A thorough investigation of the anatomy and morphology of the pedipalps the Australian black rock scorpion, Urodacus manicatus

 

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

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

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

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

More on the function of the pectines in scorpion navigation

 

There have been a lot of research on the morphology and the functions of the pectines, which is a unique organ found only in scorpions (Solifigae has a similar organ called malleoli or racquet (or racket) organs). Most of the research so far have focused on the "taste function" (the detection of chemical cues), but it also seems that the pectines have a "feeling function" (having mechanosensory abilities). Overall, the pectines help scorpions find food, navigate, avoid predators and find mates.

Hannah Peeples and Douglas Gaffin recently published a study investigating the role of the peg sensilla on scorpion pectines for mechanosensory responses. This is a very technical paper, but as far as I can tell the main conclusion is that pectines use mechanosensory stimuli to navigate in its activity area, to find home to its shelter and to retrieve dropped insect prey.

Abstract:
Scorpions possess midventral touch/taste organs called pectines, which may be important for learning the nuances of the substrate during navigation as well as the detection of pheromones, spermatophores, and food. The pectines possess thousands of minute structures called peg sensilla that are responsive to both chemicals and mechanical deflection of the peg shaft. While much is known about the chemical responsiveness of the pegs, very little is known about their mechanosensory properties. Here we ask if the peg mechanosensory response is “all-or-nothing” or graded depending on the intensity of stimulation. We made electrophysiological recordings of neural activity from individual peg sensilla while deflecting the peg to elicit apparent mechanosensory responses. Our records show the presence of a rapid firing (.100 Hz), quickly adapting waveform that is indicative of a mechanoreceptor and appears to be independent of previously identified chemo-responsive cells. We tested mechanosensory response dynamics in two ways. The first test focused on a shorter-duration touch versus a longer-duration touch, while the second focused on a smaller deflection versus a larger deflection. Both pairs of stimulations (short vs long touch; small vs large touch) produced repeatable and statistically distinct responses in terms of spiking frequency. These results indicate the mechanosensory responses of peg sensilla are graded, which sheds light on the textural resolvability of the pectines and informs models of the type of information that scorpions obtain while assessing surfaces in their environment.

Reference:
Peeples HM, Gaffin DD. An assessment of the mechanosensory responses of peg sensilla on scorpion pectines. The Journal of Arachnology. 2024;52(1):1-8.

Thanks to Matt Simon for informing me about this article and for providing insight about the article!

Hitching a ride on a scorpion

 

Phoresy is when one animal temporary attach itself to another animal solely for travel. This special behavior is seen in several organisms, e.g. in Psedoscorpions, and is often motivated by the need for travel and migration.

Sharon Warburg and co-workers published earlier this year the first observations of phoresy in scorpions involving a species of pseudoscorpion riding on the buthid Birulatus israelensis Lourenço, 2002 in Israel. Interestingly, both species are also myrmecophilic (having a symbiotic association with ant colonies and nests).

Abstract:
An observation of phoresy by pseudoscorpions on a scorpion host is recorded for the first time worldwide. Pseudoscorpions of the endemic species Nannowithius wahrmani (Beier, 1963) (Pseudoscorpiones: Withiidae) were observed phoretic on the endemic scorpion species Birulatus israelensis Lourenço, 2002 (Scorpiones: Buthidae) in Israel. Both are myrmecophiles of harvester ants of the genus Messor Forel, 1890.

Reference:
Warburg S, Zvik Y, Gavish-Regev E. Hitching a ride on a scorpion: the first record of phoresy of a myrmecophile pseudoscorpion on a myrmecophile scorpion. Arachnologische Mitteilungen: Arachnology Letters. 2023;66(1):34-7. [Open Access]

Thanks to Matt Simon for informing me about this article!

A new species of Urophonius from Chile

 

Urophonius Pocock, 1893 in the family Bothriuridae consists of small burrowing scorpions from southern South America. One special feature with this genus is that some of the species are active in winter. Andrés Ojanguren-Affilastro and co-workers have recently described a new species from Andean Mauline Chilean forests.

Urophonius trewanke Ojanguren-Affilastro, Alfaro, Ramirez, Camousseigt-Montolivo & Pizarro-Araya, 2024

The authors have also included a phylogenetic analysis of the genus based on morphological characters.

Abstract:
Urophonius trewanke sp. nov. is described from the Mauline Andean woods of northern Chilean Patagonia. This species belongs to the granulatus species group, which includes the most basal species within the genus. This species is only active in summer as in all species of its group. We performed a phylogenetic analysis of the genus Urophonius based on morphological characters to establish the position and relationships of the new species in the genus.

Reference:
Ojanguren-Affilastro AA, Alfaro FM, Ramírez MJ, Camousseigt-Montolivo B, Pizarro-Araya J. A new species of genus Urophonius Pocock, 1893 (Scorpiones, Bothriuridae), from Andean Mauline Chilean forests, with a phylogenetic re-analysis of the genus. Zoosystematics and Evolution. 2024;100(2):469-82. [Full text supplied by authors]

Thanks to Victora Tang for informing me about this article!

Family Bothriruidae

New records of the buthid Mesobuthus rakhshanii in Iran

 

Ersen Yagmur and co-workers recently published an article with new data on the distribution of  Mesobuthus rakhshanii Barahoei, 2022 (Buthidae) in Iran.

Abstract:
Mesobuthus rakhshanii Barahoei, 2022 (Scorpiones: Buthidae) was so far known only from the type locality in Sistan and Baluchestan Province, Iran. We give a list of numerous new records of this species from the same province. A map and detailed illustrations are provided.

Reference:
Yagmur EA, Baghernavesi Z, Taherkhani Z, Akbari P, Moradi M. New records of Mesobuthus rakhshanii Barahoei, 2022 in Iran (Scorpiones: Buthidae). Euscorpius. 2024(389):1-9. [Open Access]

Family Buthidae

Pushy scorpion boys get more scorpion girls

 

Sorry for the tabloid headline. ;)

Scorpion females have a greater investment in the offspring than males and because of this are selected to be more picky when it comes to allowing males to mate. And an unwilling scorpion female is no joke, she can both push and sting an unwanted male. 

Milena Moreira and co-workers recently published a study on the sexual receptivity of female Tityus pusillus Pocock, 1893 (Buthidae) from Brazil in respone to eager males' courtship attempts. As expected, the females generally behaved aggressive towards flirting males, but in spite of this, the persistence of the male had a positive effect in courtship probability. So "pushy" and males actually had a greater chances of successful mating. One theory that might explain the female behavior is that the ability to overcome the aggressive behavior of females can be an indication of the quality of males.

It has to be added that the willingness of the females also was linked to the reproductive season indicating that also environmental factors may play a significant role in the males' success. 

Abstract:
Due to the high reproductive investment, females are the decisive sex when making decisions about whether or not to reproduce. Generally, female scorpions display aggressive sexual behavior in response to male reproductive advances when they are not receptive. However, female receptivity can vary over time, depending on environmental factors favorable to reproduction Thus, the current study aimed to examine the correlation between the number of reproductive attempts by male Tityus pusillus scorpion and mating success over time, considering the female's behavioral response. Behavioral analyses were monthly conducted on 150 T. pusillus field-caught pairs over a five-month period. Our results indicate that despite females reacting aggressively to male advances, the persistence of the male has a positive effect in courtship probability. Furthermore, we observed variations in female behavior throughout the studied period, suggesting that female receptivity might be linked to the reproductive season. Therefore, environmental factors may play a significant role in regulating scorpion reproduction in Neotropical forests.

Reference:
Moreira MOM, Moura GJB, Lira AFA. Sexual receptivity of females on Neotropical scorpion Tityus pusillus Pocock, 1893 in response to male reproductive advances. Biologia. 2024; Published Online 30.04.24. [Open Access]

Genetic and morphometric analysis of Hottentotta saulcyi in Iran reveal new cryptic species

 

The medical important scorpion Hottentotta saulcyi (Simon, 1880) (Buthidae) is widespread in Iran. Masoumeh Amiri and co-workers have studied the different populations and genetic and morphometric analyses revealed a new cryptic species.

Hottentotta hatamtiorum Amiri, Prendini, Hussen, Aliabadian, Siahsarvie & Mirshamsi, 2024

Abstract:
Morphological and genetic variation among populations of the widespread buthid scorpion, Hottentotta saulcyi (Simon, 1880), occurring in western and southwestern Iran was explored using morphometric variables, one nuclear marker (28S rDNA) and three mitochondrial markers (12S rDNA, 16S rDNA, and Cytochrome c Oxidase Subunit I). Genetic and morphometric statistical analyses revealed extensive cryptic diversity. Phylogenetic analysis with Bayesian Inference and Maximum Likelihood uncovered two divergent clades, one of which is described as a new species, Hottentotta hatamtiorum sp. nov., from Ilam and Khuzestan Provinces, southwestern Iran. The description of the new species raises the total count of Hottentotta Birula, 1908 species to 61, twelve of which are endemic or subendemic to the Iranian Plateau.

Reference:
Amiri M, Prendini L, Hussen FS, Aliabadian M, Siahsarvie R, Mirshamsi O. Integrative systematics of the widespread Middle Eastern buthid scorpion, Hottentotta saulcyi (Simon, 1880), reveals a new species in Iran. Arthropod Systematics & Phylogeny. 2024;82:323-41. [Open Access]

Thanks to Victoria Tang for sending me this article!

 Family Buthidae

The distribution of Androctonus amoreuxi in Morocco

 

Androctonus amoreuxi (Audouin, 1826) (Buthidae) has been known to have a very wide distribution ranging from Africa to Asia. Many of the Asian reports are probably misidentifications, and the real distribution of this species is probably Northern Africa and part of the Middle East.

Mohamed Mousaid and Victoria Tang have recently published an article summing up the distribution of  Androctonus amoreuxi in Morocco. The article also discuss suitable habitats for this species and the possibility of some hidden species within this potential species complex.

Abstract:
This is a brief synoptic review of Androctonus amoreuxi (Audouin, 1825) in Morocco. A summary of its morphological description is provided. Five new localities of this species in Morocco from Errachidia (1 station) and Tinghir (4 stations) provinces are reported, substantiated by photos of live specimens observed therein. Based on previous ecological study of this species, with its observation records on iNaturalist and geographical references from satellite images, we suggest that A. amoreuxi may spread more widely in the extreme southern Morocco, a Saharan area with vast arid regions of suitable ecological conditions for its dispersal, into the north of Mauritania. An updated distribution map of this species in Morocco is provided as per these new records and previous studies. Finally, after comparing its morphology with its congeners, we urge a more systematic review of this species giving the ambiguity of its true identity and the likelihood of being a species-complex comprising three cryptic lineages.

Reference:
Mousaid M, Tang V. Review of the distribution of Androctonus amoreuxi (Audouin, 1825) (Scorpiones: Buthidae) in Morocco. Serket. 2024;20(2):78-92. [Full text provided bu authors]

Thanks to Victoria for sending me this article!

Family Buthidae

Ananteridae is raised to family status

 

In a recent article, Eric Ythier has raised the subfamily Ananterinae Pocock, 1900 (in family Buthidae) to family status. Seven extant genera with associated species are transferred to the new family (see family page for more details).

Ananteridae Pocock, 1900

        Ananteris Thorell, 1891

        Ananteroides Borelli, 1911 

        Himalayotityobuthus Lourenço, 1997

        Lychasioides Vachon, 1974

        Microananteris Lourenço, 2003

        Tityobuthus Pocock, 1893

        Troglotityobuthus Lourenço, 2000 

Three extinct genera are also included in this family.

        Palaeotityobuthus Lourenço & Weitschat, 2000

        Palaeoananteris Lourenço & Weitschat, 2001

        Archaeoananteroides Lourenço, 2016

A new species of Ananteris Thorell, 1891 (Ananteridae) from Brazil is described in the article.

        Ananteris lourencoi Ythier, 2024

Abstract:
A new species belonging to the genus Ananteris Thorell, 1891 (family Ananteridae Pocock, 1900, stat. n.) is described on the basis of one male specimen collected at the Pico da Neblina, Brazil. Ananteris lourencoi sp. n. was collected between 2000-2300 m altitude, representing to our knowledge the highest altitude record for the genus Ananteris. The description of this new species brings further evidence about the biogeographic patterns of distribution presented by most species of the genus Ananteris, which are highly endemic in most natural formations of South America. This new scorpion taxon represents the 97th described species among the currently recognized species for the genus Ananteris (the 31st described from Brazil) and the 128th species described for the family Ananteridae stat. n. which is hereby confirmed as a valid family. The composition, distribution and altitude for the members of this family are discussed.

Reference:
Ythier E. A new high-altitude scorpion species of the genus Ananteris Thorell, 1891 (Scorpiones: Ananteridae) from the Pico da Neblina, Brazil. Faunitaxys. 2024;12(19):1-9. [Open Access]

Thanks to Eric for sending me this article!

Family Ananteridae

Family Buthidae