A phylogenetic analysis of the ancient Asian scorpion family Pseudochactidae

 

As previously mentioned, the ancient, relictual Asian scorpion family Pseudochactidae Gromov, 1998 is probably one of the most interesting scorpion families in the world. It consist of both of extinct and extant taxa, and the latter is often labeled as "living fossils" due to their unique morphology. 

In a recent article, Lorenzo Prendini and co-workers present a new phylogenetic analysis of the genus with new information about the phylogeny and taxonomy of this fascinating family and its evolution. 

Abstract:
The ancient, relictual Asian scorpion family Pseudochactidae Gromov, 1998, has a disjunct distribution. Five genera and seven species of living pseudochactids are assigned to one epigean subfamily, Pseudochactinae Gromov, 1998, from Central Asia and southern China, and two hypogean subfamilies, Troglokhammouaninae Prendini et al., 2021, and Vietbocapinae Lourenço, 2012, from caves of the Khammouan-Phong Nha-Kẻ Bàng Karst in the northern Annamite (Trường Sơn) Mountains of Laos and Vietnam. The extinct subfamily Chaerilobuthinae Lourenço and Beigel, 2011, comprises one genus and 15 species, hypothesized to be endogean, from mid-Cretaceous Burmese amber. The discovery and uncertainty regarding the phylogenetic placement of Qianxie solegladi Tang, 2022, from South China, together with the discovery that the Cretaceous amber Chaerilobuthinae, from the Burma Terrane, is the sister group of the extant pseudochactid subfamily Vietbocapinae provided an opportunity to revisit the phylogeny and biogeography of Pseudochactidae, and their adaptation to subterranean habitats in Southeast Asia. In the present contribution, pseudochactid phylogeny is reanalyzed using three mitochondrial markers (12S rDNA, 16S rDNA, Cytochrome c Oxidase Subunit I), three nuclear markers (18S rDNA, 28S rDNA, Internal Transcribed Spacer) and 143 morphological characters, for all extant pseudochactid taxa and seven exemplar species of the extinct Chaerilobuthinae. Divergence time and ancestral range estimation are conducted and the evolution of troglomorphic characters investigated to reassess how this lineage of “living fossils” dispersed and diversified. Recent changes to the systematics of Pseudochactidae are confirmed. The four subfamilies, genera, and species were monophyletic with high support and the following scheme of relationships: (Pseudochactinae (Troglokhammouaninae (Chaerilobuthinae + Vietbocapinae))). Phylogenetic analyses, reinforced by a multivariate morphometric analysis and pairwise genetic distances, confirm the validity of the monotypic, epigean Chinese genus, Qianxie Tang, 2022, which formed a monophyletic group with the epigean Central Asian genus, Pseudochactas Gromov, 1998, rather than the hypogean Southeast Asian genus, Troglokhammouanus Lourenço, 2007. Qianxie solegladi is transferred to Pseudochactinae. A revised time tree of Pseudochactidae suggests that the Burmese Chaerilobuthinae diverged from the Indochinese subfamilies, Troglokhammouaninae and Vietbocapinae, in the Early Cretaceous (ca. 117 Ma), consistent with Early Devonian rifting of the Burma Terrane.

Reference:
Prendini L, Xuan Q, Du SE, Wang C-BE, Ehrenthal VL, Loria SF. Phylogeny and divergence time estimation of relictual Asian scorpion family suggests Early Cretaceous connections between Burma Terrane and Eurasia, and corrects placement of Chinese taxon. American Museum Novitates. 2026(4051):1–55. [Open Access]

Family Pseudochactidae 

How many Buthus species are there in Europe and how did they evolve?

 

As mentioned in  previous post, the number of Buthus Leach, 1815 (Buthidae) species in Europe grew from one single species to more than 20. Earlier this year, this number was reduced to nine valid species. This decision was based on  rigorous phylogenetic analyses combining morphology, nuclear and mitochondrial DNA sequences, morphometric analyses, and ecological data.

In a new study, which was supposed to be published before the article mentioned above, Javier Blasco-Aróstegui and co-workers looks more deeply into the DNA og genetics of the Iberian Buthus species. This is complex stuff, way beyond my knowledge. I have therefor asked co-author Yuri simon to explain this article for us in more laymen terms:

 In this study, the authors re-examined the number of species within the European Buthus scorpions. Over the years, the group experienced a rapid increase in the number of described species, mostly because they show a great morphological diversity. 

However, this high morphological diversity is not always reflected in their DNA. The fast-changing mitochondrial DNA (inherited only from the mother) often suggests many species, while the more slowly evolving nuclear DNA (inherited from both parents) tells a different story. When these two genetic signals disagree, a situation known as mito-nuclear discordance, making difficult to define clear species boundaries. Moreover, since the past climate changes and the region’s complex landscape repeatedly separated and later reconnected populations, these scorpions sometimes met again after long periods apart and interbred creating in some cases hybrid populations showing some morphological intermediate characters which has contributed to the large number of taxa described. 

By combining genetic evidence with morphology and species distribution modelling, we found that the evolutionary history of Buthus in Iberia is far more complex than a simple “split and diverge” story. It involves repeated cycles of isolation, reconnection, and hybridization. Our results show that no single source of data—neither morphology nor mitochondrial or nuclear DNA alone—is sufficient to accurately define these species. Instead, an integrative approach is necessary. Using this approach, we concluded that the number of valid European Buthus species is likely much lower than previously thought, reducing it from around 20 to roughly half.

Abstract:
Mito-nuclear (or cytonuclear) discordance, evolutionary incongruence between the mitochondrial and nuclear genomes, is a widespread but underappreciated phenomenon that may obscure signals of introgression and hybridization important for understanding evolutionary trajectories and species boundaries. The present study explored the roles of secondary contact and introgressive hybridization in the diversification of Buthus Leach, 1815 scorpions in the Iberian Peninsula, a hotspot for mito-nuclear discordance, in which complex topography and glacial history facilitated repeated cycles of isolation and secondary contact. Patterns of mito-nuclear discordance were predicted to be consistent with overlapping distributions, similar ecological niches, and intermediate phenotypes. By integrating genomic, morphological, and ecological data, the intricate evolutionary history of Buthus, shaped by vicariance, reticulation and ecological opportunity, was revealed. The results underscore the role of introgressive hybridization in shaping patterns of biodiversity and the need to consider mito-nuclear discordance in species delimitation. 

Reference:
Blasco-Aróstegui J, Simone Y, Paulo OS, Prendini L. Mito-nuclear discordance reveals introgressive hybridization following vicariance and secondary contact in Iberian scorpions (Buthidae: Buthus). BMC Ecol Evol. 2025;25(1):112. [Open access]

Thanks to Yuri for sending me their article and for for writing a layman version of a summary for the article! 

Phylogenetic analysis reveal cryptic subspecies of Euscorpius borovaglavaensis in Croatia

 

The genus Euscorpius Thorell, 1876 (Euscorpiidae) from Europa has become notorious for its hidden, cryptic species. A few decades ago this genus consisted of less than 10 species, today the number of taxa is closed to 100.

Martina Podvar and co-workers have publised a phylogenetic and phylogeographic  study of the populations of Euscorpius borovaglavaensis Tropea, 2015 in Croatia. Two distinct lineages were discovered and the population distributed in the northwestern part of the range was given subspecies status.

Euscorpius borovaglavaensis flavus Vignoli, 2024

Abstract:
The European scorpion Euscorpius borovaglavaensis Tropea, 2015 is a morphologically cryptic species that is distinguishable only with difficulty from E. tergestinus (C. L. Koch, 1837). It is distributed in the middle part of the Dinaric Alps chain and along part of the Eastern Adriatic coast, specifically, in Croatia (Middle Dalmatia, Lika karst upland), as well as in the southern part of Bosnia and Herzegovina. The new findings reported here have enhanced our knowledge of its geographic distribution in Croatia. Detailed morphological analyses highlighted the importance of carination in the ventral metasomal segments as morphological traits. Phylogenetic analyses, based on the mitochondrial cytochrome c oxidase subunit I (COI) gene, have revealed the existence of two distinct lineages. One of them, distributed in the northwestern part of the range, is described here as E. b. flavus n. ssp., while the nominal subspecies occurs in the southeastern part. A time-calibrated phylogenetic analysis has established their divergence around 0.9 million years ago, coinciding with the Mid-Pleistocene Transition (MPT) period. In contrast to the nominal subspecies, E. b. flavus n. ssp. exhibits significant phylogeographic structuring, indicating recent isolation events in multiple glacial microrefugia after the initial divergence, followed by a final Holocene dispersal in the northwestern direction deep between the mountain chains.

Reference:
Podnar M, Vignoli V, Tvrtković N. Phylogeographic structuring within recently diverged scorpion species, Euscorpius borovaglavaensis Tropea, 2015 (Scorpiones: Euscorpiidae) in Croatia, with the description of a new subspecies. Natura Croatica: Periodicum Musei Historiae Naturalis Croatici. 2024;33(1):29-52. [Open Access]

Thanks to Valerio and Gerard who both sent me this article!

Family Euscorpiidae

A new paper investigating the phylogeography and evolutionary history of the burrowing scorpion genus Scorpio

 

The genus Scorpio Linnaeus, 1758 (Scorpionidae) was for most of the last century known to have only one species, Scorpio maurus Linnaeus, 1758, which has an impressing distribution ranging from most of North Africa to the eastern parts of the Middle East. 

In the last decades it became clear that Scorpio maurus was a species complex with many hidden species, and today the genus consists of 24 species. However, the taxonomical and phylogentic situation of the genus is challenging, especially because of the lack of reliable morphological characters to distinguish the species and subspecies. Also, several new species have been described without genetic analysis confirming the species status. 

Manel Khammassi and co-workers have recently published a study with the aim of the present study to analyze the phylogenetic relationships and the evolutionary events that promoted diversification within the genus Scorpio. The study revealed twenty distinct lineages forming two geographically separate clades, a Maghrebian clade and a Middle Eastern clade. Most named species were found within the lineages, but additional lineages found are indicating potential new, unnamed species.

Abstract:
The burrowing scorpions of the genus Scorpio Linnaeus, 1758 were considered to be a single polymorphic species, Scorpio maurus Linnaeus, 1758, distributed from West Africa across the Sahel and the Saharan highlands through the Maghreb and the Middle East, to Iran. After various revisions, the complex was treated as including 18 species and seven subspecies. Five additional new Scorpio species were recently described. However, doubts remain regarding the validity of these taxa due to the lack of reliable characters and the lack of genetic data for many species. The aim of the present study was to analyze the phylogenetic relationships and the evolutionary events that promoted diversification within the genus. Phylogenetic analyses were performed using 633 base pairs of the mitochondrial COI gene from 51 individuals collected in Tunisia, Morocco, and Egypt, combined with 74 previously published sequence data. Phylogenetic analyses revealed twenty distinct lineages forming two geographically separate clades, a Maghrebian clade and a Middle Eastern clade. Although most named species formed distinct lineages, various additional lineages were identified, highlighting potential unnamed species. Divergence time estimates indicate that the division within the genus Scorpio began during the Mid-Miocene, a period characterized by tectonic events coupled with climatic oscillations. Further differentiation occurred during the Miocene-Pliocene transition when climatic fluctuations resumed and the Mediterranean became increasingly arid. Speciation within the genus Scorpio may have been driven by the expansion of the savannas and Sahara Desert, the associated reduction of a once widespread rainforest into numerous micro-refugia in the mountains of the Mediterranean region, and by adaptation to these new habitats

Reference:
Khammassi M, Nouira S, Badry A, Sadine SE, Harris DJ. Phylogeography and evolutionary history of the burrowing scorpion genus Scorpio Linnaeus, 1758 (Scorpiones: Scorpionidae) in the Mediterranean Basin. Organisms Diversity & Evolution. 2024:1-18. [Subscritpion required for full text]

Family Scorpionidae

Phylogeography of Androctonus species in Tunisia in view of their medical importance

 

The genus Androcronus Ehrenberg, 1828 hosts many medical important species in Tunisia and the rest of North Africa. Information about inter- and intraspecific variation of the Androctonus species is important, especially if this has consequences for medical importance and treatment of sting cases.

A. Ben Othmen and co-workers have recently published a study on the phylogeography and a phylogenetic analysis of Androctonus species in Tunisia. The results supported the current species Androctonus aeneas C. L. Koch, 1839, Androctonus amoreuxi (Audouin, 1839) and Androctonus australis (Linnaeus, 1758), but not the existence of subspecies of A. australis. 

The authors recommend that toxicologists should not refer to "species" or forms like "A. australis Hector", but suggest that it may be wise to produce anti-venom in Tunisia by using both morphological forms of A. australis.

Abstract:
A fragment of the mitochondrial (mt) 16S ribosomal RNA gene was amplified by PCR and sequenced from individual adult scorpions of the genus Androctonus, which were sampled from central and southern Tunisia and identified using an explicit set of morphological characters. Phylogenetic analyses placed the mtDNA haplotypes in three well-supported monophyletic lineages, corresponding to the morphospecies Androctonusaeneas, Androctonusamoreuxi and Androctonusaustralis. The latter species was the most abundant and widespread, and it was characterized by two mtDNA sub-lineages each of which predominated only north or south of the Chott el Jerid, a seasonally flooded saline depression that divides non-Mediterranean Tunisia. The divergence of the two mtDNA lineages was dated by mtDNA molecular clocks, indicating that the formation of the Chott el Jerid is unlikely to have been the barrier generating the vicariant evolution of the two lineages of A. australis, although it may have impeded their mixing following secondary contact. Both regional mtDNA lineages were found in A. australis hector and A. australisgarzonii, indicating that these two morphological forms are neither monophyletic nor geographically isolated and, therefore, should not be treated as species or subspecies. It is recommended that no subspecies of A. australis should be recognized in North Africa and toxicologists should cease the taxonomic error of referring to a species “Androctonus australis Hector”. The morphological form “hector” has no proven association with an increased risk of scorpionism compared with “garzonii”. However, it might be prudent to produce anti-venom in Tunisia by using both morphological forms of A. australis collected each side of the Chott el Jerid, because of the evidence for regional variation in toxins. The highest risk for scorpion stings occurs in the central region, where the new diagnostic markers should be used to discover any association between Androctonus species and scorpionism.

Reference:
Ben Othmen A, Said K, Mahamdallie SS, Testa JM, Haouas Z, Chatti N, et al. Phylogeography of Androctonus species (Scorpiones: Buthidae) in Tunisia: Diagnostic characters for linking species to scorpionism. Acta Trop. 2009;112(1):77-85. [Subscription required for full text]

Family Buthidae

Phylogeography of the desert scorpion Mesobuthus mongolicus in Asia

 

Phylogeography is an importing tool for understanding the spatial distribution of taxa and the genetic variation within and between taxa. 

Chen-Ming Shi and co-workers have recently published a study investigating the phylogeography of the desert scorpion Mesobuthus mongolicus (Birula, 1912) (Buthidae)*. The questions they try to answer is where and when did the desert scorpion originate and how have climatic forces shaped the dispersal of the species in Asia.

*Please note that this species was synonymized with Mesobuthus thersites (C. L. Koch, 1839) in 2022.

Abstract:
A comprehensive understanding of phylogeography requires the integration of knowledge across different organisms, ecosystems, and geographic regions. However, a critical knowledge gap exists in the arid biota of the vast Asian drylands. To narrow this gap, here we test an “out-of-Central Asia” hypothesis for the desert scorpion Mesobuthus mongolicus by combining Bayesian phylogeographic reconstruction and ecological niche modeling. Phylogenetic analyses of one mitochondrial and three nuclear loci and molecular dating revealed that M. mongolicus represents a coherent lineage that diverged from its most closely related lineage in Central Asia about 1.36 Ma and underwent radiation ever since. Bayesian phylogeographic reconstruction indicated that the ancestral population dispersed from Central Asia gradually eastward to the Gobi region via the Junggar Basin, suggesting that the Junggar Basin has severed as a corridor for Quaternary faunal exchange between Central Asia and East Asia. Two major dispersal events occurred probably during interglacial periods (around 0.8 and 0.4 Ma, respectively) when climatic conditions were analogous to present-day status, under which the scorpion achieved its maximum distributional range. M. mongolicus underwent demographic expansion during the Last Glacial Maximum, although the predicted distributional areas were smaller than those at present and during the Last Interglacial. Development of desert ecosystems in northwest China incurred by intensified aridification might have opened up empty habitats that sustained population expansion. Our results extend the spatiotemporal dimensions of trans-Eurasia faunal exchange

Reference:
Shi CM, Zhang XS, Liu L, Ji YJ, Zhang DX. Phylogeography of the desert scorpion illuminates a route out of Central Asia. Curr Zool. 2023;69(4):442-55. [Subscription required for full text]

Thanks to Victor Fet for sending me this article!

 

Major work on the phylogeny and systematics of Euscorpiinae in the eastern Adriatic region

 

The systematics and taxonomy of the members of the family Euscorpiidae is still a major challenge in site of numerous research papers in the last decades.  The four traditional European taxa known some decades ago, are now split into a huge diversity of genera and species. And there is still more to come as there are many cryptic species and geographic areas that are still not properly investigated.

Martina Podnar and co-workers have recently published an extensive phylogenetic analysis where they have reviewed the scorpions of the genera Euscorpius Thorell, 1876 and Alpiscorpius Gantenbein et al., 1999 (Euscorpiidae) with a focus on the eastern Adriatic region. 

This is a very extensive study full of new information and data, and some of it is above my head. But the main conclusions are that their analyses point to the existence of several new taxa and the ranges of several species have been revised. In addition they have made the following taxonomic conclusions:

Euscorpius lagostae Di Caporiacco, 1950 from Lastovo Island, Croatia is raised to species status (formerly Euscorpius carpaticus lagostae Di Caporiacco, 1950).

Euscorpius croaticus is moved to the genus Alpiscorpius as Alpiscorpius croaticus (Di Caporiacco, 1950). 

Why do have so many species? The current article indicate that this is probably due to complex topography creating many microhabitats, but also due to microrefugia in the Pleistocene that allowed new taxa to evolve.

Abstract:
The systematics and taxonomy of the scorpion family Euscorpiidae are still unresolved, and, within it, the eastern Adriatic scorpiofauna is largely unknown and under-researched. Based on two mitochondrial sequences (COI and 16S rRNA) and one nuclear marker sequence (ITS1), we put 107 newly analyzed samples originating from the Alps, the Eastern Adriatic, and the adjacent Dinaric karst area into phylogenetic context. Several species delineation approaches were applied to reveal cryptic diversity. Divergence time dating was used to highlight the major events in the evolutionary history of the genera Euscorpius and Alpiscorpius. The deep intraspecific genetic divergences observed in some clades warrant taxonomic revision of several taxa (Euscorpius tergestinus, Euscorpius hadzii, Euscorpius biokovensis, and Euscorpius (Alpiscorpius) croaticus). In this study, the population of E. hadzii from Lastovo Island (formerly Euscorpius carpaticus lagostae) is elevated to species level as Euscorpius lagostae Di Caporiacco, 1950, stat. nov. Euscorpius croaticus is moved to the genus Alpiscorpius as Alpiscorpius croaticus (Di Caporiacco, 1950) comb. nov. The distribution ranges of several species are revised, and based on the new data, a more detailed revision of species distribution is necessary. We attribute the major divergence events to the impact of the Middle Miocene Climate Transition, the Messinian Salinity Crisis, and the Middle Pleistocene Climate Transition. The observed patterns are therefore a direct consequence of the geological history and complex topography of the region, which provided numerous microhabitats, as well as of the Pleistocene microrefugia that enabled their persistence.

Reference:
Podnar M, Grbac I, Tvrtković N, Hörweg C, Haring E. Hidden diversity, ancient divergences, and tentative Pleistocene microrefugia of European scorpions (Euscorpiidae: Euscorpiinae) in the eastern Adriatic region. Journal of Zoological Systematics and Evolutionary Research. 2021;Accepted Manuscript:1-26. [Subscriotion required for full text]

Thanks to Luis Roque for sending me this article.

Family Euscorpidae

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 phylographic study of the widespread, southern devil scorpions Vaejovis carolinianus in the USA

 

Several studies have revealed cryptic spices within the genus Vaejovis C.L. Koch, 1836 (Vaejovidae) in the southeastern USA. With this in mind, Matthew Graham and co-workers have conducted a thorough phylographic analysis of the more widespread species Vaejovis carolinianus (Beauvois, 1805). 

The authors expected to find cryptic species in some of the different populations of this species, but the genetic analysis did not support this. Even though several genetical clades were identified, all populations are the same species. 

Check out the article to learn more about the phylography of Vaejovis carolinianus. 

Abstract:
The Southern Appalachians and adjacent provinces of the southeastern USA are geologically and biologically diverse, with high levels of endemism. Phylogeographic analyses indicate that animals with small distributions in these regions often contain cryptic diversity and that Pleistocene climate fluctuations had significant impacts on their distributions. We studied the phylogeography of Vaejovis carolinianus (Beauvois), a common forest scorpion from the region, to determine if a more widely distributed animal exhibits similar patterns. Mitochondrial and nuclear DNA, as well as species distribution models, were used to test biogeographic hypotheses. Results indicate that the species is composed of at least nine geographically structured mitochondrial clades. Seven clades are represented by only a few sampling locations, whereas two clades are much larger and appear to be the result of postglacial range expansion in the plateaus and coastal plains adjacent to the Southern Appalachians. A highly disjunct population from Tunica Hills of Louisiana appears to have been isolated since the Pliocene, rejecting a hypothesis of late glacial migration along the Blufflands escarpment. Nuclear DNA is much less structured, perhaps due to differences in habitat and dispersal capabilities between sexes. Although mitochondrial lineages are quite old, mito-nuclear discordance suggests that lineages have not sorted and that V. carolinianus should be treated as a single genetically diverse species.

Reference:
Graham MR, Garcia EL, Hendrixson BE, Sampognaro AM, Cushing PE. Pliocene origins, Pleistocene refugia, and postglacial range expansions in southern devil scorpions (Vaejovidae: Vaejovis carolinianus). Organisms Diversity & Evolution. 2021;Published online 31. July 2021. [Subscription required for full text]

Family Vaejovidae

A phylogentic analysis of the genus Buthacus

 

A few weeks ago a reported about a  a systematic revision of the Buthacus Birula, 1908 (Buthidae) species of the Levant (the Middle East including Syria, Lebanon, Jordan, Israel, the Palestinian territories, and the Sinai Peninsula (Egypt)). 

The same authors have now published a study on the phylogeny and biogeography of the genus Buthacus resulting in a revised classification of Levantine Buthacus, and invalidation of the traditional species groups of Buthacus.

Abstract:
Sand scorpions of the genus Buthacus Birula, 1908 (Buthidae C.L. Koch, 1837) are widespread in the sandy deserts of the Palearctic region, occurring from the Atlantic coast of West Africa across the Sahara, and throughout the Middle East to Central Asia. The limits of Buthacus, its two species groups, and many of its species remain unclear, and in need of revision using modern systematic methods. The study presented here set out to investigate the phylogeny and biogeography of the Buthacus species occurring in the Levant, last studied in 1980. A phylogenetic analysis was performed on 104 terminals, including six species collected from more than thirty localities in Israel and other countries in the region. Three mitochondrial and two nuclear gene loci were sequenced for a total of 2,218 aligned base-pairs. Morphological datasets comprising 22 qualitative and 48 quantitative morphological characters were compiled. Molecular and morphological datasets were analyzed separately and simultaneously with Bayesian Inference, Maximum Likelihood, and parsimony. Divergence time and ancestral range estimation analyses were performed, to understand dispersal and diversification. The results support a revised classification of Levantine Buthacus, and invalidate the traditional species groups of Buthacus, instead recovering two geographically-delimited clades, an African clade and an Asian clade, approximately separated by the Jordan Valley (the Jordan Rift Valley or Syro- African Depression), the northernmost part of the Great Rift Valley. The divergence between these clades occurred in the Early Miocene (ca. 19 Ma) in the Levant, coinciding temporally with he existence of two land bridges, which allowed faunal exchange between Africa and Asia.

Reference:
Cain S, Loria SF, Ben-Shlomo R, Prendini L and Gefen E. Dated phylogeny and ancestral range estimation of sand scorpions (Buthidae: Buthacus) reveal Early Miocene divergence across land bridges connecting Africa and Asia. Mol Phylogenet Evol. 2021:107212. [Subscription required for full text]

Family Buthidae

 

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

Taxonomical changes in the genus Grosphus

Wilson Lourenco and co-workers have recently published a study on the genus Grosphus Simon, 1880 (Buthidae) were they critise the taxonomical decisions made in a 2019 study by Graeme Lowe and Frantisek Kovarik. Lourenco et al's conclusion is that they reject most decsisions made in the latter study and in addition they describe one new species.

These are the major taxonomical changes:

The genus Teruelius Lowe & Kovarik, 2019 is placed in synonymy with Grosphus Simon, 1880 and all species in Teruelius is also transferred back to Grosphus.

Grosphus makay Lourenço & Wilmé, 2015 is restored from synonymy of  with Grosphus feti Lourenço, 1996.

Grosphus rossii Lourenço, 2013 is restored from synonymy of  with mahafaliensis Lourenço, Goodman & Ramilijaona, 2004.

Grosphus simoni Lourenço, Goodman & Ramilijaona, 2004, is restored from synonymy of  with Grosphus madagascariensis (Gervais, 1843).

Grosphus halleuxi Lourenço, Wilmé, Soarimalala & Waeber, 2017, is restored from synonymy of  with Grosphus madagascariensis (Gervais, 1843).

Grosphus mandena Lourenço, 2005, is restored from synonymy of  with Grosphus madagascariensis (Gervais, 1843).

Grosphus mavo Lourenco & Rossi, 2020 (New species from Madagascar)

The status according to Lowe & Kovarik, 2019 is summed up here.

There is a great disagreement between the "Lourenco-group" and the "Kovarik-group" when it comes to the taxonomy of several taxa. I do not know who has the correct answer for the genus Grosphus and other taxa as I'm no expert taxonomist. The Scorpion Files tries as far as possible to stay neutral and will publish the latest update for the different scorpion taxa. It is challenging though and a lot of work some times when researchers are correcting each other several times. [This paragraph was edited by the Editor 23.07.20]

Abstract:
The southwestern portion of Madagascar appears to have one of the highest levels of scorpion diversity on the island. In this contribution, the remarkable diversity of the genus Grosphus Simon, 1880 in this region is discussed. A particular attention is aimed to the area of the Cap Sainte Marie where microendemic geographic patterns are observed. These are tentatively explained in the light of some new biogeographic interpretations. A new species is also described from the Cap Sainte Marie and is characterized by a medium body size and a very pale yellow coloration. While this contribution was in preparation,  we learned about the publication of a “most controversial revision” of the genus Grosphus by authors who totally ignored a number of taxonomic particularities of this group and worse, who lack any experience on the ecological and biogeographic patterns observed for the Malagasy fauna. This calls for corrections in which their speculative decisions are refuted.

References:
Lourenco WR, Rossi A, Wilme L, Raherilalao MJ, Soarimalala V, Waeber PO. The remarkable diversity of the genus Grosphus Simon, 1880 (Scorpiones: Buthidae) in Southern Madagascar and in particular in the region of Cap Sainte Marie. Arachnida - Rivista Aracnologica Italiana. 2020;VI(XXVII):2-35.


Family Buthidae

The origin of the buthid scorpion fauna of the Caribbean islands

The Caribbean islands have a large scorpion population where many species are endemic for this area. But how did this unique fauna originate? There have been three theories of the origins of the flora and fauna diversity seen in The Caribbean: 1. Connections via land bridges, 2. Vicariance events, 3. Overwater dispersal from continents and among islands.

Lauren Esposito and Lorenzo Prendini have now published a study investigating the biogeographical diversification of the New World buthid scorpion subfamily Centruroidinae Kraus, 1955 and trying to understand the origin of the Caribbean populations of these taxa.

The results of this study show that the centruroidine scorpions colonized the Caribbean islands on two independent occasions (35 mya ago from South America and the Greater Antilles and 20 mya ago North America, probably via Cuba). Interestingly, the results also point to a case of "reverse-colonization" event for the genus Heteroctenus Pocock, 1893. This genus seems to have a Caribbean ancestor, which subsequently colonized Central America and North America, and eventually re-colonized the Greater Antilles.

Abstract:
Scorpions are an excellent system for understanding biogeographical patterns. Most major scorpion lineages predate modern landforms, making them suitable for testing hypotheses of vicariance and dispersal. The Caribbean islands are endowed with a rich and largely endemic scorpion fauna, the origins of which have not been previously investigated with modern biogeographical methods. Three sets of hypotheses have been proposed to explain present patterns of diversity in the Caribbean: (1) connections via land bridges, (2) vicariance events, and (3) overwater dispersal from continents and among islands. The present study investigates the biogeographical diversification of the New World buthid scorpion subfamily Centruroidinae Kraus, 1955, a clade of seven genera and more than 110 species; infers the ancestral distributions of these scorpions; and tests the relative roles of vicariance and dispersal in the formation of their present distributions. A fossil calibrated molecular phylogeny was estimated with a Bayesian criterion to infer the dates of diversification events from which ancestral distributions were reconstructed, and the relative likelihood of models of vicariance vs. dispersal, calculated. Although both the timing of diversification and the ancestral distributions were congruent with the GAARlandia land-bridge hypothesis, there was no significant difference between distance-dependent models with or without the land-bridge. Heteroctenus Pocock, 1893, the Caribbean-endemic sister taxon of Centruroides Marx, 1890 provides evidence for a Caribbean ancestor, which subsequently colonized Central America and North America, and eventually re-colonized the Greater Antilles. This ‘reverse colonization’ event of a continent from an island demonstrates the importance of islands as a potential source of biodiversity.

Reference:
Esposito LA, Prendini L. Island Ancestors and New World Biogeography: A Case Study from the Scorpions (Buthidae: Centruroidinae). Sci Rep. 2019;9(1):3500. [Open Access]

Cytogenetic and molecular approaches reveal cryptic diversity in Alpine scorpions in the genus Euscorpius

Phenotypic conservatism is typical for many scorpion taxa.In layman's term, this mean that many scorpion species look morphologically similar making it almost impossible to separate them by traditional taxonomical methods. The European genus Euscorpius Thorell, 1876 (Euscorpiidae) is an excellent example of this. Originally this genus contained less than then species, while today it contains no less than 64 species.

And it seems that there is still more to come. By using a new combination of cytogenetic and molecular methods, Jana Štundlováa and co-workers have recently published a study of the three Alpine species of the subgenus Euscorpius (Alpiscorpius): E. (A.) alpha, E. (A.) germanus, and E. (A.) gamma.

Their study reveals a cryptic diversity in the populations of the Alpine species, with several "races" (highly distinct karyotypic races) within each species. These races had discrete geographical distributions. Even though these results clearly shows several independent taxa, a thorough taxonomical revision with morphological studies of the subgenus is necessary before any taxonomical decisions can be made.

Some of the methods used in this study are new and open new possibilities for our understanding of the species diversity of scorpions.

Abstract:
Over time, mountain biota has undergone complex evolutionary histories that have left imprints on its genomic arrangement, geographical distribution and diversity of contemporary lineages. Knowledge on these biogeographical aspects still lags behind for invertebrates inhabiting the Alpine region. In the present study, we examined three scorpion species of the subgenus Euscorpius (Alpiscorpius) from the European Alps using cytogenetic and molecular phylogenetic approaches to determine the variation and population structure of extant lineages at both chromosome and genetic level, and to provide an insight into the species diversification histories. We detected considerable intraspecific variability in chromosome complements and localization of the 18S rDNA loci in all studied species. Such chromosome differences were noticeable as the existence of three [in E. (A.) alpha and E. (A.) germanus] or four [in E. (A.) gamma] range-restricted karyotypic races. These races differed from one another either by 2n [in E. (A.) alpha 2n=54, 60, 90; in E. (A.) gamma 2n=58, 60, 88, 86–92], or by the karyotypic formula [in E. (A.) germanus 2n=34m+12sm; 36m+10sm; 42m+4sm]. Using mitochondrial (16S rRNA, COI) and nuclear (28S rDNA) genetic markers, we examined genetic variation and reconstructed phylogenetic relationships among the karyotypic races. Both approaches provided evidence for the existence of ten deeply divergent lineages exhibiting the features of local endemics and indicating the presence of cryptic species. Molecular dating analyses suggest that these lineages diversified during the Plio-Pleistocene and this process was presumably accompanied by dynamic structural changes in the genome organization.

Reference:
Stundlova J, Smid J, Nguyen P, Stahlavsky F. Cryptic diversity and dynamic chromosome evolution in Alpine scorpions (Euscorpiidae: Euscorpius). Mol Phylogenet Evol. 2019;134:152-63. [Subscription required for full text]

Thanks to Victor Fet and Frantisek Kovarik for sending me this interesting article!

On the phylogeography of the vaejovid scorpion Smeringurus vachoni

Matthew Graham and co-workers have recently published an article on the phylogeography of Smeringurus vachoni (Stahnke, 1961) (Vaejovidae) from the USA. One of the main conclusions is that Smeringurus vachoni does not comprise of two subspecies (S. v. vachoni and S. v. immanis), but instead consists of at least 11 mitochondrial clades. The authors synonymize S. v. vachoni and
S. v. immanis under the single species S. vachoni, but they encourage future taxonomic investigations using more rigorous species delimitation approaches. I refer to the abstract and the article for further details.

Abstract:
Recent syntheses of phylogeographical data from terrestrial animals in the Mojave and Sonoran deserts have revealed a complex history of geologic and climatic vicariance events. We studied the phylogeography of Smeringurus vachoni to see how vicariance events may have impacted a large, endemic rock scorpion. Additionally, we used the phylogeographical data to examine the validity of two subspecies of S. vachoni that were described using unconventional morphological characters. Phylogenetic, network and SAMOVA analyses indicate that S. vachoni consists of 11 clades mostly endemic to isolated desert mountain ranges. Molecular clock estimates suggest that clades diversified between the Miocene and early Pleistocene. Species distribution models predict a contraction of suitable habitat during the last glacial maximum. Landscape interpolations and Migrate-n analyses highlight areas of gene flow across the Colorado River. Smeringurus vachoni does not comprise two subspecies. Instead, the species represents at least 11 mitochondrial clades that probably diversified by vicariance associated with Pleistocene climate changes and formation of ancient lakes along the Colorado River corridor. Gene flow appears to have occurred from west to east across the Colorado River during periodic river avulsions.

Reference:
Graham MR, Wood DA, Henault JA, Valois ZJ, Cushing PE. Ancient lakes, Pleistocene climates and river avulsions structure the phylogeography of a large but little-known rock scorpion from the Mojave and Sonoran deserts. Biological Journal of the Linnean Society. 2017;Ahead of Print:1-14. [Subscription required for full text]

Family Vaejovidae

Phylogeography and population structure of two Brachistosternus species from Chile

Sara Ceccarelli and co-workers have recently published an article looking into the phylogeography and population structure of two species of Brachistosternus Pocock, 1893 (Bothriuridae) from costal deserts of Chile.

Abstract:
Coastal deserts are geologically dynamic areas of the Earth, affected by historical changes in sea levels and in some cases also by fault-line tectonic activity. An example of such a dynamic area is the Chilean coastal desert of the Antofagasta and Atacama regions, which harbours many endemic species, such as the bothriurid scorpion species Brachistosternus paposo and Brachistosternus roigalsinai. In this work, we carry out phylogeographic and population genetic analyses on these scorpions, using two mitochondrial (COI and cyt b) and two nuclear (Actin 5C and wingless) markers to identify species and population structuring, and link these findings to the geological history of the area. The geographical feature separating the two species is identified as the Huasco River, and distinguishing morphological features for these scorpions are presented. Population genetic and phylogeographic outcomes reflect an unstable history across this region for B. paposo and B. roigalsinai, related to sea-level changes affecting coastal habitats, including nearby islands.

Reference:
Ceccarelli FS, Pizarro‐Araya J, Ojanguren‐Affilastro AA. Phylogeography and population structure of two Brachistosternus species (Scorpiones: Bothriuridae) from the Chilean coastal desert–the perils of coastal living. Biological Journal of the Linnean Society. 2016;Early View Article. [Subscription required for full text]

Thanks to Andres Ojanguren-Afillastro for sending me this article!

Phylogeography and microendemism in Uroctonus in California

Robert Bryson Jr and co-workers have recently published a phylogeographical study looking at microendemism in Uroctonus Thorell, 1876 (Chactidae) in California (USA). Understanding historical processes that generates diversity in an area is important, and the current study suggest tectonic plate rafting, mountain uplift, river drainage formation, and climate-induced habitat fragmentation have all likely played a role in the diversification of Uroctonus in the study area.

Abstract:
The California Floristic Province (CFP) in western North America is a globally significant biodiversity hotspot. Elucidating patterns of endemism and the historical drivers of this diversity has been an important challenge of comparative phylogeography for over two decades. We generated phylogenomic data using ddRADseq to examine genetic structure in Uroctonus forest scorpions, an ecologically restricted and dispersal-limited organism widely distributed across the CFP north to the Columbia River. We coupled our genetic data with species distribution models (SDMs) to determine climatically suitable areas for Uroctonus both now and during the Last Glacial Maximum (LGM). Based on our analyses, Uroctonus is composed of two major genetic groups that likely diverged over two million years ago. Each of these groups itself contains numerous genetic groups that reveal a pattern of vicariance and microendemism across the CFP. Migration rates among these populations are low. SDMs suggest forest scorpion habitat has remained relatively stable over the last 21,000 years, consistent with the genetic data. Our results suggest tectonic plate rafting, mountain uplift, river drainage formation, and climate-induced habitat fragmentation have all likely played a role in the diversification of Uroctonus. The intricate pattern of genetic fragmentation revealed across a temporal continuum highlights the potential of low-dispersing species to shed light on small-scale patterns of biodiversity and the underlying processes that have generated this diversity in biodiversity hotspots.

Reference:
Bryson Jr RW, Savary WE, Zellmer AJ, Bury B, McCormack JE. Genomic data reveal ancient microendemism in forest scorpions across the California Floristic Province. Mol Ecol. 2016;Accepted manuscript online: 30 May 2016. [Subscription required for full text]

What role had the formation of the Andes mountain range on the speciation in the genus Brachistosternus?

The Andes continental mountain chain in South America is one of the worlds longest, and the formation of this mountain chain (The Andean uplift) probably had a major impact of the evolution of plants and animals in this region. The bothriurid genus Brachistosternus Pocock,1893 is endemic to South America and distributed mainly in the Andean region. In a recent article, Sara Ceccarelli and co-workers have investigated the biogeographical history of Brachistosternus to determine the role of Andean uplift on the distribution and diversification of its species.

It is no surprise that this study confirms that the evolution and diversification of Brachistosternus was very much influenced by the major geological changes caused by the Andean uplift.

Abstract:
Aim 
One of the planet’s most imposing geomorphological features, the Andes, played an important role in the evolution of South America’s flora and fauna. The bothriurid scorpion genus Brachistosternus Pocock, 1893 comprises more than 40 species with high diversity and endemism in the Andes. The present contribution investigates the biogeographical history of this genus using molecular phylogenetics and dating, to determine the role of Andean uplift on the distribution and diversification of its species. 
Location 
South America.
Methods 
A dated species tree was obtained for 55 putative species based on two nuclear and three mitochondrial gene loci. Ancestral ranges and biogeographical events were estimated on the species tree, diversification rates and rate shifts calculated, and areas with high phylogenetic diversity (PD) and evolutionary distinctiveness identified.
Results 
Brachistosternus diversified at a steady rate during the main Andean uplift. The central Andean and western slope/Pacific coastal biogeographical provinces played important roles as ancestral areas. Coastal areas of central Chile and southern Peru exhibit high levels of PD in Brachistosternus, suggesting they experienced a relatively long period of ecological stability, while the Andes continued to rise.
Main conclusions 
Andean uplift created new habitats and climate regimes, favouring speciation in genera such as Brachistosternus. Coastal areas to the west of the Andes continued to harbour older lineages while accommodating more recently diverged lineages from the nearby Andes.

Reference:
Ceccarelli FS, Ojanguren-Affilastro AA, Ramırez MJ, Ochoa JA, Mattoni CI, Prendini L. Andean uplift drives diversification of the bothriurid scorpion genus Brachistosternus. Journal of Biogeography. 2016;Epub 13 May 2016. [Subscription required for full text]

Thanks to Andres Ojanguren-Affilastro for sending me their article!

Caves as microrefugia and impact on phylogeography

Pseudouroctonus reddelli can be found both inside caves and outside on rocky hillsides.

Robert Bryson and co-workers have recently published an extensive study on the Pleistocene phylogeography on the troglophylic (cave loving) North American scorpion Pseudouroctonus reddelli (Gertsch & Soleglad, 1972) (Vaejovidae) and the impact of caves as microrefugia.

The main conclusion of this study support a hypothesis that caves served as microrefugia for this species and a history of Pleistocene diversification. See abstract and article for more details.

Abstract:
Background: Survival in microrefugia represents an important paradigm in phylogeography for explaining rapid postglacial re-colonization by species in temperate regions. Microrefugia may allow populations to persist in areas where the climatic conditions on the surface have become unfavourable. Caves generally contain stable microclimates and may represent microrefugia for species capable of exploiting both cave and surface habitats (troglophiles). We examine the phylogeography of the troglophilic North American vaejovid scorpion Pseudouroctonus reddelli using 1,993 base pairs of mitochondrial and nuclear DNA sequence data generated from 12 populations. We use (i) descriptive measures of genetic diversity and population genetics statistics, (ii) reconstructions of phylogeographical structure, spatial diffusion during diversification, and population sizes through time, and (iii) species distribution modelling to test predictions of the hypothesis that caves serve as microrefugia. We compare phylogeographical patterns in P. reddelli with other troglophilic species across the Edwards Plateau karst region of Texas.
Results: Results revealed high haplotype and nucleotide diversity and substantial phylogeographical structure, probably generated during the Pleistocene. Spatial diffusion occurred along the southern edge of the Edwards Plateau from multiple refugia along the Balcones Escarpment. There was little evidence for population and geographical expansion. Species distribution models predicted substantial reductions in suitable epigean habitat for P. reddelli at the Last Glacial Maximum (LGM).
Conclusions: High genetic diversity, strong phylogeographical structure, diffusion from multiple refugia, and unfavourable climatic conditions at the LGM collectively support the hypothesis that caves served as microrefugia for P. reddelli. Similar patterns of genetic structure in P. reddelli and other troglophilic species across the Edwards Plateau karst region of Texas suggest that caves serving as microrefugia are important for the formation, maintenance, and future survival of troglophilic species in temperate karst regions.

Reference:
Bryson Jr RW, Prendini L, Savary WE, Pearman PB. Caves as microrefugia: Pleistocene phylogeography of the troglophilic North American scorpion Pseudouroctonus reddelli. BMC Evol Biol. 2014;14(9):1-16. [Free full text]

Thanks to Dr. Bryson Jr for sending me their paper!

A genetic study of the medical relevant genus Androctonus in North Africa

The genus Androctonus Ehrenberg, 1828 (Buthidae) contains the most medical important scorpions of North Africa. Because of this it is very important to study the different populations of Androctonus' taxonomy, venom composition and phylogeographical patterns.

Coelho and co-workers have now published an interesting study on the genetics of several species and populations in North Africa. This paper show many important results and will be an important basis for further studies into the taxonomy and the venom of the different taxa. See abstract for further details.

Abstract:
The genus Androctonus, commonly known as fat-tailed scorpions, contains 22 species distributed from Togo and Mauritania in the west, North Africa, through the Middle East and to as far east as India. With 13 species, a substantial amount of this genus’ diversity occurs in North Africa, which is a major hotspotof scorpion sting incidents. Androctonus are among the most medically relevant animals in North Africa.Since venom composition within species is known to vary regionally, the improvement of therapeutic management depends on a correct assessment of the existing regional specific and sub-specific variation. In this study, we assessed the phylogeographical patterns in six species of Androctonus scorpions from North Africa using mitochondrial DNA markers. We sequenced COX1, 12S, 16S and ND1 genes from110 individuals. Despite lacking basal resolution in the tree, we found taxonomical and geographically coherent clades. We discovered deep intraspecific variation in the widespread Androctonus amoreuxi and Androctonus australis, which consisted of several well-supported clades. Genetic distances between some of these clades are as high as those found between species. North African A. australis have a deep split in Tunisia around the Chott el-Djerid salt-lake. A novel split between A. amoreuxi scorpions was found in Morocco. We also found deep divergences in Androctonus mauritanicus, corresponding to areas attributed to invalidated subspecies. In addition we uncovered a clade of specimens from coastal south Morocco, which could not be ascribed to any know species using morphological characters. Based on these findings we recommend a reassessment of venom potency and anti-venom efficacy between these deep intraspecific divergent clades.

Reference:
Coelho P, Sousa P, Harris DJ, van der Meijden A. Deep intraspecific divergences in the medically-relevant fat-tailed scorpions (Androctonus, Scorpiones). Acta Trop. 2014 Feb 10;134:43-51. [Subscritpion required for full text]

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

Family Buthidae