Vitaceae-Molecular evolution with a focus on the Australian Radiation

Abstract

An updated analysis of relationships within Vitaceae (including Leea) is presented, based on sequence data from the plastid trnL (UAA) intron region and the ITSI region of nrDNA. Several key taxa are included that had been missing earlier. The results of Bayesian and parsimony analyses of these data confirm the polyphyletic nature of Australian Cissus. Cissus opaca and Clematicissus form a strongly supported clade distinct from Rhoicissus and Ci. tweediana (with which they share some morphological similarities). The sister relationship between the Australian Cissus clade and Vitis is confirmed, and Nothocissus is shown to be embedded within Cissus. A preliminary divergence time analysis was performed using a single fossil-based estimate of the age of the most recent common ancestor of the Cissus/Vitis clade to calibrate molecular evolutionary rates. Two Australian endemic clades were shown to have arisen after the separation of Australia from Antarctica. A complete phylogenetic reclassification of Vltaceae will require the placement of several key taxa and further sampling within Vitis and Cissus.