Historical Phylogeny of Tahitian Partula, an Almost Extirpated Land Snail Fauna

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Oceanic islands hold particular interest for both evolutionary andconservation biologists. Native plants and animals evolved in isolation onthese islands and provide detailed insights into fundamental evolutionaryprocesses. However, they characteristically lack well-developed defensivemechanisms and are exceptionally vulnerable to introduced predators. UsingDNA analyses of museum specimens, we aim to reconstruct the evolutionaryhistory of a critically threatened radiation of land snails from Tahiti(French Polynesia). This Pacific island snail fauna has recently beendriven to the brink of extinction by an introduced predatory landsnail. Our museum samples predate the introduction of the predator and, intheir DNA, they collectively contain a genealogical record that we can useto revise the traditional shell-based taxonomy and to determine how allthese snails evolved on such a small, geologically young, island.Our research will have practical value in helping to prioritize on-goingconservation and rehabilitation efforts. Collaborative agreements havebeen established with Zoological Society of London personnel involved inoverseeing captive Tahitian snail zoo populations and in saving the lastremnant wild populations. Our shared aim is to place the remnant wild andcaptive populations into their proper evolutionary context: that of thepreviously intact fauna, by obtaining DNA profiles of extant wild andcaptive populations that will be referenced with our historical Tahitiandatabase. Preliminary efforts have received considerable general publicity(e.g., http://whyfiles.org/shorties/151land_snail/index.html). Weanticipate that our research will be of interest to that fraction of thepublic keen on high-profile conservation biology issues.