Martín-Bravo & al. • Pleistocene speciation in Reseda sect. Glaucoreseda TAXON 59 (2) • April 2010: 466–482 SPECIATION Geographical speciation related to Pleistocene range shifts in the western Mediterranean mountains (Reseda sect. Glaucoreseda, Resedaceae) Santiago Martín-Bravo,1 Virginia Valcárcel,1 Pablo Vargas2 & Modesto Luceño1 1 Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, ctra. de Utrera km 1, 41013, Sevilla, Spain 2 Botanic Garden of Madrid, CSIC, Pza. Murillo n° 2, 28014, Madrid, Spain Author for correspondence: Santiago Martín-Bravo,
[email protected] Abstract Reseda sect. Glaucoreseda is a monophyletic group composed of five endemic tetraploid species with a disjunct dis- tribution in the high mountains and plateaus of the Iberian Peninsula and Morocco. It was previously suggested that range shifts induced by Quaternary glaciations played an important role in the speciation of the group. We studied the evolution of R. sect. Glaucoreseda in order to infer historical range dynamics and speciation processes, and to understand current distributional pat- terns. Phylogeographic analyses were performed using nuclear ribosomal ITS and plastid trnL-F and rps16 sequences. Cloning of additive ITS sequences was carried out to elucidate the origin of intra-individual polymorphisms. A dated phylogeny based on ITS and cpDNA (rbcL, matK, trnL-F) sequences was used to estimate divergence times of R. sect. Glaucoreseda. Time estimates using Penalized Likelihood analyses indicate a late Pleistocene diversification of R. sect. Glaucoreseda. Incomplete lineage sorting of ancestral polymorphisms due to recent divergence, rather than rampant hybridisation, is suggested as the main cause of the phylogenetic incongruence detected between nuclear and plastid datasets.