Were the Tertiary Radiations of the Australian Flora Synchronous? A Molecular Phylogenetic Approach

The fossil record shows that in a short period from about 20 Mya, the ancestral Gondwanan rainforest gave way to the unique Australian sclerophyll flora dominated by eucalypts, acacias and casuarinas. This coincided with a drying climate and the advent of fire. It is hypothesized that explosive evolutionary radiations rapidly increased the number of sclerophyll species, rather than a mere range expansion of pre-existing species. In a novel approach, molecular phylogenies of several distantly related plant groups will be used to test whether explosive evolutionary radiations took place simultaneously and to identify the environmental triggers.