Two papers on the venom and venom effect of Tityus species in Brazil

 

As most of you know, there are several medical important scorpions in the Genus Tityus C. L. Koch, 1836 (Buthidae) in Brazil and other countries of South America. Knowledge of the venom composition of dangerous scorpions and their clinical effect is important, both for understanding how they work, but also to develop effective anti-venom therapy. In addition, studying scorpion venom is also important to see if there are components that can be used in medical research.

Last fall there was published two papers on the biochemistry and the effects of the venom of several species of Tityus (and one species of Brotheas C.L. Koch, 1837 in Chactidae). I refer to the abstracts below for further details on these studies.

Paper 1:

Abstract:
Scorpionism is a growing public health concern in Brazil, with the Amazon region presenting the highest mortality rates but remaining understudied, especially regarding local scorpion venoms composition. This study presents the first comprehensive biochemical characterization of venoms from three Amazonian species—Tityus metuendus (TmetuV), Tityus silvestris (TsilvV), and Brotheas amazonicus (BamazV)—using an integrated approach combining Multi-Enzymatic Limited Digestion (MELD)-based bottom-up proteomics, highresolution LC-MS/MS, chromatography, zymography, and enzymatic assays. Tityus serrulatus venom was included as a reference. Significant biochemical differences were observed: TsilvV was rich in 20–30 kDa proteins and showed strong metalloprotease activity; BamazV exhibited high molecular weight proteins and potent phospholipase A2 (PLA2) activity but lacked proteolytic and fibrinogenolytic activities; TmetuV showed the highest hyaluronidase activity and abundance of α-KTx neurotoxins. Zymography revealed a conserved ~45 kDa hyaluronidase in all species. Three novel components were partially characterized: BamazPLA2 (Group III PLA2), Tmetu1 (37-residue α-KTx), and TsilvMP_A (a metalloprotease homologous to antarease). This is the first application of MELD-based proteomics to Amazonian scorpion venoms, revealing molecular diversity and functional divergence within Tityus and Brotheas, emphasizing the need for region-specific antivenoms. These findings provide a foundation for future pharmacological studies and the discovery of bioactive peptides with therapeutic potential.

Reference:
Bordon KCF, Santos GC, Martins JG, Wiezel GA, Amorim FG, Crasset T, et al. Pioneering Comparative Proteomic and Enzymatic Profiling of Amazonian Scorpion Venoms Enables the Isolation of Their First α-Ktx, Metalloprotease, and Phospholipase A(2). Toxins (Basel). 2025;17(8). [Open Access]

Paper 2:

Abstract:
Scorpion stings are considered a neglected condition and represent a serious health problem in many tropical countries, especially for children and the elderly. In Brazil, the yellow scorpion (Tityus serrulatus) is widely found and responsible for the majority of severe envenoming cases; however, other medically relevant species endemic to the Brazilian Amazon region, such as Tityus silvestris, Tityus metuendus and Tityus obscurus, remain underexplored. In the present study, we characterized the clinical, inflammatory and histopathological responses induced by venoms from these Amazonian species in a murine model (Balb/c mice), using T. serrulatus as a reference. Envenomation with T. silvestris resulted in pronounced systemic manifestations, including elevated clinical scores, hyperglycemia, leukocytosis, cytokine release (IL-6, IL-1β, IL-10), and tissue injury in the lungs and kidneys, comparable to the pathophysiological manifestations from T. serrulatus venom. In contrast, T. metuendus and T. obscurus induced milder inflammatory profiles. It is noteworthy that cross-reactivity assays revealed limited immunoreactivity and reduced in vivo neutralization of T. metuendus and T. obscurus venoms by the commercially available T. serrulatus-based antivenom. These findings reveal critical limitations in relying on a single-species antivenom for treating scorpion envenomation across diverse regions and underscore the need for region-specific therapeutic strategies tailored to the distinct venom profiles and pathogenicity of Amazonian Tityus species.

Reference:
Zoccal KF, de Castro Figueiredo Bordon K, Reis MB, Rosa Nunes de Souza Chini PB, Martins JG, Zuanazzi BA, et al. Divergent clinical, inflammatory, and histopathological responses induced by Amazonian Tityus venoms: insights and limitations of current antivenom therapy. Biochimie. 2025;238(Pt B):159–71. [Subscription required for full text]

Thanks to Jonas Martins for sending me the two articles!

Microbiota discovered in the venom of two scorpion species

 

There is a great research interest in scorpion venom these days, especially the hunt for toxins and other elements that can be used in medical research. The scorpion venom is known to contain a cocktail of peptids, enzymes and other inorganic and organic compounds, but it has been believed that the venom has been sterile venom it comes to bacteria and other microbiota.

Barbara Murdoch and co-workers recently published an article revealing the presence of several bacteria in the venom of the scorpions Paruoctonus becki (Gertsch & Allred, 1965) (Vaejovidae) and Anuroctonus phaiodactylus (Wood, 1863) (Anuroctonidae). This is the first report of microbiota in scorpion venom.

Matt Simon, who informed me about this article, noticed several interesting facts in this article. Firstly, many of the observed bacteria are known to have evolved for extreme conditions, Secondly, one of the observed genera (Nocardioides) is known to produce antimicrobial compounds. The latter is especially interesting, as it may suggest that antibiotic properties of scorpion venom may not be caused by the scorpion itself, but by bacteria in the venom.

Abstract:
With low nutrient availability and presence of numerous antimicrobial peptides, animal venoms have been traditionally considered to be harsh sterile environments that lack bacteria. Contrary to this assumption, recent studies of animal venom and venom-producing tissues have revealed the presence of diverse microbial communities, warranting further studies of potential microbiota in other venomous animals. In this study we used 16S rRNA amplicon sequencing to elucidate whether scorpion venom contained bacteria, to characterize the bacterial communities, and determine if venom microbiomes differed across geologically complex geographic locations. Our study compares the venom microbiome of two scorpion species, sampled from sites in the Mojave and Great Basin deserts, Paruoctonus becki (family of Vaejovidae) and Anuroctonus phaiodactylus (family of Anuroctonidae), and represents the first assessment of microbial diversity ever conducted using the venom secretion itself, rather than the venom-producing organ and its surrounding tissues.

Reference:
Murdoch B, Kleinschmit AJ, Santibáñez-López CE, Graham MR. Microbiota discovered in scorpion venom. PLoS One. 2026;21(1):e0328427. [Open Access]

Thanks to Matt Simon for informing me about this papers and for his comments! 

Melanism in two buthid species from Saudi Arabia

 

Body coloration is important for many animals and is assumed to play a part in part in camouflage, thermoregulation, protection against UV damage, and increased immunity to parasites. In species inhabiting dark surfaces in their habitat, dark body colors may have evolved to increase the camouflage. 

Margareta Lakusic and co-workers have recently published an article describing different levels of dark melanism in the two buthids Leiurus haenggii Lowe, Yagmur & Kovarik, 2014 and Compsobuthus manzonii (Borelli, 1915) from Saudi Arabia. The scorpions were found on dark volcanic substrate or within transition zones between light-colored substrates and dark lava flows.

Abstract:
Body colouration is involved in multiple aspects of species ecology and behaviour. Melanism, a common colour polymorphism, has been associated with camouflage and thermoregulation, particularly in diverse, high-altitude habitats of arid regions. This study reports the first case of melanism in the lacertid Acanthodactylus boskianus, two scorpions, Leiurus haenggii and Compsobuthus manzonii, and the first records of brown-black melanistic colouration in three rodent species, Acomys dimidiatus, Meriones crassus, and Sekeetamys calurus, in the dark lavafields (harrat) of north-western Saudi Arabia. Additionally, it expands observations of melanism in the endemic colubrid Rhynchocalamus hejazicus and provides the first documented records of brown-black melanistic Acomys russatus for the region, consistent with earlier predictions. These observations suggest that colour polymorphism may serve a cryptic function through background matching in both diurnal and nocturnal species, but other roles of melanism should be further investigated. Despite their extent, lava fields in arid regions remain poorly studied due to their remoteness and limited accessibility, yet they offer unique opportunities to investigate phenotypic evolution in arid ecosystems.

Reference:
Lakušić M, Roumelioti M, Licata F, Bilancioni M, Ferreira DF, Khalatbari L, et al. Melanism in scorpions, reptiles and rodents inhabiting the volcanic fields of north-western Saudi Arabia. Journal of Arid Environments. 2026;233:105548. [Full text supplied by authors]

New data on the distribution of Buthiscus bicalcaratus in Algeria

 

 Zineb Souilem and co-workers have recently published an article presenting new distribution records and range extension for the Saharan scorpion Buthiscus bicalcaratus Birula, 1905 (Buthidae) in Algeria.

Abstract:
This study includes new distribution records and range extension for the Saharan scorpion Buthiscus bicalcaratus Birula, 1905 in Algeria, where new specimens were collected from several localities across diverse biotopes. These findings document a significant expansion of the species, both northward and southwestward, providing important insights into its ecological adaptability and contributing to a better understanding of the environmental changes affecting arid and semi-arid regions. It will be crucial to keep focus on B. bicalcaratus in order to comprehend the ecological factors influencing its variations in range and to use the species as a measure of desertification in North Africa.

Reference:
Souilem Z, Sadine SE, Hammou MA, El Bouhissi  M, Chedad A, Zebsa R, et al. Range extension of Buthiscus bicalcaratus Birula, 1905 in Algeria (Scorpiones: Buthidae). Revista Iberica de Arachnologia. 2025(47):151–4. [No full text available, contact authors]

Thanks to Salah Eddine Sadine for sending me their article! 

Family Buthidae 

A redescription of Buthacus ahaggar from Algeria

 

Ersen Yagmur and co-workers have recently published a redescription of Buthacus ahaggar Lourenço, Kourim & Sadine, 2017 (Buthidae) from Algeria based on new materials. The female is described for the first time.

Abstract:
Buthacus ahaggar Lourenço, Kourim & Sadine, 2017 was originally described based on a male holotype specimen from the Tamanrasset Region, Algeria. In this study, the morphology of the species is redescribed based on additional specimens collected from the same region, including both sexes. We describe the female morphology here for the first time. A detailed color illustration is also provided.

Reference:
Yağmur EA, Benali N, Derradj L. First Description of the Female and Morphological Analysis of Buthacus ahaggar Lourenço, Kourim & Sadine, 2017 (Scorpiones: Buthidae). Commagene Journal of Biology. (1):1–5. [Open Access]

Thanks to Noureddine Benali for informing me about their new article!

Family Buthidae 

New study on the genus Auyantepuia and two new species from French Guiana

 

16.01.26: New species names are updated with correct year.  

The status of the genus Auyantepuia (Gonzalez-Sponga, 1978) (Chactidae) is controversial and some authors have synonymized the genus with other genera. In the recent years, several authors have accepted the validity of this genus, and The Scorpion Files has now listed the genus and the species originally placed within the genus.

Recently, Eric Ythier and co-workers have published a phylogenomic analysis of the genus Auyantepuia in French Guiana. Current species are diagnosed and two new species are described.

Auyantepuia kwata Ythier, Chevalier, Moreau & Murienne, 2026 

Auyantepuia mammandian Ythier, Chevalier, Moreau & Murienne, 2026 

The article has an identification key for the nine known species in French Guiana.

Abstract:
A review of the scorpions of the genus Auyantepuia (Scorpiones, Chactidae) in French Guiana is conducted using an integrative taxonomic approach combining molecular analysis performed on the mitochondrial genome of most species occurring in the territory and more traditional morphological analyses, leading to the descriptions of two new species, Auyantepuia kwata sp. nov. and Auyantepuia manmandinan sp. nov. Diagnoses are presented for all Auyantepuia species occurring in French Guiana and an identification key is proposed. The total number of recognized species in the genus Auyantepuia species is raised to 15.

Reference:
Ythier E, Chevalier J, Moreau L, Murienne J. A phylogenomic analysis of the genus Auyantepuia (Scorpiones: Chactidae) in French Guiana with the descriptions of two new species. European Journal of Taxonomy. 2026(1034):31–57. [Open Access]

Thanks to Eric for sending me this article!

Family Chactidae 

Sexual stings in scorpions - knock-out drug or love potion?

 

I have taken the liberty to steal the title of Yuqi Reitsema-Wang and co-workers very interesting review article on sexual stings in scorpion that was published recently. Scorpions use their venom and sting for several purposes like defense and prey capturing. Less known is the sexual stings that have been observed as a part of the courtship for several species of scorpions.

The authors give an introduction to this fascinating behavior in scorpions and discuss what is known about the composition of the venom used in sexual stings (venom metering, prevenom, venom heterogeneity and venom plasticity), how do males control the delivery of venom during sexual stings and how do sexual stings affect the females (are they drugged into submission or is the venom a "love potion" encouraging the females to mate?). In addition, the authors also discuss the evolution of sexual stings in scorpions.

The article is open about not having the answers to the mystery of sexual stings and suggest how to further investigate this special behavior in the future.

Abstract:
Conspecific male to female envenomation, though rare, has been documented across venomous taxa. While traditionally interpreted as a coercive mating strategy to enhance male reproductive success and to avoid cannibalism, this explanation may not fully account for the behaviour in scorpions, which exhibit minor sexual size dimorphism and complex courtship rituals. This review explores the possibly multifaceted roles of sexual stinging in scorpions. We highlight potential adaptive strategies, such as venom metering and compositional plasticity, that allow males to subdue females without causing lethal harm. We discuss hypotheses on the evolution of sexual stings, ranging from sexual coercion to chemical seduction and cooperative signalling. Finally, we propose future research directions, including comparative venomics, behavioural assays, and ecological studies, to shed light on the selective pressures that shape this enigmatic behaviour. By integrating insights from physiology, ecology, and evolution, this review advances our understanding of sexual envenomation as a dynamic interplay between conflict and cooperation in scorpion reproductive strategies.

Reference:
Reitsema-Wang Y, Simone Y, Jenner R, Lüddecke T, Herzig V, Krämer J. Sexual stings in scorpions-knock-out drug or love potion? Frontiers in Arachnid Science. 2025;4:1688532. [Open Access]