Sponges of the Guyana Shelf Author Van, Rob W. M. text Zootaxa 2017 1 1 225 journal article 37320 10.5281/zenodo.272951 e2c88f4c-3ac2-45f9-95e4-99b75561a081 1175-5326 272951 6D68A019-6F63-4AA4-A8B3-92D351F1F69B 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. 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. 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.