9314051 Fagerstrom Despite more than 80 years of research on the renowned Permian "reef" complex of the Delaware Basin (New Mexico/West Texas), there have been no detailed studies of the very abundant sponges in this bioherm. PIs will a) identify and describe the sponges to species level and interpret their phylogenetic significance; 2) assess the biostratigraphic value of these species and evaluate effects of the Permo-Triassic mass extinction on this group of sponges; 3) address paleobiogeographic issues with respect to these sponges; and 4) conduct a paleoecologic analysis of the algal-sponge community.