Notes: Excavating and encrusting sponge, covering the excavated the substratum with a thin layer of orange-red tissue, from which the excavated substratum is visible. The excavating tissue is of the same color of the external tissue. Previously placed under genus Cliona, but transferred to genus Pione by having a spicule complement of tylostyles, crenulated oxeas and spiny microrhabds. We are including here shallow reef specimens which just show tiny papillae on the substratum, which were previously named fo. occulta Rützler, 1974. Perhaps predators do not allow the sponge to overgrow the substratum. These can be confused with papillated Cliona delitrix Pang, 1973 (which were originally named C. laticavicola Pang, 1973), which has larger oscules and papillae. It can also be confused with papillated reef Tedania ignis (Duchassaing & Michelotti, 1864).
Author Reference: (de Laubenfels, 1950)
Link: World Porifera Database