Population Genetic Structure of the Endangered Kaiser’s Mountain Newt, Neurergus kaiseri (Amphibia: Salamandridae)

Abstract

Species often exhibit different levels of genetic structuring correlated to their environment. However, understanding how environmental heterogeneity influences genetic variation is difficult because the effects of gene flow, drift and selection are confounded. We investigated the genetic variation and its ecological correlates in an endemic and critically endangered stream breeding mountain newt, Neurergus kaiseri, within its entire range in southwestern Iran. We identified two geographic regions based on phylogenetic relationships using Bayesian inference and maximum likelihood of 779 bp mtDNA (D-loop) in 111 individuals from ten of twelve known breeding populations. This analysis revealed a clear divergence between northern populations, located in more humid habitats at higher elevation, and southern populations, from drier habitats at lower elevations regions. From seven haplotypes found in these populations none was shared between the two regions. Analysis of molecular variance (AMOVA) of N. kaiseri indicates that 94.03% of sequence variation is distributed among newt populations and 5.97% within them. Moreover, a high degree of genetic subdivision, mainly attributable to the existence of significant variance among the two regions is shown (θCT = 0.94, P = 0.002). The positive and significant correlation between geographic and genetic distances (r = 0.61, P = 0.002) following controlling for environmental distance suggests an important influence of geographic divergence of the sites in shaping the genetic variation and may provide tools for a possible conservation based prioritization policy for the endangered species.

Mitochondrial DNA variation and Quaternary range dynamics in the endangered Yellow Spotted Mountain Newt, Neurergus derjugini (Caudata, Salamandridae)

“…We analyzed 718 bp of the mitochondrial control region and found (a) monophyly of all analyzed Neurergus derjugini haplotypes, (b) a sister relationship of Neurergus derjugini and Neurergus kaiseri , and (c) low genetic differentiation between the Neurergus derjugini haplotypes. These results are in agreement with phylogenetic analyses based on other mitochondrial and nuclear markers (Farasat, Akmali, & Sharifi, ; Hendrix et al., ; Özdemir, Üzüm, Avci, & Olgun, ) do not reveal the existence of distinct evolutionary lineages within Neurergus derjugini and thus do not support the recognition of two forms (subspecies) as proposed originally by Nesterov (), Schneider and Schneider (). The two subspecies ( Neurergus derjugini derjugini and Neurergus derjugini microspilotus ) were originally described on the basis of the different size and number of yellow spots on the dorsal side of the body.…”

“…In our study, we investigated genetic diversity and Quaternary range dynamics of Neurergus derjugini, which is currently known from 42 highland streams in western Iran and adjacent parts of Iraq (Afroosheh et al, 2016). We analyzed 718 bp of the mitochondrial control region and found (a) monophyly (Farasat, Akmali, & Sharifi, 2016;Hendrix et al, 2014;Özdemir, Üzüm, Avci, & Olgun, 2009) do not reveal the existence of distinct evolutionary lineages within Neurergus derjugini and thus do not support the recognition of two forms (subspecies) as proposed originally by Nesterov (1916), Schneider and Schneider (2011).…”

“…However, differentiation between two haplogroups of Neurergus kaiseri found by Farasat et al. () seems to be associated with environmental heterogeneity. Northern populations of this species are located in more humid habitats at higher elevation, and southern populations inhabit drier habitats at lower elevations regions (Farasat et al., ).…”

“…On the contrary, Neurergus kaiseri has a bit smaller range than Neurergus derjugini (Sparreboom, 2014). However, differentiation between two haplogroups of Neurergus kaiseri found by Farasat et al (2016) with the field study of Afroosheh et al (2016). The authors found that average minimum neighbor distances among breeding streams in the northern part of the distribution were 11.30 km, but only 3.16 km in the southern part of the range.…”

“…() seems to be associated with environmental heterogeneity. Northern populations of this species are located in more humid habitats at higher elevation, and southern populations inhabit drier habitats at lower elevations regions (Farasat et al., ). A long‐term isolation of populations in different environments might have contributed to allopatric divergence in this species.…”