Understanding scorpion species diversity in Cuba

 

The species diversity that we see today in an area or region has been shaped by many forces, both abiotic (e.g., climate and topography) and biotic (e.g., land cover and vegetation structure). Investigating these forces are important and island communties are well suited for these kinds of studies. In addtion, scorpions are well suited organisms for these kinds of studies due to low vagility, long life cycles, and microhabitat specialization.

André Felipe de Araújo Lira and co-workers recently published recently a study trying to understand the diversity on Cuban scorpions. The found that scorpion species composition and richness differences in the Cuban archipelago mainly depend on biotic and abiotic variables such as vegetation and topography. See abstract and article for more details.

Abstract:
The assembly of communities is often viewed as a process involving the dispersal of species from a regional pool. An oceanic island provides a unique opportunity to test such a hypothesis and many others related to the patterns and processes behind biodiversity. Our aim was to investigate the patterns of scorpion diversity in the Cuban archipelago, using biotic and abiotic variables and their interactions as explanatory features. We use biotic and abiotic variables related to vegetation, climate and topography characterize the landscape of the Cuban archipelago. In this way, we analyze the patterns of beta diversity of the scorpions, verifying the effects of the variables alone and together. Scorpion fauna of the Cuban archipelago comprises 61 species, grouped into nine genera and two families: Buthidae and Diplocentridae. The interplay between biotic and abiotic variables explained scorpion species composition, especially when spatial predictors were considered. Climatic and spatial predictors affected scorpion beta diversity in terms of richness difference. These patterns are discussed emphasizing the role of biotic and abiotic environmental features and their interactions on the mechanisms of scorpion biodiversity generation and maintenance in Cuban archipelago.

Reference:
de Araújo Lira AF, Foerster SÍA, DeSouza AM, de Armas LF. Disentangling diversity patterns in Cuban scorpions (Arachnida: Scorpiones). Novitates Caribaea. 2022(19):72-91. [Open Access]

Thanks to Andre for sending me their article!

A new species of Compsobuthus from India

 

Vivek Waghe and co-workers have recently published an article with a new species of Compsobuthus Vachon, 1949 (Buthidae) from Maharashtra, India.

Compsobuthus satpuraensis Waghe, Gangalmale & Khandekar, 2022

Abstract:
A new species of the genus Compsobuthus Vachon, 1949 (Buthidae) belonging to the werneri group is described from two localities in Jalgaon District, Maharashtra, India. The new species can be easily distinguished from all four members of the werneri group known from India and Pakistan by combination of nonoverlapping morphological characters. Compsobuthus satpuraensis sp. n. is the first species of this genus to be reported from the state of Maharashtra and fourth to be reported from India.

References:
Waghe V, Gangalmale S, Khandekar A. First record of the genus Compsobuthus (Scorpiones: Buthidae) from Maharashtra, India, with description of a new species. Euscorpius. 2022(346):1-13. [Open Access]

Family Buthidae

A study of scorpion ecomorphs

 

Ecomorphs are groups of organisms that share a set of morphological traits associated with specific ecological requirements. They are created and shaped by environmental changes and adaptions to these. Scorpions have been assigned to ecomorphs for many years (mainly based on the microhabitat they use), but this assignment have never been properly tested.

Pedro Coelho and co-workers have now published a study on existence of scorpion ecomorphs by quantifying the association between their morphology and ecology across several species from many families. The study confirmed the existence of scorpion ecomorphs by showing associations between ecology and morphology.

Here are the scorpion ecomorphs that have been used for scorpions:

Psammophilous: Sand fossorials.

Phytophilous (Corticolous): Under vegetation, leaf-litter and other passive shelters.

Pelophilous: Hard soil fossorials.

Lithophilous: Rock climbers.

Abstract:
Background: Ecomorphs create the opportunity to investigate ecological adaptation because they encompass organisms that evolved characteristic morphologies under similar ecological demands. For over 50 years, scorpions have been empirically assigned to ecomorphs based on the characteristic morphologies that rock, sand, vegetation, underground, and surface dwellers assume. This study aims to independently test the existence of scorpion ecomorphs by quantifying the association between their morphology and ecology across 61 species, representing 14 families of the Scorpiones order.
Results: Without a priori categorization of species into ecomorphs, we identified four groups based on microhabitat descriptors, which reflect how scorpion ecospace is clustered. Moreover, these microhabitat groups, i.e., ecotypes, have significantly divergent morphologies; therefore, they represent ecomorphs. These ecomorphs largely correspond with the ones previously described in the literature. Therefore, we retained the names Lithophilous, Psammophilous, and Pelophilous, and proposed the name Phytophilous for vegetation dwellers. Finally, we sought to map the morphology-ecology association in scorpions and found that the morphological regions most tightly associated with ecology are at the extremities. Moreover, the major trend in ecomorphological covariation is that longer walking legs and relatively slender pedipalps (pincers) are associated with sandy microhabitats, while the inverse morphological proportions are associated with rocky microhabitats.
Conclusions: Scorpion ecomorphs are validated in a naïve approach, from ecological descriptors and whole bod anatomy. This places them on a more solid quantitative footing for future studies of ecological adaptation in scorpions. Our results verify most of the previously defined ecomorphotypes and could be used as a current practice to understand the adaptive significance of ecological morphology.

Reference:
Coelho P, Kaliontzopoulou A, Sousa P, Stockmann M, van der Meijden A. Reevaluating scorpion ecomorphs using a naïve approach. BMC Ecol Evol. 2022;22(1):17 [Open Access]

Thanks to Pedro Coelho for sending me their article!

Issues 103 and 104 of Arachnides are now available in full text in The Scorpion Files

 

Issues 103 and 104 of the journal Arachnides are now freely available in full text in The Scorpion Files. Thanks to editor Gerard Dupre for making issues of Arachnides available to the scorpion community.

New fossil species from mid-Cretaceous Burmese amber

 

Amber is a gold mine when it comes to finding new fossil scorpion species and for understanding the link between these and the modern scorpion taxa. Qiang Xuan and co-workers have now described a new species in the extinct family Palaeoburmesebuthidae from mid-Cretaceous Burmese amber from the Hukawng Valley in northern Myanmar.

Betaburmesebuthus spinipedis Xuan, Cai & Huang

Abstract:
Mesozoic fossils provide invaluable information about the origin and evolutionary history of scorpions. However, well-preserved scorpions in amber are comparatively rare, greatly limiting our understanding of early scorpion morphological diversity and disparity. Here we describe a new species of the extinct family Palaeoburmesebuthidae, Betaburmesebuthus spinipedis sp. nov., based on a complete female juvenile from the mid-Cretaceous Burmese amber from the Hukawng Valley in northern Myanmar. As some critical characters are hard to interpret, we tentatively place the species in the genus Betaburmesebuthus. We also document, for the first time in a fossil scorpion, five pairs of lateral ocelli on the carapace. Our discovery provides new evidence for the relationship between Palaeoburmesebuthidae and the Recent family Buthidae.

Reference:
Xuan Q, Cai C, Huang D. A new Palaeoburmesebuthidae scorpion from mid-Cretaceous Burmese amber (Arachnida: Scorpiones: Buthoidea). Cretaceous Research. 2022:105165. [Subscription required for full text]

New data on diversity and distribution of Asian forest scorpions in India

 

Last fall, Bagari Ramakrishna and Chelmala Srinivasulu published a study on the diversity and distribution of Asian forest scorpions (Scorpionidae) in Telangana State, India. Four species from the genera Chersonesometrus Couzijn, 1978, Gigantometrus Couzijn, 1978 and Deccanometrus Prendini and Loria, 2020 were recorded.

The Asian forest scorpions are of great interest among both researchers and scorpion enthusiasts and I thought this article would be of interest even though it was published last year.

Abstract:
Asian forest scorpions belong to the subfamily Heterometrinae and include some of the poorly known scorpion fauna in India in general and Telangana State in particular. The Asian forest scorpions occur in South Asia and Southeast Asia and are known from Pakistan in west to the Philippines in the east. There are 27 species of Asian forest scorpions belonging to seven genera Chersonesometrus, Deccanometrus, Gigantometrus, Heterometrus, Javanimetrus, Sahyadrimetrus and Srilankametrus known from India. These are the largebodied scorpions that are subjected to killing and local collections. Information on their distribution and current taxonomy is not complete. We provide the updated taxonomy, description and distribution maps of four species of Asian forest scorpions known to occur in Telangana State, India.

Reference:
Ramakrishna B, Srinivasulu C. Diversity and distribution of Asian forest scorpions (Arthropoda, Scorpionidae, Heterometrinae) in Telangana State, India. Notulae Scientia Biologicae. 2021;13(3):10977. [Open Access]

Prey capture, venom use and toxicity in Tityus fuhrmanni

 

The study of prey capure and types of prey in relation to scorpion morphology and/or venom potency has been of interest for many years. Alejandra Arroyave-Muñoz and co-workers have recently published a study trying to determine the relationship between feeding behavior and venom toxicity in the medical important species Tityus fuhrmanni Kraepelin, 1914 (Buthidae).

The main conclusions from this study is that T. fuhrmanni is a species with a generalist diet, has a venom with a different potency among prey and that is capable of discriminating between prey types and employing distinct strategies to subdue them.

Abstract:
Background: Scorpions are arachnids that have a generalist diet, which use venom to subdue their prey. The study of their trophic ecology and capture behavior is still limited compared to other organisms, and aspects such as trophic specialization in this group have been little explored.
Methods: In order to determine the relationship between feeding behavior and venom toxicity in the scorpion species Tityus fuhrmanni, 33 specimens were offered prey with different morphologies and defense mechanisms: spiders, cockroaches and crickets. In each of the experiments we recorded the following aspects: acceptance rate, immobilization time and the number of capture attempts. The median lethal dose of T. fuhrmanni venom against the three different types of prey was also evaluated.
Results: We found that this species does not have a marked difference in acceptance for any of the evaluated prey, but the number of capture attempts of spiders is higher when compared to the other types of prey. The immobilization time is shorter in spiders compared to other prey and the LD50 was higher for cockroaches.
Conclusions: These results indicate that T. fuhrmanni is a scorpion with a generalist diet, has a venom with a different potency among prey and is capable of discriminating between prey types and employing distinct strategies to subdue them.

Reference:
Arroyave-Munoz A, van der Meijden A, Estrada-Gomez S, Garcia LF. Linking toxicity and predation in a venomous arthropod: the case of Tityus fuhrmanni (Scorpiones: Buthidae), a generalist predator scorpion. J Venom Anim Toxins Incl Trop Dis. 2022;28:e20210036. [Open Access]

Thanks to Luis Fernando García for sending me their article!

Observations on regeneration of the pedipalp and legs of scorpions

 

Morphological anomalies in scorpions are well known. Some are inborne teratologies, others are caused becaused a failed molting process or due to accidents from predators attacs and similar. Scorpions can survive the loss of or damages to some of the appendages, but loss of the last part of the tail will usually cause death after a certain time as the anal organs are gone and the scorpion will die of constipation. 

Lost or damaged appendages can be reganerated completly or partly in scorpions during future molts. Martin Watz and Jason Dunlop have recently published a study on this topic and presented two cases of regeneration observed in scorpions in captivity relating to the pedipalp and legs. 

Abstract:
Two examples of scorpion limb regeneration following unsuccessful molts are documented based on material held in captivity. An Opisthacanthus asper (Peters, 1861) (Hormuridae) shows a relatively rare example of pedipalp regeneration in which the lost tibia and tarsus was replaced by a smaller, curved element of uncertain homology to either the fixed or free finger. A comparable abnormal palp described in the literature hints that pedipalps can only regenerate a structure of this form, regardless of the site of amputation. An Olivierus caucasicus (Nordmann, 1840) (Buthidae) is described in which claws (pretarsus) of leg III regenerated directly at the distal end of the tibia, while in leg IV the claws regenerated at the end of a truncated section of the metatarsus. This supports previous observations that scorpions can only regenerate the pretarsus of the leg, again irrespective of where on the limb the original breakage occurred.

Reference:
Watz M, Dunlop JA. Observations on regeneration of the pedipalp and legs of scorpions. Euscorpius. 2022(345):1-5. [Open Access]

Thanks to Martin Watz for sending me their article!