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

The genus <i>Silene</i> 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 <i>Silene sordida</i> and the widespread <i>S. odontopetala</i> 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 <i>S. sordida</i> 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 <i>Silene</i> 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.