An integrative systematic revision and biogeography of snakes (Reptilia, Colubridae) with a description of a new species from Israel.

Background: The colubrid snakes of the genus are seldom studied and knowledge of their ecology and life history is scarce. Three species of are currently recognized, (from Turkey eastwards to Iran), (Yemen and Oman), and (from the Sinai Peninsula northwards to Turkey). All are slender, secretive, mainly nocturnal and rare fossorial snakes. This comprehensive study is the first to sample all known species in order to review the intra-generic phylogenetic relationships and historical biogeography of the genus.

Methods: We revised the systematics of using an integrative approach and evaluated its phylogeography. The phylogenetic position within the Colubridae and the phylogenetic relationships within the genus were inferred using 29 individuals belonging to the three known species, with additional sampling of two other closely-related genera, and . We analysed three mitochondrial (, ) and one nuclear () gene fragments. Phylogenetic trees were reconstructed using maximum likelihood and Bayesian inference methods; the latter method also used to provide the first time-calibrated molecular phylogeny of the genus. We generated a nuclear network and carried out a topology test and species delimitation analysis. Morphological comparisons were used to differentiate among species and to describe a new species from Israel. The studied material was comprised of 108 alcohol-preserved specimens, 15 photographs, and data from the literature for the examination of 17 mensural, 14 meristic, and two categorical characters.

Results: The molecular results support as monophyletic, and as having split from its sister genus during the Late Oligocene. The three recognized species of comprise four independently evolving groups. The molecular results reveal that the genus began to diverge during the Middle Miocene. We revealed that the best-studied species, is paraphyletic. A population, formally ascribed to this species, from the Negev Mountain area in southern Israel is phylogenetically closer to from Oman than to the northern populations of the species from Israel, Syria and Turkey. Herein we describe this population as a new species:

Discussion: We identify four species within : , and , the latter, to the best of our knowledge, is endemic to southern Israel. The onset of diversification is very old and estimated to have occurred during the Middle Miocene, possibly originating in the Levant region. Radiation probably resulted from vicariance and dispersal events caused by continuous geological instability, sea-level fluctuations and climatic changes within the Levant region.