title: 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-five percent of the species found, including most of these, is restricted to forest reserves, with Ngezi Forest Reserve particularly rich. A further 45% are able to tolerate the island's woody cultivated habitats. One new snail species (Cyclophoridae: Cyathopoma) and one new slug species (Urocyclidae: Dendrolimax pro tem.) are described. New data and illustrations are provided for other taxa.
authors: B
authors: B
authors: Rowson
authors: B H
authors: BH
authors: Warren
authors: C F
authors: CF
authors: Ngereza
references: Mol Phylogenet Evol. 2003 Oct;29(1):67-85
references: 12967608
references: Mol Ecol. 2006 Oct;15(12):3769-86
references: 17032273
references: Cladistics. 2010 Oct;26(5):526-538
references: 34875766