24 March, 2015
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.
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.
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
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
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.
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!
06 March, 2015
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).
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.
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
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
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!
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.
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.
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]
04 March, 2015
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.
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.
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!
27 February, 2015
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.
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.
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!