Neopetrosia sulcata, Santos, George Garcia, Sandes, Joana, Cabral, Abigail & Pinheiro, Ulisses, 2016

Santos, George Garcia, Sandes, Joana, Cabral, Abigail & Pinheiro, Ulisses, 2016, Neopetrosia de Laubenfels, 1949 from Brazil: description of a new species and a review of records (Haplosclerida: Demospongiae: Porifera), Zootaxa 4114 (3), pp. 331-340 : 333-335

Neopetrosia sulcata sp. nov.

( Figure 2–3 , Table 1 )

Neopetrosia proxima sensu Campos et al. 2005: 13 ; Muricy et al. 2008: 97.

Type specimens. Holotype. UFPEPOR 17, Bacia Potiguar (4°37’31.7”S 36°46’0.7”W), Rio Grande do Norte State, Brazil, 70–101 m depth, leg. Petrobras, 14 May 2003. Paratypes: UFPEPOR 306, Bacia Potiguar, Rio Grande do Norte State, Brazil, leg. Petrobras, 24 may 2004.

Analysed material. MCNPOR 5107, Maranhão State (00°11’13”N 44°46’12”W), Brazil, 93 m, 10 June 1999. MCNPOR 5016, Maranhão State (00º20’38”S 44º17’38”W), Brazil, 85 m, 12 June 1999. MCNPOR 3845, Maranhão State (00°32’S 43°50’W), Brazil, 72 m, 18 November 1997. 3823, Maranhão State (01°33’81”S 43°15’87”W), Brazil, 80 m, 0 2 December 1997. MCNPOR 3791, Maranhão State (02°14’49”S 42°00’20”W), Brazil, 72 m, 0 6 December 1997.

Diagnosis. Neopetrosia sulcata sp. nov. is the only Neopetrosia combining cylindrical shape and oxeas with high variability of ends.

External morphology ( Fig. 2 A). Irregular cylindrical fragments, 16 x 7 x 5 cm (height x length x thickness). The surface is punctiform or furrowed, rugose to the touch, with circular scattered oscules (1.5 to 4 mm in diameter) always flush with the surface (without colored borders). Choanosomal cavities can be observed through these oscula ( Fig. 2 A). One of the specimens from Maranhão State has a big osculum on the top, with 1 cm in diameter (MCN 3823, see figure 8A of Campos et al. 2005). The consistency is hard but not very brittle and the color is beige to light brown in ethanol (92 %).

Skeleton ( Fig. 2 B–C). The tangential ectosome is formed by multispicular tracts, 50– 100 –250 Μm in diameter ( Fig. 2 B), producing rounded meshes (150–300 Μm in diameter). The ectosomal skeleton overlies rounded subectosomal spaces, up to about 1 mm in diameter, and above these spaces there are brushes of spicules at the surface ( Fig. 2 C). The choanosomal skeleton is isotropic but with a superimposed anisotropic orientation as it is typical for many Neopetrosia species according van Soest et al. (2014), composed by multispicular tracts and single spicules strewn in confusion ( Fig. 2 C).

Spicules ( Fig. 3 A–B). Oxeas smooth, relatively robust, usually curved, with a fairly high percentage of variations at the ends: mucronate, stepped, hastate, asymmetrical, or blunt (see Fig. 3 B), with 119– 157.5 –193 / 2.8– 4.9 –9.6 Μm. This high percentage of variation at the ends is not typical of the genus Neopetrosia .

Ecology. The outer surface of the type specimens was infested by zoanthids and in one of the paratypes there was a colony of bryozoans Steginoporella magnilabris (Busk, 1854) (acc. Winston et al. 2014). Depth range from 70– 101 m.

Distribution ( Fig. 1 ). Only from Brazil: Maranhão and Rio Grande do Norte States.

Etymology. The name sulcata is derived from the punctiform or furrowed surface, which is one of the characteristics of this species.

Remarks. This species was previously reported from Brazil as Neopetrosia proxima (Duchassaing & Michelotti, 1864) by Campos et al. (2005: 13). We analyzed the material of Campos et al. (2005) and our specimens and concluded that these are not Neopetrosia proxima sensu original description and other records from the Caribbean (e.g. Zea 1987; van Soest & Stentoft 1988; Zea et al. 2014), but is, in fact, a new species of this genus. Besides, we compared this Brazilian material with specimens that distinctly belong to N. proxima , which is described below.

The characteristics, which led us to make this decision, were morphological and skeletal. Neopetrosia sulcata sp. nov. has irregular and cylindrical shape, with punctiform/furrowed surface, beige to light brown color, apical oscules (one of the specimens) and/or oscula flush to the surface, in which choanosomal cavities can be observed, whereas Neopetrosia proxima has encrusting/massive shape, with smooth surface, dark brown to purple external color and cream internal color, and oscules located on the top of mounds. In relation to skeletal features, the former has a more disorganized skeleton than the later, since there are more spicules strewn in confusion and, consequently, the meshes are less defined. Besides, N. sulcata sp. nov. has oxeas with high percentage of variation at the ends (mucronate, stepped, hastate, asymmetrical, or blunt tips), whereas N. proxima has predominantly hastate/acerate oxeas to strongyloxeas (see Zea 1987 and Zea et al. 2014).

The punctiform/furrowed surface of N. sulcata sp. nov. can be linked to zoanthid association, in which sponges provide benefits to these organisms as substratum, microhabitat, shelter and food. Some works demonstrated that sponge species are exclusively associated with only one or two zoanthid species, whereas zoanthids, particularly Parazoanthus and Epizoanthus , have a low degree of specificity (see Swain & Wulff 2007). Furthermore, this can be also related to the form and mechanical resistance of sponges ( Montenegro-González & Acosta 2010). Besides the type specimens of N. sulcata sp. nov., the sponge-zoanthid association was also observed by Campos et al. (2005) in the specimens from Maranhão State. The same happened with population of N. proxima from Colombian ( Zea 1987, as Xestospongia proxima ), Panama and Dominica ( Swain & Wulff 2007). All these researchers reported a punctiform surface in these sponges, except Swain & Wulff (2007). Despite the likely change caused by zoanthids in a surface structure of N. sulcata sp. nov. specimens, this species remains different from others Neopetrosia species, specially N. proxima , due the characteristics proposed above. However, the association between N. sulcata sp. nov. and zoanthid species needs to be investigated, including the real identity of it, to evaluated the degree of specificity in this relationship.

Besides N. proxima , eight additional species of Neopetrosia have been reported from the Western Atlantic (see van Soest et al. 2015), viz. N. carbonaria (Lamarck, 1814 as Spongia ), N. cylindrica (Lamarck, 1815 as Alcyonium ), N. dominicana ( Pulitzer-Finali, 1986 as Xestospongia ), N. dutchi van Soest et al. 2014 , N. eurystomata van Soest et al. 2014 , N. ovata van Soest et al. 2014 , N. rosariensis ( Zea & Rützler, 1983 as Xestospongia ) and N. subtriangularis . Neopetrosia carbonaria is a black massive sponge, whereas N. subtriangularis is brown ramose/erect (van Soest et al. 2014), clearly different from N. sulcata sp. nov. in habit and color. Neopetrosia dominicana differs from our new species in the type of the spicules, which are exclusively strongyles. Neopetrosia dutchi , N. eurystomata and N. ovata are common deep-water species (from the Caribbean Netherlands), different from N. sulcata sp. nov. mainly in habit (large lobes, vase shaped and ovate, respectively). Neopetrosia rosariensis has a dark brown color and tube shape and Neopetrosia cylindrica is an erect sponge with slightly red and white color. Finally, none of these tropical sponges have the cylindrical shape, with punctiform/ furrowed surface, and oxeas with high percentage of variation at the ends as N. sulcata sp. nov. has.

Figures

FIGURE 1. Location of the collection sites of (1) Neopetrosia sulcata sp. nov. (RN - Rio Grande do Norte State) and (2) Neopetrosia proxima (SE - Sergipe State) in the Brazilian coast. For details about the collecting positions of individual samples of the species cf. the description of these.

FIGURE 2. Neopetrosia sulcata sp. nov. A, three preserved specimens; B, tangential view of ectosome; C, perpendicular section of choanosome. Scale bars: A = 5 cm; B – C = 600 µm.

FIGURE 3. SEM images of the spicules of Neopetrosia sulcata sp. nov. (UFPEPOR 17, holotype). A, two variations of oxea; B, details of the apex of oxea. Scale bars: A = 30 µm; B = 5 µm.