06 March, 2012

Buthus diversity, genetics and geographic isolation in North Africa

Jan Habel and co-workers have published a paper discussing how geographical barriers in North Africa may be the origin of the great diversity seen in the genus Buthus Leach, 1815 (Buthidae) in North Africa.

The high mountains in the region have probable acted (and stil act) as strong barriers to gene flow resulting in genetically distinct clusters found within the area. The clusters found are not necessarly congruent with current taxonomy, and the current taxonomy of the North African Buthus is in need of revision. Additional diagnostic characters must be identified and new species kleys must be developed, as the current keys available are incomplete or based on doubtful characters.

The immense biodiversity of the Atlas Mountains in North Africa might be the result of high rates of microallopatry caused by mountain barriers surpassing 4000 meters leading to patchy habitat distributions. We test the influence of geographic structures on the phylogenetic patterns among Buthus scorpions using mtDNA sequences. We sampled 91 individuals of the genus Buthus from 51 locations scattered around the Atlas Mountains (Antiatlas, High Atlas, Middle Atlas and Jebel Sahro). We sequenced 452 bp of the Cytochrome Oxidase I gene which proved to be highly variable within and among Buthus species. Our phylogenetic analysis yielded 12 distinct genetic groups one of which comprised three subgroups mostly in accordance with the orographic structure of the mountain systems. Main clades overlap with each other, while subclades are distributed parapatrically. Geographic structures likely acted as long-term barriers among populations causing restriction of gene flow and allowing for strong genetic differentiation. Thus, genetic structure and geographical distribution of genetic (sub)clusters follow the classical theory of allopatric differentiation where distinct groups evolve without range overlap until reproductive isolation and ecological differentiation has built up. Philopatry and low dispersal ability of Buthus scorpions are the likely causes for the observed strong genetic differentiation at this small geographic scale.

Habel JC, Husemann M, Schmitt T, Zachos FE, Honnen AC, Petersen B, et al. Microallopatry Caused Strong Diversification in Buthus scorpions (Scorpiones: Buthidae) in the Atlas Mountains (NW Africa). PloS one. 2012;7(2):e29403. Epub 2012/03/03. [Free fultext]

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