An integrative description of Euscorpius diagorasi sp. n. from Rhodes, Greece (Scorpiones: Euscorpiidae)

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  An integrative description of Euscorpius diagorasi sp. n. from Rhodes, Greece (Scorpiones: Euscorpiidae) Abstract The genus  Euscorpius  Thorell, 1876 comprises a diverse and taxonomically challenging group of scorpions in the Mediterranean, with Greece representing one of its principal centers of diversity. In this study, we provide an integrative description of  Euscorpius diagorasi   sp. n. , a new species from Rhodes Island, Greece. The new species is described on the basis of adult male and female morphology and mitochondrial COI sequence data. It is a small oligotrichous species characterized by a total length of approximately 21–25 mm, pale yellow to light brown coloration with darker reddish-brown pedipalps, pectinal tooth count of 8 in the male and 7 in the females, Pv = 7–8, Pe-et = 5–6, and a distinct mitochondrial lineage. Phylogenetic analyses based on COI recovered the Rhodian specimens as a strongly supported monophyletic lineage, sister to...

Beyond venomous fangs: Uloboridae spiders have lost their venom but not their toxicity

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Beyond venomous fangs: Uloboridae spiders have lost their venom but not their toxicity

Background

Venom, one of nature’s most potent secretions, has played a crucial role in the evolutionary success of many animal groups, including spiders. However, Uloboridae spiders appear to lack venom and capture their prey, unlike venomous spiders, by extensive silk-wrapping and regurgitation of digestive fluids onto the entire prey package. A prevailing hypothesis posits that toxins may have been reallocated from the venom to alternative secretions, like silk or digestive fluids. Yet, whether uloborids have retained venom toxins and the mechanisms underlying prey immobilisation remain unresolved. Here, we employed a multi-disciplinary approach to assess the absence of venom glands in Uluborus plumipes, toxin gene expression and toxicity of digestive proteins.

Results

Our findings confirm that U. plumipes lacks a venom apparatus, while neurotoxin-like transcripts were highly expressed in the digestive system. Midgut extract had comparable toxicity levels to that of the venomous Parasteatoda tepidariorum. However, no inhibitory effects on sodium nor potassium channels were observed, indicating a different toxic mechanism.

Conclusions

These findings support the hypothesis that Uloboridae spiders have lost their venom apparatus while retaining toxin-like genes. The potent toxicity of their digestive fluids, a trait conserved across spiders, likely compensate for the absence of venom, ensuring effective prey immobilisation and digestion.


Xiaojing Peng, Ludwig Dersch, Josephine Dresler et al. Beyond venomous fangs: Uloboridae spiders have lost their venom but not their toxicity, 10 April 2025, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-5827646/v1]