A new species of Mesomexovis from Mexico

 

André Felipe de Araujo Lira and González-Santillán recently identified a new species of Mesomexovis Gonzalez-Santillan & Prendini, 2013 (Vaejovidae) from Estación de Biología Chamela, Jalisco in Mexico  while studying the scorpion fauna in this area.

Mesomexovis caxcan Lira & Gonzalez-Santillan, 2025

The article also has an identification key for the scorpions in this area.

Abstract:
Mesomexovis Gonzalez-Santillan & Prendini, 2013 is a scorpion genus of the Vaejovidae family that comprises seven species, all endemic to Mexico. The present study describes a new species from Estación de Biología Chamela, Jalisco, related to M. occidentalis (Hoffmann, 1931), M. atenango (Francke & Gonzalez-Santillan, 2006), and M. subcristatus (Pocock, 1898). Mesomexovis caxcan sp. nov. differs from these species in several respects. Firstly, the carinae of the pedipalp chelae are vestigial. Secondly, the ventral lateral carinae of metasomal segments I–IV are granular, and the ventral submedian carinae of segments I–IV are costate to granular. A microstructural separation between the subex and the basal carina of the capsular area of the hemispermatophore is described for the first time. Mesomexovis caxcan sp. nov. represents the eighth species of the genus and the fifth reported in the Estación de Biología Chamela. The other scorpions identified in this location are Centruroides chamela Ponce Saavedra & Francke, 2011, C. elegans (Thorell, 1876) (Buthidae), Konetontli chamelaensis (Williams, 1986), and Thorellius intrepidus (Thorell, 1876) (Vaejovidae).

Reference:
Lira AFdA, Gonzalez-Santillan E. The scorpions of the Estación de Biología Chamela, Jalisco, Mexico with the description of a new species of Mesomexovis (Scorpiones, Vaejovidae) and an identification key. ZooKeys. 2025(1243):241–67. [Open Access]

Thanks to Gerard Dupre and Matt Simon for informing me about this new species!

Family Vaejovidae

First report of the medically significant scorpion Tityus carrilloi in Paraguay

 

As stated in earlier posts, medical important scorpions are expanding their distribution in many parts of South America. Adolfo Borges and co-workers have recently reported the findings of the medical important species Tityus carrilloi Ojanguren-Affilastro, 2021 (Buthidae) in Paraguay. This species has previously only been known from Argentina where it has been involved in severe and fatal envenomations.

Abstract:
We report the first record of the medically important scorpion Tityus carrilloi in Paraguay, from the metropolitan area of Encarnac ´on, Itapúa Department, near the Argentine border. Known for causing severe and fatal envenomings across northern Argentina, the presence of this species in southeastern Paraguay highlights the risk of cross-border dispersion. Along with the regional spread of the Brazilian Tityus serrulatus, this finding has significant epidemiological implications and underscores the urgent need for improved surveillance, diagnostics, and coordinated public health responses in Paraguay and neighboring countries, within the evolving landscape of scorpionism in southern South America.

Reference:
Borges A, Caballero C, Rojas de Arias A, Smith P, Owen M, Nishi A, et al. First report of the medically significant Argentine scorpion Tityus carrilloi (Buthidae) in Paraguay: Epidemiological implications amid rising regional scorpionism. Toxicon. 2025;264:108456. [Subscription required for full text]

Can light with certain colors/wavelengths be used in scorpion control?

 

Scorpions are a health problem in many areas, and especially in Brazil. As mentioned in a previous post, this problem is increasing due to medical important species' expansion into urban habitats. In a recent study, Marina Costa Rodrigues and co-workers tested behavioral reactions in the medical important scorpion Tityus serrulatus Lutz & Mello, 1922 (Buthidae) to light with different colors and wavelengths. 

The authors tested which colors or wavelengths that either attracted or repulsed the scorpions in a test arena. One main finding of the experiments was that the scorpions showed an avoidance to green light and violet light. More studies is necessary to see if lights with these colors can be used in scorpion control to either repel scorpions or attract them into traps.

Abstract:
Scorpions cause 150k+ accidents per year in Brazil. Control of their populations involves manual collection and pesticides. Here we tested if light could be used to attract or repel the yellow scorpion Tityus serrulatus, the main responsible for accidents in the country. Based on previous studies on scorpion´s physiological and behavioral reactions to light, we tested wavelengths that correspond to red, green and violet, controlling temperature, absolute irradiance and electromagnetic stimuli. We built a ring arena divided into 5 parts and had the individuals freely walking in the presence of a light/control. We released the scorpions either away from the LED to test attraction or close to the LED to test repellency. Results showed avoidance to green light, and violet light on a smaller portion, that could be due to wavelengths, since those correspond to primary and secondary response peaks of the animal photoreceptors, due to the absolute irradiance of lights or both. These two wavelengths, therefore, have potential for scorpion control and deserve further investigations.

Reference:
Rodrigues MC, Murayama GP, Moriyama LT, Ximenes N, de Souza L, Willemart RH. Light, camera, action: Behavioral responses of the yellow scorpion Tityus serrulatus to different lights. Behavioural processes. 2025;228:105207. [Subscription required for full text]

Cannibalism in two buthid species from Brazil

 

It is well known that scorpions catch and eat other scorpions (either the same species or other species). Guilherme Melo-dos-Santos and co-workers recently published a study documenting cannibalistic events in the species Rhopalurus laticauda Thorell, 1876 and Tityus silvestris Pocock, 1987 (Buthidae) from Brazil.

Scorpions will eat other scorpions as prey (to get food), but the study also suggests that cannibalism can be part of an intraspecific competition (e.g. competition for territories (microhabitats) or food), that may have a regulatory effect on the populations.

The study was done under controlled captive conditions, but the researchers observed similar behaviors in the scorpions' natural environment. 

Abstract:
Scorpions are predators, with diets ranging from insects to other arachnids. Despite this, their predatory habits, especially in the Brazilian Amazon, are still poorly understood. This study documents, for the first time, cannibalistic events in the species Rhopalurus laticauda Thorell, 1876 and Tityus silvestris Pocock, 1987, both species found in Roraima. The first species is more common in open areas known as lavrado, while the second inhabits humid forests. During the study, we observed that, in most cases, the individuals involved in cannibalistic acts were of similar sizes. Only in one case, an adult preyed on a juvenile. These interactions, frequently associated with territorial disputes and for food, culminated in confrontations in which the weaker individual was subjugated. Our data, obtained under controlled captive conditions, revealed an aggressive and competitive behavior among scorpions of these species. It is important to highlight that similar behaviors were recorded in videos collected during field expeditions, suggesting that cannibalism also occurs in natural environments. The subjugated animals are consumed entirely in many cases, and in others, only parts of the consumed animals were found. These results contribute significantly to the understanding of the population dynamics of scorpions in the Amazon, indicating that intraspecific competition may be an important factor in the regulation of these populations.

Reference:
Melo-dos-Santos G, Melo-dos-Santos G, Leite TM, Rocha AM, Jati SR, Frezarin-da-Silva E, et al. Cannibalistic behavior in Rhopalurus laticauda Thorell, 1876 and Tityus silvestris Pocock, 1897 (Scorpiones: Buthidae) under captivity in the extreme north of the Brazilian Amazon. Revista Chilena de Entomología. 2025;51(2):169–75. [Open Access]

A revision of the expansion of medical important scorpions in human areas in South America

 

South America has several medical important species of Tityus C. L. Koch, 1836 (Buthidae). Interestingly, scorpionism in South America is an urban problem that has been growing in the last decade as the medical species have had expansion of their distribution.

Alexis Emanuel Barrios-Montivero and coworkers have recently published a study presenting an updated overview of the current distribution of six medical important Tityus species. The study have looked at the original distribution of these species and their posterior expansion of synanthropic populations. In addition, the authors have tried to predict the future expansion of these medical important species.

The study shows that there have been a greatly accelerated expansion of medical important species in most cities of Southern South America in recent decades. In addition, they predict that there will be an even greater expansion of several of these species, and more important, they will reach countries and areas where scorpionism is not a problem today.

Abstract:
We revise the expansion of synanthropic medically important species of Scorpions of genus Tityus in southern South America: Tityus bahiensis (Perty 1833), Tityus carrilloi Ojanguren-Affilastro 2021, Tityus confluens Borelli 1899, Tityus costatus (Karsch, 1879), Tityus serrulatus Lutz & Mello, 1922, and Tityus trivittatus Kraepelin 1898, which due to their synanthropic capabilities we regard as invasive species. We also build species distribution models (SMDs) from bioclimatic variables using Maxent. We also included the human density variable in the model, because medically important species in the area are synanthropic, being more common in urban areas than in natural environments. We present their current suitable areas and the potential future distribution up to 2070. According to our analyses most species will expand in the close future, reaching countries without Scorpionism problems, such as Chile and Uruguay. We conclude that, besides synanthropic capabilities, parthenogenesis is the main factor favoring the expansion of some of these species. We also conclude that interactions between invasive Tityus species may hinder their expansion process due to potential competition or exclusion mechanisms.

Reference:
Barrios-Montivero AE, Martínez PA, Ojanguren-Affilastro AA. The Ongoing Expansion of the Medically Important Scorpions in Southern South America. Ecohealth. 2025. [Subscription required for full text]

Thanks to Andres Ojanguren for sending me this article!

Six cases of cannibalism from Turkey

 

Cannibalism has been reported in scorpions on several occasions. Predatory cannibalism is probably most common, but sexual cannibalism has also known to occur. Generally, a larger scorpion eats a smaller scorpion.

Recently, Ersen Yagmur and co-workers published a study of six cases of cannibalism in five buthid species in Turkey. The cases and cannibalism in scorpions in general are discussed in the article.

Abstract:
No abstract.

Reference:
Yagmur EA, Lira AFdA, Kurt R, Tezcan E, Kartal I, Sipahioglu Ö. Does size matter? Reports of cannibalism in scorpions (Scorpiones: Buthidae) from Turkey. North-Western Journal of Zoology. 2025;21(1):90–2. [Open Access]

Thanks to Ersen for sending me their article!

A new species of Scorpiops from Thailand

 

Eric Ythier and co-workers have recently published an article describing a new species of Scorpiops Peters, 1861 (Scorpiopidae) from the Doi Phu Kha National Park, Nan Province in Thailand.

Scorpiops doiphukha Ythier, Kosulic, Nawanetiwong & Lourenco, 2025

The new species inhabits high-altitude evergreen forests (appr. 1500 m a.s.l.).

Abstract:
A new scorpion species, Scorpiops (Euscorpiops) doiphukha sp. nov., belonging to the family Scorpiopidae Kraepelin, 1905, is described based on 12 specimens of both sexes (three adults and nine immatures) collected in Doi Phu Kha National Park, Nan Province, Thailand. The new species presents key features exhibited by scorpions of the subgenus Euscorpiops and can be characterized notably by a large size, a sexual dimorphism strongly marked with male pedipalps elongated, a distinct trichobothrial pattern and other morphological features. This new taxon represents the 115th species among the currently recognized species for the genus Scorpiops Peters, 1861, and the 44th species described for the subgenus Euscorpiops Vachon, 1980. It is likely an endemic element of Thailand’s scorpion fauna, raising the number of known Scorpiops (Euscorpiops) species in the country to 13. Ecological and distributional aspects of the new species are discussed and compared with closely related Scorpiops species, highlighting its distinctiveness within the genus.

Reference:
Ythier E, Kosulic O, Nawanetiwong W, Lourenco WR. A newly discovered species of the genus Scorpiops Peters, 1861, subgenus Euscorpiops Vachon, 1980 from Doi Phu Kha National Park, Thailand (Scorpiones, Scorpiopidae). ZooKeys. 2025(1241):171–84. [Open Access]

Thanks to Eric for sending me their article!

Family Scorpiopidae