Multiple origins of the endemic Australian Macrobrachium (Descapoda: Palaemonidae) based on 16S rRNA mitochondrial sequences

The evolutionary relationships of the freshwater prawn genus <i>Macrobrachium </i>are obscure. Members of this genus are widely distributed across tropical and subtropical regions. The phylogenetic relationships among the seven endemic and six non-endemic Australian <i>Macrobrachium</i>, along with five non-Australian species, were inferred from the mitochondrial 16S rRNA gene sequences. Methods of analysis yielded phylogenetic trees of differing topologies; however, none supported a monophyletic origin for endemic Australian <i>Macrobrachium</i>. Enforced monophyly of a single origin of endemic <i>Macrobrachium </i>was statistically tested and rejected. These results support the view that the endemic Australian <i>Macrobrachium </i>arose from multiple origins. Previous biogeographical hypotheses related to the radiation of <i>Macrobrachium </i>into Australia are re-examined in the context of these results.<br />