Phylogenetic connections of phyllodinous species of Acacia outside Australia are explained by geological history and human-mediated dispersal

Abstract

Acacia sensu stricto is found predominantly in Australia; however, there are 18 phyllodinous taxa that occur naturally outside Australia, north from New Guinea to Indonesia, Taiwan, the Philippines, south-western Pacific (New Caledonia to Samoa), northern Pacific (Hawaii) and Indian Ocean (Mascarene Islands). Our aim was to determine the phylogenetic position of these species within Acacia, to infer their biogeographic history. To an existing molecular dataset of 109 taxa of Acacia, we added 51 new accessions sequenced for the ITS and ETS regions of nuclear rDNA, including samples from 15 extra-Australian taxa. Data were analysed using both maximum parsimony and Bayesian methods. The phyloge..