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We discovered a previously unrecognized evolutionary lineage of Eremias assigned to the subgenus Rhabderemias in the Pakistan–Afghanistan border region. Although superficially similar to the recently described Iranian species E. graphica in its vermiculate dorsal pattern, mitochondrial phylogenetic analyses recover this lineage as sister to E. fasciata, while nuclear DNA data independently support its distinctiveness. The new lineage was recorded from low, mobile sand dunes in northwestern Balochistan, Pakistan, at the southeastern margin of the Registan Desert. It is clearly differentiated from E. fasciata by both mitochondrial and nuclear markers, with mean uncorrected p-distances of approximately 10.6% for mitochondrial DNA and 0.9% for nuclear DNA. Morphologically, it differs from most species traditionally assigned to Rhabderemias in retaining a vermiculate dorsal pattern in both juveniles and adults rather than the longitudinally striped pattern characteristic of the group. It is further distinguished from E. graphica and the sympatric E. fasciata by a combination of dorsal coloration, scalation, body proportions, and habitat association, with multivariate morphological analyses supporting its distinctiveness from both species. Given the continuity of suitable sandy habitats across international borders, the new species is likely to occur more widely within the Registan Desert of southwestern Afghanistan and possibly adjacent eastern Iran. Our integrative analyses also provide the first definitive confirmation of the long-debated occurrence of E. fasciata in Pakistan. These findings increase the known diversity of Rhabderemias to 12 species, five of which occur in Pakistan, and bring the total number of Eremias species recorded from the country to eight.

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We provide a diversity assessment of Iranian species of the genus Eremias based on the cytochrome oxidase I mtDNA gene fragment. We analyzed 93 genetic samples from the entire distribution of the Eremias fasciata species complex in Iran and surrounding regions, along with morphological data to support the description of two new species from Central Iran. We hypothesize that the diversification of the Eremias fasciata species complex was largely influenced by the fragmentation of sand massifs in the region. This same hypothesis has been used to explain the high level of endemism among the sand-dwelling species of reptiles along the Iranian Plateau in the same area. The two new species described herein can be distinguished from other congeneric species by their phylogenetic position and a combination of morphological characters. We use these data to discuss the taxonomy of Eremias based on morphology, habitat choice, and genetic data.