Neopetrosia subtriangularis (Duchassaing, 1850)

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 36-37

Neopetrosia subtriangularis (Duchassaing, 1850)

Figures 22 a–c

Restricted synonymy:

Spongia subtriangularis Duchassaing, 1850: 26 .

Thalysias subtriangularis ; Duchassaing & Michelotti 1864: 85, pl. XVII fig. 1

Xestospongia subtriangularis ; Wiedenmayer 1977: 113, pl. 14 figs 1–5, text-fig. 128; Van Soest 1980: 71, pl. XII fig. 2, textfig. 26 (with additional synonyms).

Neopetrosia subtriangularis ; Desqueyroux-Faúndez & Valentine 2002: 911 (with discussion of synonyms).

Material examined. RMNH Por. 9882, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station G56, 7.26°N 56.6667°W, depth 67–68 m, Agassiz trawl, 10 May 1966 ; RMNH Por. 9892, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station F45, 6.4417°N 56.5467°W, depth 34 m, Van Veen grab, 7 May 1966 ; RMNH Por. 9910, 9911, 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 ; RMNH Por. 10507, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station F46, 6.312°N 56.57°W, depth 25–29 m, bottom sand, 7 May 1966 .

Description. Fragments of branches ( Fig. 22 a), 1–1.5 cm in diameter, with scattered small oscules of 2 mm in diameter. Surface optically smooth, punctate, with some faint subdermal grooves. Color (in alcohol) reddish or orangeish brown. Consistency firm.

Skeleton. At the surface ( Fig. 22 b) there is a regular distribution of rounded to squarish meshes made by tracts of 1–3 spicules, overlying a denser choanosomal skeleton of tracts of 30–40 µm diameter forming squarish meshes of up to 150–200 µm diameter. No visible spongin.

Spicules. Oxeas only.

Oxeas ( Fig. 22 c), curved, sharply pointed, in a large size variation, 132– 202 –240 x 6 – 8.1 –9.5 µm.

Distribution and ecology. Guyana Shelf, Greater Caribbean, NE Brazil, in lagoons, reefs, on sandy bottom, from shallow-water down to 100 m depth ( Guyana Shelf 25–68 m).

Remarks. The spicules of this common, widespread species are apparently variable over its geographic range, as Van Soest (1980) gives 120–186 x 3.5–8.5 µm for predominantly Puerto Rican specimens, Zea’s (1987) Colombian length measurements are similar, but thickness reported by him is up to 11.7 µm, whereas Campos et al. (2005) measured 60–230 x 2.5–6 µm in a Brazil specimen. The present measurements of 132–240 x 6 –9.5 µm are at the higher end of the variation, possibly because the specimens were from deeper water.

Figures

FIGURE 22. Neopetrosia subtriangularis (Duchassaing, 1850), a, habitus of RMNH Por. 9882 (scale bar = 1 cm), b, light microscopic of image of ectosomal skeleton, c, SEM image of oxea.