Haplosclerida, Petrosiidae
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| Common names: | None. |
| Growth Form: | Massive, lobate, up to 10 cm wide with stiff hollow projections, about 0.5-1 cm diameter and 0.5-2 cm high. May appear as a thick encrustation. |
| Surface: | Smooth, rough to the touch; usually heavily covered with sediment or partly buried. |
| Color: | Greenish black. Color remains in alcohol. |
| Consistency: | Hard, brittle, projections fragile. Interior pulpy. |
| Exudate: | Black exudate released when damaged; colors alcohol quite dark. |
| Oscules: | On tips of tubular surface projections, round, irregularly distributed, elevated well above surface, about 0.5-1 cm across, with thin walls. |
| Skeletal components (Spicules, fibers): | One kind of megasclere: curved or straight, smooth, double-ended needles (oxeas) or bluntly rounded, rather variable in length (~120-250 x 5-15 µm). No microscleres. Spongin only binds spicules together. |
| Skeletal Architecture: | Exterior: Single spicules form a neat meshwork like a thin crust that can be easily sliced off. Interior: Spicules largely confused, interconnected singly or forming ill-defined multispicular tracts without a clear mesh. |
| Ecology: | Common on the bottom of shallow lagoons and in sea grass meadows, encrusting dead corals or rocks. |
| Distribution: | South Florida and throughout the Caribbean. |
| Notes: | The brittle consistency in combination with black color is diagnostic. Other black species are either hard and incompressible (Aaptos lithophaga); tough, woody (Spheciospongia vesparium, Tectitethya crypta) or compressible (Spongia species). |
| Reference(s): | Hechtel, 1965 (as Adocia); van Soest, 1980 (as Pellina); Zea, 1986 (as Pellina). |