The Scorpion Files Newsblog

 

The pedipalps in scorpions are important for prey capture, defense and reproduction. Russel Bicknell and co-workers recently published a thorough investigation of the anatomy and morphology of the pedipalps the Australian black rock scorpion, Urodacus manicatus (Thorell, 1876) (Scorpionidae) and related these to the behavioral use of them.

Abstract:
Pedipalps – chelate ‘pincers’ as the second pair of prosomal appendages – are a striking feature of scorpions and are employed in varied biological functions. Despite the distinctive morphology and ecological importance of these appendages, their anatomy remains underexplored. To rectify this, we examined the pedipalps of the Australian black rock scorpion, Urodacus manicatus, using a multifaceted approach consisting of microcomputed tomography, scanning electron microscopy, energy dispersive X-ray spectroscopy, and live pinch force measurements. In doing so, we document the following aspects of the pedipalps: (1) the musculature in three dimensions; (2) the cuticular microstructure, focusing on the chelae (tibial and tarsal podomeres); (3) the elemental construction of the chelae teeth; and (4) the chelae pinch force. We recognise 25 muscle groups in U. manicatus pedipalps, substantially more than previously documented in scorpions. The cuticular microstructure – endo-, meso-, and exocuticle – of U. manicatus pedipalps is shown to be similar to other scorpions and that mesocuticle reinforces the chelae for predation and burrowing. Elemental mapping of the chelae teeth highlights enrichment incalcium, chlorine, nickel, phosphorus, potassium, sodium, vanadium, and zinc, with a marked lackof carbon. These elements reinforce the teeth, increasing robustness to better enable prey capture and incapacitation. Finally, the pinch force data demonstrate that U. manicatus can exert high pinch forces (4.1 N), further highlighting the application of chelae in subduing prey, asopposed to holding prey for envenomation. We demonstrate that U. manicatus has an array of adaptions for functioning

Reference:
Bicknell RD, Edgecombe GD, Goatley CH, Charlton G, Paterson JR. Pedipalp anatomy of the Australian black rock scorpion, Urodacus manicatus, with implications for functional morphology. Aust J Zool. 2024;72(2). [Open Access]

 

Been awhile since I have seen any taxonomic news from "down under", but now I can report about a recent work by Bruno Buzatto and co-workers where two new species of the genus Urodacus Peters, 1861 (Scorpionidae*) are described from Western Australia.

Urodacus lunatus Buzatoo, Clark, Harvey & Volschenk, 2023

Urodacus uncinus Buzatoo, Clark, Harvey & Volschenk, 2023

The two new species are very similar and can only be separated based on the morphology of their hemispermatophores. I expect that a study of this genus with molecular technology may reveal more hidden species in Australia.

* The placement of the genus Urodacus is unlcear and the current authors have place it in the family Urodacidae, which currently is not used in The Scorpion Files.

Abstract:
Two new species of urodacid scorpion are described from the Pilbara region in Western Australia, where they are both patchily distributed along creek lines in the north-east of the region. Urodacus uncinus sp. nov. and Urodacus lunatus sp. nov. are indistinguishable based on external morphology: adults are medium-sized, yellow burrowing scorpions with remarkable sexual dimorphism in the, telson, in which males have a uniquely swollen vesicle and an aculeus that is more strongly curved than other known species of Urodacus. The species are superficially similar to Urodacus similis L.E. Koch, 1977 and Urodacus yaschenkoi Birula, 1903 in the morphology of the first four metasomal segments, which are extremely short and not much longer than high. The two new species canonly be discerned from each other based on the morphology of their hemispermatophores, which highlights the extremely conserved morphology of species in the genus and suggests that many new species await description with careful examination of their genitalia.

Reference:
Buzatto B, Clark H, Harvey M, Volschenk E. Two new species of burrowing scorpions Urodacus (Scorpiones: Urodacidae) from the Pilbara region of Western Australia with identical external morphology. Aust J Zool. [Open Access]

Family Scorpionidae

The higher level phylogeny and systematics of scorpions is complicated and there are several models for this. Prashant P. Sharmaa and several co-workers have now published an article on the phylogenetic placement of the family Bothriuridae. The article also presents new data on the high- level scorpion systematics and the first phylogenomic dating of the arachnid order Scorpiones.

Abstract:
The scorpion family Bothriuridae occupies a subset of landmasses formerly constituting East and West temperate Gondwana, but its relationship to other scorpion families is in question. Whereas morphological data have strongly supported a sister group relationship of Bothriuridae and the superfamily Scorpionoidea, a recent phylogenomic analysis recovered a basal placement of bothriurids within Iurida, albeit sampling only a single exemplar. Here we reexamined the phylogenetic placement of the family Bothriuridae, sampling six bothriurid exemplars representing both East and West Gondwana, using transcriptomic data. Our results demonstrate that the sister group relationship of Bothriuridae to the clade (“Chactoidea”+Scorpionoidea) is supported by the inclusion of additional bothriurid taxa, and that this placement is insensitive to matrix completeness or partitioning by evolutionary rate. We also estimated divergence times within the order Scorpiones using multiple fossil calibrations, to infer whether the family Bothriuridae is sufficiently old to be characterized as a true Gondwanan lineage. We show that scorpions underwent ancient diversification between the Devonian and early Carboniferous. The age interval of the bothriurids sampled (a derived group that excludes exemplars from South Africa) spans the timing of breakup of temperate Gondwana.

Reference:
Sharma PP, Baker CM, Cosgrove JG, Johnson JE, Oberski JT, Raven RJ, et al. A revised dated phylogeny of scorpions: Phylogenomic support for ancient divergence of the temperate Gondwanan family Bothriuridae. Mol Phylogenet Evol. 2018;122:37-45. [Subscription required for full text]

Thanks to Matt Simon for informing me about this article!

Family Bothriuridae

I just came across a very interesting article on phenotypic plasticity in scorpion venom. Scorpion venom is a cocktail of different toxins having different effects on different targets (e.g. one toxin is effective against invertebrates, another against mammals and a third against both). The matter in question in the current study is if scorpions are able to modify the ‘recipe’ of its venom cocktail, and thereby optimizing the fitness benefits of its costly venom, in different environments exhibiting differences in densities and types of predators and prey.

The Australian species Hormurus waigiensis (Gervais, 1843) (Hormuridae) was used in this study.

And interestingly, the results showed that simulated predator exposure appeared to decrease relative production of strong invertebrate toxins, while generally increasing the production of a section of the venom profile with activity towards mammalian cells. Put in other words, it seems that at least in Liocheles waigensis, increased interactions with a potential predator will cause the venom to become more effective (dangerous) against the predator and less effective against invertebrate prey.

So don't provoke your scorpions! This may make them more dangerous ;)

Abstract:
Animals embedded between trophic levels must simultaneously balance pressures to deter predators and acquire resources. Venomous animals may use venom toxins to mediate both pressures, and thus changes in this balance may alter the composition of venoms. Basic theory suggests that greater exposure to a predator should induce a larger proportion of defensive venom components relative to offensive venom components, while increases in arms races with prey will elicit the reverse. Alternatively, reducing the need for venom expenditure for food acquisition, for example because of an increase in scavenging, may reduce the production of offensive venom components. Here, we investigated changes in scorpion venom composition using a mesocosm experiment where we manipulated scorpions’ exposure to a surrogate vertebrate predator and live and dead prey. After six weeks, scorpions exposed to surrogate predators exhibited significantly different venom chemistry compared with naive scorpions. This change included a relative increase in some compounds toxic to vertebrate cells and a relative decrease in some compounds effective against their invertebrate prey. Our findings provide, to our knowledge, the first evidence for adaptive plasticity in venom composition. These changes in venom composition may increase the stability of food webs involving venomous animals.

Reference:
Gangur AN, Smout M, Liddell MJ, Seymour JE, Wilson D, Northfield TD. Changes in predator exposure, but not in diet, induce phenotypic plasticity in scorpion venom. Proc Biol Sci. 2017;284(1863). [Subscription required for full text]

Australian scorpions have received less attention that scorpions from other continents. Karen Luna-Ramirez and co-workers have recently published a study of the widely distributed scorpion Urodacus yaschenko (Birula, 1903) (Scorpionidae). Both genetic and morphological data suggest that U. yaschenkoi is a species complex, consisting of three or more species. More specimens from different areas should be studied and a revision of the species should be made in the future before final conclusions can be made.

Abstract:
Background. Australian scorpions have received far less attention from researchers than their overseas counterparts. Here we provide the first insight into the molecular variation and evolutionary history of the endemic Australian scorpion Urodacus yaschenkoi. Also known as the inland robust scorpion, it is widely distributed throughout arid zones of the continent and is emerging as a model organism in biomedical research due to the chemical nature of its venom.

Methods. We employed Bayesian Inference (BI) methods for the phylogenetic reconstructions and divergence dating among lineages, using unique haplotype sequences from two mitochondrial loci (COXI, 16S) and one nuclear locus (28S). We also
implemented two DNA taxonomy approaches (GMYC and PTP/dPTP) to evaluate the presence of cryptic species. Linear Discriminant Analysis was used to test whether the linear combination of 21 variables (ratios of morphological measurements) can predict individual's membership to a putative species.

Results. Genetic and morphological data suggest that U. yaschenkoi is a species complex. High statistical support for the monophyly of several divergent lineages was found both at the mitochondrial loci and at a nuclear locus. The extent of mitochondrial divergence between these lineages exceeds estimates of interspecific divergence reported for other scorpion groups. The GMYC model and the PTP/bPTP approach identified major lineages and several sub-lineages as putative species. Ratios of several traits that approximate body shape had a strong predictive power (83 100%) in discriminating
two major molecular lineages. A time-calibrated phylogeny dates the early divergence at the onset of continental-wide aridification in late Miocene and Pliocene, with finer-scale phylogeographic patterns emerging during the Pleistocene. This structuring dynamics is congruent with the diversification history of other fauna of the Australian arid zones.

Discussion. Our results indicate that the taxonomic status of U. yaschenkoi requires revision, and we provide recommendations for such future efforts. A complex evolutionary history and extensive diversity highlights the importance of conserving U. yaschenkoi populations from different Australian arid zones in order to preserve patterns of endemism and evolutionary potential.

Reference:
Luna-Ramirez K, Miller AD, Rasic G. Genetic and morphological analyses indicate that the Australian endemic scorpion Urodacus yaschenkoi (Scorpiones: Urodacidae) is a species complex. PeerJ. 2017;5:e2759. [Open Access]

A representative for the family Bothriuridae, probably a species in the genus Bothriurus. Photo: Jan Ove Rein (C)

Here follows the final report from Kovarik & Ojanguren Affilastro's new book Illustrated Catalog of Scorpions, Part II. Bothriuridae; Chaerilidae; Buthidae I., genera Compsobuthus, Hottentotta, Isometrus, Lychas and Sassanidotus. The sixth blog post from the book sums up the the news concerning the family Bothiuridae

Taxonomical changes in Bothriuridae:

There are actually no new species or synonymization in this review of the family Bothriuridae. A few species are declared nomen dubium:

Brachistosternus castroi Mello-Leitão, 1940 

Brachistosternus simoneae Lourenço, 2000

Cercophonius himalayensis Lourenço, 1996

Thestylus signatus Mello-Leitão, 1931

An identification key for the family and all the genera in the family is provided.

Reference:
Ojanguren Affilastro AA. Family Bothriuridae. In: Kovarik F, Ojanguren Affilastro AA, editors. Illustrated catalogue of scorpions Part II Bothriuridae: Buthidae I, genera Compsobuthus, Hottentotta, Isometrus, Lychas and Sassanidotus. Prague: Clarion Productions; 2013. p. 6-131. 

Family Bothriuridae

A Lychas asper female from Tanzania. Photo: Jan Ove Rein (C).

Another report from Kovarik & Ojanguren Affilastro's new book Illustrated Catalog of Scorpions, Part II. Bothriuridae; Chaerilidae; Buthidae I., genera Compsobuthus, Hottentotta, Isometrus, Lychas and Sassanidotus. The fifth blog post from the book sums up the the news concerning the genus Lychas C. L. Koch, 1845 (Buthidae).

Taxonomical changes in Lychas C. L. Koch, 1845 (Buthidae):

 New species:

Lychas armasi Kovarik, 2013 (Papua New Guinea)

Lychas cernickai Kovarik, 2013 (Laos)

Synonymization:

Lychas ceylonensis Lourenco & Huber, 1999 is synonymized with L. srilankensis Lourenco, 1997

Lychas eliseanneae Lourenco, 2011 is synonymized with L. shelfordi (Borelli, 1904)

Lychas feae (Thorell, 1889) is synonymized with L. shoplandi (Oates, 1888)

Lychas kaimana Lourenco, 2011 is declared nomen dubium. Lychas aberlenci Lourenco, 2013 is not mentioned in Kovarik's review. It is possible that this species was published after the manuscript for the book was finished or that Kovarik got it too late to include it into the text.

The chapter on Lychas has a section on observations on captive specimens in the genus.

An identification key for the genus is provided.

Reference:
Kovarik F. Family Buthidae. In: Kovarik F, Ojanguren Affilastro AA, editors. Illustrated catalogue of scorpions Part II Bothriuridae: Buthidae I, genera Compsobuthus, Hottentotta, Isometrus, Lychas and Sassanidotus. Prague: Clarion Productions; 2013. p. 145-212.

Family Buthidae

A beatiful, unidentified Isometrus species from India. Photo. Aamod Zambre (C).

After a long break, I'm back going through Kovarik & Ojanguren Affilastro's new book Illustrated Catalog of Scorpions, Part II. Bothriuridae; Chaerilidae; Buthidae I., genera Compsobuthus, Hottentotta, Isometrus, Lychas and Sassanidotus and here is the fourth taxonomical update from the book.

Taxonomical changes in Isometrus Ehrenberg, 1828 (Buthidae):

 New species:

Isometrus feti Kovarik, 2013 (Indonesia)

Isometrus jendeki Kovarik, 2013 (Malaysia)

Isometrus neradi Kovarik, 2013 (Thailand)

Synonymization:

Isometrus haninanensis Lourenco, 2005 is synonymized with I. petrzelkai Kovarík, 2003

Isometrus lao Lourenco & Leguin, 2012 is synonymized with I. petrzelkai Kovarík, 2003

The species I. atherii Amir & Kamaluddin, 2008 and I. liaqatii Amir & Kamaluddin, 2008 are not mentioned i Kovarik's review. I'm not sure why. Personally, I think these taxa should be considered nomen dubium as it is possible to raise questions on the quality of the article describing them (e. g. the picture of the new species probably showing a specimens belonging to another genera). The two species will be listed as normal in The Scorpion Files until anyone publish a formal change of status for them.

The chapter on Isometrus has a section on observations on captive specimens in the genus.

An identification key for the genus is provided.

Reference:
Kovarik F. Family Buthidae. In: Kovarik F, Ojanguren Affilastro AA, editors. Illustrated catalogue of scorpions Part II Bothriuridae: Buthidae I, genera Compsobuthus, Hottentotta, Isometrus, Lychas and Sassanidotus. Prague: Clarion Productions; 2013. p. 145-212.

Family Buthidae

Indo-Pacific hormurid scorpion phylogeny from one of the two new studies on hormurid scorpions.

Lionel Monod and Lorenzo Prendini have recently published a major study on the evolution, biogeography and phylogeny of Indo-Pacific scorpions belonging to several genera previously placed in Hemiscorpiidae. This is a complicated study and I recommend to read the paper to get all details concerning the conclusions listed below.

Another paper by Monod, Harvey and Prendini on hormurid scorpions was published in the end of last year. This paper actually preceded the Monod & Prendini paper in content, and I have therefor not written about it until now, when the latter paper is published. In the first paper three new species of Hormurus are described and the evolution of burrowing behavior in the reinstalled family Hormuridae is discussed.

Main conclusions:

Family Hormuridae Laurie, 1896 is elevated to family rank after being a subfamily in Hemiscorpiidae.

The genera Hormiops Fage, 1933 and Hormurus Thorell, 1876, previously placed in synonymy with Liocheles Sundevall, 1833, are reinstated as valid genera. See Scorpion Files family page for list of species which are included in the reinstalled genera.

Genera Cheloctonus Pocock, 1892, Chiromachetes Pocock, 1899, Chiromachus Pocock, 1893, Hadogenes Kraepelin, 1894, Hormiops Fage, 1933, Hormurus Thorell, 1876, Iomachus Pocock, 1893, Liocheles Sundevall, 1833, Opisthacanthus Peters, 1861, Palaeocheloctonus Lourenco, 1996 and Tibetiomachus are included in Hormuridae.

The family Hemiscorpiidae includes now only the genus Hemiscorpius Peters, 1861.

Based on the conclusions in the current paper, I have chosen to reinstall the family Heteroscorpionidae Kraepelin, 1905 in The Scorpion Files and moved the genus Heteroscorpion Birula, 1903 from Hemiscorpiidae to Heteroscorpionidae. See familiy pages (links below) for more details.

The following new species are described from Australia:

Hormurus ischnoryctes Monod & Prendini, 2013
Hormurus macrochela Monod, 2013
Hormurus ochyroscapter Monod, 2013

Hormurus longimanus (Locket, 1995) is reinstated as the valid name for this species and the replacement name, Liocheles extensus Locket, 1997 is placed in synonymy.

Abstract 1:
Scorpions previously assigned to the genus Liocheles Sundevall, 1883, of the family Hormuridae Laurie, 1896, are widely distributed in the tropical forests of the Indo-Pacific region. Revisionary systematics of these poorly known scorpions has revealed a tremendous diversity of species. As part of an ongoing investigation, the first analysis of Indo-Pacific hormurid scorpion phylogeny based on morphological data scored for all currently recognized species of Hormiops Fage, 1933, Hormurus Thorell, 1876, and Liocheles, is presented. The taxonomy of these scorpions is reassessed and their biogeography reinterpreted in the light of the phylogeny. Phylogenetic, morphological, and distributional data support the revalidation of Hormiops and Hormurus, previously synonymized with Liocheles. The phylogeny indicates that the Australasian hormurids are more closely related to the Afrotropical and Neotropical hormurids than to the Indian hormurids, as previously proposed, refuting the “out-of-India” origin of Asian hormurids. A recent paleogeographical hypothesis, the “Eurogondwana model”, is supported instead. According to this hypothesis, hormurid scorpions colonized Laurasia from Africa via the Apulia microplate (Europa terrane) in the Cretaceous, subsequently colonized the Australo-Papuan archipelago in the early-mid Cenozoic, and then went extinct in the Northern Hemisphere during the second half of the Cenozoic. These results suggest that, contrary to the traditional paradigm, dispersal and extinction may affect spatial and temporal biotic distributions as much as vicariance, even in animals with limited vagility, such as scorpions.

Abstract 2:
Three new species from the semi-arid ecosystems of Queensland, Australia, are described in the present contribution: Hormurus ischnoryctes n. spec., Hormurus macrochela n. spec., Hormurus ochyroscapter n. spec. Additionally, the discovery of the first female specimens of Hormurus longimanus (Locket, 1995) from the Northern Territory of Australia, as well as additional diagnostic characters and locality records for this species, warranted its redescription. Hormurus longimanus (Locket, 1995) is reinstated as the valid name for this species and the replacement name, Liocheles extensus Locket, 1997 placed in synonymy. Unlike most species of Hormurus and of the closely related genera, Hormiops Fage, 1933 and Liocheles Sundevall, 1883, which inhabit humid tropical ecosystems (evergreen forests), the four Australian species treated here inhabit seasonally dry (monsoon) habitats, and two of these (H. ischnoryctes and H. ochyroscapter) are the first fossorial hormurids to be recorded in Australia, and the first fossorial species of Hormurus to be described. The four species treated here appear to be relicts of an old hygrophilous lineage that sustained a major adaptive radiation during the late Tertiary aridification of the continent. Endemism and conservation issues coneerning these phylogenetically valuable species are discussed in the context of high sensitivity to habitat disturbance and high risk of extinction of stenotopic species.

Reference 1:
Monod L, Prendini L. Evidence for Eurogondwana: The roles of dispersal, extinction and vicariance in the evolution and biogeography of Indo-Pacific Hormuridae (Scorpiones: Scorpionoidea). Cladistics. 2014;In Press. [Subscription required for full text]

Reference 2:
Monod L, Harvey MS, Prendini L. Stenotopic Hormurus Thorell, 1876 scorpions from the monsoon ecosystems of northern Australia, with a discussion on the evolution of burrowing behaviour in Hormuridae Laurie, 1896. Rev Suisse Zool. 2013 Jun;120(2):281-346.

Family Hormuridae
Family Hemiscorpiidae
Family Heteroscorpionidae

Its holiday time, but I'm trying to post a message on the blog using a shaky internet connection from our cabin.

Erich Volschenk and co-workers have published a new Urodacus (Scorpionidae*) from western Australia.

Urodacus butleri Volschenk, Harvey & Prendini, 2012

*The status of the family Urodacidae is under discussion. Some authors have included the Urodacus in Scorpionidae and abolish the family, while others have retained Urodacidae as a valid family.

Abstract:
A new urodacid scorpion, Urodacus butleri, n. sp., is described from Barrow Island and the Pilbara bioregion of Western Australia. This species is unusually dark in color; it is compared and contrasted with three morphologically similar species, Urodacus manicatus (Thorell, 1876), Urodacus novaehollandiae Peters, 1861, and Urodacus planimanus Pocock, 1893.

Reference:
Volschenk, ES, Harvey, MS & Prendini, L. (2012). A new species of Urodacus ((Scorpiones: Urodacidae) from Western Australia. American Museum Novitates (3748):1-18. [Free full text]

Thanks to Gerald Dupre for sending me this paper!

Family Scorpionidae

Mark Newton, the editor of the great Aussi scorpion site, The spiral Burrow, has published a book about Aussi scorpions and their husbandery.

In addition to information about how to keep Aussi scorpions, the book also has a lot of general information about scorpions and their biology. The book has several color plates. ISBN number is 978-0-9804161-0-7.

I haven't received the book yet, but based on the information and previews on the book's promo page and my previous experiences with the author, I'm convinced that this will be a very interesting and informative book.

Australian scorpions are rarely available outside Australia due to the country's strict policy on animal exports, and this book is a great opportunity to get an insight into the scorpion fauna of Australia.

The book can be ordered from the book's promo page. PayPal payment is possible.

Erich Volschenk and Lorenzo Prendini has described an interesting new troglobitic genus and species from Ledge Cave, Barrow Island, off the north-western coast of Western Australia:

Aops Volschenk & Prendini, 2008 (Urodacidae)*
Aops oncodactylus Volschenk & Prendini, 2008 (Urodacidae)*

*The family Urodacidae was abolished by Soleglad, Fet & Kovarik in 2005 and the subfamily Urodacinae was transfered to Scorpionidae. Volschenk & Prendini have not accepted this deccision (more information about this), and retained the family Urodacidae (and placed the new genus and species in this family because of its close relationship to Urodacus). The taxonomy of The Scorpion Files follows Soleglad & Fet (2005), and I have here listed Aops in Scorpionidae. This is formally not correct, but is the best choice in the current situation until a new revision on higher scorpion systematics is published.

The paper also has a very interesting review of scorpion troglobites and discuss the different forms of troglobitic lifestyle and troglomorphisms (troglomorphic adaptions) in scorpions.

Here is the abstract from the paper:

"
We describe a new genus and species of troglomorphic scorpion from Ledge Cave, Barrow Island, off the north-western coast of Western Australia. This troglobite scorpion was initially difficult to place within the superfamily Scorpionoidea Latreille on account of its unusual morphology. Based on cladistic analysis, we demonstrate that this scorpion is phylogenetically most closely related to the endemic Australian genus Urodacus Peters (Urodacidae Pocock). The new taxon, named Aops oncodactylus, gen. et sp. nov., is the first troglobitic urodacid and the first troglobitic scorpion recorded from continental Australia. In light of this discovery, we re-assess the known diversity of troglobitic scorpions and the troglomorphic adaptations (troglomorphies) of cavernicolous scorpions. A distinction is recognised between the exclusive occurrence in cavernicolous habitats and the presence of troglomorphies, which are exhibited by some endogean (humicolous) scorpions. The definition of troglobitic scorpions is limited to species that are both restricted to cavernicolous habitats and exhibit pronounced troglomorphies. Only 20 scorpion species meet both criteria and are considered unequivocally troglobitic according to this definition.
"

Reference:
Volschenk ES, Prendini L. Aops oncodactylus, gen. et sp. nov, the frist troglobitic urodacid (Urodacidae: Scorpiones), with a re-assessment of cavernicolus, troglobitic and troglomorphic scorpions. Invertebrate Systematics. 2008;22:235. [Subscription required for fulltext]

Family Scorpionidae