03 May, 2020

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:

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.

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

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

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.

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

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

No comments: