Phylogenetic analysis suggests early divergence followed by convergent morphological evolution in the sections and (Caryophyllaceae).

Résumé

The genus presents significant taxonomic challenges, particularly for groups such as S. sect. Odontopetalae and the monotypic S. sect. Sordidae. This study investigates the evolutionary relationship between the narrowly endemic and the widespread to resolve these ambiguities. Using a multispecies coalescent framework with five genetic markers and expanded taxon sampling, the species tree and divergence times were estimated. The results revealed a moderately supported sister relationship between and S. sect. Odontopetalae, with their divergence estimated at approximately 5.5 million years ago, following the Messinian salinity crisis. Despite their profound morphological and ecological differences, the results suggest a shared evolutionary origin. This study underscores the limitations of morphology-based classification in and highlights the critical roles of ecological divergence, historical biogeography, and convergent evolution in shaping the genus's diversity. The results provide a clearer understanding of the evolutionary processes driving diversification in these complex lineages.