Afro-alpine flagships revisited II: elucidating the evolutionary relationships and species boundaries in the giant senecios (Dendrosenecio, Asteraceae)

Alpine plant radiations are common across all major mountain systems of the world, and have been regarded as main explanation for species diversity found within these areas. To study mechanisms behind origin this diversity, it is necessary to determine phylogenetic relationships boundaries in radiating alpine groups. The genus Dendrosenecio (Asteraceae) an iconic example a tropical-alpine radiation East African high mountains. date, limited sampling molecular markers has resulted insufficient resolution infrageneric classification, hindering comprehensive understanding drivers diversification. Here, we used Hyb-Seq Compositae1061 probe set generate targeted nuclear off-target plastid DNA data 42 samples representing currently accepted 11 species. We combined coalescent methods paralogy analysis infer relationships, estimate divergence times evaluate boundaries. Lineage differentiation seems occurred between Late Miocene Pleistocene, starting when first elevation habitats became available Africa. retrieved four clades corresponding geographically distant groups, testifying importance allopatric speciation early diversification group. Cytonuclear discordance suggested occurrence historical hybridization following occasional long-distance dispersal delimitation favored 10 species, but only five were fully supported, suggesting that population-level studies addressing processes such ecological after secondary contact needed current genus.