16 May, 2022

Orthochiroides is back again as a valid genus and a new species in the genus from Somaliland is described


The genus Orthochiroides  Kovarik, 1998 (Buthidae) was synonymized with Orthochirus Karsch, 1891 by Lourenco & Ythier in 2021. This decision is now changed in a recent article by Kovarik & Lowe after analyzing more than 40 morphological characters. Orthochiroides is back as a valid genus with the original four species previously assigned to the genus.

 A new species Orthochiroides is desrcibed from Somaliland increasing the number of species to five.

Orthochiroides somalilandus Kovarik & Lowe, 2022

An identification key for the genus is included.

The genus Orthochiroides Kovařík, 1998 is reanalyzed. Revised diagnoses and new illustrations for the genus and all four of its species are presented. A new species, O. somalilandus sp. n. from Somaliland is described and illustrated. Phylogenetic relationships of the genus with several other similar genera of small buthids are inferred from a parsimony analysis of 43 discrete morphological characters. The recent synonymy of Orthochiroides with Orthochirus is refuted and the genus is revalidated.

Kovarik F, Lowe G. Review of Orthochiroides Kovařík, 1998 with description of a new species (Scorpiones: Buthidae). Euscorpius. 2022(349):1-42. [Open Access]

Family Buthidae

12 May, 2022

A new species of Scorpiops from Laos


Wilson Lourenco & Eric Ythier has recently described a new species in the genus Scorpiops Peters, 1861 (Scorpiopidae) from Laos.

Scorpiops (Euscorpiops) piceus Lourenco & Ythier, 2022

The authors have kept the genera synonymizations made by Kovarik in in 2020 (all genera except for Parascorpiops Banks, 1928 were synonymized with Scorpiops), but have revalidated some of the ex-genera as subgenera in the current paper. [The information in this paragraph was corrected 13.05.22]

A new species, Scorpiops (Euscorpiops) piceus sp. n., belonging to the family Scorpiopidae Kraepelin, 1905 is described based on one adult female and one juvenile male collected in the Province of Khammouane, Laos. The new species presents most features exhibited by scorpions of the genus Scorpiops subgenus Euscorpiops, and is characterized by a very dark pigmentation overall, a large global size and a distinct trichobothrial pattern. This new species may represent one endemic element for the fauna of Khammouane region. This new taxon represents the 100th described species among the currently recognized species for the genus Scorpiops and the 36th for the subgenus Euscorpiops. Comments are also added on the validity of the generic division of the groups included in the family Scorpiopidae and a number of these are revalidated at the subgeneric level.

Lourenco WR, Ythier E. A new species of the genus Scorpiops Peters, 1861, subgenus Euscorpiops Vachon, 1980 from Laos (Scorpiones: Scorpiopidae). Faunitaxys. 2022;10(27):1-9. [Open Access]

Thanks to Gerard Dupre for informing me about this article!

Family Scorpiopidae

A new species of Lychas from Thailand


Eric Ythier and Wilson Lourenco have recently described a new species of Lychas C.L. Koch, 1845 (Buthidae) from Thailand.

Lychas chanthaburiensis Ythier & Lourenco, 2022

A new species of Lychas C. L. Koch, 1845 is described on the basis of one adult male specimen collected in Khao Khitchakut, Chanthaburi Province, in the South-East of Thailand. The new species is mainly characterized by a moderate size for the genus with a total length of 46.9 mm, a general coloration yellowish with metasomal segment V, telson and chela fingers reddish yellow and some greyish spots on the prosoma, tergites and metasoma, all carinae weakly marked with intercarinal spaces smooth to weakly granular, and a slender metasoma. This new taxon represents the 33rd described species among the currently recognized species for the genus Lychas. The number of known Lychas species in Thailand is increased to five.

Ythier E, Lourenco WR. A new species of Lychas C. L. Koch, 1845 from Thailand (Scorpiones: Buthidae). Faunitaxys. 2022;10(26):1-7. [OPen Access]

Thanks to Eric and Gerard for informing me about this article!

Family Buthidae

11 May, 2022

Redescription and new information about the little known scorpion Buthiscus bicalcaratus from Northern Africa


Faraj Aboshaala and co-workers have recently published an article with a redescription and updated information about the little known scorpion Buthiscus bicalcaratus Birula, 1905 (Buthidae) based on new materials from Libya.

The monotypic genus Buthiscus was described by Birula (1905) with the species Buthiscus bicalcaratus from the Sahara Desert of southern Tunisia. Until now, huge gaps exist in the knowledge of this species which is classified as endemic to North Africa. This paper aims to enrich the existing knowledge on this poorly known species with redescribing specimens of both sexes collected from Libya using widely illustrated redescription, in light of modern standards ruling the taxonomy of scorpions.

Aboshaala F, Yağmur EA, Sadine SE, Ghaliow M, Badry A. On the poorly known species Buthiscus bicalcaratus Birula, 1905 (Scorpiones: Buthidae). Serket. 2022;18(3):263-73.

Thanks to Ersen Yagmur for sending me this article!

10 May, 2022

Two new species of Vaejovis from Mexico


Fernanda Chavez-Samayoa and co-workers have recently described two new species of Vaejovis C.L. Koch, 1836 (Vaejovidae) from Mexico.

Vaejovis aguazarca Diaz-Plascencia & Gonzalez-Santillan, 2022

Vaejovis aquascalentensis Chavez-Samayoa & Gonzalez-Santillan, 2022

Two new species of the genus Vaejovis (C L Koch 1836) belonging to the mexicanus group from Aguascalientes, Mexico, are described and compared to other species closely related to them geographically and morphologically. The species are compared based on the nomenclature and homology proposed by Gonzalez-Santillan and Prendini (2013). An extension of the homology, functionality, and nomenclature of the hemispermatophore proposed by Monod et al. (2017) is applied to vaejovid scorpions for the first time. We provide meristic evidence to support species delimitation and an identification key to the mexicanus species group (Soleglad, 1973) from Aguascalientes. We provide new records that broaden the distribution area, supplement its diagnosis, and expand the description, including details on the hemispermatophore and the telotarsi of Vaejovis tenamaztlei Contreras- Felix et al., 2015.

Chávez-Samayoa F, Díaz-Plascencia JE, González-Santillán E. Two new species of Vaejovis (Scorpiones: Vaejovidae) belonging to the mexicanus group from Aguascalientes, Mexico, with comments on the homology and function of the hemispermatophore. Zoologischer Anzeiger. 2022;298:148-69. [Subscritpion required for full text]

Thanks to Fernanda Chavez Samayoa and Luis Roque for sending me this article!

Family Vaejovidae

03 May, 2022

The use of stinger vs pinchers in scorpion prey capture


Morphological differences in pedipalps and cauda have an impact in prey capture tactics, sting use and venom use in scorpions. Scorpions with large, powerful pedipalps will often not use their stinger and rely on the power of the pedipalps compared to species with more slender pedipalp. Also, the type of prey (defenses, restistance ability etc.) has an impact on the scorpion's prey capture strategies.

Luis Fernando García and co-workers have recently published a study testing how scorpion species with different pincher morphologies and venom efficacies use the pedipalps and the stinger differently during prey capture.

Not surprisingly they found that species with massive pinchers and high pinch force used the stinger less for prey subjugation than species with slender pinchers. They also found that species with robust pinchers had a greater pinch force than species with more slender pinchers. 

Background: Scorpions can use their pincers and/or stingers to subdue and immobilize their prey. A scorpion can thus choose between strategies involving force or venom, or both, depending on what is required to subdue its prey. Scorpions vary greatly in the size and strength of their pincers, and in the efficacy of their venom. Whether this variability is driven by their defensive or prey incapacitation functionis unknown. In this study, we test if scorpion species with different pincer morphologies and venom efficacies use these weapons differently during prey subjugation. To that end, we observed Opisthacanthus elatus and Chactas sp. with large pincers and Centruroides edwardsii and Tityus sp. with slender pincers.
Methods: The scorpion pinch force was measured, and behavioral experiments were performed with hard and soft prey (Blaptica dubia and Acheta domesticus). Stinger use, sting frequency and immobilization time were measured.
Results: We found that scorpions with large pincers such as O. elatus produce more force and use the stinger less, mostly subjugating prey by crushing them with the pincers. In C. edwardsii and Tityus sp. we found they use their slender and relatively weak pincers for holding the prey, but seem to predominantly use the stinger to subjugate them. On the other hand, Chactas sp. uses both strategies although it has a high pinch force.
Conclusions: Our results show that scorpionspecies with massive pincers and high pinch force as O. elatus use the stinger less for prey subjugation than scorpionspecies with slender pincers.

Garcia LF, Valenzuela-Rojas JC, Gonzalez-Gomez JC, Lacava M, Meijden Avd. Pinching or stinging? Comparing prey capture among scorpions with contrasting morphologies. J Venom Anim Toxins Incl Trop Dis. 2022;28:e20210037. [Open Access]

22 April, 2022

“When it comes to scorpions, the bigger the better”


The title is a quote from one of the popular Indiana Jones movies, and most of us that have been working with scorpions for many years are familiar with the rule of thumb when it comes to the potency of scorpion stings: That large scorpions have less potent venom than smaller ones or that scorpions with large pedipalps are less dangerous than scorpions with small, slender claws.

The above is also reflected in prey capture, where larger scorpions with more powerful pedipalps will more often rely on bruth force to subdue prey without using the stinger (and venom), while smaller species with more slender claws are more prone to using the stinger and venom.

Alannah Forde and co-workers have recently published an interesting study comparing LD50 potency values and morphology measures from the literature to see if the above mentioned rule of thumb when it comes to classifying dangerous scorpions is actually true.

And they did actually find that larger scorpions, with more robust chelae, are less potent than small species, with thin chelae. The evolutionary explanations for this is also discussed.

I must warn that even though it seems that Indiana Jones was correct and our commonly used rule of thumb seems to hold, there may be exceptions. Species in the infamous genus Hemiscorpius Peters, 1861 (Hemicorpiidae) are quite large and have robust pedipalps, but they can cause serious morbidity and even death in humans.

Scorpionism is a global health concern, with an estimation of over one million annual envenomation cases. Despite this, little is known regarding the drivers of scorpion venom potency. One widely held view is that smaller scorpions with less-developed chelae possess the most potent venoms. While this perception is often used as a guide for medical intervention, it has yet to be tested in a formal comparative framework. Here, we use a phylogenetic comparative analysis of 36 scorpion species to test whether scorpion venom potency, as measured using LD50, is related to scorpion body size and morphology. We found a positive relationship between LD50 and scorpion total length, supporting the perception that smaller scorpions possess more potent venoms. We also found that, independent of body size, scorpion species with long narrow chelae have higher venom potencies compared to species with more robust chelae. These results not only support the general perception of scorpion morphology and potency, but also the presence of an ecology trade-off with scorpions either selected for well-developed chelae or more potent venoms. Testing the patterns of venom variations in scorpions aids both our ecological understanding and our ability to address the global health burden of scorpionism.

Forde A, Jacobsen A, Dugon MM, Healy K. Scorpion Species with Smaller Body Sizes and Narrower Chelae Have the Highest Venom Potency. Toxins. 2022;14(3):219. [Open Access]

Thanks to Jeroen for reminding me about this article!