The Australian monsoon tropics are currently dominated by savanna and tropical woodland biomes that have arisen in response to a cooling and drying trend within the past ∼3 million years. It is expected that organisms well adapted to these conditions have expanded into available habitats, leading to the differentiation of populations and species across this landscape, a process that could be magnified by the presence of several biogeographic barriers. The broad-leaved paperbark (Melaleuca leucadendra (L.) L.) complex is one such group of plants, with 14 poorly morphologically differentiated species occupying large overlapping distributions across the region, and across several recognised biogeographic barriers. Using phylogenetic and network analyses of nuclear and plastid sequences, we tested species limits among currently described species within the complex and for phylogeographic structure within species across seven of these barriers. Overall, our data suggested patterns of differentiation among species consistent with the early to middle stages of incomplete lineage sorting, and evidence for an idiosyncratic cryptic response of species to biogeographic barriers. Unexpectedly, we found a deep molecular split across all species, broadly coinciding with the northern part of the Great Dividing Range, a feature not typically considered to be a barrier to dispersal. Our study has offered one of the first insights into the dynamics within and among widespread species across the north of Australia, suggesting considerably more geographic structure than was previously recognised.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 31 • No. 5-6