Molecular phylogeny and historical biogeography of genera Eristicophis and Pseudocerastes (Ophidia, Viperidae)

The genus Pseudocerastes comprises three species of false‐horned vipers: P. fieldi, P. persicus and P. urarachnoides. Pseudocerastes fieldi and P. persicus were once regarded as two subspecies of the same species. Recent morphological, molecular and toxicological studies elevated these two subspecies to species rank. Upon discovery of a third species, phylogeny and systematic relationships within this genus based on morphology were complicated. A total of 113 specimens of these three species across the Middle‐East were used to perform phylogenetic and biogeographic study. Using both mitochondrial (16S and Cytb) and Nuclear (C‐mos) markers and Bayesian and Maximum Likelihood approaches a robust phylogeny of the group was generated. The phylogenetic findings show that Eristicophis is the closest living relative to Pseudocerastes. Pseudocerastes fieldi holds a basal position within the genus Pseudocerastes, sister to a taxon comprising P. persicus and P. urarachnoides. Each of these three species is divided into two main clades with further subdivisions. Divergence time estimation indicates that splitting between genera Eristicophis and Pseudocerastes occurred in early Miocene with further main splitting within genus Pseudocerastes that occurred in middle to late Miocene. Additional splittings within each of these species took place during early Pliocene to late Pleistocene. Speciation and cladogensis within this genus coincide with different historical events varying from tectonics to paleoclimatic events which may have resulted in vicariance and dispersal of different populations. The clade comprised of sister genera Eristicophis and Pseudocerastes has an Arabian Peninsula – Iranian Plateau origin with an eastward distribution from western Arabia to the Iranian Plateau.