31 December, 2020

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.

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.

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

30 December, 2020

A new species of Euscorpius from Bulgaria


The unravelling of Europe's hidden Euscorpius species is continuing. Frantisek Kovarik and co-workers have recently described a new species of Euscorpius Thorell, 1876 (Euscorpiidae) from Bulgaria.

Euscorpius thracicus Kovarik, Lowe, Byronova & Stahlavsky, 2020*

Euscorpius thracicus sp. n. from eastern Bulgaria is described, fully complemented with color photographs of both live and preserved specimens, as well as their habitats. This species is described based on morphology and the cytochrome oxidase I (COI) DNA barcoding marker. In addition to the analyses of external morphology and hemispermatophore, we also describe the karyotype of E. thracicus sp. n. (2n=92).

Kovarik F, Lowe G, Byronova M, Stahlavsky F. Euscorpius thracicus sp. n. (Scorpiones: Euscorpiidae) from Bulgaria. Euscorpius. 2020(326):1-17. [Open Access]

Family Euscorpiidae

An extensive study on foraging and prey capture in Centruroides vittaus


In my forthcomming posts I will try to present many studies published in November and December that I never got time to blog about. 

C. N. McReynolds published an extensive study on prey capture and foraging in the buthid Centruroides vittatus  (Say, 1821) in South Texas in November. The study looked on how the taxa of prey captured by this scorpion changed with size of the scorpion and the season of the year. The main conclusion is that the taxa of prey captured by C. vittatus do change with size of the scorpion and the season of the year. This paper has a lot of information and data on foraging in this species and I refer to the abstract and article for further details.

Diet and foraging success of the striped bark scorpion, Centruroides vittatus, in South Texas are influenced by both scorpion size and season of the year. In the ten-year study of the striped bark scorpions in the blackbrush habitat of south Texas, the diet was variable with caterpillars (Lepidoptera) as the main prey for all seasons and all size classes of scorpions. The proportion of caterpillars did vary significantly with size class of scorpion and months of the year with intermediate size scorpions capturing more caterpillars during January–April than other size classes or months of the year. The proportion of orthopteran and intraguild prey was higher during September-December and for large scorpions. The height of scorpions was significantly different among prey types and scorpion size classes or prey types and months of the year. The median height of scorpions with caterpillar prey was significantly higher than scorpions with orthopteran or intraguild prey. The intermediate size scorpions with caterpillar prey and scorpions with caterpillar during January–April were higher in vegetation than scorpions with other prey, other size classes and/or months of the year. The foraging success of scorpions varied significantly with size class and month of the year. The highest foraging success was the intermediate size scorpions during January–April and the lowest was the large scorpions during January–April. However, the larger scorpions had the second highest foraging success during September–December. These results suggest that C. vittatus use both active search and ambush (sit-and-wait) foraging methods. The intermediate size scorpions capture more caterpillars than other size classes of scorpions by actively foraging in vegetation especially during January-April. The larger scorpions do not appear to interfere with the foraging success of intermediate or smaller scorpions even though cannibalism is observed.

McReynolds CN. Effect of seasons and scorpion size on the foraging and diet of the striped bark scorpion, Centruroides vittatus (Buthidae: Scorpiones) in blackbrush habitat of south Texas. Euscorpius. 2020(323):1-16. [Free full text]

24 December, 2020

Season Greetings from The Scorpion Files


Season Greetings to all scorpion enthusiasts around the world from the author anno 1987. Due to the Corona epidemic, home office and an increased workload there have been few posts in the last moths. I hope to get back to a normal post frequency in 2021.

Please stay safe and enjoy the holiday!

Jan Ove Rein
The Scorpion Files