Epibiotic Protozoa (Ciliophora) on a community of Thalassia testudinum Banks ex Konig in a coral reef in Veracruz, Mexico

The seagrasses are one of the most important organic substrates for the establishment of a diversity of epibiotic organisms. To date most of the literature on epiphytes living on seagrasses deals with an immense diversity of algae and sessile invertebrates. However, studies of:epibiotic microorganisms such as protozoan ciliates are scarce. The goal of this paper is to provide a list of sessile ciliate composition, their frequency, density and distribution on Thalassia testudinum shoots in a coral reef lagoon. The study site was a T. testudinum community in Isla Verde, a coral reef in Veracruz, Mexico, during August, October 1994 and May 1995. In the laboratory, the ciliates were identified using light microscopy, scanning electron microscopy and conventional staining techniques. The two way ANOVA (Model 1) was used to compare the difference between densities of sessile ciliates in relation to the different parts of the seagrass (basal parr of the leaves and foliage) and the sampling periods, Twenty-eight species were identified, belonging in the following groups: folliculinids (7), licnophorid(1), stichotrich (1), prostomatid(1) suctorians (6) and peritrichs (12). Nine species are new records for Mexico. The most frequent species on T. testudinum:basal part of the leaves were: Lagotia expansa f. depressa, Metafolliculina andrewsi:si, Parafolliculina tristanensis, Metacystis truncata, Acineta tuberosa, Cothurnia aplatita, C. ceramicola, C. maritima and on foliage were Parafolliculina amphora and Vorticella campanula. Only two species were found on the rhizomes Chaetospira mulleri and Cothurnia maritima. Maximum species richness was observed on the basal part of the leaves, where the densities of other epiphytes were low or absent. The difference in densities of the sessile ciliates are interpreted as the interaction of the sampling periods and the different parts of the seagrass studied. (C) 1999 Elsevier Science B.V. All rights reserved.