Aulospongus samariensis Hooper, Lehnert & Zea, 1999

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 59

Aulospongus samariensis Hooper, Lehnert & Zea, 1999

Figures 38 a–h

Aulospongus samariensis Hooper et al. 1999: 665 , figs 13–16, 36A–B.

Material examined. RMNH Por. 9928, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station I115, 7.21°N 54.8617°W, depth 81 m, triangular dredge, 24 April 1969 .

Description. Erect, finger-shaped sponge ( Fig. 38 a) attached to a dead gastropod shell. Surface has lengthwise ridges and depressions. Color in alcohol red-brown, with the lengthwise depressions greyish brown. Size 3 cm high, about 1 cm in greatest diameter. Consistency firm, surface easily damaged.

Skeleton. Axially condensed choanosomal skeleton with diverging secondary axes consisting of acanthostyles. Axes densely echinated by rhabostyles, diameter of echinated axial columns 150–250 µm. Extra-axial skeleton of single long styles protruding far beyond the surface at their base surrounded by dense bouquets of thin styles and thin oxeas.

Spicules. ( Figs 38 b–h) Tylostyles, acanthostyles, thin ectosomal styles, thin ectosomal oxeas, acanthorhabdostyles.

Long ectosomal tylostyles ( Figs 38 b,b1), smooth, curved, with prominent tyle smoothly grading into the shaft, in a large size range, 572– 1112 –1448 x 12– 15.0 –19 µm.

Acanthostyles from the axial column ( Figs 38 c,c1), slightly curved, with prominent tyle, lightly spined all over, occasionally almost smooth, 382– 468 –564 x 13 – 22.1 –29 µm.

Thin styles from the ectosomal bouquets ( Figs 38 d,d1), smooth, slightly curved, with narrow rounded head thinner than the shaft, 516– 634 –738 x 2.5– 4.3 –6.5 µm.

Thin oxeas from the ectosomal bouquets ( Figs 38 e,e1), similar to the thin styles but sharply pointed at both ends, 342– 496 –690 x 1.5– 4.1 –3 µm.

Rhabdostyles in a large size range ( Figs 38 f–h), usually acanthose, but occasionally almost or entirely smooth, especially in the larger rhabdostyles; divisible in three overlapping categories, (1) larger ( Figs 38 f,f1), 330– 441 –572 x 19 – 21.4 –28 µm, (2) middle sized ( Fig. 38 g), 211– 244 –279 x 10 – 13.9 –16 µm, and (3) smaller ( Figs 38 h,h1), 151– 164 –180 x 7.5– 9.4 –12 µm.

Distribution and ecology. Guyana Shelf, Colombian Caribean, Jamaica, on reefs and fore reef slopes, at 6–90 m depth ( Guyana Shelf 81 m).

Remarks. The present material conforms in all aspects with the description of the type material by Hooper et al. 1999. The division of the rhabdostyles into size categories, observed here, was not reported by Hooper et al., but the size range is comparable with the present sizes. Unpublished specimens in the ZMA collection indicate that the species is widespread in the Greater Caribbean. Zea’s hypothesis (in Hooper et al. 1999, p. 670) that this is likely a deep-water species that occasionally occurs in shallower waters is confirmed by the present sample from 81 m.

Figures

FIGURE 38. Aulospongus samariensis Hooper, Lehnert & Zea, 1999, a, habitus of RMNH Por. 9928 (scale bar = 1 cm), b – h, SEM images of spicules, b, ectosomal tylostyle, b 1, detail of b, c, choanosomal acantho (tylo-) style, c 1, detail of c, d, ectosomal thin style, d 1, details of d, e, ectosomal oxea, e 1, details of e, f, largest rhabdostyle, f 1, detail of f, g, middle-sized rhabdostyle, g, smallest rhabdostyle, g 1, detail of g.