Population genetic structure of the endangered yellow spotted mountain newt (Neurergus derjugini: Amphibia, Caudata) inferred from mitochondrial DNA sequences

Abstract

The yellow spotted mountain newt (Neurergus derjugini) is a critically endangered species restricted to fragmented habitats in highland streams of the middle Zagros Mountain in Iran and Iraq. We examined the species phylogeography by investigating sequences of a mitochondrial fragment of the ND2 gene for 77 individuals from 15 locations throughout the species known distribution. We found relatively high haplotype diversity (0.82 ± 0.025) but low nucleotide diversity (0.0038 ± 0.00022) across all populations. Phylogenetic trees supported monophyly, and the segregation of haplotypes was concordant with the haplotype network. We found a significant correlation between geographical and genetic distances among populations (r = 0.54, P ˂ 0.01), suggesting restricted gene flow. Molecular dating suggested that haplogroups diverged during the early or middle Pleistocene. Bayesian skyline plot provided evidence for an expansion of populations during the Pleistocene-Holocene transition period. Taken together, isolation by distance due to low dispersal capability, habitat fragmentation, and historical factors have shaped the current population structure of N. derjugini.