01 October, 2015

The first phylogenetic analysis of the genus Brachistosternus based on molecular and morphological data has been published

Brachistosternus Pocock, 1893 (Bothriuridae) is a very abundant taxa in most arid to semi-arid habitats of southern and western South America. Andres Ojanguren-Affilastro and co-workers have recently published the first phylogenetic analysis of Brachistosternus based on molecular and morphological data.

See abstract and article for further details.

A phylogenetic analysis of the scorpion genus Brachistosternus Pocock, 1893 (Bothriuridae Simon, 1880) is presented, based on a dataset including 41 of the 43 described species and five outgroups, 116 morphological characters and more than 4150 base-pairs of DNA sequence from the nuclear 18S rDNA and 28S rDNA gene loci, and the mitochondrial 12S rDNA, 16S rDNA, and Cytochrome c Oxidase Subunit I gene loci. Analyses conducted using parsimony, Maximum Likelihood and Bayesian Inference were largely congruent with high support for most clades. The results confirmed the monophyly of Brachistosternus, the nominal subgenus, and subgenus Ministernus Francke, 1985, as in previous analyses based only on morphology, but differed in several other respects. Species from the plains of the Atacama Desert diverged basally whereas the high altitude Andean species radiated from a more derived ancestor, presumably as a consequence of Andean uplift and associated changes in climate. Species limits were assessed among species that contain intraspecific variation (e.g., different morphs), are difficult to separate morphologically, and/or exhibit widespread or disjunct distributions. The extent of convergence in morphological adaptation to life on sandy substrata (psammophily) and the complexity of the male genitalia, or hemispermatophores, was investigated. Psammophily evolved on at least four independent occasions. The lobe regions of the hemispermatophore increased in complexity on three independent occasions, and decreased in complexity on another three independent occasions.

Ojanguren-Affilastro AA, Mattoni CI, Ochoa JA, Ramirez MJ, Ceccarelli FS, Prendini L. Phylogeny, species delimitation and convergence in the South American bothriurid scorpion genus Brachistosternus Pocock 1893: Integrating morphology, nuclear and mitochondrial DNA. Mol Phylogenet Evol. 2015 Aug 28;94(Pt A):159-70. [Subscription required for full text]

Thanks to Victor Fet and Andres Ojanguren for both sending me this article!

Family Bothriuridae

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