Long-read mitogenomes reveal hidden control-region architecture in Smeringurus mesaensis with implications for vaejovid systematics

 

Matt Simon (https://instagram.com/crawly.creepy) made me recently aware of a new article from Matthew Graham and co-workers on the mitochondrial genome for the genus Smeringurus Haradon, 1983 (Vajeovidae). This stuff is way over my head and I had planned to not blog about it, but it turns out that the results have implications for vaejovid systematics and should be mentioned in the blog. 

Fortunately, I have been allowed to use Matt's review of the papers content and bring them to you in this post. And those interested can check out the article to see if you understand more than I do. :)

The researchers of the study set out to recover the first mitochondrial genome for the genus Smeringurus. However, one part of the genome was persistently difficult to recover. "What first appeared to be an incomplete or problematic portion of the genome gradually resolved...into a large and remarkably orderly tandem-repeat array in the control region" of the mitochondrial genome.

This is a new finding. It is significant because it shows "the control region as a structured and, potentially, an evolutionarily informative component of scorpion mitogenomes." The authors believe that this finding brings clarity to a difficult mitogenomic region that in the past was under-recognized because researchers were unable to make sense of it.

However, it's complicated. The researchers observe that this repeat array in the mitogenomic control region occurs in some other scorpion taxa, but it does not occur in all scorpion groups.

Lastly, the authors note that their study has implications for vaejovid systematics. "Within the limits of currently available mitogenomic sampling, S. mesaensis was recovered as sister to the remaining sampled vaejovids. That placement is notable because it is broadly consistent with earlier studies that also placed Smeringurus or Smeringurinae near the base of Vaejovidae."

However, the researchers note, prior work by Santibáñez-López et al. with phylogenomic data "recovered Smeringurinae...not as sister to the remaining vaejovids, but as a long branch nested within the family." That means the two techniques led to different systematic pictures. "That contrast suggests that the placement of Smeringurinae may remain sensitive to character sampling and analytical scale."

Abstract:
Repetitive regions of animal mitochondrial genomes are biologically informative but often difficult to assemble, raising the possibility that structured variation in mitochondrial control regions may be overlooked, especially in short-read datasets. We used Oxford Nanopore long-read sequencing to assemble five complete mitochondrial genomes of the dune scorpion Smeringurus mesaensis and resolve and validate the structure of the mitochondrial control region. In all five individuals, the 1598–1600 bp control region contained six complete 202 bp tandem repeats and one 92 bp terminal partial repeat. Mean control-region coverage ranged from 15.9× to 49.8×, with 10–33 reads spanning the 5′ repeat-array boundary, 14–25 spanning a central repeat junction, and three reads spanning the complete repeat array. Despite this repetitive architecture, the arrays were highly organized: repeats R2–R6 were identical within individuals, whereas R1 and the terminal partial repeat retained consistent positional differences. The 5′ non-repeat region showed significant local similarity to the control regions of Vaejovis mexicanus and V. smithi (72.8% and 69.6% identity), whereas the 202 bp repeat produced only short, nonsignificant matches. This pattern suggests that replication slippage and sequence homogenization have jointly shaped control-region evolution. A comparative survey of published scorpion mitogenomes further indicated that tandem repeats are more widespread and structurally diverse than generally reported. These results demonstrate the value of long reads for direct validation of repeat-rich mitochondrial architecture and highlight control-region structure as an underappreciated feature of scorpion mitogenome evolution.

Reference:
Graham MR, Santibáñez-López CE, Murdoch B. Long-Read Mitogenomes Reveal Hidden Control-Region Architecture in Smeringurus mesaensis and Overlooked Tandem Repeats in Scorpions. Arthropoda. 2026;4(4):16. [Open Access]

Thanks to Matt Simon for informing me about the article and for allowing me to use his review of it!

Family Vaejovidae

A potential explanation for the disjunct distributions of Western Mediterranean scorpions in the genus Euscorpius

 

The genus Euscorpius Thorell, 1876 (Euscorpiidae) is widespread and have a high diversity in the Western Mediterranean, including several islands with endemic species. An interesting case is Euscorpius oglasae Caporiacco, 1950 from the island of Montecristo. Based on morphological analysis it has been regarded as closely related to the species Euscorpius balearicus Caporiacco, 1950 in the Balearic islands. But how is this possible as the distance between these islands is very large? 

Javier Blasco-Aróstegui and co-workers have recently published molecular study where they try to explain the disjunct distributions of Western Mediterranean scorpions in the genus Euscorpius. The study confirms the previous conclusion that the two above mentioned species are indeed closely related, and it offers an explanation of how the initial diversification of E. oglasae happened in the Paleogene time period.

Abstract:
Aim: Small wood-scorpions (Euscorpius Thorell, 1876) are widespread across the Mediterranean forests, mountains, coastlines, and islands of Europe. Their ancient origins make them an excellent model system for reconstructing the complex biogeographical history of the western Palaearctic. The present study focused on the islands of the western Mediterranean, which are geologically dynamic and harbour many endemic and relictual taxa, and on the relationships among Euscorpius species inhabiting Montecristo and the Balearic Islands, in particular. Two hypotheses were tested: (1) long-distance dispersal from the Balearic Islands after Montecristo emerged following the HT/LP plutonic intrusion (8.4–7.2 Ma), and (2) a multi-phase scenario beginning with vicariance from the Balearic, Calabrian, Corsican, Sardinian and Sicilian (Ba-Ca- Co- Sa- Si) microplate fragmentation, followed by dispersal to Montecristo during the Messinian Salinity Crisis (5.97–5.33 Ma) or later Pliocene–Pleistocene sea-level regressions (3.6–0.2 Ma).
Location: Western Mediterranean islands of France, Spain, and Italy, including the Balearic Islands, Corsica, Sardinia, and the Tuscan Archipelago.
Time Periods: Eocene, Oligocene, Neogene, and Quaternary.
Taxon: Scorpiones: Euscorpiidae: Euscorpius Thorell, 1876: Euscorpius balearicus Caporiacco, 1950; Euscorpius canestrinii (Fanzago, 1872); Euscorpius concinnus (C.L. Koch, 1837); Euscorpius oglasae Caporiacco, 1950; Euscorpius sicanus (C.L. Koch, 1837).
Methods: Multi-locus phylogenies were inferred from 2815 base-pairs of concatenated DNA sequence of the nuclear region comprising 18S rDNA (partial) and the Internal Transcribed Spacer II, and mitochondrial 12S rDNA, 16S rDNA, and Cytochrome c Oxidase Subunit I loci using Maximum Likelihood, and divergence times estimated in a Bayesian framework with conservative fossil calibration constraints. Ancestral areas and biogeographical transitions were reconstructed using parametric models complemented by Principal Coordinates Analysis and Isolation-by- Distance tests to assess spatial genetic structure.
Results: Molecular clock dating and biogeographical analyses suggest initial diversification of E. oglasae occurred after break-up of the Ba-Ca- Co- Sa- Si microplate during the Oligocene (25.9 Ma), which transferred the lineage to the Corsica-Sardinia block. A likely passive dispersal event (i.e., transient lands, orogenies) towards Montecristo only occurred after its emergence (8.4–7.2 Ma), probably during the Messinian Salinity Crisis (5.97–5.33 Ma).

Reference:
Blasco-Aróstegui J, Isaia M, Barba-Montoya J, Tolve M, Roppo M, Prendini L. Ancient Divergence, Recent Island: Microplate Fragmentation and Dispersal Explain Disjunct Distributions of Western Mediterranean Scorpions. Journal of Biogeography. 2026;53(9). [Subscription required for full text]

New location and DNA barcoding of Euscorpius vailatii from Trizonia Island in Greece)

 

 Konstantinos Kalaentzis and co-workers recently published a new, insular location of Euscorpius vailatii Tropea & Fet, 2015 (Euscorpiidae) from Trizonia Island in Greece. Molcular data was also collect from the species and a phylogenetic analysis is presented.

Abstract:
Euscorpius vailatii Tropea & Fet, 2015 (Scorpiones: Euscorpiidae), originally described from Aitoloakarnania and Fokida (Greece), is herein reported from Trizonia Island in the Gulf of Corinth, representing the first insular record for the species. The examined specimens are consistent with the diagnostic morphology of E. vailatii. The first molecular data for the species are provided, based on both mainland and insular populations. Comparative analyses further highlight the distinctiveness of E. vailatii from geographically close congeners, while phylogenetic results indicate a sister-taxon relationship with E. erymanthius, supporting a Quaternary biogeographic history shaped by the evolution of the Gulf of Corinth system.

Reference:
Kalaentzis K, Frigioni F, Panagiotopoulos A, Tzoras E, Minoudi S, Triantafyllidis A. First insular record and DNA barcoding of Euscorpius vailatii Tropea & Fet, 2015 from Trizonia Island (Fokida, Greece). Euscorpius. 2026;2026(439):1–6. [Open Access]

Family Euscorpiidae 

A new species of Liocheles from Western Himalays, India

 

Virender K. Bhardwaj and co-workers recently described a new species of Liocheles Sundevall, 1833 (Hormuridae) from Western Himalayas in India.

Liocheles gracilipalpus Bhardwaj, Katal, Lalremsanga & Mirza, 2026

Abstract:
Sampling in the Western Himalayas of India led to the discovery of a population of the genus Liocheles Sundevall, 1833, that differes from all Indian congeners. Molecular and morphological data confirmed the distinctiveness of the population, which is here described as a new species. The new species is morphologically similar to L. longimanus (Werner, 1939), from which it differs in the arrangement of trichobothria on external patella and structure of the hemispermatophore. A preliminary molecular phylogeny of the family Hormuridae based on the mitochondrial cytochrome oxidase I gene is presented.

Reference:
Bhardwaj VK, Katal S, Lalremsanga HT, Mirza ZA. A new species of Liocheles Sundevall, 1833 (Scorpiones: Hormuridae) from the Western Himalayas. Euscorpius. 2026(441):1–13. [Open Access]

Family Hormuridae 

Three new species of Scorpiops from India

 

Shubhankar Deshpande and co-workers have recently described three new species of Scorpiops Peters, 1861 (Scorpiopidae) from India based on morphological and molecular analysis.

 Scorpiops ketkari Deshpande, Ukale, Bapat, Bastawade, Tang, Gowande & Sulakhe, 2026

 Scorpiops shilavasi Deshpande, Ukale, Bapat, Bastawade, Tang, Gowande & Sulakhe, 2026

 Scorpiops skorupi Deshpande, Ukale, Bapat, Bastawade, Tang, Gowande & Sulakhe, 2026 

Abstract:
The scorpion genus Scorpiops Peters, 1861 exhibits significant diversity and high endemism. Our extensive arachnological surveys, species delimitation analyses and an integrative taxonomic approach revealed three new species of Scorpiops in peninsular India. Furthermore, we tested the phylogenetic placement of Scorpiops pachmarhicus Bastawade, 1992 and give the first description of a male specimen of the species. Additionally, we provide a detailed account of the hemispermatophore morphology in Scorpiops species from the maharashtraensis, satarensis, and tenuicauda clades for the first time.

Reference:
Deshpande S, Ukale S, Bapat S, Bastawade D, Tang V, Gowande G, et al. Beyond morphology alone: species delimitation, hemispermatophore comparisons and comments on the systematic status of Scorpiops Peters, 1861 (Scorpiones: Scorpiopidae) with a description of three new species from peninsular India. Zoologischer Anzeiger. 2026. [Subscription required for full text]

Thanks to Dr. Deshpande for sending me their article!

Family Scorpiopidae 

Is it possible to use venom molecular mass fingerprint for taxonomical identification of scorpions from Morocco?

 

Correct identification of scorpions is important and especially in regions and countries where there are several species that can cause serious envenomations. Boujemaa Ajdi and co-workers have recently published an article investigating whether venom molecular mass fingerprint can be used to identify scorpions in Morocco. 

I must admit that this paper is a little over my head but the main conclusions seem to be that this method seems to be a reliable tool for the taxonomic identification of scorpions from Morocco. In addition, molecular mass fingerprints of scorpion venoms contain sufficient molecular variations to differentiate scorpion species. The method seems to be promising for rapid molecular identification of scorpions in the future. See paper for more details.

Abstract:
The venom of scorpions has been the subject of numerous studies. However, their taxonomic identification is not a simple task, leading to misidentifications. This study aims to provide a practical approach for identifying scorpions based on the venom molecular mass fingerprint (MFP). Specimens (251) belonging to fifteen species were collected from different regions in Morocco. Their MFPs were acquired using MALDI-MS. These were used as a training dataset to generate predictive models and a library of mean spectral profiles using software programs based on machine learning. The computational model achieved an overall recognition capability of 99 % comprising 32 molecular signatures. The models and the library were tested using a new dataset for external validation and to evaluate their capability of identification. We recorded an accuracy classification with an average of  97 % and 98 % for the computational models and the library, respectively. To our knowledge, this is the first attempt to demonstrate the potential of MALDI-MS and MFPs to generate predictive models capable of discriminating scorpions from family to species levels, and to build a library of species-specific spectra. These promising results may represent a proof of concept towards developing a reliable approach for rapid molecular identification of scorpions in Morocco.

Reference:
Ajdi B, El Hidan MA, El Asbahani A, Bocquet M, Hamza MA, M'Barka E, et al. Taxonomic identification of Morocco scorpions using MALDI-MS fingerprints of venom proteomes and computational modeling. J Proteomics. 2024:105321. [Subscription required for full text]

Molecular study of medical important Hemiscorpius species from Iran

 

Correct identification of medical important scorpions is very important to be able to provide optimal treatment. Many species are morphological similar and this will make correct identification difficult. This is the case with many species of Hemiscorpius  Peters, 1861 (Hemiscorpiidae) in Iran. 

Shahi and Barahoei have recently published a molecular study on the Hemiscorpius fauna in the Hormozgan province in southern Iran. The study confirms the validity of the following three species in the genus:

Hemiscorpius acanthocercus Monod & Lourenço, 2005
Hemiscorpius enischnochela Monod & Lourenço, 2005
Hemiscorpius lepturus Peters, 1861

This is important information as the available antivenom for this genus do not work optimal inn all cases and this might be because there are different species involved. 

Abstract:
Three species of Hemiscorpius were identified in Hormozgan province, for which the available antivenoms lack the efficacy required for treating patients. Consequently, an exact identification of the existing species was deemed necessary as the first step in managing treatment procedures. Considering the morphological similarities among the species, the aim of this research was the molecular study of the samples to accurately identify the species. Hemiscorpius specimens were collected from various locations in Hormozgan province between 2021 to 2023. The Cytochrome c oxidase subunit I gene was amplified and sequenced. Four sequences were obtained from Hemiscorpius specimens collected from Hormozgan province, and three sequences were sourced from the NCBI for analysis. Bayesian inference and Maximum likelihood phylogenetic trees showed similar results, positioning the base of Hemiscorpius enischnochela tree as an older species and Hemiscorpius lepturus adjacent to Hemiscorpius acanthocercus, identified as the newest species at the tree's tip. The results confirmed the validity of three species, namely H. acanthocercus, H. enischnochela, and H. lepturus. Hemiscorpius acanthocercus and H. lepturus are known for having dangerous venom for humans with reported deaths due to their stings. Considering the importance of the members of this genus from the medical point of view, a comprehensive examination of all species is imperative.

Reference:
Shahi M, Barahoei H. Molecular study of Hemiscorpius Peters (Scorpiones: Hemiscorpiidae) in Hormozgan province, South of Iran. Arch Razi Inst. 2024;79(1):211-7. [Open Access]

Family Hemiscorpiidae

Confirmation of the presence of the cosmopolitan scorpion Isometrus maculatus in India

 

Isometrus maculatus (DeGeer, 1778) (Buthidae) is a real cosmopolitan with its presence in at least 70 countries around the world. Its presence in India has never been confirmed, and also Sri Lanka as the original home of this species has been debated.

 Shubhankar Deshpande and co-workers recently published a morphological and molecular analysis of specimens of Isometrus maculatus from India, Taiwan and Japan. The study confirms the presence of this species in northeast India. In addition, the authors propose to consider Sri Lanka as the true home of I. maculatus.

Abstract:
We present molecular data on Isometrus maculatus (DeGeer, 1778) for the first time from India, Japan, and Taiwan based on the COI gene and justify the cosmopolitan nature of this species. We also address the first population of I. maculatus found in Teliamura, Tripura, India and give its detailed description and comparison with the rest of the Isometrus species from India. Furthermore, we discuss the justification for considering Sri Lanka as the true home of I. maculatus.

Reference:
Deshpande S, Joshi M, Kawai K, Deb A, Lee J-D, Bastawade D, et al. Molecular and morphological confirmation of Isometrus maculatus (DeGeer, 1778) (Scorpiones: Buthidae) from Northeast India and East Asia. Euscorpius. 2023;2023(374):1-19. [Open Access]

Family Buthidae

Genetic diversity among different species of the genus Leiurus in Saudi Arabia and the Middle East

 

 Abdulaziz Alqahtani and Ahmed Badry published this Fall an article on the genetic diversity among different species of the genus Leiurus Ehrenberg, 1828 (Buthidae) in Saudi Arabia and the Middle East. They conclude that there is a clear genetic splitting between Leirus from Egypt and those from Arabia and Turkey. In addition, the results support the taxonomic status of Arabian Leiurus species.

Abstract:
The molecular phylogenetic relationship among two species of genus Leiurus, from Saudi Arabia with additional comparative sequence data available from Egypt, Oman and Turkey is presented. The molecular phylogeny was performed using maximum parsimony, neighbor joining and bayesian inference. Our results indicate a clear deep splitting between the Western clade, which represented by L. quinuestriatus sequences from Egypt and those from the Eastern clade which encompassing different Leiurus species from Saudi Arabia, Oman and Turkey was shown. Also, the phylogenetic relationship represents additional support for the taxonomic status of Arabian Leiurus species.

Reference:
Alqahtani AR, Badry A. Genetic diversity among different species of the genus Leiurus (Scorpiones: Buthidae) in Saudi Arabia and the Middle East. Saudi J Biol Sci. 2020;27(12):3348-53.[Open Access]

Thanks to Dr. Badry for sending me their article!

Family Buthidae

Karyotype evolution and preliminary molecular assessment of genera in the family Scorpiopidae

 

I have stolen the title in this post from the latest article from Frantisek Stahlavsky and co-workers of the moelcular genetics and phylogeny of the family Scorpiopidae. As previously mentioned, I'm not very good at molecular genetics and I leave it up to you readers to checkout this paper to learn more about the details of the results.

The main findings of the article is that their results support the monophyly of the family Scorpiopidae, but most genera were recovered as para- or polyphyletic. This makes the authors questioning the utility of the morphological characteristics currently used in scorpion taxonomy for generic delimitation in this family. I guess these results are the basis for the Scorpiopidae revision published in November by Kovarik et al.

Abstract:
The scorpions represent an ancient and morphologically conserved order of arachnids. Despite that, their karyotypes may differ considerably even among closely related species. In this study, we identify the trends of the karyotype evolution in the family Scorpiopidae based on integrating cytogenetic data and multi-locus molecular phylogenetic approaches. We detected considerable variability in diploid numbers of chromosomes (from 48 to 147), 18S rRNA gene cluster positions (from terminal to pericentromeric) at the interspecific level. Moreover, we identified independent fusions, fissions and inversions in the evolution of the family Scorpiopidae, leading to a remarkable diversification of the karyotypes. The dynamic system of the karyotype changes in this group is further documented by the presence of interstitial telomeric sequences (ITS) in two species. The cytogenetic differences observed among the analyzed species highlight the potential of this type of data for species-level taxonomy in scorpion lineages with monocentric chromosomes. Additionally, the results of our phylogenetic analyses support the monophyly of the family Scorpiopidae, but rendered several genera para- or polyphyletic.

Reference:
Stahlavsky F, Kovarik F, Stockmann M, Opatova V. Karyotype evolution and preliminary molecular assessment of genera in the family Scorpiopidae (Arachnida: Scorpiones). Zoology. 2021;144:125882. [Subscription required for full text]

Thanks to Frantisek Kovarik for sending me their article!

Family Scorpiopidae

A new study on the Vaejovis in the Santa Catalina Mountains, Arizona (US)

 

 Emma E. Jochim and co-workers recently published a phylogenetic analyses of the Vaejovis scorpions in the Santa Catalina Mountains (Vaejovidae). One of the main conclusions is that Vaejovis brysoni Ayrey & Webber, 2013 is synomized with Vaejovis deboerae Ayrey, 2009.

Abstract:
Scorpions belonging to the Vaejovis vorhiesi species complex are widely distributed throughout the southwestern United States and northern Mexico. Most species are endemic to single mountain ranges but two species, Vaejovis deboerae Ayrey, 2009 and V. brysoni Ayrey & Webber, 2013, have been documented from the Santa Catalina Mountains in Arizona. We reevaluated the taxonomic diversity of these scorpions by integrating data from several different sources. Phylogenetic analyses indicate that scorpions in the Santa Catalina Mountains are monophyletic but comprise two divergent mitochondrial lineages that overlap at the type locality of V. deboerae. We failed to detect congruence between these lineages and the remaining datasets which suggests that there is a single species that we refer to as V. deboerae (=V. brysoni syn. nov.). Our inability to gather molecular data from the female holotype of V. deboerae could be the basis for future nomenclatural volatility if future studies find that the mitochondrial lineages are validated by other forms of data (e.g., male morphology). Results from this study underscore the importance of integrative methods for delimiting species in morphologically cryptic groups. Furthermore, we recommend generating DNA barcodes for holotypes as part of the description process to reduce future nomenclatural quagmires.

Reference:
Jochim EE, Broussard L-LM, Hendrixson BE. Integrative species delimitation and taxonomic status of the scorpion genus Vaejovis Koch, 1836 (Vaejovidae) in the Santa Catalina Mountains, Arizona. Euscorpius. 2020(316):1-11. [Open Access]

Family Vaejovidae

Molecular phylogeny of three species of the genus Buthacus from Saudi Arabia and Egypt

The genus Buthacus Birula, 1908 (Buthidae) is a widespread genus with a complex taxonmy with several unresolved taxa. Abdulaziz Alqahtania and Ahmed Badry have recently published a study investigating the molecular phylogeny of three species of the genus from Saudi Arabia and Egypt. One main result is a support for a monophyletic status of the genus Buthacus. See abstract and article for more details and results.

Abstract:
The molecular phylogeny of three species of genus Buthacus, based on 16S rRNA mitochondrial DNA gene from Egypt and Saudi Arabia is presented. The inferred phylogeny based on maximum-parsimony, neighbor-joining and bayesian inference, indicates the monophyletic status of the genus Buthacus. A clear deep splitting between the “Egyptian clade” consisting of B. arenicola and B. leptochyles and the “Arabian clade” consisting of B. nigroaculatus was shown.

Reference:
Alqahtani AR, Badry A. Interspecific phylogenetic relationship among different species of the genus Buthacus (Scorpiones: Buthidae) inferred from 16S rRNA in Egypt and Saudi Arabia. Zoology in the Middle East. 2020. [Subscription required for full text]

Thanks to Dr. Badry for sending me information about their article!

Family Buthidae

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!

Structure of venom molecules predicts phylogenetic relationships in scorpions

Scorpions are infamous because of their venom, which actually consist of a host of different toxins and molecules. Carlos E. Santibáñez-López and several co-workes have now published a study combining a mapping of the structure of venom molecules with the challenges and disagreements in scorpion higher-level systematics and phylogeny.

I must admit that most of the content of this article is above my head. I'm a humble animal behavior student. So I will let co-author Prashant Sharma sum up the main point of the article:

"The punchline is that we analyzed parametric analyses of the shape of venom proteins on the most comprehensive molecular phylogeny of scorpions. We found that venom shape  predicts phylogenetic relationships and provides synapomorphies for the two largest scorpion clades (Buthida and Iurida)." (Sharma personal communication 15.11.18)

As far as I understand, one important conclusion of this study is that "molecular morphology" can overcome the challenges of the traditional use of anatomical characters in scorpion higher-level systematics and phylogeny.

Abstract:
Scorpions have evolved a variety of toxins with a plethora of biological targets, but characterizing their evolution has been limited by the lack of a comprehensive phylogenetic hypothesis of scorpion relationships grounded in modern, genomescale datasets. Disagreements over scorpion higher-level systematics have also incurred challenges to previous interpretations of venom families as ancestral or derived. To redress these gaps, we assessed the phylogenomic relationships of scorpions using the most comprehensive taxonomic sampling to date. We surveyed genomic resources for the incidence of calcins (a type of calcium channel toxin), which were previously known only from 16 scorpion species. Here, we show that calcins are diverse, but phylogenetically restricted only to parvorder Iurida, one of the two basal branches of scorpions. The other branch of scorpions, Buthida, bear the related LKTx toxins (absent in Iurida), but lack calcins entirely. Analysis of sequences and molecular models demonstrates remarkable phylogenetic inertia within both calcins and LKTx genes. These results provide the first synapomorphies (shared derived traits) for the recently redefined clades Buthida and Iurida, constituting the only known case of such traits defined from the morphology of molecules.

Reference:
Santibáñez-López CE, Kriebel R, Ballesteros JA, Rush N, Witter Z, Williams J, et al. Integration of phylogenomics and molecular modeling reveals lineage-specific diversification of toxins in scorpions. PeerJ. 2018;6:e5902. [Open Access]

A news report about the article

Thanks to Carlos E. Santibanez Lopez and Prashant Sharma for sending me their article and information!

Two new species in the vaejovid genus Kovarikia from California, USA

The last decades have revealed many new species that have been morphologically "hidden" in species complexes. Fortunately, the development in DNA sequencing and species delimitation modeling has made it easier for taxonomist to find and describe similar-looking, yet evolutionary distinct species.

In a recent article, Robert Bryson Jr. and co-workers have described two new species in the enigmatic genus Kovarikia Soleglad, Fet & Graham, 2014 (Vaejovidae) that are endemic to California, USA.

Kovarikia oxy Bryson, Graham & Soleglad, 2018

Kovarikia savaryi Bryson, Graham & Soleglad, 2018

The article has an identification key for the genus Kovarikia.

Abstract:
Morphologically conserved taxa such as scorpions represent a challenge to delimit. We recently discovered populations of scorpions in the genus Kovarikia Soleglad, Fet & Graham, 2014 on two isolated mountain ranges in southern California. We generated genome-wide single nucleotide polymorphism data and used Bayes factors species delimitation to compare alternative species delimitation scenarios which variously placed scorpions from the two localities with geographically adjacent species or into separate lineages. We also estimated a time-calibrated phylogeny of Kovarikia and examined and compared the morphology of preserved specimens from across its distribution. Genetic results strongly support the distinction of two new lineages, which we describe and name here. Morphology among the species of Kovarikia was relatively conserved, despite deep genetic divergences, consistent with recent studies of stenotopic scorpions with limited vagility. Phylogeographic structure discovered in several previously described species also suggests additional cryptic species are probably present in the genus.

Reference:
Bryson Jr RW, Wood DA, Graham MR, Soleglad ME, McCormack JE. Genome-wide SNP data and morphology support the distinction of two new species of Kovarikia Soleglad, Fet & Graham, 2014 endemic to California (Scorpiones, Vaejovidae). ZooKeys. 2018(739):79-106. [Open Access]

Family Vaejovidae

First molecular phylogeny of scorpions of the family Buthidae from India

As the title implies, as recent article by Vivek Suranse and co-workers presents the first molecular phylogeny of buthid scorpions from India (or more precisely central western India). This is a preliminary study as not all Indian species in Buthidae have been sampled, but the current results confirm the taxonomical placement of many taxa. In addition, the data also add new information and insight on the phylogeny of several taxa and raises questions that need to be looked into in future research. Especially the results for the infamous Hottentotta tamulus Fabricius, 1798 should be further investigated because of its medical significance.

Abstract:
Scorpions of the family Buthidae are widespread species in India. While studies are available on diversity and distribution of Indian buthid scorpions, no information is available on the phylogenetic relationships among the members of the family, within India and Asia in general. In the current study, we provide the first molecular phylogeny of buthid scorpions from central western India based on the mitochondrial cytochrome oxidase subunit I (COI) gene. Our analysis confirms the current placement of the species, previously assigned to Mesobuthus in the genus Hottentotta. However, the analysis also suggests that the member of this genus from India form a monophyletic group distinct from the members of Hottentotta from Africa. Species of Lychas formed a monophyletic group. Although Orthochirus was nested within the larger clade of buthidae comprising genera such as Androctonus, Buthacus, Buthus and Odontobuthus, the exact phylogenetic placement will require more taxonomic sampling of the known genera of Buthidae. We also show that there is a substantial genetic variation among the populations of medically important scorpion species Hottentotta tamulus, and the genetic distance is linearly correlated with the geographical distance between the populations.

Reference:
Suranse V, Sawant NS, Paripatyadar SV, Krutha K, Paingankar MS, Padhye AD, et al. First molecular phylogeny of scorpions of the family Buthidae from India. Mitochondrial DNA Part A DNA mapping, sequencing, and analysis. 2016 Jun 1:1-6. [Subscription required for full text]

Thanks to Carlos Turiel for informing me about this article!

Family Buthidae

DNA barcoding indicates hidden diversity of Euscorpius in Turkey

For many years, only two species of Euscorpius Thorell, 1876 (Euscorpiidae) were reported from Turkey. Today, we list 12 valid species from Turkey. Victor Fet and co-workers have now published an article were they have studied the phylogenetic relationships of some additional Anatolian Euscorpius populations using molecular markers. The results confirm the validity of several existing species (previously only described by morphological methods), but also show the presence of undescribed taxonomic forms, possibly of species level.

Abstract:
The Anatolian fauna of the genus Euscorpius (Scorpiones: Euscorpiidae) is in the process of reassessment. Twelve species of this genus are currently recognized for Anatolia, of which seven have been recently described on the basis of morphology. We demonstrate additional cryptic diversity in Anatolian Euscorpius by applying molecular markers (mitochondrial COI and 16S rDNA genes) from 14 populations, of which 13 were morphologically characterized by “em=3,” a phenotypic marker on the pedipalp patella. All studied Anatolian forms are strongly supported as a single clade compared to the European (from the Alps to the Balkans) taxa of the subgenus Alpiscorpius. Of these, six are assigned to known species (E. ciliciensis, E. mingrelicus, E. eskisehirensis, E. phrygius, and E. uludagensis); and two (Ankara and Sakarya) are closely related to a clade containing E. phrygius and E. uludagensis. Four clades represent undescribed taxonomic forms, possibly of species level: Balikesir/Canakkale (Kazdağları National Park), Konya, Denizli, and Trabzon, all with em=3. Another putative species from Kayseri Province, Aladağlar (=Antitaurus) Mts., is related to (E. ciliciensis + E. eskisehirensis) clade; however, it exhibits em=4, which appears to be the first case of reversal in this important trait for the genus Euscorpius.

Reference:
Fet V, Graham MR, Blagoev G, Karatas A, Karatas A. DNA Barcoding Indicates Hidden Diversity of Euscorpius (Scorpiones: Euscorpiidae) in Turkey. Euscorpius. 2016 (216):1-12. [Open Access]

Family Euscorpiidae

The evolution of scorpion venom

An artcile on the origin and diversification of scorpion venom has been recently published by Kartik Sunagar and co-workers.

All scorpions possess venom and and a few species have venom which can cause death or serious symptoms in humans. The venom of one species is a cocktail of different toxins and there is such a cocktail for each scorpion species. But how did these different venoms evolve?

Kartik Sunagar and co-workers have now published a study on scorpion venom evolution. Lacking biochemistry and molecular biology in my education this article is a little over my head, so I just refer to the abstract for the conclusions :)

Abstract:
The episodic nature of natural selection and the accumulation of extreme sequence divergence in venom-encoding genes over long periods of evolutionary time can obscure the signature of positive Darwinian selection. Recognition of the true biocomplexity is further hampered by the limited taxon selection, with easy to obtain or medically important species typically being the subject of intense venom research, relative to the actual taxonomical diversity in nature. This holds true for scorpions, which are one of the most ancient terrestrial venomous animal lineages. The family Buthidae that includes all the medically significant species has been intensely investigated around the globe, while almost completely ignoring the remaining non-buthid families. Australian scorpion lineages, for instance, have been completely neglected, with only a single scorpion species (Urodacus yaschenkoi) having its venom transcriptome sequenced. Hence, the lack of venom composition and toxin sequence information from an entire continent’s worth of scorpions has impeded our understanding of the molecular evolution of scorpion venom. The molecular origin, phylogenetic relationships and evolutionary histories of most scorpion toxin scaffolds remain enigmatic. In this study, we have sequenced venom gland transcriptomes of a wide taxonomical diversity of scorpions from Australia, including buthid and non-buthid representatives. Using state-of-art molecular evolutionary analyses, we show that a majority of CSα/β toxin scaffolds have experienced episodic influence of positive selection, while most non-CSα/β linear toxins evolve under the extreme influence of negative selection. For the first time, we have unraveled the molecular origin of the major scorpion toxin scaffolds, such as scorpion venom single von Willebrand factor C-domain peptides (SV-SVC), inhibitor cystine knot (ICK), disulphide-directed beta-hairpin (DDH), bradykinin potentiating peptides (BPP), linear non-disulphide bridged peptides and antimicrobial peptides (AMP). We have thus demonstrated that even neglected lineages of scorpions are a rich pool of novel biochemical components, which have evolved over millions of years to target specific ion channels in prey animals, and as a result, possess tremendous implications in therapeutics.

Reference:
Sunagar K, Undheim E, Chan A, Koludarov I, Muñoz-Gómez S, Antunes A, et al. Evolution Stings: The Origin and Diversification of Scorpion Toxin Peptide Scaffolds. Toxins. 2013;5(12):2456-87. [Free full text]

Thanks to Bryan Fry for sending me this article!