Genomic and transcriptomic analyses reveal the adaptation to semi-aquatic and aquatic life in spiders

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  Genomic and transcriptomic analyses reveal the adaptation to semi-aquatic and aquatic life in spiders Abstract Spiders are largely terrestrial, but some lineages have independently adapted to marine and freshwater habitats. Although physiological and behavioral traits supporting these evolutionary transitions have been characterized, the genomic basis of adaptation to aquatic and semi-aquatic habitats in spiders remains unclear. Here, we report a chromosome-level genome assembly for the aquatic spider Argyroneta aquatica. Comparative analysis of 22 spider species supports two independent transitions in semi-aquatic (∼56 Mya) and aquatic (∼44 Mya) lineages. The aquatic spider show distinct respiratory morphology compared with terrestrial spiders, including anterior spiracles and denser tracheoles. Molecular evolution analyses identified lineage-specific shifts in selective constraint or evidence of positive selection linked to trachea development (e.g., Wnt-1, Catenin beta, TMEM23...

Scorpion envenoming by Parabuthus is a public health concern in Namibia

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Scorpion envenoming by Parabuthus is a public health concern in Namibia

Abstract

Scorpion stings by members of the genus Parabuthus (Buthidae) can lead to life-threatening envenoming. Namibia harbours a rich diversity of scorpions, including seventeen species of the highly venomous genus Parabuthus, although the biology and medical relevance of most species are poorly documented. Severe envenoming is caused by at least P. granulatus, P. villosus, P. kraepelini and P. schlechteri, which are considered to be of particular importance. Data on epidemiology, venom composition and variation, and clinical effects remain scarce. A lack of effective antivenom and long distances to hospitals in rural areas complicate clinical management and compromise patient outcomes.