Phylogeny of kangaroo apples (Solanum subg. Archaesolanum, Solanaceae).

Kangaroo apples, subgenus Archaesolanum, are a unique and still poorly known group within the genus Solanum. Here we aimed to reveal phylogeny, historical biogeography and age of diversification of Archaesolanum. We sampled all recognized species of the group and sequenced three chloroplast regions, the trnT-trnL spacer, trnL intron and trnL-trnF spacer to calibrate a molecular clock to estimate the age of the group. Distributional data were combined with the results of phylogenetic analysis to track the historical processes responsible for the current range of the group. Our analysis supported the monophyly of the kangaroo apples and the biogeographical disjunction between the two subclades within the group. Based on the divergence time estimates the most recent common ancestor of kangaroo apples is from the late Miocene age (~9 MYA). Based on the age estimate the common ancestors of the kangaroo apples are presumed to have arrived in Australia by long-distance dispersal. The two distinct lineages within the group have separated during the aridification of the continent and further speciated in the brief resurgence of rainforests during the Pliocene.