Testing biogeographic hypotheses in Wallacea using freshwater gastropods

2010-2015: In cooperation with Thomas von Rintelen (Museum für Naturkunde, Berlin). Supported by DFG grant AL 1076/1-1

The biogeography of the oceanic island region called Wallacea between the Asian and Australian continental shelves has been controversely discussed for almost 150 years. The geology of the region is extremely complex and an Australian origin of some parts of the Indonesian island Sulawesi in particular is generally assumed. Specifically, some taxa of Sulawesi are believed to have arrived on continental fragments (terranes) from Australia. This intriguing assumption has never been rigorously tested, though. Geologists disagree on whether these terranes were submerged during their drift from Australia, and from a biological perspective most groups are not suited for respective analyses, as the alternative hypothesis of oceanic or airborne dispersal can often not be rejected. We aim to use molecular phylogenies of several freshwater gastropod taxa to (i) seek the first conclusive evidence for an Australian origin of groups with a notoriously poor dispersal potential on Sulawesi and (ii) to apply a molecular clock approach in order to correlate the arrival of these gastropods on the island with the age of the candidate terranes, and thus identify the most likely terrane. The outcome of this project is expected to provide a general contribution to the highly complex biogeography of the region and may also yield interdisciplinary insights for geologists by indicating the probabality of a subaerial drift of certain terranes.