CHEMOTAXONOMIC RELATIONSHIPS WITHIN, AND COMPARISONS BETWEEN, THE ORDERS HAPLOSCLERIDA AND PETROSIDA (PORIFERA, DEMOSPONGIAE) USING STEROL COMPLEMENTS

The sterol chemistry of 21 species of sponges from the orders Haploscl erida and Petrosida (Porifera: Demospongiae) was examined and compared , and the results analyzed using cluster analysis and ordination. Repl icate samples within some species were examined statistically to deter mine if variability of sterol complements was constant within a specie s. The results of this study did not support separation of sponge spec ies into the two orders, Haplosclerida and Petrosida, on the basis of sterol complements. While previous analyses of species within the Petr osida revealed the presence of unconventional sterol cyclopropenes and cyclopropanes, no such sterols were found in the petrosid sponges we examined. Species within the same families failed to group on the basi s of sterol chemistry, suggesting either their taxonomic allocations a t this level are incorrect, or sterol complement is not a useful featu re at this taxonomic level. Some species within the same genus grouped together while others did not. Sterol complements of species remained constant irrespective of geographic locality or season collected. Spo nge species have both a qualitative and quantitative sterol fingerprin t. The data set provided evidence of a species complex within Xestospo ngia muta. Three specimens of this species contained significantly dif ferent sterol complements.