Origin and radiation of rissooidean gastropods (Caenogastropoda) in ancient lakes of Sulawesi

We investigated diversity and origin of as well as relationships among rissooidean gastropods from the ancient lakes of Sulawesi. Analyses of morphological, anatomical and genetic data (16S rRNA, COI and 18S rRNA) revealed ten new species: Sulawesidrobia perempuan sp. n., which is probably parthenogenetic, Sulawesidrobia soedjatmokoi sp. n., Sulawesidrobia mahalonaensis sp. n., Sulawesidrobia anceps sp. n., Sulawesidrobia bicolor sp. n., Sulawesidrobia megalodon sp. n., Sulawesidrobia abreui sp. n., Sulawesidrobia datar sp. n., Sulawesidrobia yunusi sp. n. and Sulawesidrobia towutiensis sp. n. In two cases morphological and anatomical differentiation between pairs of species were not paralleled by genetic differentiation suggesting young speciation events and incomplete lineage sorting as a likely explanation. A Bayesian phylogenetic analysis including representatives of most rissooidean families placed Sulawesidrobia Ponder & Haase 2005 among Tateidae and thus indicated an Australasian origin of the genus. Relationships among the Sulawesian species suggested that isolated Lake Poso was colonised only once whereas the lakes of the Malili system experienced repeated colonizations.