Polymastia nigra Alcolado 1984

The author of this species, Pedro Alcolado, kindly provided an English translation of the original description in the Spanish language, which clarifies some of the uncertainties: Description. This sponge appears filling crevices in reef bottoms, without protruding markedly. So, it appears as patches with tuberculate surface [PAPILLAE] and oscular chimneys [OSCULAR PAPILLAE] bearing oscules of about 1 cm in diameter. These oscules contract considerably like the rest of the sponge, when extracted from water. The tubercles [PAPILLAE] are hemispherical protubernances of 3-5 mm in diámeter and 2-4 mm in height, which can appear solitary or fused with neighbor ones. Surface color is dark grey, almost black, (thus, its name) and chonaosome is beige. Consistency is very tough and hard as rubber. The ectosome if formed by a dense palisade of tylostiles, comparatively small, with points directed outward. Choanosome is formed by ascending tracts with both big and smal tylostyles. These tracts alternate with hyaline fibers which look alike fungus hyfae, of unknown nature, and to which the sponge possibly owes its toughness. Spicules are [BIG] fusiform subtylostyles of 550-750 x 15-19 ¼m, short robust subtylostyles of 240-455 x 1-8 ¼m, and small thin subtylostyles of 150-480 x 1-8 ¼m. Spherical hyaline bodies (spherules) of 5-11 in diameter were also observed. Locality. Collected ath the fore-reef of Barlovento (Havana City) at 15 m deep. Collector. The author Remarks. In consulted literature species with the above features are not mentioned. Apparently, this genus was not mentioned for the West Indies. [I have seen this species several times further with paler grey or pruplish grey color in less lit places] Source of original description: Alcolado, P. M. (1984). Nuevas especies de esponjas encontradas en Cuba. Poeyana 271: 1-22.