Molecular phylogenetics of Haemodoraceae in the Greater Cape and Southwest Australian Floristic Regions

Abstract

Molecular phylogenetic studies of Haemodoraceae in the Greater Cape and Southwest Australian Floristic Region (SWAFR) using trnL, trnL-F and matK sequence data affirm the presence of old and young rapidly radiated lineages in both regions. Commencement of tribal and generic divergence in the subfamilies occured in the Eocene in the two regions, but subsequent patterns of radiation differ slightly. The hypothesis of rapid recent speciation in these regions from the late Pliocene as the major explanation for endemic species richness is still repeated by several contemporary authors despite increasing molecular phylogenetic evidence to the contrary. Our estimates of the age of lineages in Haemodoraceae show significant lineage turnover occurring over the last 15 million years, since the mid-Miocene, with divergence of the major clades beginning in the Eocene. The search for independent evidence to date speciation episodes reliably and investigation of molecular analyses across a broad spectrum of these clades must be pursued to advance ideas rigorously concerning origins of species richness. These regions continue to confound attempts to develop theory concerning origins of global species richness, with consequent implications for conservation biology.