Systematics of the ‘thorellii’ clade of Centruroides and the efficacy of mini-barcodes for museum specimens

 

Museums around world have large collections of scorpions collected in the last centuries and the specimens found in these collections are naturally important in the study of scorpion taxonomy and diversity. 

Today's studies on taxonomy and phylogeny are relying more and more on molecular and genetic tools, and old museum specimens may pose a problems for these tools as they have never been preserved in the collections with these in mind. 

Aaron Goodman and co-workers have recently published an article investigating the efficacy of mini-barcodes combined with longer sequences of the Cytochrome c Oxidase Subunit I (COI) gene in the systematics of scorpions. This method can be used on old, badly preserved museums specimens from complete barcodes cannot be obtained.

The results also support the recognition of nine species of the ‘thorellii’ clade, in accordance with a recent taxonomic revision published by the same authors.

Abstract:
Fragmented and degraded DNA is pervasive among museum specimens, hindering molecular phylogenetics and species identification. Mini-barcodes, 200–300-base-pair (bp) fragments of barcoding genes, have proven effective for species-level identification of specimens from which complete barcodes cannot be obtained in many groups, but have yet to be tested in arachnids. The present study investigated the efficacy of mini-barcodes combined with longer sequences of the Cytochrome c Oxidase Subunit I (COI) gene in the systematics of the arboreal Neotropical ‘thorellii’ clade of Centruroides Marx, 1890 bark scorpions (Buthidae, C.L. Koch 1837), the species of which have proven to be difficult to identify and delimit due to their similar morphology. The phylogeny of 53 terminals, representing all nine species of the clade and representative species belonging to related clades of Centruroides, rooted on Heteroctenus junceus (Herbst, 1800) and based on up to 1078 base pairs of COI and 112 morphological characters, is presented to test the monophyly of the clade and the limits of its component species. The results support the recognition of nine species of the ‘thorellii’ clade, in accordance with a recent taxonomic revision, and highlight the efficacy of mini-barcodes for identifying morphologically similar cryptic species using specimens of variable age and preservation.

Reference:
Goodman AM, Prendini L, Esposito LA. Systematics of the Arboreal Neotropical ‘thorellii’Clade of Centruroides Bark Scorpions (Buthidae) and the Efficacy of Mini-Barcodes for Museum Specimens. Diversity. 2021;13(9):441. [Open Access]

Family Buthidae

Another discovery of a scorpion with a double stinger

 

Malformations in scorpions are well-known, but in a recent research note Salah Eddine Sadine presents one of the more special malformations: The presence of a a double aculeus. This was seen in a female Androctonus amoreuxi (Audouin, 1826) (Buthidae) from Algeria. The female was normal except for the double stinger and this special malformation is probably not a handicap for the scorpion.

Abstract:
An adult female of the buthid scorpion Androctonus amoreuxi (Audouin, 1826) from a palm grove of Ghardaïa region (central Algeria) having a bifid aculeus (double aculeus) is recorded. This type of malformation of the telson has not been previously reported for this species.

Reference:
Sadine SE. A remarkable bifid aculeus in Androctonus amoreuxi (Audouin, 1826) from central Algeria (Scorpiones: Buthidae). Revista Iberica de Arachnologia. 2021(38):191-2.

Thanks to Dr. Sadine for sending me his article!

All you need to know about scorpions of medical importance in Brazilian Amazonas: Epidemiology, medical important species, venom, distribution, habitat and much more

 

Scorpions are a health problem in many parts of the world and Brazil is one of the world's hotspots in this regard. Knowledge of taxonomy (species diversity and who are dangerous or not), distribution, habitat preferences, ecology, venom and reproduction (how fast can a population grow and spread) is essential for preventing sting accidents and scorpionism.

Jonas Gama Martins and co-workers have recently published a very thorough and interesting review on most aspects concerning scorpions of medical importance in Brazilian Amazonas. This article will be an important tool for scientists, health personnel, public agencies and others working with scorpionism in Brazil and in the world.

Abstract:
Scorpionism is a relevant medical condition in Brazil. It is responsible for most accidents involving venomous animals in the country, which leads to severe symptoms that can evolve to death. In recent years, an increase of almost 50% in the incidence of scorpionism has been observed in the Northern Region, where the highest severity of envenoming has been notified since the beginning of the 21^st century. This review aims to provide an in-depth assessment of public data and reports on symptoms and epidemiology of envenoming, ecological aspects of scorpions, and characterization of venoms and toxins to access the gaps that need to be filled in the knowledge of the scorpion species of medical importance from the Brazilian Amazon. A systematic search using the string words “Amazon” and “scorpion” was performed on 11 databases. No restriction on date, language or status of the publication was applied. Reports not related to the Brazilian Amazon were excluded. Therefore, 88 studies remained. It is shown that populations of scorpions of medical importance, even of the same species, may present significant toxic variations peculiar to some regions in the Brazilian Amazon, and commercial scorpion antivenoms were not able to shorten the intensity and duration of neurological manifestations in patients stung by T. silvestris, T. apiacas or T. obscurus. It is also highlighted that the toxins responsible for triggering these alterations have not been elucidated yet and this is a fruitful field for the development of more efficient antivenoms. Furthermore, the geographic distribution of scorpions of the genus Tityus in the Brazilian Amazon was revised and updated. The cumulative and detailed information provided in this review may help physicians and scientists interested in scorpionism in the Brazilian Amazon.

Reference:
Martins JG, Santos GC, Procópio REL, Arantes EC, Bordon KCF. Scorpion species of medical importance in the Brazilian Amazon: a review to identify knowledge gaps. J Venom Anim Toxins Incl Trop Dis. 2021;27:e20210012. [Open Access]

Thanks to Jonas Gama Martins for sending me their article!

A review of the enigmatic family Pseudochactidae and troglobitism/troglomorphism in scorpions

 

Most scorpion researchers agree that the most remarkable scorpion discovery in the last century was the discovery of the very special scorpion Pseudochactas ovchinnikovi Gromov, 1998 in a remote, mountainous region of southeastern Uzbekistan and southwestern Tajikistan. This species "gave birth" to the family Pseudochactidae. Later one more species in the genus was discovered and the family was further increased two more genera with a few more species. Most of the latter are cavernicolous (found in caves), but not all of them have troglomorphisms like reduced eyes and pigmentation. All of the species in the family are rare and have a relictual distribution.

Lorenzo Prendini and co-workers have now conducted a thorough review of the family Pseudochactidae. Based on morphological and phylogenetical analysis they have concluded the following:

New subfamily:

 Troglokhammouaninae Prendini, Ehrenthal & Loria, 2021.

New genus:

Aemngvantom  Prendini, Ehrenthal & Loria, 2021.

New species:

Aemngvantom thamnongpaseuam Prendini, Ehrenthal & Loria, 2021.

New combination:

Aemngvantom lao (Lourenço, 2012).

Synonymizations:

Troglokhammouanus louisanneorum Lourenço, 2017 is synonymized with  Troglokhammouanus steineri Lourenço, 2007.

Vietbocap thienduongensis Lourenço and Pham, 2012 is synonymized with Vietbocap canhi Lourenço & Pham, 2010.

Vietbocap aurantiacus Lourenço et al., 2018 is synonymized with Vietbocap canhi Lourenço & Pham, 2010.

Vietbocap Vietbocap quinquemilia Lourenço et al., 2018 is synonymized with Vietbocap canhi Lourenço & Pham, 2010.

The family consists now of three subfamilies, four genera and six species. The article has revised descriptions of all species, pictures and habitat information with conservation status. An identification key for the family is also provided.

The article also provide a review of the global diversity of cavernicolous, troglomorphic and troglobitic scorpions and an ecological key to the classification of this kind of scorpions is also presented. 

Abstract:
The first integrative systematic revision of the relictual Asian scorpion family Pseudochactidae Gromov, 1998, making use of an unprecedented collection of material acquired during several expeditions to most of the type localities, is presented. The subfamilies, genera and species of Pseudochactidae are revised based on a phylogenetic analysis of 140 morphological characters and 8608 nucleotide base pairs of concatenated DNA sequence from two nuclear and three mitochondrial gene loci, and a multivariate statistical analysis of 22 ratios and 8 counts for 60 specimens. Three subfamilies, four genera and six species are recognized in the family. Troglokhammouaninae, subfam. nov., is created to restore the monophyly of the nominotypical subfamily Pseudochactinae Gromov, 1998. Aemngvantom, gen. nov., is created to accommodate Aemngvantom lao (Lourenço, 2012), comb. nov., and Aemngvantom thamnongpaseuam gen. et sp. nov. Four new synonyms are presented: Troglokhammouanus louisanneorum Lourenço, 2017 = Troglokhammouanus steineri Lourenço, 2007, syn. nov.; Vietbocap thienduongensis Lourenço and Pham, 2012 = Vietbocap canhi Lourenço and Pham, 2010, syn. nov.; Vietbocap aurantiacus Lourenço et al., 2018 = V. canhi, syn. nov.; Vietbocap quinquemilia Lourenço et al., 2018 = V. canhi, syn. nov. Revised diagnoses of the subfamilies, genera and species, with comparative images, a key and distribution maps are provided, along with a summary of available data on ecology and conservation status, where applicable. Among the Southeast Asian pseudochactids, all of which appear to be obligately cavernicolous, the three species of Vietbocapinae Lourenço, 2012, are highly troglomorphic whereas the sole species of Troglokhammouaninae is barely so. Applying recently revised definitions of the Schiner-Racovitza system for the classification of subterranean organisms, only Vietbocapinae can be considered troglobitic. The global diversity of cavernicolous, troglomorphic and troglobitic scorpions is similarly revisited and a key to ecological classification of cavernicolous and troglomorphic scorpions presented. The world totals of troglomorphic vs. troglobitic scorpions are currently 58 vs. 28 species, in 29 vs. 17 genera and 15 vs. 13 families, respectively.

Reference:
Prendini L, Ehrenthal VL, Loria SF. Systematics of the relictual Asian scorpion family Pseudochactidae Gromov, 1998, with a review of cavernicolous, troglobitic, and troglomorphic scorpions. Bulletin of the American Museum of Natural History. 2021(453):1-149. [Open Access]

Thanks to Matt Simon for informing me about this article!

Family Pseudochactidae

Six new species of Centruroides from Guatemala and Mexico

 

Aaron Goodman and co-workers have recently published a phylogenetic analysis based on morphology and genetics of the Neotropical “thorellii” clade of Centruroides Marx, 1890 (Buthidae). Six new species have been described. All of them are tree- and bark living, some of them having been found more than 15 meters above the ground. 

Centruroides berstoni Goodman, Prendini, Francke & Esposito, 2021 (Guatemala)

Centruroides catemacoensis Goodman, Prendini, Francke & Esposito, 2021 (Mexico)

Centruroides chanae Goodman, Prendini, Francke & Esposito, 2021 (Mexico)

Centruroides cuauhmapan Goodman, Prendini, Francke & Esposito, 2021 (Mexico)

Centruroides hamadryas Goodman, Prendini, Francke & Esposito, 2021 (Mexico)

Centruroides yucatanensis Goodman, Prendini, Francke & Esposito, 2021 (Mexico)

Revised diagnosis are given for Centruroides hoffmanni Armas, 1996, Centruroides rileyi Sissom, 1995, and Centruroides schmidti Sissom, 1995. A identification key for the species in the “thorellii” clade of Centruroides is also available.

Abstract:
The arboreal Neotropical “thorellii” clade of Centruroides Marx, 1890, bark scorpions (Buthidae C.L. Koch, 1837) is revised, using a novel approach to species delimitation. A phylogenetic analysis, based on 112 morphological characters and 1078 aligned DNA nucleotides from the mitochondrial Cytochrome c Oxidase Subunit I (COI) gene, provided the framework for placing singletons from geographically disparate localities (and often with suboptimal preservation) using COI minibarcodes, thereby enlarging the taxon sample for diagnosis and delimitation of morphological species. Six new species are described, tripling the known diversity in the clade to nine: Centruroides berstoni, sp. nov.; Centruroides catemacoensis, sp. nov.; Centruroides chanae, sp. nov.; Centruroides cuauhmapan, sp. nov.; Centruroides hamadryas, sp. nov.; Centruroides yucatanensis, sp. nov. Revised diagnoses are presented for Centruroides hoffmanni Armas, 1996, Centruroides rileyi Sissom, 1995, and Centruroides schmidti Sissom, 1995. Comparative images, a key and distribution maps for all species of the clade are provided, along with a summary of available data for their ecology.

Reference:
Goodman AM, Prendini L, Francke OF, Esposito LA. Systematic Revision of the Arboreal Neotropical “Thorellii” Clade of Centruroides Marx, 1890, Bark Scorpions (Buthidae C.L. Koch, 1837) with Descriptions of Six New Species. Bulletin of the American Museum of Natural History. 2021(452):1-92. [Open Access]

Thanks to Oscar Francke for sending me their article!

Family Buthidae