Rare dental anomalies in two sympatric European bat species (Pipistrellus spp.)

Over the past twenty years, we documented striking non-lethal anomalies in the dentition of the common pipistrelle (Pipistrellus pipistrellus) during field work in various parts of Germany. In 2019 we got knowledge of two bat nurslings (P. pipistrellus, P. pygmaeus) from the Rhine-Main area (Hesse, Germany) with ultimately fatal dental anomalies. The aberrations were documented with high-resolution X-ray techniques. Here we discuss our results in the context of published, but mostly minor and obvious non-lethal teeth anomalies in bats

Improved non-destructive 2D and 3D X-ray imaging of leaf venation

Background: Leaf venation traits are important for many research fields such as systematics and evolutionary biology, plant physiology, climate change, and paleoecology. In spite of an increasing demand for vein trait data, studies are often still data-limited because the development of methods that allow rapid generation of large sets of vein data has lagged behind. Recently, non-destructive X-ray technology has proven useful as an alternative to traditional slow and destructive chemical-based methods. Non-destructive techniques more readily allow the use of herbarium specimens, which provide an invaluable but underexploited resource of vein data and related environmental information. The utility of 2D X-ray technology and microfocus X-ray computed tomography, however, has been compromised by insufficient image resolution. Here, we advanced X-ray technology by increasing image resolution and throughput without the application of contrast agents. Results: For 2D contact microradiography, we developed a method which allowed us to achieve image resolutions of up to 7 µm, i.e. a 3.6-fold increase compared to the industrial standard (25 µm resolution). Vein tracing was further optimized with our image processing standards that were specifically adjusted for different types of leaf structure and the needs of higher imaging throughput. Based on a test dataset, in 91% of the samples the 7 µm approach led to a significant improvement in estimations of minor vein density compared to the industrial standard. Using microfocus X-ray computed tomography, very high-resolution images were obtained from a virtual 3D–2D transformation process, which was superior to that of 3D images. Conclusions: Our 2D X-ray method with a significantly improved resolution advances rapid non-destructive bulk scanning at a quality that in many cases is sufficient to determine key venation traits. Together with our high-resolution microfocus X-ray computed tomography method, both non-destructive approaches will help in vein trait data mining from museum collections, which provide an underexploited resource of historical and recent data on environmental and evolutionary change. In spite of the significant increase in effective image resolution, a combination of high-throughput and full visibility of the vein network (including the smallest veins and their connectivity) remains challenging, however

Taxonomic diversity masks leaf vein–climate relationships: lessons from herbarium collections across a latitudinal rainfall gradient in West Africa

<p>Cross-biome data suggest that leaf venation density increases with decreasing moisture availability. If leaf venation traits were related to climatic conditions in such a predictable manner, these traits could serve, for example, as proxies for the reconstruction of past climates from fossil leaf remnants. However, our knowledge on vein–climate relationships is still scarce and relationships are poorly understood, particularly concerning broad-scale patterns in tropical regions. In this study, based on phylogenetic generalized least squares regression, we analysed leaf venation traits together with climatic niche data from 238 herbarium specimens to infer trait–trait and trait–climate relationships along a strong north–south rainfall gradient crossing West African savannas. Variation in leaf venation traits was strong along the climate gradient, yet vein–climate relationships were weak overall. This is in contrast to our expectation from the strong adaptive forces operating in drought-adapted vegetation covered by the gradient. On the other hand, several common patterns including intervein and vein–leaf size relationships were confirmed. A key finding was that while trait–climate relationships were mostly weak, some of these relationships became stronger when breaking down the entire taxon assemblage into smaller family-level units. This suggests that vein traits underlie partially opposing constraints in different clades, a pattern that is likely to become stronger with increasing higher-rank taxonomic diversity of species assemblages.</p

MOESM2 of Improved non-destructive 2D and 3D X-ray imaging of leaf venation

Additional file 2: Fig. S2. 2D image from 3D-CT-volume data of Bauhinia rufescens. Note rarifications of leaf venation in the dark (empty) areas as a consequence of insufficient reconstruction