22 June, 2017

On the phylogeny of diplocentrid scorpions


Carlos E. Santibáñez-López and co-workers have recently published an article on the phylogeny of diplocentrid scorpions. I have to be honest and say that this stuff is very much over my head and I just have to ask you to check out the abstract and the article for more details. Unfortunately, phylogeny and molecular taxonomy was not on the curriculum when I got my zoology educations in the previous millenium.

In a revision of the higher scorpion systematics, Soleglad & Fet (2003) abolished the family Diplocentridae and included all genera into Scorpionidae. This have been criticized by parts of the scorpion expert community, who treat this taxa as a valid family (Diplocentridae). This is also the case with the present article. The scorpion Files still lists Diplocentridae as a subfamily, but this is under consideration and may change in the time to come after I get input from my contacts in the scorpion expert community.

Abstract:
Morphology still plays a key role in the systematics and phylogenetics of most of the scorpion families and genera, including the Diplocentridae Karsch, 1880. The monophyly of this family, and the monophyly of its two subfamilies is supported by morphological characters; however, neither hypothesis has been tested using molecular data. The lack of a molecular phylogeny has prevented the study of the evolution of morphology within the family. Here, we examine the morphological evolution of several key character systems in diplocentrid systematics. We tested the monophyly of the Diplocentridae, and subsequently the validity of its two subfamilies using a five-locus phylogeny.We examined the variation and evolution of the shape of the carapace, the external surface of the pedipalp patella and the retrolateral surface of the pedipalp chelae of males and females. We also examined the phylogenetic signal of discrete and continuous characters previously reported. We show that Diplocentridae is monophyletic, but Nebinae is nested within Diplocentrinae. Therefore, Nebinae is synonymised with Diplocentrinae (new synonymy). Finally, we show that a new character system proposed here, tarsal spiniform and macrosetal counts, retains high phylogenetic signal and circumscribes independently evolving substructures within this character system.

Reference: 
Santibanez Lopez CE, Kriebel R, Sharma PP. eadem figura manet: Measuring morphological convergence in diplocentrid scorpions (Arachnida : Scorpiones : Diplocentridae) under a multilocus phylogenetic framework. Invertebrate Systematics. 2017;31:233-48. [Subscription required for full text]

Thanks to Dr. Santibáñez-López for sending me their article!

Family Scorpionidae

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