Aplysina insularis (Duchassaing & Michelotti, 1864)
Verongida, Aplysinidae

Common Name(s): Yellow finger tube sponge
Growth Form: Clusters of low often coalescing tubes, sometimes forming irregular lobate or branching clusters. Irregular branches or runners may dominate but always arise from low tubes.
Surface: Covered with fine, low conical projections (conulose), but sometimes almost smooth. Fingerlike projections range from absent through few, upright and slender, to extensive irregular branches.
Color: Yellow to yellow-green, yellow-brown or yellow-orange. Turns brownish-black to black when dried.
Consistency: Tough, compressible.
Oscules: Terminal on top of tubes, 0.4-2 cm across, usually in a depression, and with an iris-diaphragm-like marginal membrane the same color as the surrounding tissue.
Skeletal components (Spicules, fibers): No spicules. Fibers are amber-colored, 30-125 μm across, with organic pith 15-60% of the fiber diameter.
Skeletal Architecture: No surface specialization; fibers from the interior form conules when they reach the surface. Interior skeleton: regular fiber meshwork forming hexagonal to rounded meshes.
Ecology: Shallow hardgrounds and coral reefs.
Distribution: Florida, Bahamas, Caribbean.
Notes: This species has been confused with Aplysina fistularis, which forms clusters of up to 20 rugose or weakly ridged yellow to yellow-brown tubes up to 50 cm tall (rarely with long slender irregular tendril-like projections). Soest (1978) referred to this species as Aplysina fistularis insularis. The upper photograph on page 21 of Humann and Deloach (2002) identified as Aplysina fistularis is A. insularis.
Reference(s): Soest (1978).