Two new species described in the fascinating genus Megacormus from eastern Mexico

 

The genus Megacormus Karsch, 1881 (Euscorpiidae) is a small and fascinating genus that are reported  from tropical forest habitats in southeastern Mexico.  A special characteristics with this genus is that the species share a number of morphological features with the widespread European genera Alpiscorpius Gantenbein et al., 1999, Euscorpius Thorell, 1876 and Tetratrichobothrius Birula, 1917, and this is the reason why this genus is currently placed in the family Euscorpiidae. 

Rolando Teruel and co-workers have now described two new species in the genus from eastern Mexico.

Megacormus orizaba Teruel, Kovarik, Lowe & Stahlavsky, 2023

Megacormus seductus Teruel, Kovarik, Lowe & Stahlavsky, 2023

The article has information about the new species' habitat and also provides an updated identification key for the genus.

Abstract:
Two new species of the very interesting euscorpiid scorpion genus Megacormus Karsch, 1881, are herein described from eastern Mexico. Both had been previously misidentified in the published literature, one as Megacormus segmentatus Pocock, 1900, the other as Megacormus granosus (Gervais, 1844), but the direct comparison of adults of both sexes to adult topotypes from all members of the genus currently accepted as valid taxa, revealed solid morphological characters that warrant their recognition as distinct taxa. Both new species seem also to be endemics with a small distribution area, but apparently not restricted to a single locality. This addition raises the known composition of the genus to eight species, all of them exclusively from mountain sites of eastern Mexico.

Reference:
Teruel R, Kovarik F, Lowe G, Stahlavsky F. Two new species of the remarkable scorpion genus Megacormus Karsch, 1881 (Scorpiones: Euscorpiidae). Euscorpius. 2023(375):1-22. [Open Access]

Family Euscorpiidae

A revision of the genus Nebo in Saudi Arabia and a description of a new species from the Jazan Province

 

Bassam Abu Afifeh and co-workers have recently published a revision of the genus Nebo Simon, 1878 (Diplocentridae) in Saudi Arabia and a description of a new species from  the Jazan Province.

Nebo jazanensis Abu Afifeh, Aloufi, Al-Saraireh & Amr, 2023

Notes on the new species' habitat is also provided.

Abstract:
The genus Nebo Simon, 1878 in Saudi Arabia is revised based on morphometric and morphological characters for adult specimens. The presence of Nebo hierichonticus (Simon, 1872) has been justified for the first time from Saudi Arabia and compared with materials collected from Jordan. More specimens of Nebo yemenensis Francke, 1980 including adult males and females were collected and recorded in this study. Nebo jazanensis sp. n. is described and fully illustrated based on adult males and females collected from Jazan Province and compared with other species of the genus Nebo known from the Arabian Peninsula and Jordan. Notes on its habitats are provided.

Reference:
Afifeh BA, Aloufi A, Al-Saraireh M, Amr ZS. Revision of the Genus Nebo (Simon, 1878) in Saudi Arabia with a Description of a New Species from the Jazan Province (Scorpiones: Diplocentridae). Jordan Journal of Natural History. 2023;10(1):40-56. [Full text provided by authors]

Family Diplocentridae

A new species of Vaejovis from mountains in west Mexico

 

Mexico has a very diverse scorpion fauna with many species from different habitats. New species are still being discovered, especially in habitats that may have been isolated for a long time due to geographical barriers. In a recent article, Gerardo A. Contreras-Félix and co-workers have described a new species of Vaejovis C.L. Koch, 1836 (Vaejovidae) from mountains in west Mexico.

Vaejovis tilae Contreras-Felix, del-Pozo & Navarrete-Heredia, 2023

Abstract:
One new species of scorpion is described from the high lands of the Trans-Mexican Volcanic Belt province in the Mexican state of Jalisco; this species inhabit the pine forest of the Sierra de Quila mountain range. It is assigned to the “mexicanus” group and compared with other species geographically closer or morphologically similar, besides biology. The species honors Dr. Tila María Pérez Ortiz for its great career in arachnology.

Reference:
Félix GAC, del-Pozo OG, Navarrete-Heredia JL. A new species of Vaejovis from the mountains of west Mexico (Scorpiones: Vaejovidae). Dugesiana. 2023;30(2):229-45. [Open Access]

Thanks to Oscar Del-Pozo for sending me their article!

Family Vaejovidae

The genus Anuroctonus is transferred into a new family Anuroctonidae

 

The studies of higher-level classification of scorpions are far from resolved (superfamilies and families). Carlos E. Santib
anez-L
opez and co-workers have recently published a study on the monophyly and phylogenetic placement of Chactidae.

The results have lead to a decision to create a new family Anuroctonidae Santibanez-Lopez, Ojanguren-Affilastro, Graham & Sharma, 2023 and move the genus Anuroctonus Pocock, 1893 with its two species  from Chactidae to the new family. 

The authors state that this is only a first step in the analysis of Chactidae's position and more studies are necessary before we have the final answers.

Abstract:
Scorpions are ancient and historically renowned for their potent venom. Traditionally, the systematics of this group of arthropods was supported by morphological characters, until recent phylogenomic analyses (using RNAseq data) revealed most of the higher-level taxa to be non-monophyletic. While these phylogenomic hypotheses are stable for almost all lineages, some nodes have been hard to resolve due to minimal taxonomic sampling (e.g. family Chactidae). In the same line, it has been shown that some nodes in the Arachnid Tree of Life show disagreement between hypotheses generated using transcritptomes and other genomic sources such as the ultraconserved elements (UCEs). Here, we compared the phylogenetic signal of transcriptomes vs. UCEs by retrieving UCEs from new and previously published scorpion transcriptomes and genomes, and reconstructed phylogenies using both datasets independently. We reexamined the monophyly and phylogenetic placement of Chactidae, sampling an additional chactid species using both datasets. Our results showed that both sets of genome-scale datasets recovered highly similar topologies, with Chactidae rendered paraphyletic owing to the placement of Nullibrotheas allenii. As a first step toward redressing the systematics of Chactidae, we establish the family Anuroctonidae (new family) to accommodate the genus Anuroctonus.

Reference:
Santibáñez-López CE, Ojanguren-Affilastro AA, Graham MR, Sharma PP. Congruence between ultraconserved element-based matrices and phylotranscriptomic datasets in the scorpion Tree of Life. Cladistics. 2023. [Subscription required for full text]

Thanks to Matt Simon and Victor Fet for informing me about this article!

Family Anuroctonidae