Neopetrosia proxima (Duchassaing & Michelotti, 1864)

(Figure 4–5, Table 1)

For synonyms see Muricy et al. (2011).

Examined material. UFSPOR 116, 118, 135, 162, off Pirambu city (10°45’36”S 36°36’08”W), Sergipe State, Brazil, 20 m depth, coll. Cosme e Damião Assis, June 2003.

External morphology (Fig. 4 A–B). Massive lobed sponge. The largest specimen is 7 x 4 x 4 cm (length x width x height) and the smallest is 2 x 1.5 x 0.5 cm (length x width x height). The surface is smooth to rough with scattered oscules, up to about 2 mm in diameter, on the top of lobes, or slightly raised on the surface. The consistency is firm, hard and brittle. In ethanol, the color is purplish-brown or dark brown externally and light brown internally.

Skeleton (Fig. 4 C–E). The tangential ectosome is an irregular reticulation of dense multispicular tracts, forming vague rounded meshes with various amounts of spongin (Fig. 4 C). At the surface there are fine brushes of oxeas issued from fascicular tracts (Fig. 4 D). The choanosome is an irregular reticulation formed by fascicules made of an isotropic to confused reticulation of multispicular tracts or single spicules strewn in confusion. The meshes are rounded to oval, 250–875 Μm in diameter (Fig. 4 E).

Spicules (Fig. 5 A–C). Hastate oxeas, smooth, slightly curved with thinner developmental stages (Fig. 5 A) and few styloids modifications (Fig. 5 C): 96– 149.1 –177 / 1.6– 5.3 –9.6 Μm.

Ecology. This species was found at 20 m depth.

Geographical distribution. Tropical Northwestern Atlantic: U.S. Virgin Islands, Puerto Rico, Colombia, Jamaica, Barbados, Panama and Belize (Muricy et al. 2011). In the Brazilian coast: Northeastern Region: Sergipe State (present study).

Remarks. Neopetrosia proxima is a sponge that usually inhabits rocky shores and shallow to deep waters (Zea et al. 2014). The specimens examined here were similar to Neopetrosia proxima from the Caribbean, both characterized by having massive form, oscules raised on small lobes and confused and disorganized skeleton (e.g. van Soest 1980; Zea 1987; Lehnert & van Soest 1996; Zea et al. 2014). According to Zea et al. (2014), the external morphology and spicules of this species are very diverse in different populations in Caribbean Sea and, probably, there are more than one species within the current scope of N. proxima from this area (Zea, personal communication). Compared to Bahamian, Colombian and Panamanian populations, the Brazilian specimens were more similar to the Colombian ones, sharing the massive form, purple color and robust hastate oxeas reaching larger and thicker sizes (75–223 / 1.7–10.7 µm in Colombia and 96– 149.1 –177 / 1.6– 5.3 –9.6 Μm in Brazil). However, the Brazilian population is different from the Caribbean one in two aspects: the internal light-brown color and a tangential ectosome with dense and irregular reticulation in Brazilian versus the internal cream color and the tangential reticulation with erect spicule brushes at the intersections in Caribbean.

References: (1) Present work - UFPEPOR 17, 396, UFSPOR 116, 118, 135, 162; (2) Zea et al. (2014); (3) Zea & Rützler (1983); (4) Topsent (1933); (5) van Soest et al. (2014); (6) Desqueyroux-Faúndez & Valentine (2002); (7) Pulitzer-Finali (1986).

When we compared the population of Neopetrosia proxima from Brazil with N. sulcata sp. nov., we observed some differences. The former has massive form, smooth surface, purplish-brown to dark brown external color, oscules on the top of mounds, irregular ectosomal reticulation and hastate oxeas, whereas the later has digitiform shape, punctiform surface, beige to light brown color, without differentiation between external and internal regions, apical oscules and/or flush with the surface, regular ectosomal reticulation and oxeas with high percentage of variation at the ends.