Venomics of the six-eyed sand spider, Sicarius rugosus (Araneae: Sicariidae), from the neotropical dry forest of Costa Rica

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  Venomics of the six-eyed sand spider, Sicarius rugosus (Araneae: Sicariidae), from the neotropical dry forest of Costa Rica Abstract Background Sicarius rugosus , the only member of the genus that inhabits Central America, is phylogenetically related to South American  Sicarius  spiders. These originated from a common ancestor with sister African species. Like  Loxosceles ,  Sicarius  exhibits venom phospholipase D activity due to a group of toxins known collectively as SicTox. Methods A gel-assisted, bottom-up, proteomic analysis was performed to characterize the venom composition of  S. rugosus . Hyaluronidase activity was determined using zymography. Results We identified several SicTox sequences, all classified as β-clade paralogs and sharing unique peptides with proteins from  S. patagonicus ,  S. peruensis,  and other species. Enzymes such as metalloproteinases, including putative astacins, carboxypeptidases, and angiotensin-conv...

Heavy metal predators: diverse elemental enrichment across the weapons of scorpions

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Heavy metal predators: diverse elemental enrichment across the weapons of scorpions

Abstract

Scorpions diverged from their closest relatives around the Ordovician Period, and since then, environmental interactions have shaped the evolution of the material properties of their exoskeletons. Hardening of this structure via the incorporation of transition metals has enabled biomechanical advancements in weapon development. Scorpion weapons consist of the stinger (telson) and claws (chelae) and contain diverse metals such as zinc, manganese and iron, though little is known about comparative patterns of incorporation across the wider clade. In this study, we harness X-ray-driven microanalytical techniques to characterize the different elemental enrichment patterns within the weapons of 18 species from a range of scorpion families. We hypothesized that enrichment by metal would be inversely correlated between weapons, tied to their functional roles and morphological diversity. We identified cryptic enrichment strategies, including weapon-selective elemental replacement and an inverse enrichment of Zn between weapons. Chela enrichment by Zn was found to positively correlate with a morphological indicator of chelae pinch strength, wherein Zn enrichment was greater in specimens with reduced crushing power. This study supports a growing body of research into the evolution of metal enrichment among invertebrates and provides a greater understanding of the material properties of the exoskeleton within weapon development.

Sam I. D. Campbell, Edward P. Vicenzi, Thomas Lam, Bryan G. Fry, Hannah M. Wood; Heavy metal predators: diverse elemental enrichment across the weapons of scorpions. J R Soc Interface 1 April 2026; 23 (237): 20250523. https://doi.org/10.1098/rsif.2025.0523