Description: Irregular encrustations, up to 2-3 cm in thickness, following the contours of the substratum, and reaching tens of cm in diameter (sometimes up to 1 m). Surface is generally uneven, microrugose, but can be smooth, but always having many low mounds and irregular lobes; sometimes lobes grow upwards and ramify. Oscules up to about 5 mm, scattered, located either on top of elevations or in depressions. Color usually light to dark purple or golden brown; shallow-water specimens are dull golden yellow with tan tinges in concave areas; subsurface dark purple, interior cream. Consistency very crumbly. The architecture of the skeleton is difficult to discern owing to the remarkable amount of dark granular cells that block light under the microscope. It appears to be an irregular isotropic unispicular to paucispicular reticulation, with no surface specialization. Spicules of material from St. Eustatius are slender, curved styles, 330-505 µm long and 2.5-13 µm wide, with terminal or subterminal irregular swellings and many with characteristically v-shaped tips; there are fewer oxeas of about the same size, most with mammiform tips which are slightly asymmetric. Material from the continental coast of Colombia and from Panama lacks oxea and the styles are much stouter, 380-500 µm by 3-25 µm wide.
Notes: This is a shallow to deep reef sponge, living usually exposed. It has the dark granular cells characteristic of the genus Svenzea, and we recently saw the large yellow egg-larvae which occur in other species of this genus (see also Svenzea zeai in this guide and Rützler et al., 2003). The contrast in color that appears to exist between shallow and deeper-dwelling specimens is remarkable, but they coincide in consistency, spiculation and in the presence of dark granular cells. Most specimens from the localities where this species was originally described (Belize, Jamaica) have also oxea spicules, but these are reported to be sometimes absent. The greater thickness of Colombia and Panama spicules is consistent with the greater amount of silicon in neritic continental waters.
Author Reference: Alvarez, van Soest & Rützler, 2002
Link: World Porifera Database