A review of the Heterometrus of Thailand

 

The status of some members of the genus Heterometrus Ehrenberg, 1828 (Scorpionidae) and their presence in Thailand has been burdened with uncertainty. In a recent review authored by Kazusa Kawai and co-workers, five species of Heterometrus species are now confirmed for Thailand. In addition, two previously synonymized species are restored to species status:

Heterometrus cimrmani Kovařík, 2004 (previously synonymized with Heterometrus laevigatus (Thorell, 1876))

Heterometrus minotaurus Pliskova, Kovarik, Kosulic & Stahlavsky, 2016 (previously synonymized with Heterometrus laevigatus (Thorell, 1876))

Heterometrus laevigatus (Thorell, 1876) is now considered nomen dubium.

Abstract:
Five species of the genus Heterometrus Ehrenberg, 1828 are currently confirmed from Thailand and revised, with their respective distribution range in this country updated. Heterometrus laevigatus (Thorell, 1876) is considered a nomen dubium, while its two previous junior synonyms, H. cimrmani Kovařík, 2004, stat. rev. and H. minotaurus Plíšková et al., 2016, stat. rev. are revalidated and redescribed based on the examination of topotypes. Females of H. minotaurus Plíšková et. al., 2016, stat. rev. were also collected and examined, and their characters are herein described with a special attention to sexual dimorphism. Furthermore, some populations previously regarded as H. laoticus Couzijn, 1981 found in Thailand turned out to belong to H. silenus (Simon, 1884). Additionally, ambiguous records of H. spinifer (Ehrenberg, 1828) in Thailand are now confirmed. Finally, we speculate that the difference in pedipalp length between males of H. cimrmani and H. minotaurus is evolved due to the armspan competition.

Reference:
Kawai K, Unnahachote T, Suttisatid Y, Tang V. А Review of Heterometrus in Thailand (Scorpiones: Scorpionidae). Euscorpius. 2023(373):1-25. [Open Access]

Family Scorpionidae

New method for scorpion venom research spares the scorpion's life

 

Scorpion venom is highly investigated, both because of the medical important of this animal group, but also because the different scorpion venom types are candidates of pharmaceutically active molecules with potential drug applications.

The most popular method today to study scorpion venoms is transcriptome studies. The current method for obtaining a scorpion venom gland transcriptome is based on sacrificing the animal to extract the venom gland from the telson (they cut of the telson). This means a lot of dead scorpions each year in the name of science.

Freek J. Vonk and several co-workers have now published an article describing a new method of generating a scorpion venom gland transcriptome without sacrificing the animal. This is good news as it will spare many scorpion lives, but also opens up new possibilities for testing the venom from the same scorpion several times (e.g. by allowing the study of the transcriptome at various time points within a single individual).

Abstract:
Scorpion venoms are mixtures of proteins, peptides and small molecular compounds with high specificity for ion channels and are therefore considered to be promising candidates in the venoms-to-drugs pipeline. Transcriptomes are important tools for studying the composition and expression of scorpion venom. Unfortunately, studying the venom gland transcriptome traditionally requires sacrificing the animal and therefore is always a single snapshot in time. This paper describes a new way of generating a scorpion venom gland transcriptome without sacrificing the animal, thereby allowing the study of the transcriptome at various time points within a single individual. By comparing these venom-derived transcriptomes to the traditional whole-telson transcriptomes we show that the relative expression levels of the major toxin classes are similar. We further performed a multi-day extraction using our proposed method to show the possibility of doing a multiple time point transcriptome analysis. This allows for the study of patterns of toxin gene activation over time a single individual, and allows assessment of the effects of diet, season and other factors that are known or likely to influence intraindividual venom composition. We discuss the gland characteristics that may allow this method to be successful in scorpions and provide a review of other venomous taxa to which this method may potentially be successfully applied.

References:
Vonk FJ, Bittenbinder MA, Kerkkamp HMI, Grashof DGB, Archer JP, Afonso S, et al. A non-lethal method for studying scorpion venom gland transcriptomes, with a review of potentially suitable taxa to which it can be applied. PLoS One. 2021;16(11):e0258712. [Open Access]

Thanks to Arie van der Meijden for sending me their interesting article!

Phylogeny of the Asian forest scorpions and the evolution of ecomorphotypes

Last year,  Lorenzo Prendini and Stephanie Loria published a huge systematic revision of the Asian Forest Scorpions (Scorpionidae). Recently, they have published a follow-up article with a phylogenetic analysis of these scorpions. This analysis seems to confirm the taxonomic decisions made in the 2020 paper. 

The new article also looks into the ecomorphological adaptions seen in Heterometrinae. Three ecomorphotypes were found: A wet silvicolous (living in or inhabiting woodlands) ecomorphotype inhabiting evergreen forest, a dry silvicolous ecomorphotype inhabiting deciduous forest, and a savannicolous ecomorphotype inhabiting savanna or scrubland. Most Asian scorpionid genera exhibited one or two of these ecomorphotypes among their species. The authors conclude that the ancestor of Asian scorpionids probably was wet silvicolous and inhabited humid, evergreen forests.

Abstract:
Asian forest scorpions (Scorpionidae Latreille, 1802: Heterometrinae Simon, 1879) are distributed across South and Southeast Asia. All are fossorial, constructing burrows under stones or in open ground, in habitats differing in precipitation and vegetation cover, from rainforests and tropical deciduous forests to savanna and scrubland. The systematics of these scorpions has long been confused due to bad taxonomy and the absence of a phylogenetic framework. Although the monophyly of the group was previously confirmed as part of broader phylogenetic analyses based on exemplar species, the only quantitative analysis of species-level variation to date was based on overall similarity. This contribution presents the first species-level phylogenetic analysis of Asian Scorpionidae, based on 186 morphological characters and 4188 aligned base-pairs of DNA sequence data from two nuclear and three mitochondrial loci for 132 terminals including all 41 ingroup species and four outgroup species. Simultaneous analyses of the morphological and molecular datasets with parsimony, Maximum Likelihood and Bayesian Inference provided the framework for a revised classification presented elsewhere. In order to understand how adaptation following dispersal into new habitats has driven the morphological diversification of Asian forest scorpions, species were scored for 10 characters concerning morphology and burrow architecture, which contributed to an ensemble index of adaptation to habitat aridity. Species were classified into three ecomorphotypes based on the index, and ancestral state reconstruction of ecomorphotypes performed on the phylogeny. A pattern was recovered in which lineages and species occurring in different habitats on a continuum from wet (evergreen forest) to dry (savanna, scrubland) exhibited characters presumed to be adaptive and hence responsible for driving scorpion diversification.

Reference:
Loria SF, Prendini L. Burrowing into the forest: Phylogeny of the Asian forest scorpions (Scorpionidae: Heterometrinae) and the evolution of ecomorphotypes. Cladistics. 2021;37(2):109-61. [Subscription required for full text]

Family Scorpionidae

A hypothesis for the evolution and diversification of the Asian forest scorpions

 

Stephanie Loria and Lorenzo Prendini published last fall an interesting article on the evolution and diversification of the Asian forest scorpions (subfamily Heterometrinae of Scorpionidae). There are several hypothesis for explaining explain patterns of distribution among Southeast Asian animal taxa. The authors concludes that the "out of India" hypothesis is the most probable for the Asian forest scorpion. What does this mean:

1. Scorpionid taxa originated in Africa and the Heterometrinae diverged from other Scorpionidae on the African continent after the Indian subcontinent became separated in the Cretaceous period. 

2. A mass extinction event with subsequent environmental stress restricted Heterometrinae to refugia in southern India (the Western Ghats) and Sri Lanka (the Central Highlands).

3. Heterometrinae dispersed to Southeast Asia three times during India’s collision with Eurasia ("Out of India").

4.  Indian Heterometrinae, confined to southern India and Sri Lanka during the mass extinction mentioned above, recolonized the Deccan Plateau and northern India, diversifying into new, more arid habitats after environmental conditions stabilized.

This article confirms previous suggestions that the ‘Out of India’ hypothesis best explains the origin of Southeast Asian Heterometrinae, given their sister-group relationship with the African Pandininae, and the absence of Heterometrinae or Pandininae between the Middle East and the Indian subcontinent.

Abstract:
The ‘Out of India’ hypothesis is often invoked to explain patterns of distribution among Southeast Asian taxa. According to this hypothesis, Southeast Asian taxa originated in Gondwana, diverged from their Gondwanan relatives when the Indian subcontinent rifted from Gondwana in the Late Jurassic, and colonized Southeast Asia when it collided with Eurasia in the early Cenozoic. A growing body of evidence suggests these events were far more complex than previously understood, however. The first quantitative reconstruction of the biogeography of Asian forest scorpions (Scorpionidae Latreille, 1802: Heterometrinae Simon, 1879) is presented here. Divergence time estimation, ancestral range estimation, and diversification analyses are used to determine the origins, dispersal and diversification patterns of these scorpions, providing a timeline for their biogeographical history that can be summarized into four major events. (1) Heterometrinae diverged from other Scorpionidae on the African continent after the Indian subcontinent became separated in the Cretaceous. (2) Environmental stresses during the Cretaceous–Tertiary (KT) mass extinction caused range contraction, restricting one clade of Heterometrinae to refugia in southern India (the Western Ghats) and Sri Lanka (the Central Highlands). (3) Heterometrinae dispersed to Southeast Asia three times during India’s collision with Eurasia, the first dispersal event occurring as the Indian subcontinent brushed up against the western side of Sumatra, and the other two events occurring as India moved closer to Eurasia. (4) Indian Heterometrinae, confined to southern India and Sri Lanka during the KT mass extinction, recolonized the Deccan Plateau and northern India, diversifying into new, more arid habitats after environmental conditions stabilized. These hypotheses, which are congruent with the geological literature and biogeographical analyses of other taxa from South and Southeast Asia, contribute to an improved understanding of the dispersal and diversification patterns of taxa in this biodiverse and geologically complex region.

Reference:
Loria SF, Prendini L. Out of India, thrice: diversification of Asian forest scorpions reveals three colonizations of Southeast Asia. Sci Rep. 2020;10(1):22301.[Open Access]

Family Scorpionidae

Advanced warning: Hugh revision of the genus Heterometrus and several parts of Scorpionidae recently published

I just got an email from Gerard Dupre containing a 500 page revision of Heterometrus Ehrenberg, 1828 and other parts of the family Scorpionidae. I normally do not blog about new articles until I have read and "processed" them, but in this case the taxonomical changes are massive and it will take me quite some time to update The Scorpion Files. Because the Scorpionidae is an important and popular family among both professionals and enthusiasts, I'm posting the news about this paper immediately. 

I will post more details in a separate post later.

Abstract:
See article for the large abstract.

Reference:
Prendini L, Loria SF. Systematic revision of the Asian Forest Scorpions (Heterometrinae simon, 1879), revised suprageneric classification of Scorpionidae latreille, 1802, and revalidation of Rugodentidae Bastawade et al., 2005. Bulletin of the American Museum of Natural History. 2020(442):1-480. [Open Access]

Thanks to Gerard Dupre for informing me about this important paper!

Family Scorpionidae (not updated yet!)

 

 

A new species of Heterometrus from Sri Lanka

Frantisek Kovarik and co-workers have recently published a new article describing a new species of Hetereometrus Ehrenberg, 1828 (Scorpionidae) from Sri Lanka.

Heterometrus yaleensis Kovarik, Ranawana, Jayarathne, Hoferek & Stahlavsky, 2019

Abstract:
Heterometrus yaleensis sp. n. from Sri Lanka, Southern Province, Yale National Park is described and compared with other species of the genus. The presence of a unique dorsointernal carina on the pedipalp chela distinguishes H. yaleensis sp. n. from all other Heterometrus species. Additional information is provided on the taxonomy and distribution of the genus Heterometrus in Sri Lanka, fully complemented with color photos of specimens of both sexes of the new species, as well as of their habitat. In addition to external morphology and hemispermatophore, we also describe the karyotype of H. yaleensis sp. n. (2n=99).

Reference:
Kovarik F, Ranawana KB, Jayarathne VAS, Hoferek D, Stahlavsky F. Scorpions of Sri Lanka (Arachnida: Scorpiones). Part III. Heterometrus yaleensis sp. n. (Scorpionidae). Euscorpius. 2019(283):1-13. [Open Access]

Family Scorpionidae

An update on the scorpion fauna of Kerala, India

Information about the scorpion fauna is important and we still have a lot of undiscovered taxa or populations in many areas of the world. Aswathi & Sureshan recently published the results of a survey of the scorpion fauna of Kerala, India, also including a checklist and an identification key for the taxa in this region.

Abstract:
Two species of scorpions (Arachnida: Scorpiones) Lychas laevifrons (Pocock), and Heterometrus flavimanus (Pocock) are reported for the first time from Kerala, and an illustrated key to the genera and checklist of scorpion species of Kerala are provided. Currently, 22 species belonging to nine genera of scorpions are known from the state.

Reference:
Aswathi K, Sureshan PM. Additions to the scorpion fauna (Arachnida: Scorpiones) of Kerala, India, with an illustrated key to the genera. Journal of Threatened Taxa. 2017;9(2):9844–50. [Open Access]

Thanks to Dr. Aswathi for sending me their article!

A new Heterometrus species from Thailand

Jana Pliskova and co-workers have recently published a new species of Heterometrus Ehrenberg, 1828 (Scorpionidae) from Thailand.

Heterometrus minotaurus Pliskova, Kovarik, Kosulic & Stahlavsky, 2016

The karyotype of the new species is presented and the known karyotypes of the genus is discussed.

Abstract:
A new species of the genus Heterometrus is described on the basis of a specimen recently collected in Thailand. Heterometrus minotaurus sp. nov. is morphologically closest to H. longimanus. The newly described species is well distinguished by its smaller overall size (83 mm) and shorter and less narrow metasoma with specific dorsolateral carinae on the fourth metasomal segment consisting of 9 or fewer granules. No females are known and so knowledge of sexual dimorphism in this species is currently lacking. In addition to the morphological characterization of H. minotaurus sp. nov., we present here also a description of the male holotype’s karyotype. The diploid set of H. minotaurus sp. nov. consists of 54 chromosomes with a predominance of metacentrics, which gradually decrease in size. The presence of two types of multivalent association observed in postpachytene and metaphase I is commented on. Current knowledge of karyotypes of Heterometrus species is briefly summarized and compared with our cytogenetic results. In conclusion, we discuss the possible usefulness of karyotype as another interspecific feature applicable in the taxonomy of this scorpion group.

Reference:
Pliskova J, Kovarik F, Kosulic O, Stahlavsky F. Description of a new species of Heterometrus Ehrenberg, 1828 (Scorpiones: Scorpionidae) from Thailand with remarks about the utilization of cytogenetic data in taxonomy of the genus. Annales Zoologici. 2016;66(3):467-76.

Thanks to Frantisek Kovarik for sending me this article!

Family Scorpionidae

A new Heterometrus from India

Heterometrus atrascorpius from Western Ghats in India (Photo: Zeeshan Mirza)

Zeeshan Mirza and co-workers have recently described a new species of Heterometrus Ehrenberg, 1828 (Scorpionidae) from Western Ghats in India.

Heterometrus atrascorpius Mirza, Joshi, Desouza & Sanap, 2012

Abstract:
A new species of scorpion belonging to the genus Heterometrus Ehrenberg, 1828 is described from the Southern Western Ghats of Tamil Nadu, India. Heterometrus atrascorpius sp. nov. differs from all other known species of the genus reported from India, in particularly from Heterometrus beccaloniae Kovarík, 2004 by bearing the following set of characters: moderate size in comparison to other members of the genus 91.68 (holotype); body coloration dark blackish brown both dorsally and ventrally, with the exception of the vesicle which is yellowish white and the leg tarsi which are paler; pectines, sternum and pectinal basal piece yellowish brown; pedipalp manus tuberculate with carina; patella and femur dorsally tuberculate; pedipalp femur longer than twice as wide; manus length/width ratio 3.22; pectines with 16-16 teeth.

Reference:
Mirza ZA, Joshi D, Desouza G, Sanap RV. Description of a new species of scorpion of the genus Heterometrus Ehrenberg, 1828 (Scorpiones: Scorpionidae) from the Western Ghats, India. Indian Journal of Arachnology. 2012;1(2):1-8. [Free full text]

Thanks to Zeeshan Mirza and Gerard Dupre for sending me this paper and to Zeeshan for allowing me to use his picture of the new species!

Family Buthidae

New Heterometrus from India

Javed and co-workers has recently described a new Heterometrus (Scorpionidae) from India:

Heterometrus telanganaensis Javed, Mirza, Tampal & Lourenco, 2010

The papers also has some information about the new species' natural history.

Abstract:
A distinctive new species of the genus Heterometrus Ehrenberg, 1828 is described from the Indian state of Andhra Pradesh. Heterometrus telanganaensis sp. nov. differs from all Indian species of the genus in being one of the smallest species with a relatively short metasoma.

Reference:
Maqsood Javed SM, Mirza ZA, Tampal F, Lourenco WR. A new species of the genus Heterometrus Ehrenberg, 1828 (Scorpiones: Scorpionidae) from India with notes on its natural history. Boletin de la SEA. 2010(47):143-8.

Thanks to Javed for sending me the paper and sharing the picture with The Scorpion Files!

Family Scorpionidae

The reproductive biology of Heterometrus phipsoni

Zeeshan Mirza & Rajesh Sanap have studied the reproductive biology of the Indian scorpion Heterometrus phipsoni Pocock, 1893 (Scorpionidae) and a paper is now available describing mating and breeding of this species.

This paper will be of interest both to preofessionals studing scorpion behavior and to enthusiasts wanting to breed Heterometrus in captivity.

Abstract:
The present communication presents a detailed description of the breeding behavior of Heterometrus phipsoni exhibited under laboratory conditions. As also the studies include notes on gestation period, brood size and description of the post insemination spermatophore.

Reference:
Mirza ZA, Sanap R. Notes on the reproductive biology of Heterometrus phipsoni Pocock, 1893 (Scorpiones: Scorpionidae). Journal of Threatened Taxa. 2009;1 (9):488-90. [Free fulltext]

Family Scorpionidae

A new Heterometrus species from Vietnam

A just learned about a new species of Heterometrus (Scorpionidae) described from Vietnam:

Heterometrus liangi Zhu & Yang, 2007

I have not read this paper myself (it is in Chinese), so this information is based on the papers bibliographical data. This species is not included in Kovarik's latest revision of this genus in his recently published "Illustrated Catalog of Scorpions".

Reference:
Zhu MS, Yang X-F. Two species of the genus Heterometrus Ehrenberg, 1828 (Scorpionidae) from South Vietnam sold in pet shops in China. Acta Arachnologica Sinica. 2007;16 (2):92-103.

Thanks to Gérard Dupre for informing me about this paper!

Family Scorpionidae

Courtship and mating in Heterometrus petersii

Jiao & Zhu has recently published a study on mating behavior and courtship in the Asian scorpion Heterometrus petersii (Scorpionidae). The study confirms most previously observed behavior components in other species (suggested readings: Polis & Sissom (1990), Benton (2001), Tallarovic et al. (2000) and Ross (2009)).

Heterometrus is a popular genus for captive breeding, and this paper is interesting for those that want to breed scorpions in this genus.

Abstract:
Courtship and mating in Heterometrus petersii (Thorell, 1876) (Scorpiones: Scorpionidae) was observed in the laboratory. In this paper the behavior components displayed in courtship and mating are identified, analyzed and discussed.

Reference:
Jiao G-B, Zhu MS. Courtship and mating in Heterometrus petersi (Thorell, 1876) (Scorpiones: Scorpionidae). Euscorpius. 2009; (84):1-5. [Free fulltext]

Suggested Readings:
Polis, G. A. & W. D. Sissom. 1990. Life history. Pp. 161–223 in G. A. Polis (ed.) The Biology of Scorpions. Stanford, CA: Stanford University Press.

Benton, T. G. 2001. Reproductive ecology. Pp. 288–294 in Brownell, P. H. & G. A. Polis (eds.) Scorpion Biology and Research. New York, NY: Oxford University Press.

Tallarovic, S. K., J. M. Melville & P. H. Brownell. 2000. Courtship and mating in the giant hairy desert scorpion, Hadrurus arizonensis (Scorpionidae, Iuridae). Journal of Insect Behavior, 13(6): 827–838.

Ross, L. K. 2009. Notes and observations on courtship and mating in Tityus (Atreus) magnimanus Pocock, 1897 (Scorpiones: Buthidae). Journal of Venomous Animals and Toxins Including Tropical Diseases, 15(1):43–53.

Family Scorpionidae

Part I of an Illustrated catalog of scorpions is published

I just received information that František Kovařík has published the first part of his Illustrated Catalog of Scorpions. Part one includes introductory remarks, keys to families and genera, subfamily Scorpioninae with keys to Heterometrus and Pandinus species.

I have not seen this book myself yet, so I'm including the information available from the publisher:
An often encountered problem in estimations of animal diversity is a paucity of illustrated reviews allowing those not engaged in descriptive taxonomy fast orientation in given groups. Whereas for some invertebrates, namely butterflies and beetles, such reviews are available for most families, no such work has so far existed for the scorpions. To fill the gap, I have prepared the present volume. It consists of introductory remarks (morphology, toxicity, reproduction, ontogeny etc.), keys to all families and genera described by the end of 2008, a list of genera with their distributions and numbers of species, and 650 color photos depicting most species of the subfamily Scorpioninae (Heterometrus, Pandinus, Scorpio and Opistophthalmus). Many of the illustrated specimens are types, whose study has in several instances necessitated taxonomic changes. The treatment of Heterometrus and Pandinus includes species diagnoses and keys to species. All species of Pandinus are illustrated, most of them for the first time. The genus Scorpio includes characterizations and photos of all 11 valid subspecies. The volume is printed in A4 format, with a hard cover>

More information about how to order the book can be found on Kovarik's homepage.

10 pages from the book is freely available (pdf).

Jan Ove Rein
Editor of The Scorpion Files

Prey capture behavior in Heterometrus petersii

Studies on scorpion prey capture are rare these days. This is unfortunate as there are still many aspects of scorpion behavior that still need studies and investigation. Hopefully, we will see more behavioral studies in the future.

Jiao & Zhu has published a study on prey capture behavior in Heterometrus petersii (Scorpionidae) from Vietnam. The different behavioral components during prey capture are identified, described and analyzed. An ethogram (behavioral flow chart) for prey capture in H. petersii is also presented.

Reference:
Jiao G-B, Zhu M-S. Prey capture behavior in Heterometrus petersii (Thorell, 1876) (Scorpiones: Scorpionidae). Euscorpius. 2009(80):1-5. [Free fulltext]

Family Scorpionidae