Notes: Dark green ears partly or totally encrusted onto the substratum; hard and brittle, with a smooth but crusty surface; no oscules usually apparent. Can be confused with Petrosia pellasarca (de Laubenfels, 1934), which is brown, grows more off the substratum and is crumbly and has small toxa spicules in addition to the oxea in a wide size range that both share. There are deep reef cave-wall fully encrusting specimens with scattered, slightly elevated oscules, usually creamy but sometimes green, a bit more crumbly, with the same spicule complement and skeletal architecture of fan-shaped P. weinbergi. We are placing these tentatively within this species.

Author Reference: van Soest, 1980

Link: World Porifera Database