Conclusions
The identification of new plant species usually requires a broad understanding of taxon boundaries applying multidisciplinary methodologies. Our study exemplifies the complexity of identifying new species by integrating different types of data: target capture sequencing data from herbarium specimens to reveal phylogenomic patterns and introgression between clades, differences in allelic ratios to estimate ploidy, spatial analysis estimating current and past distribution ranges and niche overlaps, and macro- and micromorphometric comparisons. By integrating all these results, we have newly corroborated the existence of four species in the Mediterranean Tamus clade of Dioscorea , maintaining D. orientalis as a distinct species, and demonstrating that D. edulis and D. cretica are species discrete from the synonymy of the morphologically variable D. communis .