Studies on the Ecology and systematics of the Terrestrial Molluscs of the Lake Sibaya area of Zululand, South Africa

CONTENTS Ι. General introduction................ 3 2. Notes on the climate, ecology and isolation of the coastal dune forest at Lake Sibaya, pertinent to its molluscan fauna........... 5 2a. Introduction................. 5 2b. Climate.................. 7 2c. Description of the habitats............. 12 2d. Ecological observations on the Mollusca.......... 13 2e. The origin and isolation of the dune forest environment...... 14 3. Systematic part................. 17 3a. Gastropoda Prosobranchia............. 18 3b. Gastropoda Pulmonata.............. 19 3c. Zoogeographical conclusions............. 38 4. Summary................... 41 5. References.................. 41 1. GENERAL INTRODUCTION Lake Sibaya (sometimes misspelt Sibayi) is a freshwater lake on the subtropical coastal plain of Zululand, the northeastern part of the province of Natal, South Africa. Northern Zululand, usually called Tongaland, a fairly narrow stretch of country wedged between the Indian Ocean and the eastern border of Swaziland and bounded to the north by Mozambique, is particularly interesting from biogeographical and ecological points of view. The area harbours a rich terrestrial malacofauna, which has been partly discussed by Van Bruggen (1969), while some early data are also recorded in Connolly's monograph (1939).The junior author (Appleton) was privileged