New study shows that Androctonus venom causes rapid blood clotting in humans

 

Scorpion venom is known for its neurotoxic effects that can cause death and serious morbidity in humans. A recent study by Sam Campbell and co-workers shows that the venom in four Androctonus Ehrenberg, 1828 (Buthidae) species also have a procoagulant toxicological function. In plain text, the venom causes blood clots that make the blood coagulate. Interestingly, antivenom for Androctonus envenomations seem to fail to neutralise procoagulation. 

These findings are important in assessing envenomated patients and their treatment. In addition, the findings can also have potential when it comes to developing diagnostic tools for blood disorders or treatments.

Abstract:
While scorpion venoms are well-characterised as being potently neurotoxic, their effects upon blood coagulation are understudied. Here, we report novel procoagulant toxicological functions for Androctonus amoreuxi, A. australis, A. bicolor and A. crassicauda venoms. Factor activation tests with A. amoreuxi venom revealed cofactor-dependent activation of Factor VII (FVII) and Factor X (FX) to be the primary zymogen targets, with FX the more potently activated. Activation of both factors was demonstrated to be dependent upon the proteinaceous cofactor Factor Va (FVa) and the biochemical cofactors calcium and phospholipid. It was also shown that venom was able to convert Factor V (FV) into a form of FVa that was equipotent to endogenous FVa, suggestive of the venom cleaving FV at the same activation site as thrombin. Intriguingly, low level FXII activation only proceeded with the venom-activated form of FVa and was not reliant upon calcium or phospholipid. Antivenom produced with Androctonus species included in the immunising mixture failed to neutralise procoagulation. However, neutralisation of procoagulant activities was achieved by the metalloprotease inhibiting drugs marimastat and prinomastat, thereby not only revealing the enzyme type responsible for the effects upon blood coagulation, but also suggesting therapeutic options. These results indicate that venom-induced coagulopathy resulting from scorpion envenomation may require greater consideration in pathophysiological profiling of envenomed patients. The implications extend beyond the field of toxinology, building a foundation for evolutionary studies into the selection pressures that have resulted in some species having potent effects upon blood biochemistry, whether as a weapon for predation or defence.

Reference:
Campbell SID, Seneci L, Jones L, Champagne PS, Fry BG. The sting that clots: The Factor VII and Factor X activating procoagulant effects of Androctonus scorpion venoms are potentiated by Factor Va as a cofactor. Biochimie. 2026;245:31–9. [Open Access]

Thanks to Jeroen Kooijman for informing me about this article! 

 

A phylogenetic analysis of the ancient Asian scorpion family Pseudochactidae

 

As previously mentioned, the ancient, relictual Asian scorpion family Pseudochactidae Gromov, 1998 is probably one of the most interesting scorpion families in the world. It consist of both of extinct and extant taxa, and the latter is often labeled as "living fossils" due to their unique morphology. 

In a recent article, Lorenzo Prendini and co-workers present a new phylogenetic analysis of the genus with new information about the phylogeny and taxonomy of this fascinating family and its evolution. 

Abstract:
The ancient, relictual Asian scorpion family Pseudochactidae Gromov, 1998, has a disjunct distribution. Five genera and seven species of living pseudochactids are assigned to one epigean subfamily, Pseudochactinae Gromov, 1998, from Central Asia and southern China, and two hypogean subfamilies, Troglokhammouaninae Prendini et al., 2021, and Vietbocapinae Lourenço, 2012, from caves of the Khammouan-Phong Nha-Kẻ Bàng Karst in the northern Annamite (Trường Sơn) Mountains of Laos and Vietnam. The extinct subfamily Chaerilobuthinae Lourenço and Beigel, 2011, comprises one genus and 15 species, hypothesized to be endogean, from mid-Cretaceous Burmese amber. The discovery and uncertainty regarding the phylogenetic placement of Qianxie solegladi Tang, 2022, from South China, together with the discovery that the Cretaceous amber Chaerilobuthinae, from the Burma Terrane, is the sister group of the extant pseudochactid subfamily Vietbocapinae provided an opportunity to revisit the phylogeny and biogeography of Pseudochactidae, and their adaptation to subterranean habitats in Southeast Asia. In the present contribution, pseudochactid phylogeny is reanalyzed using three mitochondrial markers (12S rDNA, 16S rDNA, Cytochrome c Oxidase Subunit I), three nuclear markers (18S rDNA, 28S rDNA, Internal Transcribed Spacer) and 143 morphological characters, for all extant pseudochactid taxa and seven exemplar species of the extinct Chaerilobuthinae. Divergence time and ancestral range estimation are conducted and the evolution of troglomorphic characters investigated to reassess how this lineage of “living fossils” dispersed and diversified. Recent changes to the systematics of Pseudochactidae are confirmed. The four subfamilies, genera, and species were monophyletic with high support and the following scheme of relationships: (Pseudochactinae (Troglokhammouaninae (Chaerilobuthinae + Vietbocapinae))). Phylogenetic analyses, reinforced by a multivariate morphometric analysis and pairwise genetic distances, confirm the validity of the monotypic, epigean Chinese genus, Qianxie Tang, 2022, which formed a monophyletic group with the epigean Central Asian genus, Pseudochactas Gromov, 1998, rather than the hypogean Southeast Asian genus, Troglokhammouanus Lourenço, 2007. Qianxie solegladi is transferred to Pseudochactinae. A revised time tree of Pseudochactidae suggests that the Burmese Chaerilobuthinae diverged from the Indochinese subfamilies, Troglokhammouaninae and Vietbocapinae, in the Early Cretaceous (ca. 117 Ma), consistent with Early Devonian rifting of the Burma Terrane.

Reference:
Prendini L, Xuan Q, Du SE, Wang C-BE, Ehrenthal VL, Loria SF. Phylogeny and divergence time estimation of relictual Asian scorpion family suggests Early Cretaceous connections between Burma Terrane and Eurasia, and corrects placement of Chinese taxon. American Museum Novitates. 2026(4051):1–55. [Open Access]

Family Pseudochactidae 

A revision of the rare genus Liobuthus with a description of four new species from Central Asia

 

The genus Liobuthus Birula, 1898 (Buthidae) is a rare, psammophilic genus with one species from Central Asia. Victor Fet and co-workers recently published a revision of the genus, and based on DNA-analysis and morphology, four new species are described.

Liobuthus atamuradovi (Turkmenistan)

Liobuthus danovi (Kazakhstan, Northern Turkmenistan, Uzbekistan)

Liobuthus shukurovi (Southwestern Tajikistan)

Liobuthus vachoni (Southern Kazakhstan)

An identification key for the five species in the genus is included.

Abstract:
The rare Central Asian psammophilic scorpion genus, Liobuthus Birula, 1898 (Scorpiones: Buthidae), is revised. Five species are delineated according to results from three species delimitation approaches using mitochondrial DNA. Results are supported by diagnostic morphology, including an assessment of the distinctive neobothriotaxy. The type species, L. kessleri Birula, 1898, is confirmed for Iran (northeast), Turkmenistan and Uzbekistan (south). Four new species are described: L. atamuradovi sp. n. (Turkmenistan), L. danovi sp. n. (Kazakhstan, northern Turkmenistan, Uzbekistan), L. shukurovi sp. n. (southwestern Tajikistan), and L. vachoni sp. n. (southern Kazakhstan), The unique additive neobothriotaxy (on both pedipalp femur and patella) first discovered by Vachon (1958) is confirmed and analyzed.

Reference:
Fet V, Kovarik F, Lowe G, Graham MR. A revision of the psammophilic genus Liobuthus Birula, 1898 (Scorpiones: Buthidae), with a description of four new species from Central Asia. Euscorpius. 2026(427):1–67. [Open Access]

family Buthidae 

A new species of Scorpio from northern Iraq

 

Ersen Yagmur and co-workers recently published an article describing a new species of Scorpio Linnaeus, 1758 (Scorpionidae) from northern Iraq.

Scorpio assyriacus Yagmur, Kachel, Hussen, Al-Jubouri & Al-Khazali, 2026 

Abstract:
Scorpio assyriacus sp. n., from northern Iraq is described illustrated and compared with all known species of the genus Scorpio Linnaeus, 1758, occurring in Turkey, the Middle East, and Iran. Aspects of the ecology and distribution of the new species are discussed and compared with those of other closely related Scorpio species from nearby localities in Turkey. The new species can be distinguished by its reduced number of pectinal teeth, the cardial-triangular configuration of the genital operculum (which is not posteriorly elongated in females), a more hirsute body, globular vesicle, flattened and discrete granules on the external surface of the chela manus, and significantly longer chela fingers compared to other species. With this discovery, the total number of documented scorpion species in Iraq has reached 23.

Reference:
Yagmur EA, Kachel HS, Hussen FS, Al-Khazali AM, Ali FR, Al-Jubouri MAK, et al. A new Scorpio (Scorpiones, Scorpionidae) species from Northern Iraq. Zoodiversity. 2026;60(1):1–15. [Open Access]

Thanks to Ersen for sending me their article!

Family Scorpionidae 

A new cave-dwelling scorpion from Brazil

 

More or less obligatory, cave-dwelling scorpions are found in several areas. Some with distinct troglomorphic traits like reduced pigmentation and the lack of eyes. Jonas Eduardo Gallão and Deyvison Bonfim Ribeiro have recently described a new obligatory, subterranean species in the genus Troglorhopalurus Lourenço, Baptista & Giupponi, 2004 (Buthidae) from three caves in Ituaçu, State of Bahia in Brazil.

Troglorhopalurus araras Gallão & Ribeiro, 2026

The new species lack typical troglomorphic traits except for having thinner cuticle than normal. This may represent a troglomorphic trait.

An identification guide for the genus is presented. Please note that this guide (and article) is missing Troglorhopalurus iuiu Carvalho, Silva, Emanuela de Souza & Feirreira, 2025. According to the authors, the reason for this was that they weren't aware of the description of this species when the paper was submitted. [Info about the missing species updated 02.03.26]

Abstract:
We describe Troglorhopalurus araras sp. n. based only on females, as a new obligatory and exclusively subterranean scorpion occurring in three caves from Ituaçu, State of Bahia, Brazil. The caves of Ituaçu belong to an isolated portion of the Una geomorphological group. Troglorhopalurus araras is the third known species of Troglorhopalurus and differs from its congeners by size, carination mainly in chela hand and metasoma, teeth of pecten, shape of telson spine, and colour. This new species enhances the diversity of cave-dwelling species in Brazilian caves, as well as the knowledge of cave scorpions. Troglorhopalurus araras must be considered threatened due to its restricted endemism at caves in the Chapada Diamantina.

Reference:
Gallão JE, Ribeiro DB. Troglorhopalurus araras (Scorpiones: Buthidae) a new subterranean scorpion from Chapada Diamantina, Bahia, Brazil. Journal of Natural History. 2026;60(9-12):557–72. [Subscription required for full text]

Family Buthidae 

Predicting the occurence of dangerous scorpions based on analysis of environmental conditions

 

Scorpions are a medical problem in many countries and regions, but often the knowledge of which species are found were is limited. In a recent paper, Fouad Salhi and co-workers have presented a study from Morocco where they have tried to use ecological niche modelling to predict scorpion distribution based on the scorpions environmental requirements.

It seems that soil type is the strongest predictor of where many scorpions live, while temperature, including both average conditions and seasonal swings, seem to play a major role for some of the species studied in Morocco.

The model used is very promising and can be an important tools for government agencies working to prevent and reduce public health challenges related to scorpion stings. 

Abstract:
Ecological niche modelling (ENM) is a powerful analytical approach for predicting species distribution by elucidating their environmental requirements. The present study used the MaxEnt approach, integrating high-resolution environmental data and extensive in situ observations, to create habitat suitability maps for 19 scorpion species in central Morocco and assess the influence of environmental variables on their distribution. The models demonstrate excellent predictive ability, highlighted by area under the curve (AUC) values systematically greater than 0.9. Soil type emerged as the most influential environmental variable for 74% of species, while the remaining taxa were mainly affected by temperature annual range and annual mean temperature. Habitat suitability maps revealed distinct habitat preferences between species. H. gentili is a habitat generalist, showing a broad predicted distribution covering 62% of the study area, while A. bourdoni (0.14%), B. parroti (0.13%), O. innesi (0.62%) and B. atlantis (0.55%) showed a very restricted prediction of suitable habitats. This species-specific information on habitat conditions is essential not only to improve our understanding of their ecology, but also to formulate more effective public health strategies aimed at reducing the frequency of scorpion envenomings in Morocco.

Reference:
Salhi F, Elbahi A, Ouakri N, Lawton C, Abou Oualid J, Dugon MM. Ecological Niche Modelling and Distribution of Scorpion Fauna in Central Morocco: A MaxEnt Study. Environmental Research Communications. 2026;8:025008. [Open Access]

 

Differences in pedipalp form and size affect courtship behavior in Tityus species

 

Differences in male morphology within the same species have been observed in many species. In a recent paper, Lais Pordeus and Andre Lira show that differences in the male pedipalp chela in Tityus pusillus Lourenço, 2013 (Buthidae) are associated with differences in reproductive behavior. Males with "robust" pedipalp chela performed a higher number of reproductive attempts and female manipulations than than males with "gracile" chela.

Interestingly, the reproductive success of the males in the two groups was quite similar.

Abstract:
This study investigates male pedipalp chela dimorphism and its association with reproductive behaviour in the litter-dwelling scorpion, Tityus pusillus. Using geometric morphometrics, two distinct male morphotypes were identified based on pedipalp chela shape: robust and gracile. These morphotypes were associated with measurable variation in courtship behaviour aspects. Males with robust chelae performed a higher number of reproductive attempts and female manipulations than gracile-chela males, although these differences were not statistically significant. Notably, robust-chela males completed courtship significantly faster than gracile-chelae males (8.03 ± 5.14 minutes vs. 18.40 ± 13.84 minutes), measured as the time until mating successful conclusion. Both morphotypes exhibited similar reproductive success rates (37% and 31%, respectively). These results indicate that robust and gracile differ in courtship dynamics, particularly in courtship duration and patterns of female handling. Variation in female resistance during courtship may help explain why male reproductive behaviours vary. This study documents male chela dimorphism in T. pusillus and reports its correlation with variation in courtship behaviour.

Reference:
Pordeus LM, Lira AFA. Dimorphism in male pedipalps affects the reproductive behaviour in the litter-dwelling scorpion Tityus pusillus Pocock, 1893 (Scorpiones: Buthidae). Invertebrate Reproduction & Development. 2026;Published online 17 Feb 2026. [Subscription required for full text]