Molecular systematics of the Acmena alliance (Myrtaceae): phylogenetic analyses and evolutionary implications with reference to Australian taxa

Abstract

The existence within Australia of several Acmena alliance taxa with morphological features inconsistent with current generic boundaries has meant that phylogenetic assessment of relationships has proved difficult. Sequences of nrDNA from the ITS and ETS regions were obtained for 66 Australian taxa, including representatives from both subfamilies and five genera. The ingroup taxa included 54 Australian endemics and 13 species with distributions that also range outside continental Australia. Parsimony analysis and Bayesian inference of posterior possibilities from the combined molecular datasets do not correlate with the species associations implied by the current taxonomic circumscription of genera: Acmena, Acmenosperma, Anetholea, Syzygium and Waterhousea. The molecular phylogeny recognises five supported lineages within the Acmena alliance, and several novel species associations. The recognition of five species groups indicates a need for a reappraisal of all currently recognised morphological groups within the alliance.