The Gray Toad-headed Agama,Phrynocephalus scutellatus,on the Iranian Plateau: The degree of niche overlap depends on the phylogenetic distance

The Gray Toad-headed Agama (Phrynocephalus scutellatus) occurs in Iran, Pakistan and Afghanistan and is represented in Iran by four distinctive genetic clades. We built distribution models for three of these clades (one clade was not included due to a low number of distribution records) using Maximum Entropy Algorithm in order to determine the contribution of ecological factors to the distribution pattern. The degree of spatial niche overlap between every pair of clades were measured using Schoener's D niche overlap metric. The results showed that at species-level climate variables (annual precipitation, annual mean temperature) were the most influential parameters determining the boundaries of the distribution in Iran. Temperature seasonality was found to be the most influential factor in the distribution of both Clade I and Clade II. However, this variable was replaced by the annual mean temperature for Clade VI. Based on the results of Schoener's D metric, Clades I and II had the lowest, and Clades II and VI the highest level of ecological niche overlap. Comparing the result of niche overlap with genetic distance between the clades, it was found that the ecologically least similar clades were those with the longer history of genetic segregation.