Prosuberites laughlini ( Díaz, Alvarez & Van Soest, 1987 ), Diaz, Alvarez & Van Soest, 1987

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 119-120

Prosuberites laughlini ( Díaz, Alvarez & Van Soest, 1987)

Figures 73 a–e

Eurypon laughlini Díaz, Alvarez & Van Soest, 1987: 33 , pl. IA, text-fig. 2.

Prosuberites laughlini ; Nichols 2005: 82, 84 (table 1A); Rützler et al. 2014: 44.

Material examined. RMNH Por. 10543, 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. ( Fig. 73 a) Thinly encrusting and consolidating pieces of shells and limestone. Lateral extension several cm2, thickness 1–2 mm. Surface provided with faint venal pattern. Microhispid. Color (in alcohol) pale beige. Consistency soft.

Skeleton. ( Fig. 73 b) Single tylostyles and groups of tylostyles stand erect on a basal spongin plate, all with points directed upwards, carrying the surface membrane, the longer spicules protruding beyond it. No special ectosomal skeleton.

Spicules. ( Figs 73 c–e) Tylostyles only.

Tylostyles, with prominent tyles but grading into the shaft, not abruptly set off from the shaft, in an extreme size range, divisible with considerable overlap in three length categories, with thickness almost the same in all three, (1) larger ( Figs 73 c,c1) 984– 1148 –1425 x 11– 13.4 –16 µm, (2) intermediate ( Figs 73 d,d1) 402– 555 –719 x 11 – 11.9 –14 µm, and (3) smallest ( Figs 73 e,e1) 218–271–336 x 6 – 9.2 –13 µm.

Distribution and ecology. Guyana Shelf, Los Roques ( Venezuela), Curaçao, rocky and sandy bottoms, from shallow-water down to 64 m (previously 7–35 m).

Remarks. The recognition of the true presence of the genus Prosuberites in the Caribbean fauna is rather recent. The earliest records of Prosuberites species, P. microsclerus De Laubenfels, 1936 (from Florida) and Prosuberites geracei Van Soest & Sass, 1981 (from the Bahamas) turned out to be members of the genera Terpios Duchassaing & Michelotti, 1864 and Protosuberites Swartschewsky, 1905 respectively (see Van Soest et al. 2016). Previous assignments of specimens with the skeletal structure and spiculation described above were made by Díaz et al. (1987) to the raspailiid genus Eurypon as E. laughlini and by Pulitzer-Finali (1986) to the suberitid genus Laxosuberites , as L. psammophilus (a species from the Dominican Republic). Nichols (2005) reassigned E. laughlini to Prosuberites on the basis of molecular sequence analysis. Rützler et al. (2014) by inference reassigned L. psammophilus to Prosuberites . These last authors added a third species, P. carriebowensis Rützler, Díaz, Piantoni & Van Soest, 2014 (from Belize) to the genus. All three species appear quite similar differing in thickness, sand content and surface characters ( Rützler et al. 2014), but due to the variability of tylostyle lengths and shapes, the distinction is not easy. The identification of the present material to P. laughlini is made on the basis of comparison with the type material of P. laughlini , paratypes ZMA Por. 0 5839 and 0 5830 from Curaçao. These are strikingly similar in spicular characters to the present specimen.

Figures

FIGURE 73. Prosuberites laughlini (Díaz, Alvarez & Van Soest, 1987), a, habitus of RMNH Por. 10543 (scale bar = 1 cm), b, cross section of the skeleton encrusting carbonate rubble, c – e, SEM images of spicules, c, large tylostyle, c 1, details of c, d, intermediate tylostyle, d 1, details of d, e, small tylostyle, e 1, details of e.