Geodia gibberosa Lamarck 1815

Geodia gibberosa Lamarck, 1815

(Figures 14–15)

Synonyms (modified from da Silva, 2002).

Geodia gibberosa Lamarck, 1815: 334.

Pyxitis gibberosa Lamarck, 1815: Schmidt 1870: 70.

Geodia (Geodia) gibberosa Lamarck, 1815: Hechtel 1965: 68, pl. VIII, fig. 2. Geodia cariboea Duchassaing de Fonbressin and Michelotti, 1864 (in part): 105, pl. XXV, fig. 8. Geodia tumulosa Bowerbank, 1872: 628, pl. XLVII.

Geodia media Bowerbank, 1873 (non G. m e d ia Lendenfeld, 1910): 13, pl. II. Geodia dysoni Bowerbank, 1873: 14, pl. III.

Geodia reticulata Bowerbank, 1874: 300, pl. XLVI, figs. 14–20. Sidonops stromatodes Uliczka, 1929: 54, figs. 51–56, pl. I, fig. 10. Geodia media var. leptoraphes Uliczka, 1929: 56, figs. 57–67, pl. I, fig. 11. Geodia flexisclera Pulitzer-Finali, 1986: 76, figs. 10–11.

Holotype. MNHN DT –608, dry, French Guiana.

Material. 5 specimens, all collected in Solarte lagoon, on mangrove roots, 0.5–1 m depth. Two specimens (fragments) are deposited: ZMBN 77928 and 81780.

Additional material examined. Geodia gibberosa, MNHN DT –608, holotype, French Guiana; YPM 5302, 5304, 5311, mangrove boat channel, Port Royal, Jamaica (from Hechtel, 1965); USNM 4997, off Florida, USA, 14 m; ZMAPOR 03772b, Plaja Kalkie, Westpunt, Curaçao; UFBA-POR 207, Barra do Pote, Veracruz, Bahia, Brazil, 12°59'00" S / 38°36'00" W, V. Almeida coll., intertidal.

Outer morphology (Fig. 14 A–D). Massive, irregularly lobate large sponge (‘gibberosa’ means ‘hunchbacked’) (Fig. 14 A–B). Size can be up to 30 cm in diameter. Color alive is dark–green to light–brown when exposed to light, otherwise whitish. Color in ethanol is whitish, except the oscule area that stays dark brown. Choanosome color, alive and in ethanol, is whitish. However, in live green specimens, the choanosome just below the cortex can also be greenish. It is a slightly compressible sponge with a dense choanosome, and a tough cortex, difficult to break. Surface is usually smooth, but can be hispid in some areas. Often overgrown by other sponges (e.g. Tethya actinia de Laubenfels, Chalinula molitba (de Laubenfels), Haliclona spp.), ascidians, polychaetes, clams and algae. Oscules are uniporal (0.5–1.5 mm in diameter), each with a sphincter (Fig. 14 F), grouped in circular slightly depressed areas (2–4 cm diameter) (Fig. 14 C). These oscular plates can be situated at the end of lobate projections or not; they are never covered by ectosymbionts. These plates usually are of darker color, brownish. Pores (Fig. 14 D) are cribriporal (diameter of a pore plate: 0.5–1 mm), numerous and evenly distributed over the whole surface.

Skeleton (Fig. 14 E–F). The cortex is 0.4–0.9 mm thick and is subdivided between a very thin ectocortex of acanthoxyasters III (ca 20 µm) and a thicker endocortex of sterrasters (ca 500 µm). Oxeas I and plagiotriaenes are radially positioned under the cortex with cladomes supporting the endocortex. Under this layer of plagiotriaenes the radial arrangement is less obvious. Most acanthoxyasters II are present right under the cortex while acanthoxyasters I and III are quite abundant throughout the choanosome, as well as developing sterrasters. Oxeas II can be found in the choanosome but are especially placed on the cortex around the oscules (Fig. 14 F).

Spicules (measurements from ZMBN 77928, except for the rosette diameter measured in ZMBN 81780) (Fig. 15). Megascleres: (a) oxeas I, stout, straight or very slightly bent, length: 1044– 1342.1 –1824 µm; width: 16– 31.2 –42 µm. (b) oxeas II, usually straight, length: 157– 201.5 –238 µm; width: 3.6– 4.3 –7.2 µm. (c) plagiotriaenes (Fig. 15 A), rhabdome length: 792– 1266 –1620 µm; rhabdome width: 35– 48.1 –70 µm; clad length: 98– 211.4 –308 µm. (d) anatriaenes (Fig. 15 B), rare, rhabdome length: 1433 µm (N=1); rhabdome width: 6– 7.9 –11 µm (N=3); clad length: 23– 26.5 –33 µm (N=3). Microscleres: (e) sterrasters (Fig. 15 C–D), oval, with smooth 3–5 branched rosettes at their surface (diameter: ca. 4 µm), length: 75– 84.1 –93.1 µm; width: 54– 79.5 –93.1 µm. (f) acanthoxyasters I (Fig. 15 E), 6–12 thin actines, diameter: 16– 21.3 –34 µm. (g) acanthoxyasters II (Fig. 15 F), large centrum, with thicker and shorter actines than acanthoxyasters I, 14–20 actines, diameter: 9.7– 13.4 –16.2 µm. (h) acanthoxyasters III (Fig. 15 G), 9–17 actines, diameter: 4.3– 6.5 –7.6 µm.

Habitat in the Bocas del Toro region. Common on mangrove roots, 1–2 m depth.

Distribution. Georgia, Florida, Texas, U.S.A. (de Laubenfels 1936b; 1953; Little 1963; Freeman et al. 2007); Bermudas (de Laubenfels 1950); Bahamas (de Laubenfels 1949; Wiedenmayer 1977); Cuba (Alcolado 2002); Jamaica (Bowerbank 1872; Hechtel 1965; Lehnert & van Soest 1998); Dominican Republic (Bowerbank 1873); Puerto Rico (Pulitzer-Finali, 1986); St. Thomas (Duchassaing de Fonbressin & Michelotti 1864); St. John (Uliczka 1929); Barbados (Uliczka 1929; van Soest & Stentoft 1988); Mexico (Lehnert 1993); Honduras (Bowerbank 1872); Belize (Rützler et al. 2000); Costa–Rica (Loaiza Coronado 1991; Cortés 1996); Panama (de Laubenfels 1936a; Wulff 2000); Colombia (Díaz 2007); Curaçao (van Soest 1981); Venezuela (Carter 1882; Sutherland 1980); French Guiana (Lamarck 1815); Brazil (da Silva 2002).

Remarks and discussion. After the Galeta and Panama Canal locality records, this is the third record of G. gibberosa in Panama. In fact, G. gibberosa is one of the sponge species that have been able to cross to the Pacific side using the Panama Canal (de Laubenfels 1936a). The spicule sizes and morphologies of our specimens fitted previous descriptions (da Silva 2002) and the comparative material, except for the Florida specimen (USNM 4997) which had a more regular gross morphology and smaller sterrasters with a different rosette pattern (data not shown). We suggest that the status of Florida populations should be tested in the future. This is the first observation of anatriaenes in G. gibberosa but due to their rarity, they could have easily been overlooked in previous observations. It is also the first time that oxeas II are observed in high density around the oscules (Fig. 14 F). The lobate morphology of our specimens (Fig. 14 B) was very similar to that of the holotype of Geodia tumulosa (Bowerbank 1872, pl. XLVII), later synonymized with G. gibberosa (Carter, 1882; da Silva, 2002). G. gibberosa is a common wide-spread Tropical western Atlantic species. In the literature it appears that G. gibberosa is very polymorphic when it comes to its gross morphology (lobate to flat, massive to encrusting) and its color (white, brown, green and black). A pattern emerges when one considers its two habitats (reef and mangrove). Reef specimens tend to be smaller in size with common encrusting forms, and are usually white to brown. On the other hand, mangrove specimens like ours tend to be large, massive, lobate, and darker colored. Ecology studies have shown that G. gibberosa is very palatable for reef fishes and has no chemical defenses (Pawlik et al. 1995). Therefore, it uses secondary metabolites to promote overgrowth of other species better equipped to defend themselves from fish predation (Engel & Pawlik 2005). All the specimens we observed in Bocas del Toro were indeed covered with numerous sponges, ascidians, algae, etc. Fish predation being lower in mangroves (Dunlap & Pawlik 1996), G. gibberosa can reach bigger sizes and grow in more open habitats thereby receiving more sunlight and having darker colors. Conversely, predation pressure in reefs being higher, G. gibberosa is usually smaller and prefers cryptic habitats (under rocks or other sponges, crevices). When not exposed to light it is of lighter color, often white. Seemingly, two other mangrove sponges (Tedania (Tedania) ignis (Duchassaing de Fonbressin & Michelotti) and Chondrosia sp.) were found in cryptic habitats when collected on reefs (Dunlap & Pawlik 1996). An alternative to the polymorphism hypothesis is that we simply have two (or more) cryptic species. Both hypotheses should be tested combining morphology and molecular data.