Topsentia bahamensis Diaz, Pomponi

Rützler, Klaus, Piantoni, Carla, Van, Rob W. M. & Díaz, Cristina, 2014, Diversity of sponges (Porifera) from cryptic habitats on the Belize barrier reef near Carrie Bow Cay, Zootaxa 3805 (1), pp. 1-129 : 75-76

Topsentia bahamensis Diaz, Pomponi & van Soest, 1993

( Figure 2 b)

Synonymy and references. Topsentia bahamensis Diaz, Pomponi & van Soest, 1993: 290, fig. 11, 14.

Material. USNM 1229089, Curlew Bank forereef cave, 20 m; C. Piantoni col. 2 Jul 2007. USNM 1229090, Carrie Bow Cay forereef crevice, on wall, 25 m; M. C. Diaz col. 8 Sep 2009. USNM 1229091, Curlew Bank, forereef cave, ceiling, 1 m from entrance, 20 m; C. Piantoni and M. Parrish col. 22 Aug 2012. USNM 1229092, Curlew Bank forereef cave, 18 m; C. Piantoni and M. Parrish col. 25 Aug 2012.

External morphology. A whitish knob, plate, or cup protruding from the cave wall, also penetrating crevices in rock, up to 3 cm thick, 9–12 cm maximum width by length. Very hard, brittle consistency, macroscopically no obvious oscula or ostia. Color white, to off-white (grayish to brown), with yellow-orange symbiotic zoanthids ( Parazoanthus swiftii ) covering part of the surface.

Skeleton structure. Spicules densely packed in criss-cross fashion throughout the body, generally directed in some angle toward the sponge surface. Many of the smaller spicules tend to be near or in the ectosome, more or less tangential.

Spicules. Fusiform oxeas, straight or curved, with sharp points. Size varies greatly but two main classes can be distinguished, I: 540–890 x 15–32 (721 x 23) Μm; II: 115–300 x 3–12 (243 x 8) Μm

Ecology. On deep reef and rock bottoms, more shallow in caves, 18– 160 m.

Distribution. Bahamas and Caribbean.

Comments. The type material was collected my manned submersibles from deep-reef areas in the Bahamas (40–160 m). These are the first samples from shallower cave habitats.

Figures

FIGURE 2. The most common cryptic habitats studied in the Carrie Bow Cay vicinity (measurements in parentheses are picture widths): a, lower surface of platy coral rock showing the characteristic red foraminiferan Homotrema rubrum, calcareous serpulid polychaete tubes, and two encrusting sponges, Clathria (Thalysias) venosa (left) and Clathria (Thalysias) curacaoensis (10 cm); b, wall inside a forereef framework cave, showing the massive Smenospongia cf. echina (yellow) and Topsentia bahamensis, and encrusting Clathria (Microciona) bulbotoxa (17 cm); c, ceiling of the drowned karst cave in the barrier reef lagoon near Columbus Cay, about 20 m away from the entrance (“ blue hole ”), showing cemented (mostly dead) serpulid tubes, a branching form of Geodia gibberosa (center) and a few knobby specimens of Gastrophanella cavernicola (far left and right; 20 cm); d, broken-up rock from a forereef cave bottom, showing deserted polychaete borings that are colonized by Cryptosyringa membranophila specimens (6 cm); e, broken-up coral rock showing chambers of excavating sponge Cliona cf. mucronata (7 cm); f, Queen conch (Strombus gigas) shell discarded by local fishermen are a common cryptic habitat on the shallow reef (the slot cut by machete near the apex (arrow) to remove the conch assures good ventilation inside the shell); this shell is colonized outside by Chondrilla caribensis, which occurs fully light exposed as well as in darkness (20 cm); g, peat cave (undercut) in the Twin Cays mangrove, the wall covered by Scopalina ruetzleri (80 cm).