First comprehensive insights into nuclear and mitochondrial DNA based population structure of Near East mountain brook newts (Salamandridae: genus Neurergus) suggest the resurrection of Neurergus derjugini

Abstract

Due to their extraordinary coloration, mountain brook newts of the genus Neurergus found in the Near East have fascinated herpetologists since their initial description more than 150 years ago. Although the monophyly of Neurergus newts within the Salamandridae has been unambiguously shown for mitochondrial genes, and recent comprehensive molecular phylogenies placed Neurergus as a sister taxon of banded newts (genus Ommatolriron), we know almost nothing about the structure and relatedness of populations at the intraspecific level. In this study, we therefore analysed sequence variation of a mitochondrial DNA segment (covering a partial region of the control region and the 12S ribosomal RNA) from more than 100 individuals and of two nuclear genes (KIAA and SACS) for a representative subset of individuals originating from nine distinct populations, representing N. strauchii, N. crocatus and N. microspitotus. We also studied individuals of N. derjugini, a taxon that has long been synonymized as N. crocatus, and of which individuals have not been accessible to the scientific community since its original description in 1916. Our results suggest high genetic diversity of populations within species for the mitocbondrial DNA marker, while the resolution of applied nuclear genes did not go beyond the level of species. For N. strauchii and N. crocatus, two species that inhabit the largest geographic ranges within the genus, we found a high proportion of diversity both within and between populations for the mitochondrial control region. Individuals of N. microspilotus and N. derjugini only displayed considerable genetic differentiation for one nuclear gene (SACS), while only very little or none genetic differentiation could be found for the mitochondrial control region and the KIAA gene, respectively. As both taxa are also morphologically not well differentiated, we suggest on the basis of the current dataset to taxonomically synonymize N. microspilotus due to priority reasons as N. derjugini. It can be therefore concluded that the most accurate taxonomy of the genus Neurergus should consider N. crocatus, N. strauchii, N. iiaiseri and N. derjugini as valid taxonomic units at the species level.

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.…”

“…The low intraspecific divergence of Neurergus derjugini contrasts with higher genetic divergence found in other Neurergus species (Hendrix et al., ). In the case of Neurergus strauchii and Neurergus crocatus, we can hypothesize that with their larger ranges, the probability of allopatric divergence increases due to physical barriers.…”

“…The genus Neurergus involves four currently recognized species ( Neurergus strauchii , Neurergus crocatus , Neurergus kaiseri, and Neurergus derjugini ), which are specific for their small ranges restricted to mountainous areas in southern Turkey, north‐eastern Iraq, and western Iran (Hendrix et al., ). Due to its limited distribution in relatively remote regions, the Neurergus newts are still poorly known and studied compared to other salamandrid species.…”

“…Hendrix et al. () however did not find any diverged evolutionary lineages (subspecies) within the species. In this paper, we follow taxonomy proposed by Hendrix et al.…”

“…Finally, Fleck (), Schneider and Schneider (, ), and Hendrix et al. () suggested that Neurergus derjugini and Neurergus microspilotus should be considered as one species with Neurergus derjugini being the valid name due to priority reasons (Fleck, ; Hendrix et al., ; Schneider & Schneider, , ). Fleck () and Schneider and Schneider (, ) suggested Neurergus derjugini derjugini (Nesterov, ) and Neurergus derjugini microspilotus (Schmidtler & Schmidtler, ) as valid subspecies.…”