Venom Mass Fingerprints for Species Delimitation, Reloaded: A Test Case with Italian Scorpions (Euscorpius)

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  Venom Mass Fingerprints for Species Delimitation, Reloaded: A Test Case with Italian Scorpions (Euscorpius) Abstract Scorpion venoms are complex mixtures of bioactive compounds including proteins, peptides and enzymes. Although venoms exhibit substantial intraspecific variation, some compounds appear to be species-specific, highlighting their potential as chemotaxonomic markers. Venom mass fingerprints (MFPs) derived from Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry (MS) have been proposed as a means of delimiting species. However, their utility for species delimitation has rarely been evaluated against independent sources of taxonomic evidence. In the present study, the performance of MALDI-TOF MS-based venom peptide barcoding (mass ranges of m/z 800‒4500 and m/z 3000‒10,000) was assessed in 52 populations of eight Italian species of the scorpion genus Euscorpius Thorell, 1876, representing different levels of evolutionary divergenc...

Scorpion Group 1 discovered in the venom of Anuroctonus phaiodactylus

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Scorpion Group 1 discovered in the venom of Anuroctonus phaiodactylus

Abstract

Scorpion Group 1 (SG1) represents a novel, highly divergent lineage of symbiotic bacteria within the class Mollicutes (phylum Mycoplasmatota). Currently, SG1’s distribution remains restricted - it has been identified exclusively within the scorpion family Vaejovidae, specifically in the genera Vaejovis and Mesomexovis. To date, SG1 has not been detected in other major scorpion families, suggesting a specialized host-symbiont relationship. In this study, we utilized the long-read capabilities of Oxford Nanopore Technology to sequence the 16S rRNA gene from the venom of two scorpion species: Paruroctonus becki (family Vaejovidae) and Anuroctonus phaiodactylus (family Anuroctonidae). We aimed to uncover cryptic microbial diversity, such as SG1, that may have been overlooked by previous short-read sequencing platforms. Our results revealed SG1 was indeed present in A. phaiodactylus but its presence was undetected in P. becki. We thus extend the host range of SG1 beyond Vaejovidae to include Anuroctonidae, refining the evolutionary boundaries of this unusual Mollicutes-scorpion association.

Heidorn, A., Graham, M. R., & Murdoch, B. (2026). Scorpion Group 1 discovered in the venom of Anuroctonus phaiodactylus. Frontiers in Arachnid Science, 5, 1858835. https://doi.org/10.3389/frchs.2026.1858835