Molecular Assessment and Taxonomic Status of the Rapid Racerunner (Eremias velox complex) with Particular Attention to the Populations in Northwestern China

The rapid racerunner, Eremias velox, is a widely distributed lizard from the northern Caucasus across entire Central Asia eastward to China. It is increasingly common to accept E. velox as a species complex in its entire range. To date, published morphological and molecular systematic hypotheses of this complex are only partially congruent, and its taxonomic status and evolutionary history are still far from clear. The mitochondrial cytochrome b gene and 12S rRNA sequences were used to evaluate the taxonomy of this complex, with particular attention to the phylogenetic placement of populations in northwestern China. Examination of the phylogenetic analyses recovers seven distinct, biogeographically discrete, and well-supported clades, revealing genetically identifiable populations corresponding to some previously morphology-defined subspecies. Chinese E. v. roborowskii appears to have split from other Central Asian rapid racerunner lizards well before differentiation occurred among the latter taxa. Specifically, we corroborate that there are two subspecies occurring in China, i.e., E. v. velox and E. v. roborowskii. We recommend a novel subspecific status for the phenotypically and genetically distinct populations in southern Aral Sea region of Uzbekistan previously assigned to E. v. velox. Finally, each of the three independently evolving lineages from Iranian Plateau should be recognized as three species new to science under the general lineage concept.