PHYLOGENY OF MESOBUTHUS EUPEUS (C.L.Koch, 1839) IN IRAN USING CO1 SEQUENCES

Abstract

The genus Mesobuthus belonging to family Buthidae is most diverse in Central Asia and Iran. The<br><br>scorpion M.eupeus is one of the most naturally widespread members of the family Buthidae, being<br><br>present in eastern Turkey, Caucasia, southern Russia, Middle East, Central Asia, southern Mongolia<br><br>and northern China. Additionally, considerable morphological variation has been attributed to<br><br>populations of M.eupeus within this extensive geographic distribution and 21 recognized valid<br><br>subspecies have been described. A recent comprehensive update or revision of M.eupeus is not<br><br>available.<br><br>In this study, the first molecular phylogeny assessment of M.eupeus in Iran based on sequence<br><br>data of a ~700bp fragment of Cytochrome C oxidase, subunit I is presented. Fifteen populations<br><br>collected from different localities within Iran were included in the study. Phylogenetic<br><br>relationships were inferred using neighbour-joining (p-distance) and maximum likelihood under<br><br>GTR+&#915; substitution model. The results support monophyly for M.eupeus, but they do show<br><br>a clear deep split between northern and southern clades within the species. The northern clade<br><br>included M.e.eupeus, M.e philippovitschi, M.e.afghanus, and M.e.thersites, while the southern<br><br>clade comprised M.e.phillipsi and M.e.kirmanensis. In the topology observed, the \\"southern clade\\"<br><br>has a basal position relative to the \\"northern clade\\". Accordingly, some scenarios for the evolution<br><br>and phylogeographic structure of this species based on the paleogeography and geological history<br><br>of Iranian plateau were proposed and tested. In addition to the intraspecific divergence, our<br><br>topology showed a deeper phylogenetic split within the genus Mesobuthus. Here, a \\"western<br><br>clade\\" consisting of M. gibbosus and M. cyprius is separated from an \\"eastern clade\\" containing M.eupeus and M.caucasicus. Finally, the molecular clock hypothesis using the likelihood ratio test<br><br>was applied in order to test the constancy of the evolutionary rates across the tree.