Petrocoptis montsicciana and P. pardoi are two Iberian endemic taxa of Caryophyllaceae family with an unclear taxonomic delimitation, being variously treated as independent species, subspecies or even synonyms. In the present study, allozyme raw data obtained in the early 2000s have been reused with improved tools to survey genetic structure, and complemented with modeling and niche comparative analyses to shed light on species delimitation. Genetic structure was investigated using four approaches: Bayesian clustering, Monmonier’s algorithm, Principal Coordinate Analysis (PCoA), and Analysis of Molecular Variance (AMOVA). Ecological niche differences have been assessed through Ecological Niche Modeling (ENM) using MaxEnt, and Principal Component Analysis using both occurrence records and background climate (PCA-env). Genetic analysis confirms the distinction between both taxa, and the scenario of a progenitor–derivative (P–D) is suggested. In agreement with genetic data, niche analysis shows clear differences between their climate regarding species occurrences and background spaces. Climate divergence could be explained, at least partially, by the abundance of rocks where species live although differences at the microclimate instead of the regional climate should be explored in future research. Given the genetic distinction between P. montsicciana and P. pardoi, both taxa should be regarded as separate ‘Management Units’ (MUs).