Egypt. Jour. Paleontol., Vol. 10, 2010, p. 49-60 ISSN 1687 - 4986 PRELIMINARY INVESTIGATION OF DIATOM TAXA DISTRIBUTION IN RECENT SURFACE SEDIMENTS OF SOCOTRA ISLAND (YEMEN), INDIAN OCEAN Abdelfattah A. ZALAT 1 and Mohammed A. AL-WOSABI 2 1. Tanta University, Faculty of Science, Geology Department, Tanta 31527, Egypt. 2. Sana'a University, Faculty of Earth Science and Environment, Geology Department, Sana'a, Yemen Correspondence author: abzalat @yahoo.com ABSTRACT The diatom assemblages from the Recent surface sediments of different localities in the Socotra Island have been recovered and studied in detail. The studied localities were selected to cover different habitats such as Beach, wadis, village and stream. A total of 82 species belonging to 31 genera were identified. All the recorded taxa have been considered as new records to Socotra Island. The distribution pattern of the identified taxa varied significantly between the studied localities and indicated changes in diatom composition, which are related to environmental conditions. The composition of the diatom assemblages denotes that the non- planktonic taxa are predominant over the planktonic forms. Multivariate statistical technique including correspondence analysis was used to distinguish five diatom assemblages according to water resources and the dominant taxa at each assemblage. INTROUDTION The Socotra is the largest Yemeni island, located at the eastern limit of the Gulf of Aden in the northwest Indian Ocean. This island is considered one of the most fascinating places on earth. It has very rich and diverse animals and plants, which are found nowhere else on the earth. These flora and fauna have received relatively little attention from the scientific community. However, Socotra Island has drawn the attention of some workers in the recent time, among them Webster et al. (1998), Krupp & Hariri (1999), Krupp and Klaus (1999), Simo es & Jones (2000), Stramma et al. (2002), Klaus et al. (2003), Combes et al. (2005), Fleitmann et al. (2007), Shakun et al. (2007) and many others. Their studies mainly dealt with the biology, geochemistry, ecology, biodiversity, fisheries and climate of the Island. Relatively a few geological studies were carried out on this island due to its extremely isolated location. Beydoun & Bichan (1969) presented a comprehensive account of the geology of Socotra. Diatom flora from Socotra Island did not studied before. Therefore, the present work is considered a first contribution about the diatom assemblages in the surface sediments of the Island. During recent years, the diatom composition of surface sediments has been used to explore and quantify the relationship between the diatom assemblage and a number of environmental variables to evaluate the data for environmental inference. For the present study, the diatom species compositions in the surface sediments of different habitants in Socotra Island were recorded and assessed.