Petrosia (Petrosia) weinbergi Van Soest, 1980

Figures 23 a–e

Petrosia weinbergi Van Soest, 1980: 75, Pl. XII figs 3–4, text-fig. 27; Pulitzer-Finali 1986: 151, fig. 69; Alcolado & Gotera 1986: 2, figs 1–2; Zea 1987: 119; Campos et al. 2005: 17, figs 10A–D.

Material examined. RMNH Por. 9898, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station G7, 7.28°N 56.7933°W, depth 64 m, bottom sand, 7 May 1966 .

Description. Creeping branch (Fig. 23 a) with one cut-off side branch. Size 9 cm long, 2–3 cm in diameter. Surface with a few oscules of 2–4 mm in diameter, and regularly pitted with ingrown zoanthids. Color (in alcohol) dark red-brown, possibly because of exposure to pigments from other sponges collected simultaneously. Consistency hard.

Skeleton. The choanosomal skeleton (Fig. 23 b) is a reticulation of thick spongin-enforced spicule tracts of 80–200 µm in diameter (consisting of 10+ spicules), making meshes of 200 to 500 µm. The surface skeleton is an incomplete unispicular network ‘echinated’ by small spicules, carried by the choanosomal tracts.

Spicules. (Figs 23 c–e) Larger and smaller oxeote spicules.

Oxeas, in three size categories, straight or curved, with strongylote and stylote modifications, especially in the larger category, (1) largest (Fig. 23 c), often with blunt or rounded apices, 227– 243 –261 x 9 – 12.2 –14.5 µm, (2) intermediate sizes (Fig. 23 d), likewise often with blunt apecies, 135– 157 –179 x 8 – 9.2 –11 µm, and (3) smallest (Fig. 23 e), usually with sharply pointed apices, 57– 96 –106 x 4.5– 6.8 –7.5 µm.

Distribution and ecology. Guyana Shelf, Curaçao, Puerto Rico, Dominica, Cuba, Caribbean Colombia, Jamaica, Belize, NE Brazil, predominantly known from the deeper reef environment, but here reported from sandy bottom at 64 m depth. According to Campos et al. (2005) the species can reach 184 m.

Remarks. The specimen was compared to the holotype from Curaçao, ZMA Por. 0 3670 and found to be closely similar. The nature of the larger megascleres is variably oxeote, strongylote and rarely style-like, which is a characteristic feature of this species. Not all records of P. weinbergi are certainly conspecific (e.g. Lehnert’s (1993) description from Cozumel appears to be likely a different Petrosia), but the distribution is wide, covering most of the Caribbean and the Northeast Brazilian regions.