Arm-span competition between males in the buthid scorpion Tityus rosenbergi

 

Courtship and mating behaviors between male and female scorpions are well documented. Intrasexual interactions (between female-female or male-male scorpions) are not mentioned often in the literature. Recently, a new ritualized behavior between the same sex was described and labeled "arm-span competition”.

In a recent article, Jules Thornton Wyman and co-workers present observations of "arm-span competition" between males of Tityus rosenbergi Pocock, 1898 (Buthidae). The behavior is interpreted as a ritualized male-male contests. 

The authors suggest that the elongated pedipalps seen in males of many species might be the result of selective pressure related to ritualized arm-span competition.

Abstract:
Although courtship and mating behaviors have been described for nearly all scorpion lineages, intrasexual interactions in scorpions remain understudied. Recently, a novel ritualized behavioral unit, termed “arm-span competition,” in which individuals face off and extend their pedipalps laterally, was described from analyses of male-male contests in several scorpionid species. Here, we present the first documented observation of arm-span competition in a buthid scorpion, Tityus cf. rosenbergi Pocock, 1898. Interestingly, both T. cf. rosenbergi and most scorpionid species known to engage in arm-span competition exhibit a similar sexual dimorphism: males have markedly longer and more slender pedipalps than females. We suggest that the elongated pedipalps in males of these species might be the result of selective pressure related to ritualized armspan competition. We also highlight the potential for citizen science to contribute rare observations to scientific literature.

Reference:
Wyman JT, Wright-Ueda J, Agnew Q, Castellano I, Simone Y. First report of arm-span competition in buthid scorpions: male-male contest in Tityus cf. rosenbergi Pocock, 1898. The Journal of Arachnology. 2025;52(3):210-3. [Open Access]

Thanks to Yuri for sending me this article!

A study of the fluorescent sensilla on the scorpion aculeus (stinger)

 

It is well-known that scorpions fluorescence under UV light. This also apply for the scorpion's stinger (aculeus), but previous studies has shown a lack of fluorescence in the distal aculeus. Graeme Lowe has recently published an article where he used SEM imaging to study UV fluorescence in the acuelus of many species.

He observed numerous brightly fluorescent punctae in the non-fluorescent distal aculeus. These punctae were identified as aculear sensilla coeloconica (ASC). The ASC probably have a chemoreceptive function.

The author suggests that the ASC are playing an important role in the sensory coordination of telson function when the scorpions are trying to sting their prey and inject venom.

Abstract:
The aculeus of the scorpion telson was studied by UV fluorescence microscopy. Numerous brightly fluorescent punctae were observed on the non-fluorescent distal aculeus, including the tip region. The punctae were identified as aculear sensilla coeloconica (ASC), and were connected to fluorescent canals running through the cuticle. ASC were present in both sexes, and in adults and immatures as early as the second instar juvenile, but were absent from the first instar. The distal aculeus was found to be encased in a thick, non-fluorescent dark exocuticle (DX), covering an underlying thin, fluorescent hyaline exocuticle (HX). Fluorescent ASC were recorded from 183 species belonging to 97 genera in 19 families, encompassing all major scorpion lineages. The number of ASC in the tip region, the width of ASC canals, and the depth of the tip region, all exhibited positive correlation and allometric scaling with respect to carapace length. Higher tip densities of ASC occurred in some buthids, and in Scorpionoidea. The ASC are probably ubiquitous across the Order Scorpiones, playing an essential role in the sensory coordination of telson function during prey envenomation.

Reference:
Lowe G. Star-studded stingers: fluorescent sensilla on the scorpion aculeus (Arachnida: Scorpiones). Euscorpius. 2024;2024(402):1-39. [Open Access]

The postembryonic development of Centruroides ochraceus from Mexico

 

Happy New Year!

Wilson Lourenco and Eric Ythier have recently published some old observations of postembryonic development of Centruroides ochraceus (Pocock, 1898) (Buthidae) from Yucatan, Mexico. It is also suggested that parthenogenesis exists in this species.

Abstract:
Since general data on the biology of scorpions remain rare, we propose in this note some results on the postembryonic development of the buthid scorpion Centruroides ochraceus (Pocock, 1898), species distributed in the Yucatan peninsula, Mexico. The results were originally observed almost 40 years ago, based on some specimens collected by the senior author. A possible case of parthenogenesis is also suggested for this species.

Reference:
Lourenço WR, Ythier E. The postembryonic development of Centruroides ochraceus (Pocock, 1898) from Yucatan, Mexico (Scorpiones: Buthidae), with comments on parthenogenesis. Revista Iberica de Arachnologia. 2024(45):119-22. [Full text supplied by author]

A new species of Odontobuthus from Southern Iran

 

More Christmas species. Hossein Barahoei and Mehran Shahi just published a description of a new species of Odontobuthus Vachon, 1950 (Buthidae) from Southern Iran.

Odontobuthus persicus Barahoei & Shahi, 2024

The article has an updated identification key for the genus.

Abstract:
Odontobuthus Vachon, 1950, with nine described species, is a genus of digger scorpions in the Buthidae family, which can be distinguished by having large tooth-like processes on the ventrosubmedian carinae of the second and third metasomal segments. Morphological and molecular investigation of coastal specimens from the Hormozgan province in Iran led to the discovery of a new species named Odontobuthus persicus sp. nov. that is described here. It is closely related to O. chabaharensis morphologically. The new Odontobuthus species has two large and conical tooth-like processes on ventrosubmedian carinae of the second and third metasomal segments, while O. chabaharensis has three or four medium to large tooth-like processes. Based on phylogenetic analysis using partial COI sequences, the new species is placed as a sister taxon of O. brevidigitus. Genetic differences with the other species of Odontobuthus (mean = 0.107) confirmed the validity of this species.

Reference:
Barahoei H, Shahi M. New Species of the Digger Scorpions, Odontobuthus Vachon, 1950 (Buthidae) from Southern Iran. Zoological Studies. 2024;63(48). [Open Access]

Thanks to Kian for sharing this article with me!

Family Buthidae

Two new species in the genus Scorpio have been described from Southeastern Turkey

 

No Christmas holiday for scorpion news! Happy Seasons Greetings everyone! 

Ersen Yagmur and co-workers recently published an article describing two new species of Scorpio Linnaeus, 1758 (Scorpionidae) from Southeastern Turkey.

Scorpio karakurti Yagmur, 2024

Scorpio Sirnakensis Yagmur, 2024

Abstract:
Two new species, Scorpio karakurti sp.n. and S. sirnakensis sp.n. are described and illustrated from the Southеastеrn region of Turkey. S. karakurti sp.n. is detected from Batman and Diyarbakır provinces and can be distinguished from all species of the genus Scorpio by its higher pectinal teeth numbers, especially in males (10–11 in females and 11–15 in males). S. sirnakensis sp.n is detected from Şırnak province and can be distinguished by elongated chela and telson shape and genital operculum shape of females. The new species are compared with the known species of the genus Scorpio Linnaeus, 1758 in the Middle East.

Reference:
Yagmur EA, Hussen FS, Karakurt S, Kurt R, Sipahioglu Ö, Kartal I. Two new species of the genus Scorpio L., 1758 from Southеastеrn Turkey (Scorpiones: Scorpionidae). Arthropoda Selecta. 2024;33(4):559-89. [Open Access]

Thanks to Ersen for sending me their new article!

Family Scorpionidae

 

A new species of Scorpiops from Yunnan in China

 

Tonight, Victoria Tang published a description of a new species of Scorpiops Peters, 1861 (Scorpiopidae) from Yunnan, China.

Scorpiops reini Tang, 2024

In my opinion, a very beautiful and interesting scorpions, but then again I'm probably not objective when I'm writing this ;) 

Abstract:
Scorpiops reini sp. n. is described from Yingjiang County (Dehong Prefecture, Yunnan Province) based on an adult pair. It can be readily discriminated from all of its congeneric geographic neighbors in Yunnan, namely S. jendeki Kovařík, 1994, S. shidian (Zhu et al., 2005), S. tongtongi Tang, 2022, and S. zhangshuyuani (Ythier, 2019). Within Yunnan, it resembles S. validus (Di et al., 2010) and S. yangi (Zhu et al., 2007) most, but can be identified by its large median ocelli (relative to the width of ocular subislet), pedipalp chelal finger morphology and pectinal tooth count. Beyond Yunnan, it shows the highest similarity with S. beccaloniae (Kovařík, 2005), from which it distinguishes itself mainly by a different chelal morphology (weaker finger lobe and notch, longer and narrower manus with chelal carinae composed of smaller and denser granules). The validity of this new species is supported molecularly (to be published). The ocular islets are reviewed for all Yunnan Scorpiops.

Reference:
Tang V. Scorpiops reini sp. n. from Yunnan, China (Scorpiones: Scorpiopidae). Euscorpius. 2024(403):1-19.

A big thanks to Victoria for naming this species after me!

Family Scorpiopidae

An Algerian Buthus seen preying on a solifugid

 

Scorpions prey on a large variety of other invertebrates and even on some small vertebrates. Camel spiders (Solifugae) is another fierce arachnid predator inhabiting the same habitats as many scorpions. These two arachnids probably prey on each other when they have the opportunity. 

Noureddine Benali and co-workers recently published a case of natural predation on a solifugid by Buthus apiatus Lourenço, El Bouhissi & Sadine, 2020 (Buthidae) in North-western Algeria.

Abstract:
During nighttime in Aïn Deheb, Tiaret region (North-western Algeria). An adult female of the buthid scorpion Buthus apiatus Lourenço, El Bouhiss i& Sadine, 2020 was observed feeding on an adult Galeodessp.Such observation can contribute to the knowledge of the trophic ecology ofthis scorpion species.

Reference:
Benali N, Elkahar FMA, Boukhors AH. Natural case of predation on Camel spider (Arachnida: Solifugae) by the scorpion Buthus apiatus Lourenço, El Bouhissi & Sadine, 2020 (Arachnida: Scorpiones) in Tiaret, North-western Algeria. Revista Iberica de Arachnologia. 2024(45):159-60. [Open Access provided by author]

Thanks to Noureddine for sharing this article with me!