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Gulella menkeana (Pfeiffer, 1853) is the type species of the highly diverse genus Gulella Pfeiffer, 1856 and study of its morphology and DNA is critical to our ability to define the genus sensu stricto in relation to research on the systematics of this complex genus. However, we have established that current use of the name is inconsistent with both the original description and first figure of the species. The name-bearing type is lost, and purported paratypes in the Museum für Naturkunde der Humboldt-Universität, Berlin, on which Connolly's widely-followed redescription was based, are not authentic. They have no type status and are instead specimens of Gulella albersi (Pfeiffer, 1855). Recently collected specimens conforming to Pfeiffer's description and figure of G. menkeana have been identified and a neotype is designated. This material also corresponds with the current broad interpretation of G. adamsiana (Pfeiffer, 1859), which, with its several established synonyms, we include in the synonymy of G. menkeana. There is also considerable resemblance to G. wahlbergi (Krauss, 1848), a name based on composite material and for which the lectotype is lost. We also designate a neotype for this species so as to preserve current application of the name. The possible synonymy of G. menkeana and G. wahlbergi, an older name, is of nomenclatural concern, but is not critical to the issue of defining Gulella s.s. [ABSTRACT FROM AUTHOR]

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, are 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. [ABSTRACT FROM AUTHOR]