Ecological and geological processes impacting speciation modes drive the formation of wide-range disjunctions within tribe Putorieae (Rubiaceae). Drivers of wide-range disjunctions within Putorieae

Wide-range geographically discontinuous distributions have long intrigued scientists. We explore the role of ecology, geology, and dispersal in the formation of these large-scale disjunctions, using the angiosperm tribe Putorieae (Rubiaceae) as a case study. From DNA sequences of nuclear ITS and six plastid markers, we inferred a phylogeny, obtained an ancestral niche reconstruction and estimated divergence times, ancestral ranges, and diversification rate shifts using Bayesian inference. As a result, we identified seven major clades in Putorieae, some of which exhibit striking geographical disjunctions and a probable reason for their distribution, including ecological and geographical vicariance, ecological and ecogeographical speciation and long-distance dispersal.