Alborz Heritage: Geographic distribution and genetic differentiation of the Iranian Paradactylodon (Amphibia: Hynobiidae)

Abstract

Paradactylodon, a genus of Hynobiidae, is distributed in mountainous regions of the Middle East. This genus comprises three species, Paradactylodon mustersi (Afghanistan), Paradactylodon persicus, and Paradactylodon gorganensis (Iran). Initially, P. persicus was reported from Talysh Mountains, and afterward, P. gorganensis was described from the eastern Alborz Mountains. Although these two Iranian Paradactylodon species were distinguished based on morphological features, there are arguments about their systematic status. In this contribution, 30 samples of hynobiid salamanders were collected from Talysh and Alborz Mountains and the phylogenetic relationship between the two species was assessed using two mtDNA markers (COI and 16S). Additionally, in order to survey the potential habitat suitability for the species, Species Distribution Models (SDMs) were performed and projected on climate scenarios that reflect current and past (6 ky and 21 ky before present) conditions. Our results indicated that P. gorganensis is nested within P. persicus. Overall, both SDM and molecular analyses suggest that the Iranian Paradactylodon population was affected by the Quaternary glacial period, and according to haplotype networks, haplotype diversity was higher in the western part of the distribution range of the species. Given the low genetic distance among all samples, we suggest P. gorganensis be synonymized with P. persicus. Considering the conservational values and numerous threats that this endemic species is facing, we encourage a revision of the IUCN Red List category of the species immediately.