Abstract
A review of the systematic literature on the free living interstitial ciliates of Saudi Arabia is presented. A checklist comprising 235 species of ciliates that have been reported from the Arabian Gulf, its offshore islands and the brackish waters of the nearby Al Hassa Oasis is included. The list presents 45 species of the order Hypotrichida, 42 of the order Karyorelictida, 33 of the order Heterotrichida, 27 of the order Prostomatida, 26 of the order Haptorida, 23 of the order Pleurostomatida, 15 of the order Hymenostomatida, 11 of the order Oligotrichida, 9 of the order Scuticociliatida. 5 of the order Cryptophorida, 3 of the order Trichostomatida, and a single species of the order Synhymeniida. The distribution of each species is compared to that in similar habitats world-wide. A significant increase in ciliate abundance (mean density, cm(-3)) of the Gulf shores. both annually and at corresponding months was observed during 1994 to 1997, although no significant increase was observed in the number of species.