A biosemiotic interpretation of certain genital morphological structures in the spiders Dysdera erythrina and Dysdera crocata (Araneae: Dysderidae).

A biosemiotic approach to the interpretation of morphological data is apt to highlight morphological traits that have hitherto gone unnoticed for their crucial roles in intraspecific sign interpretation and communication processes. Examples of such traits include specific genital structures found in the haplogyne spiders Dysdera erythrina (Walckenaer 1802) and Dysdera crocata (Koch 1838). In both D. erythrina and D. crocata, the distal sclerite of the male bulb and the anterior diverticulum of the female endogyne exhibit a striking, previously unreported correspondence in size and shape, allowing for a precise match between these structures during copulation. In D. erythrina, the sclerite at the tip of the bulb and the anterior diverticulum are semi-circular in shape, whereas in D. crocata they are rectangular. From the perspective of biosemiotics, which studies the production and interpretation of signs and codes in living systems, these structures are considered the morphological zones of an intraspecific sign interpretation process. This process constitutes one of the necessary prerequisites for sperm transfer and the achievement of fertilization. Therefore, these morphological elements deserve particular attention as they hold higher taxonomic value compared to morphological traits of the bulb for which a relevant role in mating and fertilization has not been proven. Thus, an approach to species delimitation based on biosemiotics, with its specific evaluation of morphological structures, provides new insights for the multidisciplinary endeavour of modern integrative taxonomy.

Formalizing Invertebrate Morphological Data: A Descriptive Model for Cuticle-Based Skeleto-Muscular Systems, an Ontology for Insect Anatomy, and their Potential Applications in Biodiversity Research and Informatics.

The spectacular radiation of insects has produced a stunning diversity of phenotypes. During the past 250 years, research on insect systematics has generated hundreds of terms for naming and comparing them. In its current form, this terminological diversity is presented in natural language and lacks formalization, which prohibits computer-assisted comparison using semantic web technologies. Here we propose a Model for Describing Cuticular Anatomical Structures (MoDCAS) which incorporates structural properties and positional relationships for standardized, consistent, and reproducible descriptions of arthropod phenotypes. We applied the MoDCAS framework in creating the ontology for the Anatomy of the Insect Skeleto-Muscular system (AISM). The AISM is the first general insect ontology that aims to cover all taxa by providing generalized, fully logical, and queryable, definitions for each term. It was built using the Ontology Development Kit (ODK), which maximizes interoperability with Uberon (Uberon multispecies anatomy ontology) and other basic ontologies, enhancing the integration of insect anatomy into the broader biological sciences. A template system for adding new terms, extending, and linking the AISM to additional anatomical, phenotypic, genetic, and chemical ontologies is also introduced. The AISM is proposed as the backbone for taxon-specific insect ontologies and has potential applications spanning systematic biology and biodiversity informatics, allowing users to: 1) use controlled vocabularies and create semiautomated computer-parsable insect morphological descriptions; 2) integrate insect morphology into broader fields of research, including ontology-informed phylogenetic methods, logical homology hypothesis testing, evo-devo studies, and genotype to phenotype mapping; and 3) automate the extraction of morphological data from the literature, enabling the generation of large-scale phenomic data, by facilitating the production and testing of informatic tools able to extract, link, annotate, and process morphological data. This descriptive model and its ontological applications will allow for clear and semantically interoperable integration of arthropod phenotypes in biodiversity studies.

Patterns of morphological simplification and innovation in the megadiverse Holometabola (Insecta).

We analyzed patterns of complexity and simplicity in holometabolan insects using parsimony and maximum-likelihood. By contrast with other groups of arthropods (and most other groups of animals), insects have undergone a stepwise process of structural simplification in their evolution. The megadiverse Holometabola are characterized mainly by structurally simplified larvae, which differ strongly from the adults in their morphology and usually also in their life habits. Although smaller groups such as Neuropterida have largely maintained their structural complexity in adults and immature life stages, a series of reductions occurred with the appearance and diversification of Coleopterida, Mecopterida and especially Antliophora. Parasitic Strepsiptera or fleas display conspicuous patterns of reduction in different life stages and body regions, and high degrees of simplification also occur in groups with short-lived adults. Larvae living in moist substrates display far-reaching structural simplifications and also morphological uniformity, especially in the species-rich Diptera, but also in other groups. Liquid feeding leads to correlated simplifications and innovation of adult head structures, especially of the mouthparts. Functional or anatomical dipterism leads to an optimization of the flight apparatus in most holometabolous groups, which is correlated with reductions in one of the pterothoracic segments, and coupled (e.g. by hamuli), partly reduced or transformed wings (e.g. halteres). In flightless groups, the pterothoracic skeleto-muscular apparatus is strongly simplified. In the abdomen of adult females a stepwise reduction of the lepismatoid ovipositor occurs. By contrast, the male genital apparatus often undergoes an extreme diversification. Our evaluations revealed a highly correlated complexity between larval and adult stages.

Emergency department thoracotomy of severely injured patients: an analysis of the TraumaRegister DGU®.

AIM OF THE STUDY: Emergency department thoracotomy (EDT) may be the last chance for survival in some severe thoracic trauma. This study investigates a representative collective with the aim to compare the findings in Europe to the international experience. Moreover, the influence of different levels of trauma care is investigated. METHODS: All emergency thoracotomies in patients with an ISS ≥ 9 from TR-DGU (2009-2014) within the first 60 min after arrival were identified. EDTs were identified separately, and mini thoracotomies and drainage systems were excluded. RESULTS: 99,013 patients with sufficient data were observed. 1736 (1.8%) received thoracotomy during their hospital stay. 887 patients had a thoracotomy within the first hour in the emergency department (ED). 52.5% were treated in supraregional trauma centers (STC), 36.4% in regional (RTC) and 11.0% in local trauma centers (LTC). The mortality rates were 39.4% (STC), 20.9% (RTC) and 20.8% (LTC). The overall mortality rate showed no significant differences for blunt (28.2%) and penetrating trauma (31.3%). In case of cardiac arrest in the ED, a survival rate of 4.8% for blunt trauma and 20.7% for penetrating trauma was determined if EDT was carried out. Those patients showed a higher rate in severe thoracic organ injuries due to penetrating trauma but less extrathoracic injuries. CONCLUSION: Just over half of EDTs were performed in STC. Emergency room resuscitation followed by EDT had survival rates of 4.8% and 20.7% for blunt and penetrating trauma patients, respectively.

Potential of electrospun cationic BSA fibers to guide osteogenic MSC differentiation via surface charge and fibrous topography.

Large or complex bone fractures often need clinical treatments for sufficient bone repair. New treatment strategies have pursued the idea of using mesenchymal stromal cells (MSCs) in combination with osteoinductive materials to guide differentiation of MSCs into bone cells ensuring complete bone regeneration. To overcome the challenge of developing such materials, fundamental studies are needed to analyze and understand the MSC behavior on modified surfaces of applicable materials for bone healing. For this purpose, we developed a fibrous scaffold resembling the bone/bone marrow extracellular matrix (ECM) based on protein without addition of synthetic polymers. With this biomimetic in vitro model we identified the fibrous structure as well as the charge of the material to be responsible for its effects on MSC differentiation. Positive charge was introduced via cationization that additionally supported the stability of the scaffold in cell culture, and acted as nucleation point for mineralization during osteogenesis. Furthermore, we revealed enhanced focal adhesion formation and osteogenic differentiation of MSCs cultured on positively charged protein fibers. This pure protein-based and chemically modifiable, fibrous ECM model allows the investigation of MSC behavior on biomimetic materials to unfold new vistas how to direct cells' differentiation for the development of new bone regenerating strategies.

The evolution and genomic basis of beetle diversity.

The order Coleoptera (beetles) is arguably the most speciose group of animals, but the evolutionary history of beetles, including the impacts of plant feeding (herbivory) on beetle diversification, remain poorly understood. We inferred the phylogeny of beetles using 4,818 genes for 146 species, estimated timing and rates of beetle diversification using 89 genes for 521 species representing all major lineages and traced the evolution of beetle genes enabling symbiont-independent digestion of lignocellulose using 154 genomes or transcriptomes. Phylogenomic analyses of these uniquely comprehensive datasets resolved previously controversial beetle relationships, dated the origin of Coleoptera to the Carboniferous, and supported the codiversification of beetles and angiosperms. Moreover, plant cell wall-degrading enzymes (PCWDEs) obtained from bacteria and fungi via horizontal gene transfers may have been key to the Mesozoic diversification of herbivorous beetles-remarkably, both major independent origins of specialized herbivory in beetles coincide with the first appearances of an arsenal of PCWDEs encoded in their genomes. Furthermore, corresponding (Jurassic) diversification rate increases suggest that these novel genes triggered adaptive radiations that resulted in nearly half of all living beetle species. We propose that PCWDEs enabled efficient digestion of plant tissues, including lignocellulose in cell walls, facilitating the evolution of uniquely specialized plant-feeding habits, such as leaf mining and stem and wood boring. Beetle diversity thus appears to have resulted from multiple factors, including low extinction rates over a long evolutionary history, codiversification with angiosperms, and adaptive radiations of specialized herbivorous beetles following convergent horizontal transfers of microbial genes encoding PCWDEs.

Ocean acidification has little effect on the biochemical composition of the coccolithophore Emiliania huxleyi.

Owing to the hierarchical organization of biology, from genomes over transcriptomes and proteomes down to metabolomes, there is continuous debate about the extent to which data and interpretations derived from one level, e.g. the transcriptome, are in agreement with other levels, e.g. the metabolome. Here, we tested the effect of ocean acidification (OA; 400 vs. 1000 µatm CO2) and its modulation by light intensity (50 vs. 300 µmol photons m-2 s-1) on the biomass composition (represented by 75 key metabolites) of diploid and haploid life-cycle stages of the coccolithophore Emiliania huxleyi (RCC1216 and RCC1217) and compared these data with interpretations from previous physiological and gene expression screenings. The metabolite patterns showed minor responses to OA in both life-cycle stages. Whereas previous gene expression analyses suggested that the observed increased biomass buildup derived from lipid and carbohydrate storage, this dataset suggests that OA slightly increases overall biomass of cells, but does not significantly alter their metabolite composition. Generally, light was shown to be a more dominant driver of metabolite composition than OA, increasing the relative abundances of amino acids, mannitol and storage lipids, and shifting pigment contents to accommodate increased irradiance levels. The diploid stage was shown to contain vastly more osmolytes and mannitol than the haploid stage, which in turn had a higher relative content of amino acids, especially aromatic ones. Besides the differences between the investigated cell types and the general effects on biomass buildup, our analyses indicate that OA imposes only negligible effects on E. huxleyi´s biomass composition.

Species identification of European forest pathogens of the genus Milesina (Pucciniales) using urediniospore morphology and molecular barcoding including M.woodwardiana sp. nov.

Species of rust fungi of the genus Milesina (Pucciniastraceae, Pucciniales) are distributed mainly in northern temperate regions. They host-alternate between needles of fir (Abies spp.) and fronds of ferns (species of Polypodiales). Milesina species are distinguished based on host taxonomy and urediniospore morphology. In this study, 12 species of Milesina from Europe were revised. Specimens were examined by light and scanning electron microscopy for urediniospore morphology with a focus on visualising germ pores (number, size and position) and echinulation. In addition, barcode loci (ITS, nad6, 28S) were used for species delimitation and for molecular phylogenetic analyses. Barcodes of 72 Milesina specimens were provided, including 11 of the 12 species. Whereas urediniospore morphology features were sufficient to distinguish all 12 Milesina species except for 2 (M.blechni and M.kriegeriana), ITS sequences separated only 4 of 11 species. Sequencing with 28S and nad6 did not improve species resolution. Phylogenetic analysis, however, revealed four phylogenetic groups within Milesina that also correlate with specific urediniospore characters (germ pore number and position and echinulation). These groups are proposed as new sections within Milesina (sections Milesina, Vogesiacae M. Scholler & Bubner, sect. nov., Scolopendriorum M. Scholler & Bubner, sect. nov. and Carpaticae M. Scholler & Bubner, sect. nov.). In addition, Milesinawoodwardiana Buchheit & M. Scholler, sp. nov. on Woodwardiaradicans, a member of the type section Milesina, is newly described. An identification key for European Milesina species, based on urediniospore features, is provided.

Simultaneous thermal analysis of cationic, nonionic and anionic polyacrylamide.

Polyacrylamide (PAM) and its derivatives are the most commercially available water-soluble polymers and are frequently used for the production of clay-polymer composites. The characterization of their thermal behavior and decomposition was carried out mainly under reduced conditions by using N2, He or Ar gas flow. The object of this study was to investigate the thermal decomposition of cationic (PAMS,τ40Cl), nonionic (PAM°S), and anionic (NaPAMS,τ40) polyacrylamide under synthetic air (SynA) in detail using a thermogravimetry/differential scanning calorimetry (TG/DSC) system connected to a quadrupole mass spectrometer (MS). MS data indicated the release of NH3, CH4 and NO together with H2O, CO2 and NO2 during decomposition. The gas release differed between the three polymers. Stoichiometric calculations showed that PAMS,τ40Cl and PAM°S decomposed completely, while NaPAMS,τ40 decomposed only partially and the Na present for charge balancing remained in the form of Na2O. The thermal decomposition of PAMS,τ40Cl, PAM°S and NaPAMS,τ40 under SynA occurred via pyrolysis and oxidation reactions.

Phylogenomics and the evolution of hemipteroid insects.

Hemipteroid insects (Paraneoptera), with over 10% of all known insect diversity, are a major component of terrestrial and aquatic ecosystems. Previous phylogenetic analyses have not consistently resolved the relationships among major hemipteroid lineages. We provide maximum likelihood-based phylogenomic analyses of a taxonomically comprehensive dataset comprising sequences of 2,395 single-copy, protein-coding genes for 193 samples of hemipteroid insects and outgroups. These analyses yield a well-supported phylogeny for hemipteroid insects. Monophyly of each of the three hemipteroid orders (Psocodea, Thysanoptera, and Hemiptera) is strongly supported, as are most relationships among suborders and families. Thysanoptera (thrips) is strongly supported as sister to Hemiptera. However, as in a recent large-scale analysis sampling all insect orders, trees from our data matrices support Psocodea (bark lice and parasitic lice) as the sister group to the holometabolous insects (those with complete metamorphosis). In contrast, four-cluster likelihood mapping of these data does not support this result. A molecular dating analysis using 23 fossil calibration points suggests hemipteroid insects began diversifying before the Carboniferous, over 365 million years ago. We also explore implications for understanding the timing of diversification, the evolution of morphological traits, and the evolution of mitochondrial genome organization. These results provide a phylogenetic framework for future studies of the group.

Reconstructing the anterior part of the nervous system of Gordius aquaticus (Nematomorpha, cycloneuralia) by a multimethodological approach.

The Nematomorpha (horsehair worms) and Nematoda (round worms) are sister taxa (together Nematoida) and closely related to Scalidophora (Priapulida, Kinorhyncha, Loricifera). To date, all species were assumed to possess a specific brain type, i.e., the "cycloneuralian" brain that forms a ring-shaped neuropil around the pharynx and is composed of anteriorly and posteriorly located somata. However, descriptions of the nematomorph nervous system are rare and somewhat variable, calling in to question the validity of the cycloneuralian condition. To clarify whether there is a typical cycloneuralian pattern in the nematomorph brain, we investigated the anterior end of Gordius aquaticus with different methods: histology, immunohistochemistry and micro-CT analysis. Three-dimensional reconstructions were made from histological serial sections. The brain is composed of a central neuropil and a ring-shaped structure with associated somata. The unpaired ventral nerve cord emerges from the posteroventral part of the brain. A pharynx/esophagus is absent. In addition to the brain, a peripheral nerve plexus was detected. In summary, we interpret the architecture of the brain as potentially derived from a cycloneuralian structure, but being highly modified. The central position of the neuropil is possibly a consequence of the reduction of the anterior intestinal system as a result of the parasitic lifestyle. The ring-shaped arrangement of the somata may be a remnant of a cycloneuralian arrangement, after the two rings of somata (= cycloneuralian condition) either fused or one ring was reduced to form one massive ring-shaped structure in G. aquaticus. J. Morphol. 278:106-118, 2017. ©© 2016 Wiley Periodicals,Inc.

The larval head anatomy of Rhyacophila (Rhyacophilidae) with discussion on mouthpart homology and the groundplan of Trichoptera.

The external and internal features of the larval head of Rhyacophila fasciata (Trichoptera: Rhyacophilidae) were described in detail. Anatomical examinations were carried out using a multimethod approach including histology, scanning electron microscopy, confocal laser-scanning microscopy, microcomputed tomography, and computer-based three-dimensional reconstructions. Additionally, the information on the larval head of Limnephilus flavicornis (Limnephilidae) and Hydropsyche angustipennis (Hydropsychidae) available in the literature were reinvestigated. These anatomical data were used to address major questions of homology and terminology, that is, the ventral closure of the head capsule, the sclerites, and appendages of labium and maxilla and their muscles. These topics were discussed by summarizing the main hypotheses present in the literature and a critical inclusion of new findings. Consequently, the inner lobe of the maxilla very likely represents the galea. The distal maxillary sclerite (palpifer) is an anatomical composite formation at least including dististipes and lacinia. Based on these homology hypotheses several potential groundplan features of the larval head of Trichoptera were reconstructed. The head of Rhyacophila shows several presumably plesiomorphic features as for instance the prognath orientation of the mouthparts, the well-developed hypocranial bridge, the triangular submentum and eyes composed of seven stemmata. Derived features of Rhyacophila are the reduced antennae, the anterior directing of three stemmata and the shift of the tentorio-stipital muscle to the mentum.

Finding our way through phenotypes.

Despite a large and multifaceted effort to understand the vast landscape of phenotypic data, their current form inhibits productive data analysis. The lack of a community-wide, consensus-based, human- and machine-interpretable language for describing phenotypes and their genomic and environmental contexts is perhaps the most pressing scientific bottleneck to integration across many key fields in biology, including genomics, systems biology, development, medicine, evolution, ecology, and systematics. Here we survey the current phenomics landscape, including data resources and handling, and the progress that has been made to accurately capture relevant data descriptions for phenotypes. We present an example of the kind of integration across domains that computable phenotypes would enable, and we call upon the broader biology community, publishers, and relevant funding agencies to support efforts to surmount today's data barriers and facilitate analytical reproducibility.

Phylogenomics resolves the timing and pattern of insect evolution.

Insects are the most speciose group of animals, but the phylogenetic relationships of many major lineages remain unresolved. We inferred the phylogeny of insects from 1478 protein-coding genes. Phylogenomic analyses of nucleotide and amino acid sequences, with site-specific nucleotide or domain-specific amino acid substitution models, produced statistically robust and congruent results resolving previously controversial phylogenetic relations hips. We dated the origin of insects to the Early Ordovician [~479 million years ago (Ma)], of insect flight to the Early Devonian (~406 Ma), of major extant lineages to the Mississippian (~345 Ma), and the major diversification of holometabolous insects to the Early Cretaceous. Our phylogenomic study provides a comprehensive reliable scaffold for future comparative analyses of evolutionary innovations among insects.

Anti­citrullinated protein antibody positivity correlates with cartilage damage and proteoglycan levels in patients with rheumatoid arthritis in the hand joints.

Objective: To investigate the factors associated with cartilage proteoglycan content in patients with rheumatoid arthritis (RA) Methods: 32 RA patients received high-field 3 Tesla Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) for determining cartilage proteoglycan content. Measurements were performed in three individual cartilage regions (medial, central, lateral) of the metacarpophalangeal joints 2 and 3. dGEMRIC values were then related to disease duration, disease activity, anti-citrullinated protein antibody (ACPA) status, rheumatoid factor status and C-reactive protein level. Results: dGEMRIC values were not significantly different between the MCP2 and MCP3 joint. Inter-class correlations were high (>0.92) for all three (medial, central and lateral) cartilage compartments. dGEMRIC values were significantly lower in RA patients with longer disease duration (≥3 years) and those with ACPA positivity than those with a short disease duration (<3 years)(p=0.034) or negative ACPA (p=0.0002), respectively. In contrast, no association between cartilage proteoglycan content and disease activity, C-reactive protein level and rheumatoid factor status was found. Conclusion: Decreased cartilage proteoglycan content in RA patients is associated with disease duration and ACPA positivity but not with the actual disease activity, CRP level or rheumatoid factor status. These data suggest that the cumulative burden of inflammation as well as ACPA are the determinants for cartilage damage in RA.

Tranzschelia in the Americas revisited: two new species and notes on the Tranzschelia thalictri complex.

Two new species of Tranzschelia (Pucciniales) are described from the Americas. Tranzschelia pseudofusca is a microcyclic species on Anemone spp. (Ranunculaceae) with North American distribution. T. mexicana on Prunus salicifolia (Rosaceae) is found in Colombia, Ecuador and Mexico. It is assumed that T. mexicana is a macrocyclic host-alternating species. T. thalictri, a holarctic microcyclic species, has variable morphology and probably is an aggregate of related species. Specimens are documented with scanning electron microscopy (ESEM) and light microscopy including a simple new technique to illuminate urediniospore germ pores. Results are discussed with respect to similar species, distribution and life-cycle characters. A key for American species on telial hosts is provided.

The evolutionary history of holometabolous insects inferred from transcriptome-based phylogeny and comprehensive morphological data.

BACKGROUND: Despite considerable progress in systematics, a comprehensive scenario of the evolution of phenotypic characters in the mega-diverse Holometabola based on a solid phylogenetic hypothesis was still missing. We addressed this issue by de novo sequencing transcriptome libraries of representatives of all orders of holometabolan insects (13 species in total) and by using a previously published extensive morphological dataset. We tested competing phylogenetic hypotheses by analyzing various specifically designed sets of amino acid sequence data, using maximum likelihood (ML) based tree inference and Four-cluster Likelihood Mapping (FcLM). By maximum parsimony-based mapping of the morphological data on the phylogenetic relationships we traced evolutionary transformations at the phenotypic level and reconstructed the groundplan of Holometabola and of selected subgroups. RESULTS: In our analysis of the amino acid sequence data of 1,343 single-copy orthologous genes, Hymenoptera are placed as sister group to all remaining holometabolan orders, i.e., to a clade Aparaglossata, comprising two monophyletic subunits Mecopterida (Amphiesmenoptera + Antliophora) and Neuropteroidea (Neuropterida + Coleopterida). The monophyly of Coleopterida (Coleoptera and Strepsiptera) remains ambiguous in the analyses of the transcriptome data, but appears likely based on the morphological data. Highly supported relationships within Neuropterida and Antliophora are Raphidioptera + (Neuroptera + monophyletic Megaloptera), and Diptera + (Siphonaptera + Mecoptera). ML tree inference and FcLM yielded largely congruent results. However, FcLM, which was applied here for the first time to large phylogenomic supermatrices, displayed additional signal in the datasets that was not identified in the ML trees. CONCLUSIONS: Our phylogenetic results imply that an orthognathous larva belongs to the groundplan of Holometabola, with compound eyes and well-developed thoracic legs, externally feeding on plants or fungi. Ancestral larvae of Aparaglossata were prognathous, equipped with single larval eyes (stemmata), and possibly agile and predacious. Ancestral holometabolan adults likely resembled in their morphology the groundplan of adult neopteran insects. Within Aparaglossata, the adult's flight apparatus and ovipositor underwent strong modifications. We show that the combination of well-resolved phylogenies obtained by phylogenomic analyses and well-documented extensive morphological datasets is an appropriate basis for reconstructing complex morphological transformations and for the inference of evolutionary histories.

Drinking water biofilms on copper and stainless steel exhibit specific molecular responses towards different disinfection regimes at waterworks.

Biofilms growing on copper and stainless steel substrata in natural drinking water were investigated. A modular pilot-scale distribution facility was installed at four waterworks using different raw waters and disinfection regimes. Three-month-old biofilms were analysed using molecular biology and microscopy methods. High total cell numbers, low counts of actively respiring cells and low numbers of cultivable bacteria indicated the high abundance of viable but not cultivable bacteria in the biofilms. The expression of the recA SOS responsive gene was detected and underlined the presence of transcriptionally active bacteria within the biofilms. This effect was most evident after UV disinfection, UV oxidation and UV disinfection with increased turbidity at waterworks compared to chemically treated and non-disinfected systems. Furthermore, live/dead staining techniques and environmental scanning electron microscopy imaging revealed the presence of living and intact bacteria in biofilms on copper substrata. Cluster analyses of DGGE profiles demonstrated differences in the composition of biofilms on copper and steel materials.

The head of Merope tuber (Meropeidae) and the phylogeny of Mecoptera (Hexapoda).

External and internal features of the head of adults of Merope tuber were examined and described in detail. The results were compared to conditions found in other members of Mecoptera and other antliophoran lineages. A list of characters of different body parts and life stages is presented. The parsimony analysis and a recent evaluation of thoracic features suggest a basal placement of Merope within monophyletic Pistillifera. The monophyly of Mecoptera was not supported by our data set. Nannochoristidae (Nannomecoptera) was placed as sistertaxon of a clade comprising Diptera and Siphonaptera. Cephalic features supporting this group are modifications of the mouthparts linked to feeding on liquid substrates. Considering recent results of extensive morphological and molecular investigations we consider this placement of Nannochoristidae and the implied mecopteran paraphyly as a possible artefact. Potential cephalic autapomorphies of Mecoptera are the presence of a tooth-like projection of the gena and a prepharyngeal tube, the absence of M. frontolabralis, and the origin of M. tentoriooralis on the middle region of the anterior tentorial arm. Despite of the conspicuous morphological differences between Caurinus and the other boreid genera the family forms a well supported clade. A sistergroup relationship between Boreidae and Pistillifera is confirmed. A unique synapomorphy is the presence of specialized dilator muscles of the salivary duct. The reconstruction of the relationships of the pistilliferan taxa is strongly impeded by a serious lack of morphological data. However, a group comprising Eomeropidae, Choristidae, Apteropanorpidae, Panorpidae and Panorpodidae is supported in our analyses. Further well documented anatomical data are needed for a reliable reconstruction of mecopteran relationships. The collecting and morphological study of larvae should also have high priority. Inherent problems are extreme secondary modifications of cephalic features of Caurinus and Nannochorista.

The thoracic skeleto-muscular system of Mengenilla (Strepsiptera: Mengenillidae) and its phylogenetic implications.

The thorax of Mengenilla was examined using traditional morphological techniques and its features were documented in detail using scanning electron microscopy and computer-based 3D reconstructions. The results were compared to conditions found in other holometabolan insects. The implications for the systematic placement of Strepsiptera are discussed. The observations are interpreted in the light of the recently confirmed sistergroup relationship between Strepsiptera and Coleoptera (Coleopterida). The synapomorphies of the thorax of Strepsiptera and Coleoptera are partly related with posteromotorism (e.g., increased size of the metathorax), partly with a decreased intrathoracic flexibility (e.g., a fused pronotum and propleurum), and partly independent from these two character complexes (e.g., not connected profurca and propleuron). Strepsiptera are more derived than Coleoptera in some thoracic features (e.g., extremely enlarged metathorax) but have also preserved some plesiomorphic conditions (e.g., tegulae in both pterothoracic segments). All potential apomorphies of Mecopterida are missing in Strepsiptera. The last common ancestor of Coleopterida had already acquired posteromotorism but the wings were still largely unmodified. Several reductions in the mesothorax likely occurred independently.