29 March, 2019

A new species of Chaerilus from Vietnam

Wilson Lourenco has recently published a new species of Chaerilus Simon, 1877 (Chaerilidae) from Vietnam.

Chaerilus honba Lourenco, 2019


Lourenco WR. The genus Chaerilus Simon, 1877 (Scorpiones: Chaerilidae) in Vietnam, with the description of a new species. Arachnology. 2019;18(1):32-6.

Family Chaerilidae

28 March, 2019

A new phylogenomic study reassessing the relationships of Vaejovidae and a new high-level classification of Scorpiones

The higher-level systematics of scorpions has been significantly revised and discussed in the recent year, not without controversies.The family division chosen in The Scorpion Files are not accepted by all researchers, but fortunately more research are being done making the picture more clearly. There may be changes in the family structure in The scorpion Files in the time to come when I have the time to review recent contributions on higher-level systematics.

Carlos E. Santibáñez-López and co-workers have recently published a study  reassessing the relationships of Vaejovidae and a new high-level classification of Scorpiones. According to co-author Prashant Sharma, the main conclusions are:

1. As presently defined, Vaejovidae is diphyletic (Uroctonus are not true vaejovids).

2. The true Vaejovidae (excluding Uroctonus) are the sister group of Scorpionoidea.

3. To accommodate this tree topology, the study established two  superfamilies to redress the paraphyly of Chactoidea: Vaejovoidea and Superstitionoidea.

The scorpion Files doesn't list higher-level systematics, but it is important to note that status of Uroctonus Thorell, 1876 has to be set to incertae sedis because it doesn't belong to either Vaejovidae or Chactidae. More studies are necessary before its family placement can be decided. Until this happens, I keep the genus in Chactidae.

The Neartic family Vaejovidae (Scorpiones: Chactoidea) has long been treated as a diverse and systematically cohesive group of scorpions, but its monophyly and relationship to other scorpion families have historically been questioned. Morphological data have supported its monophyly and a variety of phylogenetic placements within the superfamily Chactoidea. Recent phylogenomic analyses have instead recovered vaejovids as polyphyletic (albeit with minimal taxonomic sampling) and Chactoidea as paraphyletic. Here, we reexamined the monophyly and phylogenetic placement of the family Vaejovidae, sampling 17 new vaejovid libraries using high throughput transcriptomic sequencing. Our phylogenomic analyses revealed a previous misplacement of Smeringurus mesaensis. Regardless, we recovered Vaejovidae as diphyletic due to the placement of the enigmatic genus Uroctonus. The remaining vaejovids formed a clade that was strongly supported as the sister group of the superfamily Scorpionoidea, a placement insensitive to matrix completeness or concatenation vs. species tree approaches to inferring the tree topology. Chactoidea was invariably recovered as a paraphyletic group due to the nested placement of Scorpionoidea. As first steps to resolving the paraphyly of Chactoidea, we take the following systematic actions: (1) we establish the superfamily Superstitionoidea (new superfamily) to accommodate Superstitioniidae; (2) we restore Vaejovoidea (status revalidated) as a valid superfamily that excludes Uroctonus; and (3) we treat the families Caraboctonidae, Troglotayosicidae, and the subfamily Uroctoninae as incertae sedis with respect to superfamilial placement. Our systematic actions thus establish the monophyly of the presently redefined Chactoidea and Vaejovoidea.

Reference:Santibanez-Lopez C, Gonzalez-Santillan E, Monod L, Sharma PP. Phylogenomics facilitates stable scorpion systematics: Reassessing the relationships of Vaejovidae and a new high-level classification of Scorpiones (Arachnida). Mol Phylogenet Evol. 2019;135:22-30. [Subscription required for full text]

Thanks to Dr. Prashant Sharma for sending me this article and for explaining to me the main points of this study. Thanks also to Carlos E. Santibáñez-López for sending me the paper.

14 March, 2019

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.

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.

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!

Distribution and habitat of Euscorpius carpathicus in Romania

Euscorpius carpathicus (Linnaeus, 1767) (Euscorpiidae) was previously distributed all over Europe, but modern taxonomy revealed that it was a major species complex hiding many unique species. Today, E. carpathicus is limited to Romania only.

Severus-Daniel Covaciu-Marcov & Sára Ferenţi have recently published an article on the distribution of E. carpathicus in parts on Romania. Data on habitat is also presented.

In 2016-2018, we identified 48 distribution records of Euscorpius carpathicus in the Cozia National Park, from the Romanian Southern Carpathians. The Carpathian scorpion was found between 300 and 847 m a.s.l., in forested regions, being more numerous in the lower areas situated along the Olt River. E. carpathicus is a native species in the region; it populates natural areas with low human impact.

Covaciu-Marcov S-D, Ferenti S. An Endemic Species in a Protected Area: Euscorpius carpathicus (L., 1767) in the Cozia National Park, Romania (Scorpiones: Euscorpiidae). Euscorpius. 2019(279):1-6. [Open Access]

Family Euscorpiidae