27 February, 2015

A new phylogenetic study on scorpions

The phylogeny of scorpions has long been under discussion. Numerous workers have historically emphasized different morphological characters of scorpions, resulting in variable hypotheses of phylogeny, none of which has been generally accepted (e.g. there is no consensus on the family structure in scorpions). In this study, the authors have applied a phylogenomic assessment to resolve scorpion phylogeny based on molecular data. See abstract for more information.

Scorpions represent an iconic lineage of arthropods, historically renowned for their unique bauplan, ancient fossil record and venom potency. Yet, higher level relationships of scorpions, based exclusively on morphology, remain virtually untested, and no multilocus molecular phylogeny has been deployed heretofore towards assessing the basal tree topology. We applied a phylogenomic assessment to resolve scorpion phylogeny, for the first time, to our knowledge, sampling extensive molecular sequence data from all superfamilies and examining basal relationships with up to 5025 genes. Analyses of supermatrices as well as species tree approaches converged upon a robust basal topology of scorpions that is entirely at odds with traditional systematics and controverts previous understanding of scorpion evolutionary history. All analyses unanimously support a single origin of katoikogenic development, a form of parental investment wherein embryos are nurtured by direct connections to the parent’s digestive system. Based on the phylogeny obtained herein, we propose the following systematic emendations: Caraboctonidae is transferred to Chactoidea new superfamilial assignment; superfamily Bothriuroidea revalidated is resurrected and Bothriuridae transferred therein; and Chaerilida and Pseudochactida are synonymized with Buthida new parvordinal synonymies.

Sharma PP, Fernández R, Esposito LA, González-Santillán E, Monod L. Phylogenomic resolution of scorpions reveals multilevel discordance with morphological phylogenetic signal. Proceedings of the Royal Society B. 2015;282(1804):1-10. [Subscription required for full text]

Thanks to Prashant Sharma and Paulo André Margonari Goldoni for sending me this article!

No comments: