Hierbei wurden insgesamt elf für Libellen bisher unbekannte Muskeln beschrieben. Mit Hilfe dieser Daten wird das erste vollständige Homologie-Schema zwischen der Thoraxmuskulatur von Odonata und neopteren Insekten aufgestellt. Weiterhin werden die bereits aufgestellten Homologien der skelettalen Elemente des Flugapparates belegt und deutlich erweitert. Hierfür wurden unter anderem die Muskelansatzstellen als weiteres wichtiges Homologiekriterium erstmalig diskutiert. Die Gesamtheit dieser Homologiefeststellungen ermöglicht zum ersten Mal den direkten Vergleich von Libellen, die einen stark abgeleiteten Flugapparat besitzen, mit allen anderen geflügelten Insekten (Pterygota) vorzunehmen. Somit ist es möglich, Rückschlüsse auf die Evolution und deren Grundmuster von Libellen einerseits aber auch den gesamten Pterygota andererseits zu ziehen. Diese Homologien erö!nen neue Vergleichsmöglichkeiten und ein komplett neues Set an Merkmalen für spätere Verwandtschaftsanalysen der Pterygota. So gibt uns die Ausbildung eines der wichtigsten Teile des Flügelgelenks, des Subalare, Hinweise auf die Verwandschaftshypothese der Palaeoptera [Libellen+Eintagsfliegen]. Darüber hinaus war es möglich, einen generalisierten Libellenthorax mit allen derzeit bekannten Muskeln zu erstellen, was die Arbeit und die Identifikation von Muskeln im Libellenthorax erheblich vereinfacht und den Zugang zu diesem komplexen Gebiet deutlich erleichtert. Dieser generalisierte Libellenthorax ist der Ausgangspunkt für ein hypothetisches Grundmuster der Pterygota und kann tiefe Einblicke in die Entstehung und Evolution des Flugapparates der Insekten ermöglichen.The aim of my dissertation was to study the morphology and evolution of the thorax of damselflies and dragonflies (Odonata). One focus was the morphology of the thorax musculature and the homology between Odonata and a generalized Neoptera thorax as well as ground pattern of Pterygota (all winged insects). Furthermore, wing base skeletal element morphology was studied to extend and underscore the recent homology hypotheses. Beyond that, I examined the morphology, genetics and biogeography, and relating phylogeny of a very rare and enigmatic group of Odonata, Epiophlebia. Epiophlebia present a unique position within the Odonata. The group of Epiophlebia is closely related to all dragonflies but represents the only group of Odonata not belonging to dragonflies (Anisoptera) or damselflies (Zygoptera). The four known species of Epiophlebia are adapted to an extreme habitat in Asian mountain regions. They prefer cold and swiftflowing mountain streams at an altitude ranging from 1000 to 3500 meters above sea level (stenoecious lifestyle). The habitats of the Epiophlebia species are highly separated from each other on the Asian continent. Their respective range shows no overlap areas today, which typifies speciation via spatial isolation (separation). Results of genetic investigation of three of the four species‘ DNA segments (sequences) show surprising, extreme homogeneity. These results lead to a biogeographical scenario, which assumes a shared habitat of Epiophlebia during the Würm ice age (approximately 20,000 years ago). When the warming phase started, Epiophlebia-populations were separated into distinct populations each located in a di!erent glacial refuge (simplified, cold withdraw areas). This short time frame could explain the genetic homogeneity observed. Nevertheless, the question of the species status of Epiophlebia remains: Is there only one species – Epiophlebia superstes – in four di!erent populations or are there four di!erent species? During a subsequent morphological study the species status at least of Epiophlebia laidlawi Tillard, 1921 could also be confirmed. Another study that draws directly on the genetic investigation of Epiophlebia, comprises a genetic sequence (S4-region of the 28s rRNA gene), which is suitable as a universal species identification tool for insects. Most insect specimens from all insect groups were successfully identified to species level with this tool. The investigation comprised 85 samples of 65 insect species, with at least one species per major clade of which the former represented a genus. We were able to demonstrate that our analysis system – which provides universal applicability and extended functionality – has advantages over the existing one (e.g. COI). The S4-method is applicable for degraded DNA that has, for example, been caused by aging, weathering or chemical influences. Investigation of the Odonata thorax comprised three studies. Two of the musculature and sclerites of adult Zygoptera flight apparatus and one of the entire nymphal Anisoptera thorax musculature. The aim was to understand and highlight peculiarities of the odonatan thorax.To obtain the data and reach the best overall result possible, traditional morphological methods – such as dissecting and hand drawing – were combined with one of the latest morphological methods, which included computer tomography (SR!CT) aided by 3D reconstruction. By doing this, we discovered a total of 11 new, previously unknown muscles for Odonata. These morphological data were used to present the first complete homologization scheme of Odonata and neopterous insect thorax musculature. Furthermore, the homologies of the skeletal elements of the flight apparatus were confirmed and distinctly enhanced. This study also mark the first time muscle attachment points were discussed as important homology criteria. As a whole, these homology assessments allow unprecedented direct comparison between Odonata, which have a highly derived flight apparatus, and all other insects. Insights into the evolution and ground pattern of Odonata, even of all winged insects (Pterygota), were consequently gained. The homologies enable comparison and provide a complete new set of characters for subsequent analysis of the relationship (phylogenetic analysis) of Pterygota. A key, wing base sclerites‘ characteristic – the subalare – , points to the phylogenetic hypothesis of Paleoptera [Odonata+Ephemeroptera (mayflies)]. A generalized Odonata thorax that includes all recently known muscles will allow simplified work and access to the complex structure for future studies and will aid in furthering knowledge. This generalized thorax might be the initial point for a hypothetical ground pattern of pterygote insects and will allow insights into the development and evolution of the insect flight apparatus

The spinning apparatus of webspinners – functional-morphology, morphometrics and spinning behaviour

Webspinners (Insecta: Embioptera) have a distinctly unique behaviour with related morphological characteristics. Producing silk with the basitarsomeres of their forelegs plays a crucial role in the lives of these insects – providing shelter and protection. The correlation between body size, morphology and morphometrics of the spinning apparatus and the spinning behaviour of Embioptera was investigated for seven species using state-of-the-art methodology for behavioural as well as for morphological approaches. Independent contrast analysis revealed correlations between morphometric characters and body size. Larger webspinners in this study have glands with greater reservoir volume, but in proportionally smaller tarsi relative to body size than in the smaller species. Furthermore, we present a detailed description and review of the spinning apparatus in Embioptera in comparison to other arthropods and substantiate the possible homology of the embiopteran silk glands to class III dermal silk glands of insects

Illuminating nature's beauty: modular, scalable and low-cost LED dome illumination system using 3D-printing technology

Presenting your research in the proper light can be exceptionally challenging. Meanwhile, dome illumination systems became a standard for micro- and macrophotography in taxonomy, morphology, systematics and especially important in natural history collections. However, proper illumination systems are either expensive and/or laborious to use. Nowadays, 3D-printing technology revolutionizes lab-life and will soon find its way into most people's everyday life. Consequently, fused deposition modelling printers become more and more available, with online services offering personalized printing options. Here, we present a 3D-printed, scalable, low-cost and modular LED illumination dome system for scientific micro- and macrophotography. We provide stereolithography ('.stl') files and print settings, as well as a complete list of necessary components required for the construction of three differently sized domes. Additionally, we included an optional iris diaphragm and a sliding table, to arrange the object of desire inside the dome. The dome can be easily scaled and modified by adding customized parts, allowing you to always present your research object in the best light

Louse flies holding on mammals' hair: Comparative functional morphology of specialized attachment devices of ectoparasites (Diptera: Hippoboscoidea)

Hippoboscidae and Nycteribiidae of the dipteran superfamily Hippoboscoidea are obligate ectoparasites, which feed on the blood of different mammals. Due to their limited flight capability, the attachment system on all tarsi is of great importance for a secure grasp onto their host and thus for their survival. In this study, the functional morphology of the attachment system of two hippoboscid species and two nycteribiid species was compared in their specificity to the host substrate. Based on data from scanning electron microscopy and confocal laser scanning microscopy, it was shown that the attachment systems of both Hippoboscidae and Nycteribiidae (Hippoboscoidea) differ greatly from that of other calyptrate flies and are uniform within the respective families. All studied species have an attachment system with two monodentate claws and two pulvilli. The claws and pulvilli of the Hippoboscidae are asymmetric, which is an adaptation to the fur of even-toed ungulates (Artiodactyla). The fur of these mammals possesses both, thinner woolen and thicker coat hair; thus, the asymmetry of the attachment system of the hippoboscid species enables a secure attachment to all surfaces of their hosts. The claws and pulvilli of the nyceribiid species do not show an asymmetry, since the fur of their bat (Chiroptera) hosts consists of hairs with the same thickness. The claws are important for the attachment to mammals' fur, because they enable a secure grip by mechanical interlocking of the hairs through the claws. Additionally, well-developed pulvilli are able to attach on thicker hairs of Artiodactyla or on smooth substrates such as the skin

Endolithic Algae Affect Modern Coral Carbonate Morphology and Chemistry

While burial diagenetic processes of tropical corals are well investigated, current knowledge about factors initiating early diagenesis remains fragmentary. In the present study, we focus on recent Porites microatolls, growing in the intertidal zone. This growth form represents a model organism for elevated sea surface temperatures (SSTs) and provides important but rare archives for changes close to the seawater/atmosphere interface with exceptional precision on sea level reconstruction. As other coral growth forms, microatolls are prone to the colonization by endolithic green algae. In this case, the algae can facilitate earliest diagenetic alteration of the coral skeleton. Algae metabolic activity not only results in secondary coral porosity due to boring activities, but may also initiate reprecipitation of secondary aragonite within coral pore space, a process not exclusively restricted to microatoll settings. In the samples of this initial study, we quantified a mass transfer from primary to secondary aragonite of around 4% within endolithic green algae bands. Using δ 18 O, δ 13 C, Sr/Ca, U/Ca, Mg/Ca, and Li/Mg systematics suggests that the secondary aragonite precipitation followed abiotic precipitation principles. According to their individual distribution coefficients, the different isotope and element ratios showed variable sensitivity to the presence of secondary aragonite in bulk samples, with implications for microatoll-based SST reconstructions. The secondary precipitates formed on an organic template, presumably originating from endolithic green algae activity. Based on laboratory experiments with the green algae Ostreobium quekettii, we propose a conceptual model that secondary aragonite formation is potentially accelerated by an active intracellular calcium transport through the algal thallus from the location of dissolution into coral pore spaces. The combined high-resolution imaging and geochemical approach applied in this study shows that endolithic algae can possibly act as a main driver for earliest diagenesis of coral aragonite starting already during a coral’s life span

Incorporation of minor and trace elements into cultured brachiopods : implications for proxy application with new insights from a biomineralisation model

his project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 643084 (BASE-LiNE Earth), and was also supported by the collaborative research initiative CHARON (DFG Research Group 1644 – Phase II) funded by the German Research Foundation.Brachiopods present a key fossil group for Phanerozoic palaeo-environmental and palaeo-oceanographical reconstructions, owing to their good preservation and abundance in the geological record. Yet to date, hardly any geochemical proxies have been calibrated in cultured brachiopods and only little is known on the mechanisms that control the incorporation of various key elements into brachiopod calcite. To evaluate the feasibility and robustness of multiple Element/Ca ratios as proxies in brachiopods, specifically Li/Ca, B/Ca, Na/Ca, Mg/Ca, Sr/Ca, Ba/Ca, as well as Li/Mg, we cultured Magellania venosa, Terebratella dorsata and Pajaudina atlantica under controlled experimental settings over a period of more than two years with closely monitored ambient conditions, carbonate system parameters and elemental composition of the culture medium. The experimental setup comprised of two control aquariums (pH0 = 8.0 and 8.15, T = 10 °C) and treatments where pCO2−pH (pH1 = 7.6 and pH2 = 7.35), temperature (T = 16 °C) and chemical composition of the culture medium were manipulated. Our results indicate that the incorporation of Li and Mg is strongly influenced by temperature, growth effects as well as carbonate chemistry, complicating the use of Li/Ca, Mg/Ca and Li/Mg ratios as straightforward reliable proxies. Boron partitioning varied greatly between the treatments, however without a clear link to carbonate system parameters or other environmental factors. The partitioning of both Ba and Na varied between individuals, but was not systematically affected by changes in the ambient conditions. We highlight Sr as a potential proxy for DIC, based on a positive trend between Sr partitioning and carbonate chemistry in the culture medium. To explain the observed dependency and provide a quantitative framework for exploring elemental variations, we devise the first biomineralisation model for brachiopods, which results in a close agreement between modelled and measured Sr distribution coefficients. We propose that in order to sustain shell growth under increased DIC, a decreased influx of Ca2+ to the calcifying fluid is necessary, driving the preferential substitution of Sr2+ for Ca2+ in the crystal lattice. Finally, we conducted micro-computed tomography analyses of the shells grown in the different experimental treatments. We present pore space – punctae – content quantification that indicates that shells built under increased environmental stress, and in particular elevated temperature, contain relatively more pore space than calcite, suggesting this parameter as a potential novel proxy for physiological stress and even environmental conditions.Publisher PDFPeer reviewe

Phylogeographic Analysis Elucidates the Influence of the Ice Ages on the Disjunct Distribution of Relict Dragonflies in Asia

Unusual biogeographic patterns of closely related groups reflect events in the past, and molecular analyses can help to elucidate these events. While ample research on the origin of disjunct distributions of different organism groups in the Western Paleartic has been conducted, such studies are rare for Eastern Palearctic organisms. In this paper we present a phylogeographic analysis of the disjunct distribution pattern of the extant species of the strongly cool-adapted Epiophlebia dragonflies from Asia. We investigated sequences of the usually more conserved 18 S rDNA and 28 S rDNA genes and the more variable sequences of ITS1, ITS2 and CO2 of all three currently recognised Epiophlebia species and of a sample of other odonatan species. In all genes investigated the degrees of similarity between species of Epiophlebia are very high and resemble those otherwise found between different populations of the same species in Odonata. This indicates that substantial gene transfer between these populations occurred in the comparatively recent past. Our analyses imply a wide distribution of the ancestor of extant Epiophlebia in Southeast Asia during the last ice age, when suitable habitats were more common. During the following warming phase, its range contracted, resulting in the current disjunct distribution. Given the strong sensitivity of these species to climatic parameters, the current trend to increasing global temperatures will further reduce acceptable habitats and seriously threaten the existences of these last representatives of an ancient group of Odonata

Rentapia hosii FMNH 244892, iodine-stained CT volume

Species: Rentapia hosii Collection number: FMNH 244892 Institution of origin: Field Museum of Natural History, Chicago Data: CT volume of iodine-stained specimen (1% I2KI in water) Coverage: full specimen Scanner: Skyscan1172 Scanning parameters: 100 kV; 100 µA; filter: Al 0.5 mm Voxel size: 26.66 µ