16 December, 2014

Involuntary limb twitching after ingestion of scorpion-based Chinese medicine

Scorpions are known to be used in traditional Chinese cousin and medicine. The most used species is the butid Mesobuthus martensii (Karsch, 1879), which is commercially bred in farms in China.

Lam and co-workers now report about a man compalining about chest pain, dizziness, and generalised tremors 15 minutes after ingestion of a teaspoon of herbal powder with water. The powder was made of scorpions (M. martensii).

After ruling out other potential causes, the diagnosis of this case was compatible with neurotoxicity associated with the consumption of M. martensii powder, even though it could not be directly confirmed by chemical analysis.

Mesobuthus martensii Karsch, commonly known as the Chinese scorpion or Manchurian scorpion, has been used in traditional Chinese medicine as Quanxie to treat chronic pain, tetanus, tremors, convulsion, and paralysis for more than a thousand years. We report a case of poisoning after ingestion of a teaspoon of Quanxie powder. The patient presented with chest pain, dizziness, diaphoresis, generalised involuntary limb twitching, and hypertonia around 15 minutes post-ingestion. The patient recovered uneventfully after supportive management. Intravenous diazepam appeared to be effective in alleviating limb twitching. Failure to accurately measure the dose and to boil before consumption may have contributed to his clinical toxicities.

Lam PK, Wong TW, Chan YC, Mak TW. Generalised involuntary limb twitching after ingestion of Mesobuthus martensii Karsch (Quanxie) powder. Hong Kong Med J. 2014 Dec;20(6):552-5. [Free full text]

15 December, 2014

The phylogeny of the genus Diplocentrus

The genus Diplocentrus Peters, 1861 (Scorpionidae) is a very diverse genus with species in North and Central America (Mexico being the hotspot for this genus).

Carlos Santibanez-Lopez and co-workers have now conducted a phylogenetic analysis of the genus based on 29 species. The conclusions are presented in the abstract below.

Karsch, 1880. There is considerable morphological variation among the species of Diplocentrus. It is necessary to test the monophyly and phylogenetic position of Diplocentrus in order to revise its diagnosis and taxonomic limits. The present contribution provides a phylogenetic analysis of 29 species of Diplocentrus, five exemplar species representing the three putatively most closely related diplocentrid genera, and an exemplar of a more distantly related diplocentrid genus. The analysis was based on 95 morphological characters and 4202 aligned nucleotides from DNA sequences of five markers in the nuclear and mitochondrial genomes. Separate and simultaneous parsimony analyses of the morphological and DNA sequence data were conducted with equal weighting and six implied weighting regimes. The nuclear and mitochondrial DNA datasets were also analyzed separately and simultaneously with Bayesian inference. The resulting topologies recovered the monophyly of Diplocentrus, with the exception of two neobothriotaxic species from central Mexico, for which a new genus Kolotl Santibáñez-López et al., 2014, is justified. The keyserlingii group, as previously defined, was not monophyletic due to the placement of two species in the mexicanus group; the rest of its component species were monophyletic, however. A third clade was recovered that has not been previously recognized: the zacatecanus group, comprising four species from northern Mexico and the southwestern U.S.A. New insights are provided concerning relationships among Diplocentrus and the diplocentrid genera Bioculus Stahnke, 1968 and Didymocentrus Kraepelin, 1905, the phylogenetic positions of which were previously ambiguous.

Santibanez-Lopez CE, Francke OF, Prendini L. Phylogeny of the North American scorpion genus Diplocentrus Peters, 1861 (Scorpiones: Diplocentridae) based on morphology, nuclear and mitochondrial DNA. Arthropod Systematics & Phylogeny. 2014;72(3):257-79. [Subscription required for full text]

Thanks to Carlos Santibanez-Lopez for sending me his paper!

Family Scorpionidae

12 December, 2014

A major study of the scorpions' lateral eyes

Scorpions have two types of visual organs (usually called eyes): the median and the lateral eyes. Most scorpions have a single pair of median eyes (except for a few troglomorphic species), but the number of pairs of lateral eyes varies very much between the different scorpion taxa and even within some species.

Loria and Prendini have now published a comparative study of variation in the lateral eyes of scorpions based on examinations of a broad range of taxa. The main conclusions of the study can be found in the abstract below.

Scorpions possess two types of visual organs, the median and lateral eyes. Both eyes consist of simple ocelli with biconvex lenses that differ in structure and function. There is little variation in the number of median ocelli across the order. Except for a few troglomorphic species in which the median ocelli are absent, all scorpions possess a single pair. In contrast, the number of pairs of lateral ocelli varies from zero to five across Scorpiones and may vary within species. No attempt has been made to homologize lateral ocelli across the order, and their utility in scorpion systematics has been questioned, due to the variation in number. A recent study examined the number of lateral ocelli among various Asian Buthidae C.L. Koch, 1837 and proposed a ‘‘five-eye model’’ for the family. This model has not been examined more broadly within Buthidae, however, nor compared with the patterns of variation observed among other scorpion families. An eyespot, referred to as an accessory lateral eye, situated ventral or posteroventral to the lateral ocelli, has also been reported in some scorpions. Analysis of its structure suggests it serves a nonvisual function. We present the first comparative study of variation in the lateral ocelli across the order Scorpiones, based on examination of a broad range of exemplar species, representing all families, 160 genera (78%), 196 species (9%), and up to 12 individuals per species. We propose a six-ocellus model for Recent scorpions with four accessory ocelli observed in various taxa, homologize the individual ocelli, and correct erroneous counts in the recent literature. We also investigate the presence of the eyespot across scorpions and discover that it is more widespread than previously recognized. Future work should investigate the genetic and developmental mechanisms underlying the formation of the lateral ocelli to test the hypotheses proposed here.

Loria SF, Prendini L. Homology of the Lateral Eyes of Scorpiones: A Six-Ocellus Model. PLoS One. 2014;9(12):e112913. [Free full text]

Thanks to Matt Simon for informing me about this article!

The importance of environmental factors on scorpion populations in tropical forests

Scorpion ecology is still relatively unknown (with the exception of Gary Polis' and co-workers' extensive studies on North American desert scorpions), especially in tropical forests. Andre Lira and co-workers have now published a study on how environmental factors have an impact on the population structure on co-occuring scorpion species in a tropical forest.

The authors compared the relative abundance of Tityus pusillus Pocock, 1893 and Ananteris mauryi Lourenço, 1982 (Buthidae) and investigated how these species respond to habitat changes (remnant areas, understory density, diameter at breast height (DBH) of tree, canopy openness) and microhabitat requirement (litter depth and dry mass).

The results of this work suggests that environmental factors on a microhabitat scale rather than broad-scale variation in the forest fragments had more influence on the abundance of the leaf litter scorpions T. pusillus and A. mauryi in the Brazilian Atlantic Forest. Furthermore, differences related to hunting behavior (sit-andwait or wandering) and microhabitat selection may explain the influence of litter dry mass on the abundance of T. pusillus but not on the abundance of A. mauryi.

Understanding scorpion responses to environmental disturbances in forest remnants is important because, as generalist predators, they exert pressure on a wide variety of arthropod populations that contribute to forest health. In this study, we investigate the drivers of scorpion Tityus pusillus Pocock, 1893 and Ananteris mauryi Lourenço, 1982 abundance in 11 Brazilian Atlantic Forest remnants. Six environmental factors (litter dry mass, remnant area, leaf litter depth, diameter at breast height of tree, canopy openness, and tree density) were assessed. Field surveys were conducted at night using ultraviolet lamps. From a sample of 1125 captured specimens, approximately 90% were T. pusillus and 7% were A. mauryi. The abundance of T. pusillus, but not A. mauryi, was positively correlated with litter dry mass. Other variables had no effect on the abundance of either species. These results suggest differences in the response of the species to environmental factors on a smaller scale. Behavior difference in foraging between T. pusillus (sit-and-wait) and A. mauryi (wandering) and microhabitat selection may also contribute to explain the influence of litter dry mass on the abundance of T. pusillus but not on the abundance of A. mauryi.

Lira AFA, Rego FNAA, Albuquerque CMR. How important are environmental factors for the population structure of co-occurring scorpion species in a tropical forest? Can J Zool. 2015;93:15-9. [Subscription required for full text]

Thanks to Andre Lira for sendign me his paper!

11 December, 2014

Two new species of Euscorpius from Bulgaria, Serbia and Greece

Several researchers are studying the Euscorpius Thorell, 1876 (Euscorpiidae) fauna of Eastern Europe and Balkan, and several previous "hidden" species have been published in the last decade. In a recent study, Victor Fet and co-workers have described two new species from Bulgaria, Serbia and Greece.

Euscorpius deltshevi Fet, Graham, Webber & Blagoev, 2014 (Known from Stara Planina Mts., Bulgaria, and adjacent areas of Bulgaria and Serbia).

Euscorpius solegladi Fet, Graham, Webber & Blagoev, 2014 (Known from southwestern Bulgaria and northeastern Greece).

Two new species of Euscorpius Thorell, 1876 (subgenus Euscorpius s.str.) (Scorpiones: Euscorpiidae) are described based on morphology and the COI DNA barcoding marker: E. deltshevi sp. n. from northern Bulgaria and neighbouring Serbia (formerly reported as E. carpathicus) and E. solegladi sp. n. from southwestern Bulgaria and neighbouring Greece (formerly reported as E. hadzii).

Fet V, Graham MR, Webber MM, Blagoev G. Two new species of Euscorpius (Scorpiones: Euscorpiidae) from Bulgaria, Serbia, and Greece. Zootaxa. 2014 (3894):83-105. [Subscription required for full text]

Thanks to professor Victor Fet for sending me their article!

Family Euscorpiidae

09 December, 2014

Two new species of Opisthacanthus from Madagascar

Just days after reporting about a new species of Opisthacanthus Peters, 1861 (Hormuridae) from Madagascar, I can report about two new species from this hotspot of biodiversity. Again, it is professor Wilson Lourenco who is the author of the recent article describing the new species.

Opisthacanthus ambanja Lourenço, 2014

Opisthacanthus antsiranana Lourenço, 2014

Two new scorpion species, Opisthacanthus antsiranana sp.n. and O. ambanja sp.n., are described from the North of Madagascar. The new species clearly suggest cases of micro-endemic and vicariant populations within the island. The total number of species of the genus in Madagascar is now elevated to 10 and its known geographical distribution within the island is expanded.

Lourenco WR. Micro-endemic and vicariant populations of Opisthacanthus Peters, 1861 (Scorpiones: Hormuridae) in Madagascar, with descriptions of two new species. Arthropoda Selecta. 2014;23(4):383-9. [Free full text]

Thanks to professor Lourenco for sending me his paper!

Family Hormuridae

08 December, 2014

A new species of Chactas from Ecuador

Wilson Lourenco has recently described a new species of Chactas Gervais, 1844 (Chactidae) from the Province of Morona Santiago in Ecuadorian Amazonia.

Chactas yaupi Lourenco, 2014

A new species, Chactas yaupi sp. n., is described from the Province of Morona Santiago in Ecuadorian Amazonia. This is the third confirmed record of the genus Chactas Gervais from Ecuador. The geographical pattern of distribution of the genus Chactas is discussed. Comments are also addressed about the remarkable diversity and high level of endemic elements of the Ecuadorian fauna.

Lourenco WR. The third confirmed record of the scorpion genus Chactas Gervais, 1844 (Scorpiones: Chactidae) from Ecuador, with description of a new species from the Amazonian Province of Morona Santiago. Entomologische Mitteilungen aus dem Zoologischen Museum Hamburg. 2014;17(193):171-8.

Thanks to professor Lourenco for sending me his article!

Family Chactidae