Evolutionary history of a vanishing radiation: isolation-dependent persistence and diversification in Pacific Island partulid tree snails

摘要: Partulid tree snails are endemic to Pacific high islands and have experienced extraordinary rates of extinction in recent decades. Although they collectively range across a 10,000 km swath Oceania, half the family’s total species diversity is single Eastern hot spot archipelago (the Society Islands) all three partulid genera display highly distinctive distributions. Our goal was investigate broad scale (range wide) fine (within-Society molecular phylogenetic relationships two widespread genera, Partula Samoana. What can such data tell us regarding genesis divergent generic distribution patterns, nominal levels Oceania? Museum, captive (zoo) contemporary field specimens enabled genotype 54 ~120 recognized species, including many extinct or extirpated taxa, from 14 archipelagoes. The Samoana products very distinct diversification processes. Originating at western edge familial range, derived genus relatively arrival far eastern archipelagoes (Society, Austral, Marquesas) where it exhibits stepping-stone pattern has proven adept both intra-and inter- colonization. pronounced east—west geographic disjunction exhibited by stems much older long-distance dispersal event its taxonomic Islands product long history within-archipelago diversification. central importance isolation for lineage persistence evident time-calibrated trees that show remote least impacted continental biotas bear oldest clades and/or most speciose radiations. In being progressively undermined these now directly exposed introduced predators throughout range. Persistence partulids wild will require proactive exclusion alien some designated refuge islands.