Gazella arabica dareshurii: a remarkable relict population on Farur Island, Iran

BACKGROUND: The islands in the Persian Gulf are home to several species of gazelles, i.e., Gazella bennettii, G. subgutturosa, and a new subspecies of Mountain gazelles which was discovered on Farur Island and described for the first time in 1993 as Gazella gazella dareshurii. Later, phylogenetic analyses showed that the Mountain gazelles consist of two species: G. gazella and G. arabica. As the Farur gazelles are more closely related to the Arabian forms of the Mountain gazelles, this subspecies is regarded to be G. arabica dareshurii. Until now, the origin of this subspecies has been an enigma. RESULTS: Here, we used mitochondrial cyt b, two nuclear introns (CHD2 and ZNF618), and morphological data to address this question by investigating the taxonomic position of the Farur gazelles. The results show that this population is monophyletic and split from other G. arabica populations probably 10,000 BP. CONCLUSIONS: It is a natural relict population that was trapped on the island due to the rising sea levels of the Persian Gulf after the Last Glacial Maximum. Intermittent drought and flooding are suggested to be the main factors balancing population growth in the absence of natural predators on this monsoon-influenced island. Conservation actions should focus on preserving the natural situation of the island (cease introducing mesquite tree and other invasive species, stop building new construction and roads, and caution in providing water sources and forage), and possibly introducing individuals to other islands (not inhabited by gazelles) or to fenced areas on the Iranian mainland (strictly isolated from other gazelle populations) when the population reaches the carrying capacity of the island.