Phylogenetic study gives Hadruridae family status ("Another one bites the dust")

There have been buzz about Carlos E. Santibáñez-López' and co-worker's new phylogenetic study of the family Caraboctonidae Kraepelin, 1905 for several months, but due to several reasons I have been slow to post this on the blog. But here it is and The Scorpion Files' family pages have also been updated.

I'm not going to go into details about the study here as I must admit that the more technical stuff is above my head, but I will list the main conclusions from the study:

1.
Hadrurinae Stahnke, 1973 is split from Caraboctonidae and elevated to family status, Hadruridae. Hadruridae consists of nine species in the two genera Hadrurus Thorell, 1876 and Hoffmannihadrurus Fet & Soleglad, 2004. Distributed in North America.

2.
Caraboctonidae now consists of 23 species in two two genera Caraboctonus Pocock, 1893 and Hadruroides Pocock, 1893. Distributed in South America.

3.
Two new superfamilies have been created: Caraboctonoidea Kraepelin, 1905 (Caraboctonidae and Superstitioniidae) and Hadruroidea Stahnke, 1974 (Hadruridae).

4.
The genera Uroctonus Thorell, 1876  (currently in Chactidae)  and Belisarius Simon, 1879 (currently in Belisaridae) are regarded as insertae sedis with respect to superfamilial placement.

More phylogenomic analyses will probably give us more insight in the complicated higher-level relationships in scorpions.

Abstract:
Historically, morphological characters have been used to support the monophyly, composition, and phylogenetic relationships of scorpion families. Although recent phylogenomic analyses have recovered most of these traditional higher level relationships as non-monophyletic, certain key taxa have yet to be sampled using a phylogenomic approach. Salient among these is the monotypic genus Caraboctonus Pocock, 1893, the type species of the family Caraboctonidae Kraepelin, 1905. Here, we examined the putative monophyly and phylogenetic placement of this family, sampling the library of C. keyserlingi Pocock, 1893 using high throughput transcriptomic sequencing. Our phylogenomic analyses recovered Caraboctonidae as polyphyletic due to the distant placement of the genera Caraboctonus and Hadrurus Thorell, 1876. Caraboctonus was stably recovered as the sister-group of the monotypic family Superstitioniidae Stahnke, 1940, whereas Hadrurus formed an unstable relationship with Uroctonus Thorell, 1876 and Belisarius Simon, 1879. Fourcluster likelihood mapping revealed that the instability inherent to the placement of Hadrurus, Uroctonus and Belisarius was attributable to significant gene tree conflict in the internodes corresponding to their divergences. To redress the polyphyly of Caraboctonidae, the following systematic actions have been taken: (1) the family Caraboctonidae has been delimited to consist of 23 species in the genera Caraboctonus and Hadruroides Pocock, 1893; (2) Caraboctonidae, previously included in the superfamily Iuroidea Thorell, 1876 or as incertae sedis, is transferred to the superfamily Caraboctonoidea (new rank); (3) the superfamily Hadruroidea (new rank) is established and the status of Hadrurinae Stahnke, 1973 is elevated to family (Hadruridae new status) including 9 species in the genera Hadrurus and Hoffmannihadrurus Fet & Soleglad, 2004 and (4) we treat Uroctonus and Belisarius as insertae sedis with respect to superfamilial placement. Our systematic actions engender the monophyly of both Iuroidea and Caraboctonidae. Future phylogenomic investigations should target similar taxon-poor and understudied

References:
Santibáñez-López CE, Ojanguren-Affilastro AA, Sharma PP. Another one bites the dust: Taxonomic sampling of a key genus in phylogenomic datasets reveals more non-monophyletic groups in traditional scorpion classification. Invertebrate Systematics. 2020;34(2):133-43. [Subscription required for full text]

Thanks to Carlos E. Santibáñez-López and Prashant P. Sharma who have kept me informed about their study. I have also been informed about this article by Kari McWest and Matt Simon. Big thanks to them!

Family Caraboctonidae
Family Hadruridae

Density, spatial distribution and biomass of Hoffmannihadrurus gertschi

Ana Quijano-Ravell and co-workers have recently published an article on the density, spatial distribution and biomass of Hoffmannihadrurus gertschi (Soleglad, 1976) (Caraboctonidae)* in an area in Mexico.

The paper is written in Spanish so I have only read the English abstract.

[*The authors have placed this species in Hadrurus, but it was transfered to Hoffmannihadrurus by Fet & Soleglad i 2008 and this species is listed as Hoffmannihadrurus gertschi (Soleglad, 1976) in The Scorpion Files. Some scientists disagree on the validity of Hoffmannihadurus, as this paper is an example of. Also, some scientists choose to put Hadrurus in Iuridae and reject the validity of Caraboctonidae. See details here.]

Abstract:
Density, spatial dispersion and biomass of Hadrurus gertschi Soleglad 1976 were estimated from field data obtained during a year of observations at “La Coronilla” hill in the municipality of Tepecoacuilco de Trujano, Guerrero, Mexico. Five quadrants of 400 m2 with differing slope exposures were used. The highest density was recorded in the quadrant without slope or “flat quadrant” with 0.3450 burrows per m2 and the southern exposure quadrant (0.2300 burrows per m2). The lowest densities occurred in the quadrants with northern and western exposures (0.1325 and 0.0825 burrows per m2 respectively). The highest values of the year were recorded in the months of May to July. The spatial dispersion of burrows in all exposures studied corresponds with a clumped distribution according to the Morisita Index. Average dry weight of adults was 2.22 ± 0.73 g and 6.4 ± 0.89 g in fresh weight. The juveniles weighted 0.08 ± 0.05 g in dry weight and 0.2 of fresh weight instar II and 1.10 ± 0.41 g dry weight and 3.63 ±1.95 g in fresh weight in the preadult stage. The biomass per ha was estimated in 2471.26 g of dry weight and 6190.02 g of fresh weight.

Reference:
Quijano-Ravell AF, Ponce-Saavedra J, Francke OF. Densidad, distribucion espacial y biomasa de Hadrurus gertschi Soleglad (Scorpiones, Iuridae) en una localidad de Guerro, Mexico. Revista Iberica de Arachnologia. 2012;20:35-43.

Thanks to Dr. Francke for sending me this paper!

Family Caraboctonidae

Life cycle of Hadrurus gertschi from Mexico

Ana Quijano-Ravell and co-workers have now published a study on the life cycle of Hadrurus gertschi Soleglad, 1976 (Caraboctonidae)*

[*This species was transfered to Hoffmannihadrurus by Fet & Soleglad i 2008 and this species is listed as Hoffmannihadrurus gertschi (Soleglad, 1976) in The Scorpion Files. Some scientists disagree on the validity of Hoffmannihadurus, as this paper is an example of. Also, some scientists choose to put Hadrurus in Iuridae and reject the validity of Caraboctonidae. See details here.]

Abstract:
The life cycle of Hadrurus gertschi Soleglad 1976 was reconstructed from field data taken during one year of observations in “La Coronilla”, near Ahuehuepan, in Tepecoacuilco de Trujano municipality, Guerrero, Mexico. The species inhabits tropical dry schrub forest in sympatry with three other scorpion species: Centruroides limpidus (Karsch 1879), Vaejovis variegatus Pocock 1898 and Vaejovis atenango Francke and González-Santillán 2007. A growth factor of 1.27 for the carapace length was determined and then used to estimate the morphometric changes between each instar to reach the adult stage and compared them with data obtained in the field. We concluded that this species requires 7 instars and 6 molts, and at least four years to reach adulthood. We also present the phenology of Hadrurus gertschi during one year, measured in relative abundance and surface activity pattern. Matting activity was observed in July, August, September and October.

Reference:
Quijano-Ravell AF, Ponce-Saavedra J, Francke OF. Ciclo de vida de Hadrurus gertschi Soleglad (Scorpiones, Iuridae) en una localidad del Estado de Guerrero, Mexico. Revista Iberica de Arachnologia. 2011;19(133-145).

Thanks to Oscar Francke for sending me this paper!

Family Caraboctonidae

More on the genera Hadrurus and Hoffmannihadrurus

Michael Soleglad and Victor Fet have recently published a paper with further observations on the genera Hadrurus Thorell, 1876 and Hoffmannihadrurus Fet & Soleglad, 2004 (both Caraboctonidae).

Abstract:
Multiple populations of Hadrurus pinteri from Baja California Sur, Mexico have been examined. It is demonstrated that the southern populations of this species have a larger number of accessory trichobothria (neobothriotaxy) than the northern populations, numbers exceeding the maximum currently recorded for the genus. Examination of carapace and chela coloration and its patterns show a close affinity between H. pinteri and the dark phase of H. concolorous. A new morphometric ratio of the carapace is defined that distinguishes Hadrurus from Hoffmannihadrurus, further supporting the monophyly of the latter genus.

Reference:
Soleglad ME, Fet V. Further observations on scorpion genera Hadrurus and Hoffmannihadrurus (Scorpiones, Caraboctonidae). ZooKeys. 2010;59:1-13. [Free fultext]

Thanks to Victor Fet for sending me this paper!

Family Caraboctonidae

Cladistic analysis of superfamily Iuroidea, with emphasis on subfamily Hadrurinae (Scorpiones: Iurida) and Hoffmannihadurus is reinstated

The Caraboctonid genus Hoffmannihadrurus Fet & Soleglad, 2004 was synonized with Hadrurus by Francke & Prendini, 2008 in June in their review of the taxonomic history of the North American genus Hadrurus.

This decision has now been refuted by Fet & Soleglad, 2008 in their recently published cladistic analysis of superfamily Iuroidea, with emphasis on subfamily Hadrurinae. The genus Hoffmannihadrurus is reinstated and the two species belonging to the genus are transfered from Hadrurus:

Hoffmannihadrurus Fet & Soleglad, 2004 (Caraboctonidae)

Hoffmannihadrurus aztecus (Pocock, 1902)
Hoffmannihadrurus gertschi (Soleglad, 1976)

References:
Fet V, Soleglad ME. Cladistic analysis of superfamily Iuroidea, with emphasis on subfamily Hadrurinae (Scorpiones: Iurida). Boletin Sociedad Entomológica Aragonesa. 2008(43):255-81.

Family Caraboctonidae

A phylogenetic review of the genus Hadurus and synonymization of Hoffmannihadrurus with Hadurus

Oscar Francke and Lorenzo Prendini have recently published a paper where they review the taxonomic history of the North American genus Hadrurus Thorell, 1876 and re-evaluate the phylogenetic relationships among the genus' species. In the same paper they also propose a synonymization of Hoffmannihadrurus Fet & Soleglad 2004 with Hadrurus. This means that the following names are valid for the two species previously included in Hoffmannihadrurus:

Hadrurus aztecus Pocock, 1902
Hadrurus gertschi Soleglad, 1976

Here is the abstract of the paper:

The ‘giant hairy scorpions’, genus Hadrurus Thorell, are the largest and most conspicuous scorpions in North America, but their systematics has long been confused. A new genus, Hoffmannihadrurus Fet et al. was recently created to accommodate the two species endemic to mainland Mexico, Hadrurus aztecus Pocock and Hadrurus gertschi Soleglad. In the present contribution, we review the taxonomic history of Hadrurus, re-evaluate the phylogenetic relationships among its component species with an analysis based on morphological characters and a taxon sample representing the known morphological variation, and assess the validity of the new genus. Seven independent analyses of the morphological character matrix, under weighting regimes that minimised length as well as those that maximised fit, each located a single most parsimonious tree with the following scheme of relationships: (Iurus ((Caraboctonus + Hadruroides) (H. aztecus ((H. gertschi + H. pinteri) (H. concolorous + H. hirsutus)) ((H. obscurus + H. spadix) (H. a. arizonensis (H. a. austrinus + H. a. pallidus)))))). This topology supports the monophyly of Caraboctoninae, Caraboctonini, Hadrurini, the ‘arizonensis’ subgroup, H. arizonensis and H. concolorous. It does not support the monophyly of Hoffmannihadrurus, Hadrurus, the ‘aztecus’ group, the ‘hirsutus’ group, and the ‘hirsutus’ subgroup, all of which were rendered paraphyletic by the grouping of H. gertschi with H. pinteri, rather than with H. aztecus. The results unequivocally demonstrate that the creation of a new genus for the mainland Mexican species was unfounded. We therefore propose the following new synonymy: Hoffmannihadrurus Fet et al., 2004 = Hadrurus Thorell, 1876, syn. nov.

Did you know that in Mexico the large Hadrurus are known as "Matacaballos", which actually means "Horse killers". Fortunately, studies have shown that the venom of these impressing scorpions has low toxicity against mammals.

Reference:
Francke OF, Prendini L. Phylogeny and classification of the gigant hairy scorpions, Hadrurus Thorell (Iuridae Thorell): a reappraisal. Systematics and Biodiversity. 2008;6(2):205-23. [Subscription required for fulltext]

Family Caraboctonidae