Integration of morphologic and genetic data clarifies the evolution and species boundaries within a Nychiodes Lederer, 1853 species complex (Lepidoptera, Geometridae)

Young species radiations are valuable from an evolutionary perspective, as they can reveal traits involved in species formation, but they are challenging for taxonomists due to discordance among independent lines of evidence. The present study integrates morphologic, ecological, and phylogenetic data to resolve delimitation of species within the geometrid moth genus Nychiodes Lederer, 1853, with a particular focus on the closely related species pair N. divergaria Staudinger, 1892 and N. subvirida Brandt, 1938. Our findings revealed significant ecological niche differentiation across the Iranian mountain ranges between the range of taxa distinguished by morphology and DNA barcodes. While individual gene trees from mtCOI and nuclear loci showed conflicting results regarding species boundaries, our multispecies coalescent analyses support the distinction of taxa with different female genitalia characters. Our study highlights how the combination of morphological, genetic, and ecological data helps to define the boundaries between closely related species, to solve taxonomic uncertainties in regions with a complex evolutionary background.