| Common Name(s): |
Branching tube sponge |
| Growth Form: |
A cluster of erect tubes, broadening only slightly upward from the base; individual tubes up to ~25 cm tall and 6 cm across. Tubes may interconnect and in some cases produce hollow flattened fans. |
| Surface: |
Weak to well developed conical projections (conules), up to 1 cm high, 3-10 mm apart; sometimes partly to entirely smooth and finely porous. |
| Color: |
Gray; sometimes bluish-, pinkish-, brownish- or purplish gray. |
| Consistency: |
Compressible, elastic. |
| Exudate: |
None. |
| Oscules: |
Small, 0.5-2 mm, inside the tubes. The large circular, oval, compressed or irregularly round apical opening (1-5 cm across) is not a true oscule; its margin is usually smooth but may be conulose. Fan-shaped openings may reach 20 cm in greatest dimension. |
| Skeletal Components (Spicules, Fibers): |
Spongin fibers of two to three diameters sparsely cored with slightly curved rods with 2 pointed ends (oxea), 60-160 x 1.0-7.0 μm. Fibers may lack interior spicules. |
| Skeletal Architecture: |
Exterior skeleton a polygonal meshwork of coarse primary fibers (18-30 μm across) with meshes 200-350 μm across, and finer secondary fibers (5-12 μm across) forming triangular meshes 50-100 μm across. Fibers are cored by a single row of spicules and are supported by subsurface fiber bundles. Interior skeleton of well-developed fiber bundles (fibrofascicles) up to 350 μm across that interconnect and diverge, producing an irregular radial-plumose skeleton. Fiber meshwork between bundles composed of primary (35-80 μm across), secondary (15-60 μm), and smaller tertiary interlacing (5-20 μm) fibers. In general, the smaller the fiber diameter, the fewer spicules in its interior. Fiber bundles diverging toward the surface produce the conules. |
| Ecology: |
On coral reefs and hard bottoms, typically where coral is not dense. |
| Distribution: |
Bermuda, Gulf of Mexico, North Carolina to Brazil, in 2-70 m depth. |
| Notes: |
Frequently infested with the zoanthid Parazoanthus parasiticus. The species requires revision; the distinctly tube- and fan-shaped forms may represent separate taxa. |
| References: |
van Soest (1980), Zea (1987), Ruetzler et al. (2009). |
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| Similar species: |
Callyspongia plicifera |
Niphates digitalis |
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