Terrestrial molluscs of Pemba Island, Zanzibar, Tanzania, and its status as an "oceanic" island.

ABSTRACT: Pemba is thought to have had a longer and/or stronger history of isolation than its better-known counterpart, Unguja. The extent to which the biota support this hypothesis of greater oceanicity have been debated. Here, Pemba's terrestrial mollusc ("land-snail") fauna is surveyed and reviewed for the first time. We find at best equivocal evidence for the following hallmarks of greater oceanicity: impoverishment, imbalance, and a high rate of endemism. At least 49 species are present, families are represented in typical proportions, and there are only between two and four island-endemic species - i.e. a 4% to 8% rate of endemism. For land-snails, isolation thus seems to have been short (Pleistocene) or, if longer, weak. Nevertheless, Pemba does host endemic and globally rare species. Forty-f

SUBMITTER: Rowson B 

PROVIDER: S-EPMC3088446 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature