24 March, 2015

Venom spraying in scorpions


It is well known that scorpions use venom in prey capture and defense. This is normally done by injecting venom thought the scorpion's stinger. It is less known that a few species also can spray venom up 50 cm away. This behavior has only been reported from seven species in the South African genus Parabuthus Pocock, 1890 (Buthidae). It has been assumed that the venom spraying behavior has an anti-predator effect against potential predators of scorpions. Getting venom spray into the eyes is probably also harmful for humans, as many Parabuthus scorpions are of medical importance.

Nissani and Hayes have now published a very interesting analysis of the venom spraying behavior in Parabuthus transvaalicus Purcell, 1899, a medical important species from South Africa. Their study supported the hypothesis that that P. transvaalicus modulates venom spraying depending on level of threat. The authors argue that venom spraying increase the likelihood that venom makes contact with sensitive tissues of the predator, particularly its eyes. The authors believe that there is a possibility that scorpions modulate the quantity of venom expelled during spraying, but this requires further investigations.

Abstract:
Many animals use chemical squirting or spraying behavior as a defensive response. Some members of the scorpion genus Parabuthus (family Buthidae) can spray their venom. We examined the stimulus control and characteristics of venom spraying by Parabuthus transvaalicus to better understand the behavioral context for its use. Venom spraying occurred mostly, but not always, when the metasoma (tail) was contacted (usually grasped by forceps), and was absent during stinging-like thrusts of the metasoma apart from contact. Scorpions were significantly more likely to spray when contact was also accompanied by airborne stimuli. Sprays happened almost instantaneously following grasping by forceps (median = 0.23 s) as a brief (0.07 - 0.30 s, mean = 0.18 s), fine stream (< 5 * arc) that was not directed toward the stimulus source; however, rapid independent movements of the metasoma and/or telson (stinger) often created a more diffuse spray, increasing the possibility of venom contact with the sensitive eyes of potential scorpion predators. Successive venom sprays varied considerably in duration and velocity. Collectively, these results suggest that venom spraying might be useful as an antipredator function and can be modulated based on threat.

Reference:
Nisani Z, Hayes WK. Venom-spraying behavior of the scorpion Parabuthus transvaalicus (Arachnida: Buthidae). Behavioural Processes. 2015 Mar 3;115:46-52. [Subscription required for full text]

19 March, 2015

A new species of Vaejovis from Mexico


Contreras-Felix and co-workers have described a new species of Vaejovis C. L. Koch, 1836 (Vaejovidae) from Mexico.

V. tenamaztlei Contreras-Félix, Francke & Bryson Jr., 2015

Abstract:
A new species of Vaejovis is described from the Mexican state of Aguascalientes. It is assigned to the “mexicanus” group and compared with similar species from Jalisco, Guanajuato, and San Luis Potosí. A map with their known distributions is provided.

Reference:
Contreras-Felix GA, Francke OF, Bryson Jr RW. A new species of the “mexicanus” group of the genus Vaejovis C. L. Koch, 1836 from the Mexican state of Aguascalientes (Scorpiones: Vaejovidae). Zootaxa. 2015;3936(1):131-40. [Subscription required for full text]

Thanks to Oscar Francke for sending me this article!

Family Vaejovidae

06 March, 2015

A scorpion with four pectines and other anomalies


Morphological anomalies of scorpions are rare, but a few case have been reported. In a recent papers, Rolando Teruel and José Guadalupe Baldazo-Monsivaiz report of a specimen of Mesomexovis punctatus (Karsch, 1879) (Vaejovidae) from Mexico with a combination of hermaphroditism, gynandromorphism, and pectinal duplication (i.e., presence of four pectines).

Abstract:
In the present note, we describe in detail an aberrant anomalous specimen of the scorpion Mesomexovis punctatus (Karsch, 1879) (Vaejovidae). This strange individual is an adult and exhibits a combination of hermaphroditism, gynandromorphism, and pectinal duplication (i.e., presence of four pectines); the latter represents the first report ever made of such teratology. It was collected by the authors in northeastern Guerrero State, Mexico.

Reference:
Teruel R, Baldazo-Monsivaiz JG. Hermaphroditism, Gynandromorphism, and Four Pectines: an Extreme Case of Developmental Anomaly in Scorpions (Scorpiones: Vaejovidae). Euscorpius. 2015 (197):1-7. [Open Access]

Thanks to Rolando for sharing this very special discovery with me a few weeks ago!

05 March, 2015

A major reference book on scorpion venoms and scorpionism


Last Fall a major reference book on scorpion venoms and scorpionism around the world was published. I haven't read this book yet, but I will later and I plan to post information about the most interesting chapters in the blog. Unfortunately, the book is very expensive to purchase (unless your university has a Springer ebook subscription).

Information about the book Scorpion Venoms from Springer

The publisher has the following information about the content of the book:
  • Provides accessible yet in-depth entries on the state of the art of scorpion venom research
  • Introduces scorpion biology and ecology and covers studies of their venom and “anti-venoms”
  • Contains species-centered overviews and examines the scorpion toxins
  • Explores the complex interactions of scorpion venoms with the immune system
Scorpions have fascinated humans for a long time, first and foremost because of the harm the sting of a few species could cause but also due to their unique natural history and for the many biologically active compounds found in their venoms. This volume of the Toxinology handbook series covers all those aspects. The subjects are divided into seven sections starting with an introduction to the general aspects of scorpion biology and ecology, followed by the description of the “envenomation” pathophysiology, pharmacokinetics, and pharmacodynamics of venoms and their complex interactions with the immune system. The future of anti-scorpion venom therapy is then covered in two chapters dedicated to alternatives to the century-old techniques currently used to produce “anti-venoms”. The next section presents a world tour of “scorpionism” and dangerous scorpion species and their impact on human health. It is worth remembering that envenomation due to scorpion stings is a substantial health hazard in Asian, Middle Eastern, African, and Latin American countries, with over one million people stung by scorpions every year, resulting in more than 3,000 deaths. Species-centered overviews of “scorpion venoms” are presented in the next section, after which a section details the two main types of “scorpion toxins”. The last section covers high-throughput transcriptome and proteome screenings now known as “venomics”.

Reference:
Gopalakrishnakone P, Possani LDF, Schwartz E, Rodríguez de la Vega RC, editors. Scorpion Venoms. Dordrecht: Springer; 2014. [Subscritpion is required for access to the full text of the book]

Thanks to Dr. Adolfo Borges for sending me a copy of his chapter in the book and thereby notifying me about this book!

Two new species of Babycurus from Ethiopia


Frantisek Kovarik and co-workers have now published part II of their study of the scorpion fauna of Ethiopia (part I was about the genus Butheoloides Hirst, 1925). In the recent paper, the status of the genus Babycurus Karsch, 1886 (Buthidae) is presented. Two new species are described.

Babycurus dunlopi Kovarik, Lowe, Seiter, Pliskova & Stahlavsky, 2015
Babycurus sofomarensis Kovarik, Lowe, Seiter, Pliskova & Stahlavsky, 2015

In addition, Babycurus wituensis taramassoi Borelli, 1919 is raised to species status as Babycurus taramassoi Borelli, 1919.

The paper has several habitat photos for Babycurus in Ethiopia.

Abstract:
Two new species, Babycurus dunlopi sp. n. and B. sofomarensis sp. n. from Ethiopia, are described, compared with other species and fully illustrated with color photos of habitus and localities. B. subpunctatus Borelli, 1925 is recorded for the first time in Ethiopia, Somali Province. All data about the distribution of Babycurus Karsch, 1886 in Ethiopia including photos of all known Ethiopian localities of Babycurus are summarized. B. wituensis taramassoi Borelli, 1919 is raised back to species status as B. taramassoi Borelli, 1919.

Reference:
Kovarik F, Lowe G, Seiter M, Pliskova J, Stahlavsky F. Scorpions of Ethiopia (Arachnida: Scorpiones). Part II. Genus Babycurus Karsch, 1886 (Buthidae), with description of two new species. Euscorpius. 2015 (196):1-31. [Open Access]

Family Buthidae

04 March, 2015

A new species of Scorpiops from Vietnam


Wilson Lourenco and Dinh-Sac Pham have described a new species of Scorpiops Peters, 1861 (Euscorpiidae) collected in a limestone formation covered by rainforest, in the extreme north of Vietnam.

Scorpiops dentidactylus Lourenco & Pham, 2015

A new subgenus, Vietscorpiops Lourneco & Pham, 2015, is also presented in the paper.

Abstract:
Scorpiops (Vietscorpiops) dentidactylus subgen. n. et sp. n., belonging to the family Euscorpiidae Laurie, 1896, is described on the basis of single male collected in Dien Bien Province, Muong Nhe District, Nam Vi Commune, in a limestone formation covered by rainforest, in the extreme North of Vietnam. The new subgenus is characterized by the presence of only two lateral eyes represented by lenses and a strong, peculiar apophysis on the internal face of the chelal movable finger. This new scorpion taxon may represent yet another endemic element in the fauna of Southeast Asia, mainly Vietnam and Laos.

Reference:
Lourenco WR, Pham DS. An interesting new subgenus of Scorpiops Peters, 1861 from North Vietnam (Scorpiones: Euscorpiidae: Scorpiopinae). Comptes Rendus Biologies. 2015 Mar;338(3):212-7. [Subscription required for full text]

Thanks to Professor Lourenco for sending me this article!

Family Euscorpiidae

27 February, 2015

A new phylogenetic study on scorpions


The phylogeny of scorpions has long been under discussion. Numerous workers have historically emphasized different morphological characters of scorpions, resulting in variable hypotheses of phylogeny, none of which has been generally accepted (e.g. there is no consensus on the family structure in scorpions). In this study, the authors have applied a phylogenomic assessment to resolve scorpion phylogeny based on molecular data. See abstract for more information.

Abstract:
Scorpions represent an iconic lineage of arthropods, historically renowned for their unique bauplan, ancient fossil record and venom potency. Yet, higher level relationships of scorpions, based exclusively on morphology, remain virtually untested, and no multilocus molecular phylogeny has been deployed heretofore towards assessing the basal tree topology. We applied a phylogenomic assessment to resolve scorpion phylogeny, for the first time, to our knowledge, sampling extensive molecular sequence data from all superfamilies and examining basal relationships with up to 5025 genes. Analyses of supermatrices as well as species tree approaches converged upon a robust basal topology of scorpions that is entirely at odds with traditional systematics and controverts previous understanding of scorpion evolutionary history. All analyses unanimously support a single origin of katoikogenic development, a form of parental investment wherein embryos are nurtured by direct connections to the parent’s digestive system. Based on the phylogeny obtained herein, we propose the following systematic emendations: Caraboctonidae is transferred to Chactoidea new superfamilial assignment; superfamily Bothriuroidea revalidated is resurrected and Bothriuridae transferred therein; and Chaerilida and Pseudochactida are synonymized with Buthida new parvordinal synonymies.

Reference:
Sharma PP, Fernández R, Esposito LA, González-Santillán E, Monod L. Phylogenomic resolution of scorpions reveals multilevel discordance with morphological phylogenetic signal. Proceedings of the Royal Society B. 2015;282(1804):1-10. [Subscription required for full text]

Thanks to Prashant Sharma and Paulo André Margonari Goldoni for sending me this article!