Sperm carriers in Silurian sea scorpions

Invasion of the land by arachnids required adaptations of numerous organs, such as gills evolving into lungs, as well as mechanisms facilitating sperm transfer in a terrestrial environment. Many modern arachnids use spermatophores for this purpose, i.e. sperm transmitters detached from the body. Exceptionally preserved Silurian (423?Ma) fossils of Eurypterus tetragonophthalmus Fischer, 1839 (Chelicerata: Eurypterida) preserve so-called 'horn organs' which we here demonstrate as being equivalent to the spermatophore-producing parts of the genital tract in certain modern arachnids. This clarifies a long-running debate about sexing eurypterids based on the shape of the median abdominal (or genital) appendage. To our knowledge this is also the oldest direct evidence for spermatophore-mediated sperm transfer in the fossil record and suggests that eurypterids had evolved mating techniques using spermatophores as early as the Silurian, a valuable prerequisite for life on land. Spermatophores are absent in sea spiders (Pycnogonida) and horseshoe crabs (Xiphosura); thus the shared presence of sclerotized sperm-transfer devices in eurypterids and arachnids is a novel character, newly elucidated here, which offers explicit support for (Eurypterida + Arachnida). For this clade the name Sclerophorata n. nov. is proposed. Arachnida can be further defined by fusion of the originally paired genital opening.     

Dynamic real-time risk analytics of uncontrollable states in complex internet of things systems: cyber risk at the edge

The Internet of Things (IoT) triggers new types of cyber risks. Therefore, the integration of new IoT devices and services requires a self-assessment of IoT cyber security posture. By security posture this article refers to the cybersecurity strength of an organisation to predict, prevent and respond to cyberthreats. At present, there is a gap in the state of the art, because there are no self-assessment methods for quantifying IoT cyber risk posture. To address this gap, an empirical analysis is performed of 12 cyber risk assessment approaches. The results and the main findings from the analysis is presented as the current and a target risk state for IoT systems, followed by conclusions and recommendations on a transformation roadmap, describing how IoT systems can achieve the target state with a new goal-oriented dependency model. By target state, we refer to the cyber security target that matches the generic security requirements of an organisation. The research paper studies and adapts four alternatives for IoT risk assessment and identifies the goal-oriented dependency modelling as a dominant approach among the risk assessment models studied. The new goal-oriented dependency model in this article enables the assessment of uncontrollable risk states in complex IoT systems and can be used for a quantitative self-assessment of IoT cyber risk posture.

     

Meter-scale variation within a single transect demands attention to taxon accumulation curves in riverine microbiome studies

● Riverine microbiomes exhibited hyperlocal variation within a single transect. ● Certain family-level taxa directionally associated with river center and bank. ● Taxon accumulation curves within a transect urges more nuanced sampling design. Microbial communities inhabiting river ecosystems play crucial roles in global biogeochemical cycling and pollution attenuation. Spatial variations in local microbial assemblages are important for detailed understanding of community assembly and developing robust biodiversity sampling strategies. Here, we intensely analyzed twenty water samples collected from a one-meter spaced transect from the near-shore to the near-center in the Meramec River in eastern Missouri, USA and examined the microbial community composition with 16S rRNA gene amplicon sequencing. Riverine microbiomes across the transect exhibited extremely high similarity, with Pearson’s correlation coefficients above 0.9 for all pairwise community composition comparisons. However, despite the high similarity, PERMANOVA revealed significant spatial differences between near-shore and near-center communities (p = 0.001). Sloan’s neutral model simulations revealed that within-transect community composition variation was largely explained by demographic stochasticity (R² = 0.89). Despite being primarily explained by neutral processes, LefSe analyses also revealed taxa from ten families of which relative abundances differed directionally from the bank to the river center, indicating an additional role of environmental filtering. Notably, the local variations within a river transect can have profound impacts on the documentation of alpha diversity. Taxon-accumulation curves indicated that even twenty samples did not fully saturate the sampling effort at the genus level, yet four, six and seven samples were able to capture 80% of the phylum-level, family-level, and genus-level diversity, respectively. This study for the first time reveals hyperlocal variations in riverine microbiomes and their assembly mechanisms, demanding attention to more robust sampling strategies for documenting microbial diversity in riverine systems.     

Conserving alpha and beta diversity in wood-production landscapes

International demand for wood and other forest products continues to grow rapidly, and uncertainties remain about how animal communities will respond to intensifying resource extraction associated with woody bioenergy production. We examined changes in alpha and beta diversity of bats, bees, birds, and reptiles across wood production landscapes in the southeastern United States, a biodiversity hotspot that is one of the principal sources of woody biomass globally. We sampled across a spatial gradient of paired forest land-uses (representing pre and postharvest) that allowed us to evaluate biological community changes resulting from several types of biomass harvest. Short-rotation practices and residue removal following clearcuts were associated with reduced alpha diversity (−14.1 and −13.9 species, respectively) and lower beta diversity (i.e., Jaccard dissimilarity) between land-use pairs (0.46 and 0.50, respectively), whereas midrotation thinning increased alpha (+3.5 species) and beta diversity (0.59). Over the course of a stand rotation in a single location, biomass harvesting generally led to less biodiversity. Cross-taxa responses to resource extraction were poorly predicted by alpha diversity: correlations in responses between taxonomic groups were highly variable (−0.2 to 0.4) with large uncertainties. In contrast, beta diversity patterns were highly consistent and predictable across taxa, where correlations in responses between taxonomic groups were all positive (0.05–0.4) with more narrow uncertainties. Beta diversity may, therefore, be a more reliable and information-rich indicator than alpha diversity in understanding animal community response to landscape change. Patterns in beta diversity were primarily driven by turnover instead of species loss or gain, indicating that wood extraction generates habitats that support different biological communities.