ИСТИНА

The species plays a fundamental role in zoological fields such as ecology, evolution, biogeography, and conservation. Therefore, objective and clear-cut recognition of species is paramount. Molecular methods, especially barcoding, have become a popular tool to identify and delimit species and facilitated traditional morphology-based species recognition. However, following the plea for an integrative taxonomy, more lines of evidence should be incorporated when identifying species. While an increasing number of studies use ecological niche modelling (ENM) within an ecological and evolutionary framework, there are only few examples of ENM used to support taxonomy. The Middle Eastern mountain newts (genus Neurergus) currently comprise six taxa whose taxonomical status has been under debate. We aim to delimit species within this genus by combining different, independent lines of evidence. These include DNA barcoding (using the two mitochondrial genes 16S rRNA and COI), multi-locus species trees evaluated using Bayesian species delimitation under different priors, morphological overlap analyses through n-dimensional hypervolumes of morphometric and colouration characters, and comparison of n-dimensional hypervolumes of the ecological niches using PCA-derived variables of environmental data obtained from occurrence records. The consensus of all methods suggests four species within Neurergus. However, the conflicting results regarding species delimitation between the used methods underline the necessity of combining multiple approaches within an integrative framework. Especially in threatened taxa like Neurergus, focussing on one method can mislead taxonomy and consequently hinder species-based conservation assessments. Different realised niches indicate specific divergence, as physiological tolerances that define the niche evolve during or trigger speciation. Accordingly, ENM provides a further, well applicable tool to test species hypotheses, but needs to be interpreted with caution.