Identification and fatty acids composition of Xestospongia vansoesti and Aaptos suberitoides

Taxonomic identification is the most significant step in any research, and this is especially true of the sponge fauna. Two marine sponges were identified based on their morphology, skeleton, and spicules characteristics and the fatty acid composition was also studied for Xestospongia vansoesti and Aaptos suberitoides. In both species, the main saturated acids were 16:0 and 18:0. Saturated fatty acids C14-18 of iso /anteiso-structure were detected in both species with different percentages. The positional isomers of octadecenoic acid were the most common in both species with 6.78 % in Xestospongia vansoesti and 5.3% in Aaptos suberitoides. Two demospongic acids C25:2 Δ 5, 9 and C26:2 Δ 5, 9 were detected in both species and the percentage of 5,9-Hexacosadienoic acid in Aaptos suberitoides is high with 7.26% of the total fatty acids content. The characterization of 5,9-pentacosadienoic acid was achieved based on the MS spectra to confirm the presence of demospongic acids in both species.