XVI International Botanical Congess

The ability to live exclusively in mangrove habitats evolved at least 15 times within angiosperms. Historical biogeographers have suggested several contrasting scenarios for origins and routes of subsequent spread of mangrove lineages. A frequent practice in biogeographical research to use present-day distributions, including center of biodiversity and the ages and locations of fossils to interpret the history of a group and infer underlying processes. Accordingly, lineages with similar present-day distributions should have similar histories. We tested this hypotheses by comparing the unrelated mangrove genera Avicennia and Rhizophora, which not only live in similar habitats and have broadly concordant distributions and centers of diversity, but also both disperse by floating propagules. We reconstructed the phylogenies of both groups based on several molecular data sets and used fossil information as well as tectonic events to establish a time scale for each lineage. Our reconstructions suggest that Avicennia and Rhizophora originated in different areas and that their similar present-day distributions are the product so substantially different subsequent histories.