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Rundell - Evolution of the Palau Diplommatinids and Conservation of the Land Snails of Palau and the Southwest Islands

Evolution of the Palau Diplommatinids and Conservation of the Land Snails of Palau and the Southwest Islands

Rebecca J. Rundell

Committee on Evolutionary Biology, 1025 East 57th Street, University of Chicago, Chicago, IL 60637, USA, and Department of Zoology, Field Museum, 1400 S. Lake Shore Drive, Chicago, IL 60605, USA, rundell@uchicago.edu

The western Micronesian islands of Palau comprise over 350 islands, many of which are less than 1 km2 . Babeldaob, the largest island, is only 333 km2 , and represents 80% of Palau's total land area. Despite the small size of the islands, the species richness of Palauâs landsnail fauna is extraordinary. This may be due in part to the varied geology of the islands, which are of both volcanic and coralline (limestone) origin and encompass high and low limestone island types, atolls, high volcanic islands, and islands that consist of both limestone and volcanic rock. The minute, endemic diplommatinid land snails are found throughout the Palau archipelago on all island types. In my 2003 survey, 39 diplommatinid species were found on 20 islands; many of these species are undescribed. In a single locality, as many as five diplommatinid species were found to co-occur. Diplommatinids are found in leaf litter, on limestone rock faces and in limestone rubble, and shell morphology roughly correlates with substrate type. Preliminary sequence data from 16S rDNA suggest complex biogeographical patterns among Palau diplommatinid species and, unsurprisingly, a need for systematic revision of the group. A thorough census of non-diplommatinid land snails in Palau was also conducted, and comprised all 16 states, including the relatively unknown and isolated low limestone Southwest Islands. Notably, live endodontids and partulids were found. Although Palauâs rainforest remains largely intact, relative to many other Pacific island groups, recent development on the island of Babeldaob in particular is cause for conservation concern.


next up previous
Next: Slapcinsky - Diversity of Up: Special Symposium - Pacific Previous: Pearce-Kelly - A Summary
Peter Roopnarine 2005-04-12