Auletta sycinularia Schmidt, 1870

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 49-50

Auletta sycinularia Schmidt, 1870

Figures 31 a–d

Auletta sycinularia Schmidt, 1870: 45 ; Van Soest & Stentoft 1988: 105, text-fig. 52; Alvarez et al. 1998: 32, fig. 18.

Material examined. RMNH Por. 9790, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 51, 7.6833°N 57.0333°W, depth 98 m, bottom calcareous sand, 30 August 1970 ; RMNH Por. 10541, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station B23, 7.2976°N 55.3883°W, depth 99–101 m, Agassiz trawl, 27 April 1966 .

Description. Two specimens, each consisting of a group of tubes growing out of a single stalk ( Fig. 31 a). Height of both specimens 7 cm, diameter of stalk 0.8 cm, of tubes 0.5–1 cm. Tube aperture about equal to tube diameter. Color beige brown (10541) or dark brown (9790), in alcohol, the latter probably darkened due to aerophobic discoloration from other sponges in the catch. Surface finely hispid, velvety. Consistency firm.

Skeleton. Reticulate. In cross section (thickness about 0.5–1 mm) the wall of the tubes shows ascending tracts (directed towards the surface) of 60–100 µm diameter consisting mostly of shorter styles, interconnected by bundles of sinuous strongyles bound by little spongin. At the outer surface long styles protrude, causing the velvety surface.

Spicules. ( Figs 31 b–d) Styles, strongyles.

Styles ( Figs 31 b–c) straight to slightly curved, isodiametrical over a large part of the shaft, ending rather gradually pointed, in a wide size range, divisible in (1) longer styles ( Figs 31 b,b1), 332– 432 –513 x 7.5– 9.5 – 12 µm, and (2) shorter styles ( Figs 31 c,c1), 159– 217 –273 x 6 – 6.9 –9 µm.

Strongyles ( Figs 31 d,d1), isodiametrical, equiended, usually with one or two opposing curves (‘sinuous’ strongyles), in a large size range but not divisible into apparent size categories, 268– 469 –606 x 3 – 8.7 –11 µm.

Distribution and ecology. Guyana Shelf, Florida, Gulf of Mexico, Barbados, also reported from the Azores, on soft bottoms from 70–200 m ( Guyana Shelf 98–101 m).

Remarks. The specimens described here conform to Schmidt’s A. sycinularia , but differ from the description in Alvarez et al. (1998) in the upper size of the styles, recorded by these authors as up to 1400 µm. In contrast, style sizes of Van Soest & Stentoft (1988) only went up to 310 µm. Possibly these differences are indicative of more diversity in these stalked tubular Auletta ’s in the Central West Atlantic.

Figures

FIGURE 31. Auletta sycinularia Schmidt, 1870, a, habitus of RMNH Por. 9790 (scale bar = 1 cm), b – d, SEM images of spicules, b, large style, b 1, detail of b, c, small style, c 1, detail of c, d, sinuous strongyles, d 1, detail of d.