Geodia gibberosa Lamarck, 1815

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 : 25

Geodia gibberosa Lamarck, 1815

( Figure 2 c)

Synonymy and references. Geodia (Geodia) gibberosa Lamarck, 1815 : Wiedenmayer (1977): 178, fig. 172, pl. 38: 2, 3. Geodia gibberosa Lamarck, 1815 : Uriz (2002b): 138, fig. 6.

Material. USNM 32872 Columbus Cay cave, 18–25 m; G. Hendler, I. Macintyre, P. Kier, T. Rath and C. Clark col. 21 Mar 1979. USNM 1228918, Columbus Cay Cave, 21 m deep, 7 m from sinkhole entrance; I. Macintyre col. 6 Mar 1987. USNM 1228919, 1228920, Curlew Bank, forereef cave, 20 m; C. Piantoni col. 2 Jul 2007.

External morphology. Irregularly massive (10 cm diameter), cone shaped (hanging from cave ceiling, point down: 14 cm height, 6 cm diameter at base), or cluster of branches (also hanging from cave ceiling, 2–11 cm length, 1.5–2.5 cm thickness). Surface rugose but smooth, oscula in groups (cribiporal, 2–4 cm), with individual oscula 1–4 mm in diameter. Tiny ostia (<0.5 mm) cribiporal and scattered. Color white, more or less brownish with increasing habitat exposure to light.

Skeleton structure. There is a cortex, about 1 mm thick, mainly composed of sterrasters, accompanied in places by small cortical oxeas; tiny strongylasters occur in the outermost layer, just below the pinacoderm. Megascleres (oxeas, triaenes) are arranged in bundles, radially oriented near the periphery, with oxeas often protruding beyond the surface, triaenes with cladomes positioned at the inner cortex; in the inner choanosome, oxeas occur without orientation, along with asteroid microscleres.

Spicules. Principal oxeas, straight or curved, sharply pointed at both ends, except for some rare styloid modifications where one end is rounded: 1000–1690 x 10–35 (1324 x 26) Μm; triaenes (ortho- or plagiotriaenes), length x width: 900–1300 x 18–50 (1104 x 41) Μm, clad length: 70–215 (136) Μm; cortical oxeas, with one end tapering but rounded (strongyloxeas): 160–300 x 3–5 (238 x 4) Μm; sterrasters, spherical to slightly depressed (not including developmental (spherasteroid) stages: 58–90 (67) Μm; oxyasters with microspined rays: 15–30 (20) Μm; microspined strongylasters: 5–8 (6) Μm.

Ecology. A shallow-water species found in reef habitats, oftentimes obscured by epizoans; also in caves, to 25 m. One study reports it from 100 m depth off Barbados (van Soest and Stentoft, 1988).

Distribution. Tropical West Africa, Bermuda, South Carolina, Florida, Bahamas, the entire Caribbean region, Guiana, and Brazil.

Comments. As already reported by Pulitzer-Finali (1986) from specimens in shallow coastal habitats in Puerto Rico and by Cárdenas et al. (2009) who redescribed the type specimen, our material too has cortical oxeas with one rounded end (strongyloxeas), a feature not mentioned by other authors describing Caribbean G. gibberosa . We examined this characteristic in other museum specimens, from Bermuda, off Georgia, Florida (Gulf of Mexico), Bahamas, Virgin Islands, and Belize and found that all had more or less modified strongloxeas. None, however, had distinct cortical styles, as described and illustrated for G. corticostylifera Hajdu et al. (1992) from Brazil.

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).