New study on taxonomy, distribution and habitat of the medical important genus Hemiscorpius in Iran

 

The genus Hemiscorpius Peters, 1861 (Hemiscorpiidae) is the probably the main scorpion taxa outside the family Buthidae that can cause death and serious morbidity in humans. This genus is represented with eight species in Iran and information about taxonomy, distribution and habitat preferences is very information to prevent sting cases.

Hossein Dehghan and co-workers have recently published a study on morphology, genetics, and ecological niche modeling to clarify the taxonomy and distribution of Hemiscorpius in southern Iran. The study also resulted in a new species from the Kerman Province.  

Hemiscorpius aratta Barahoei & Prendini, 2025

Abstract:
Eight species of the medically important scorpion genus Hemiscorpius Peters, 1861 have been reported in Iran, three of which are responsible for most of the severe clinical cases of envenomation. However, morphological similarity complicates species delimitation in this genus, hindering the identification of species implicated in envenomations. The present study integrates morphology, DNA sequences, and ecological niche modeling to clarify the taxonomy and distribution of Hemiscorpius in southern Iran, providing taxonomic insights relevant to public health and biodiversity conservation. Morphometric analyses were performed to evaluate size and shape differences; molecular phylogenetic analyses were conducted on DNA sequences of the mitochondrial Cytochrome c Oxidase Subunit I gene; and species distribution models, based on occurrence records and bioclimatic variables, were developed. Morphometric analyses revealed significant interspecific differences and sexual dimorphism. A new species was identified and described as Hemiscorpius aratta sp. n. Molecular phylogenetic analysis confirmed the distinctiveness of the new species and revealed intraspecific variation in the type species, Hemiscorpius lepturus Peters, 1861, suggesting possible cryptic diversity. Southern Iran, particularly the coastline of the Persian Gulf and the Gulf of Oman, represents a diversity hotspot for Hemiscorpius. Topographical barriers such as the Jebal Barez, Makkoran, and Zagros Mountain ranges promoted isolation and speciation, leading to high levels of endemism in the genus. Ecological niche models revealed that the distributions of Hemiscorpius species are strongly influenced by temperature and precipitation. Coastal species are restricted to thermally stable maritime habitats, whereas semi-arid species occupy regions with higher temperature seasonality. Range-restricted species are habitat specialists, vulnerable to environmental change. This study reinforces the importance of integrating morphological, molecular, and ecological data for resolving taxonomic ambiguity.

Reference:
Dehghan H, Amiri Ghanat Saman E, Madjdzadeh SM, Amiri M, Moeinadini A, Prendini L, et al. Molecules, Morphometrics and Modeling of the Medically Important Genus Hemiscorpius Peters, 1861 (Scorpiones: Hemiscorpiidae) in Iran Reveal New Species from Kerman. Insects. 2025;17(1):18. [Open Access]

Thanks to Gerard for informing me about this article!

Family Hemiscorpiidae 

 

A redescription of Centruroides infamatus and the description of a new species from Mexico

 

Happy New Year! 

Javier Ponce-Saavedra and co-workers recently published an article with a redescription of Centruroides infamatus (C.L. Koch, 1844) from Mexico. The study also identify a new species that previously were considered a population of this species from the municipality of Jalpa in the southern region of the state of Zacatecas, Mexico.

Centruroides rommeli Ponce-Saavedra, Linares-Guillen, Quijano-Ravell & Chassin-Noria, 2025

The article is in Spanish. 

Abstract:
Centruroides infamatus (C.L. Koch) is redescribed based on individuals obtained from a population from the León, Guanajuato region, in central Mexico. The species is redescribed because in the original description only the country is mentioned as the type locality with no further details. Also, Centruroides rommeli sp. nov. is described based on individuals obtained from a population of scorpions from Jalpa, municipality of Jalpa in the southern region of the state of Zacatecas, Mexico. This species is placed in the subgroup "infamatus" as part of the "striped" scorpions. Morphological comparisons are carried out with C. suffusus (Pocock) and C. vittatus (Say), both species that belong to the same subgroup talso recorded in Zacatecas. Additionally, is included the redescription of C. infamatus, because the population of the new species was previously identified with this specific name. Centruroides rommeli sp. nov. is sympatric with Mesomexovis spadix (Hoffmann), scorpions of the Vaejovidae family.

Reference:
Ponce J, Linares Guillén JW, Quijano-Ravell A, Chassin-Noria O. Redescription of Centruroides infamatus (Scorpiones: Buthidae) and description of a new species of “striped” scorpion of the “infamatus” subgroup from north-central México. Revista de la Sociedad Entomologica Argentina. 2025;84(4):e0409. [Full text supplied by authors]

Family Buthidae 

Scorpionism in Ecuador - An updated review

 

Scorpion envenomations are a problem in many countries in South America, but a majority of studies have focused on Brazil. A recent article by Adolfo Borges and co-workers shows that also Ecuador is a hotspot for scorpion envenomations in South America.

The study provides an overview of scorpion stings in Ecuador between 2017 and 2021 and the implications in form of deaths and morbidity. The authors also identify taxa of medical importance and their distribution. Unsurprisingly, two species in the genus Tityus C. L. Koch, 1836 (Buthidae) are probably responsible for the most serious cases.  

Abstract:
This study assessed scorpion envenoming risk in Ecuador at provincial and district levels between 2017 and 2021, estimated national incidence and mortality rates, and identified the likely implicated taxa. Data were obtained from the Ministry of Public Health and aggregated by province and district, with incidence and mortality rates calculated per 100,000 inhabitants using annual population estimates. District-level risk was visualized with choropleth maps, and scorpion diversity and distribution were compiled from updated national inventories. A total of 1,514 scorpion stings were reported between 2017 and 2021. National incidence and mortality rates (per 100,000 inhabitants) averaged 1.75 and 0.02. Regional incidence was highest in the Amazonian region (16.81), followed by the coastal (1.39) and Andean highlands (0.66). Hyperendemic districts (≥95th percentile of risk) included Taisha and Tiwintza (Morona Santiago), Arajuno (Pastaza), Flavio Alfaro (Manabí), and La Concordia (Santo Domingo de los Tsáchilas). Mortality was highest in the Amazonian and piedmont coastal regions, with 10 deaths per region and an Amazonian rate of 0.44 per 100,000 inhabitants. These areas are inhabited by Tityus species from distinct morphological and toxinological groups, notably Tityus cf. rosenbergi in western Ecuador and Tityus cisandinus in Morona Santiago and Pastaza. Geographical variation in incidence and mortality likely reflects both the distribution of noxious taxa and population density. Despite high scorpion endemicity (79.2%), a national lethality rate of 1.32% that appears higher than reported in other countries where scorpionism is a public health concern, and the concentration of fatalities in children (75% in ages 1–9), Ecuador still depends on imported scorpion antivenoms, including that prepared against Centruroides species, which show low reactivity to Tityus toxins. These findings highlight the urgent need for preclinical neutralization studies to evaluate local antivenom efficacy and to investigate regional differences in clinical outcomes, to guide future adjustments to immunotherapy based on the biogeographic distribution of medically important Tityus species.

Reference:
Borges A, De Sousa L, Borja-Cabrera GP, Rivera A. Scorpion Envenoming in Ecuador: District-Level Risk, Updated Scorpion Diversity, and Challenges for Treatment and Public Health. Acta Trop. 2025:107942 (In Press). [Subscription required for full text.]

Thanks to Adolfo Borges for informing me about their new article! 

Are scorpion envenomations a neglected tropical disease?

 

For us who work or have experiences with scorpions, it is well known that some genera and species can cause death and serious morbidity in humans. This is a problem in some countries and regions in the world.

Eduardo Alfonso Hernández Muñoz and co-workers recently published an article summing up the status of scorpionism globally and raise a concern that scorpion envenomations are not given priority as a serious tropical disease today. According to the authors, the serious consequences from scorpion stings in many areas of the world should support that scorpion sting envenomations should be given a status as a neglected tropical disease by health authorities. This will hopefully increase the focus on prevention and treatment of scorpion envenomations.

That article present a table with list of countries and taxa that have potential medical importance.

Abstract:
⇒Each year, scorpion sting envenomation (SSE) leads to thousands of deaths and severe complications, disproportionately affecting vulnerable populations with limited access to timely treatment, especially children under 10 years of age; however, it is not formally recognised by the WHO as a neglected tropical disease (NTD).

⇒ In 2018, the WHO concluded that SSE did not meet the NTD criteria, citing ‘extremely rare mortality, lack of long-term disability and difficulties in defining a broad control strategy’.

⇒ This analysis presents evidence-based arguments for the urgent reconsideration of SSE as an NTD, considering new data that addresses previous objections and underscores its significant and underestimated public health impact.

⇒ Addressing SSE as an NTD is a crucial step towards achieving global health equity and preventing avoidable deaths in vulnerable communities, particularly among children.

Reference:
Hernández Muñoz EA, Borges A, Zavala-Sánchez EV, Rojas de Arias A, Oukkache N, de Souza CMV, et al. Scorpion sting envenomation: a neglected tropical disease in the shadow of global health priorities: an urgent call to action. BMJ Glob Health. 2025;10(11):e020682. [Open Access]

Thanks to Dr. Adolfo Borges for sending me their article!

A study of circadian rhythms in two species of cave-dwelling Troglorhopalurus species in Brazil

 

Circadian rhythms are important for all animals including humans in governing the organisms daily activities when it comes to both physiology and activity. These rhythms are controlled by a biological clock that usually are adjusted by external stimuli like light and dark.

Cave-dwelling scorpions like members of the genus Troglorhopalurus Lourenço, Baptista & Giupponi, 2004 (Buthidae) are more or less living in the dark permanently. Priscila Emanuela de Souza and Rodrigo Lopes Ferreira have recently published an article studying locomotor behavior in two species of Troglorhopalurus when exposed to different light-dark regimes. 

Interestingly, their study show that both species were able to retain their normal circadian rhythmicity in all regimes (they were able to "keep the time"), even though this varied between the two species. This can be explained by the different degree of adaptation to cave habitats seen in the two species.

Abstract:
Circadian rhythms, typically synchronized with light–dark cycles, regulate key biological processes in surface organisms. In caves, however, the absence of light may disrupt these rhythms or promote alternative temporal patterns. We examined locomotor activity in two cave-dwelling scorpions with contrasting degrees of subterranean adaptation: Troglorhopalurus translucidus (troglobitic) and Troglorhopalurus lacrau (troglophilic). Activity was monitored under constant darkness (DD), light–dark (LD), and constant light (LL). Both species retained circadian rhythmicity, but with distinct responses: T. translucidus and T. lacrau exhibited diurnal activity under LD and changes in period under DD and LL. These findings demonstrate that circadian regulation persists in cave adapted scorpions, but its expression is shaped by evolutionary pressures, highlighting the plasticity of biological clocks in light-deprived environments.

Reference:
de Souza PE, Ferreira RL. Oscillating in darkness: Circadian rhythms of cave-dwelling scorpions. Chronobiol Int. 2025:1–8. [Subscription required for full text]

An updated look at scorpion envenomations in Namibia

 

Scorpion envenomations and their medical importance in Namibia have been underreported and neglected. Namibia is the home for several Parabuthus Pocock, 1890 (Buthidae) species, a genus known for hosting several species of medical importance.

Francois Theart and co-workers recently published an article with updated information about scorpionism in Namibia. They conclude that scorpions are a health concern in this country and especially the species Parabuthus granulatus (Ehrenberg, 1831), P. villosus (Peters, 1862), kraepelini Werner, 1902 and P. schlechteri Purcell, 1899 can cause death and serious morbidity. No antivenom is available. More research is necessary to understand more about the situation and to develop measures to improve prevention and treatment.

Abstract:
Namibia harbours a rich diversity of scorpions, including seventeen species of the highly venomous genus Parabuthus, although the biology and medical relevance of most species are poorly documented. Severe envenoming is caused by at least P. granulatus, P. villosus, P. kraepelini and P. schlechteri, which are considered to be of particular importance. Data on epidemiology, venom composition and variation, and clinical effects remain scarce. A lack of effective antivenom and long distances to hospitals in rural areas complicate clinical management and compromise patient outcomes.

Reference:
Theart F, Buys C, Lagneau S, Berg P. Scorpion envenoming by Parabuthus is a public health concern in Namibia. Toxicon. 2025;270:108934. [Subscription required for full text]

On the occurence of the medically important scorpion Tityus stigmurus in the São Paulo area in Brazil

 

As mentioned in several other posts, the expanding distribution of medical important Tityus C. L. Koch, 1836 (Buthidae) species in Brazil and other South American countries has had an increasing attention, especially because many of these species are also spreading into urban habitats.

Paulo Goldoni and co-workers have recently published an article looking into the distribution of the medically important scorpion Tityus stigmurus Kraepelin, 1898 (Buthidae) in the municipality of Sorocaba, São Paulo in Brazil. The study conforms that this species is introduced and successfully established on this area.

Abstract:
Tityus stigmurus (Thorell, 1876) is among the most venomous scorpion species in Brazil. It occurs mainly in the northeastern region, particularly within the Caatinga biome, where it represents a major public health concern, with several fatal envenomation cases reported. The species has also been recorded as introduced in urban areas of São Paulo, confirming its establishment in a colder and more humid environment than its native range in the country. During the 2010s and 2020s, records of T. stigmurus were also reported from Sorocaba, about 100 km from São Paulo city. Here, we confirm the successful establishment of the species in Sorocaba, based on 53 examined specimens (41 females and 12 juveniles) collected between 1997 and 2025 and deposited in the arachnid collection of the Instituto Butantan (IBSP). Although no envenomation cases have been reported for this species in the municipality, our findings underscore the need for strengthened surveillance of T. stigmurus in Sorocaba and surrounding areas, as this and other Tityus species already confirmed in the region represent a major public health concern.

Reference:
Goldoni PA, Ennser JRP, Iniesta LF, Brescovit AD. Long-term surveillance and monitoring of Tityus stigmurus (Thorell, 1876): a study in the municipality of Sorocaba, São Paulo, Brazil. Studies in Environmental and Animal Sciences. 2025;6(3):e21937.

Thanks to Paulo Goldoni for sending me their article!