New widow spider record of Latrodectus dahli Levi (Araneae: Theridiidae) extends known range in Northern Saudi Arabia

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  Image Credit: iNaturalist Photo 400937400, (c) Kian, some rights reserved (CC BY), uploaded by Kian, https://www.inaturalist.org/photos/400937400 New widow spider record of Latrodectus dahli Levi (Araneae: Theridiidae) extends known range in Northern Saudi Arabia ABSTRACT Researchers have documented the first confirmed occurrence of Dahl’s widow spider ( Latrodectus dahli vn Saudi Arabia’s Ha’il Region, extending the species’ known range into the country’s north. The finding fills an important gap in the spider’s Middle Eastern distribution and highlights how even medically important species remain under-documented in parts of the Arabian Peninsula. L. dahli Levi is a medically significant widow spider that is found in North Africa, Cyprus, Turkey, Azerbaijan, Kazakhstan, the Middle East, Iran and Central Asia. Prior to our work, there had been no records of it in northern Saudi Arabia although it had been found in central regions of Saudi Arabia such as Al Duwadimi, Riyadh and ...

Evaluation of indirect hemolysis induced by snake venoms and its neutralization by corresponding antivenoms: comparative study across five genera

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Evaluation of indirect hemolysis induced by snake venoms and its neutralization by corresponding antivenoms: comparative study across five genera

Abstract 

Hemolytic activity of snake venoms represents a toxic effect with significant biochemical complexity. In this study, we conducted a comprehensive comparative assessment of the indirect hemolytic activity (expressed as HD50) of 25 medically important venom samples, encompassing five genera. Additionally, we evaluated the efficacy of commercial AV in neutralizing this activity (NHD50). Elapidae venoms displayed the highest hemolytic potency (lowest HD50), correlating with high phospholipase A2 activity. Within the Bothrops genus, we observed wide variation in potency, with species like B. insularis and B. moojeni exhibiting high activity, while the venom of B. erythromelas consistently proved to be the most resistant to neutralization by antibothropic antivenom. The functional activity data were integrated with chromatographic profiles, enzymatic activities, and phylogenetic analyses, revealing that hemolytic potency is not solely determined by PLA2 activity but also by its molecular context. Ancestral State Reconstruction suggests multiple events of gain and loss of hemolytic potency within the Bothrops clade. These findings highlight the need for improvements in anti-venom composition, especially for the treatment of envenoming caused by species whose venoms exhibit high resistance to neutralization.

Serino-Silva, C., de Lima, E.O.V., Tasima, L.J. et al. Evaluation of indirect hemolysis induced by snake venoms and its neutralization by corresponding antivenoms: comparative study across five genera. Sci Rep (2026). https://doi.org/10.1038/s41598-026-69542-y