Columnitis squamata Schmidt, 1870

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 176-177

Columnitis squamata Schmidt, 1870

Figures 110 a–f

Columnitis squamata Schmidt, 1870: 25 , pl. V figs 3–4; Sollas 1888: 441; Sarà & Bavestrello 1996: 374, figs. 3A, 4A–C, 5A–F; Sarà 2002: 252, figs. 4A–D.

Material examined. RMNH Por. 9818, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station I120, 6.505°N 54.9833°W, depth 36–37 m, bottom sandy mud, 25 April 1969 .

Description. Lumpy mass ( Fig. 110 a), greyish brown to beige brown in alcohol. Surface covered with rounded mounds, several of which bear slightly sunken oscules. Surface also bumpy with barnacles partially or wholly coverd by sponge tissue. Size 10 x 7 cm in lateral dimensions, 1–2 cm thick, mounds 0.5–2 cm in diameter, approximately 0.5–1 cm high. Surface of mounds covered with low flattened tubercles, each with a glassy greyish colored center, and separated by thin grooves. Between the mounds the surface is veined and slightly rough. Microhispid. Consistency firm to hard.

Skeleton. Typically tethyid, with flattened tubercles in cross section showing cortical bundles of styles fanning out to carry a 200–300 µm thick dense layer of acanthoxyasters. Styles protrude beyond the surface in places, especially in the grooves. Between the bundles of styles masses of megasters complete the cortical skeleton. The choanosome is less densely spiculated, and shows brown-pigmented tissue with scattered (smaller) styles, acanthoxyasters and micrasters. The choanosome is traversed vertically by bundles of large strongylostyles.

Spicules. ( Figs 110 b–f) Styles, megasters, acanthoxyasters/acanthostrongylasters, micrasters.

Styles, straight, slightly fusiform but not typical tethyid strongylostyles or strongyloxeas, in two distinct size categories, (1) larger ( Figs 110 b,b1), closely resembling (sub-)tylostyles, with elongated tyle, sharply pointed, barely fusiform, 930– 1163 – 1494 x 12 – 19.7 –27 µm, and (2) smaller ( Figs 110 c,c1), more style-like with barely swollen tyles, 342– 561 –870 x 4 – 6.9 –10 µm.

Megasters ( Fig. 110 d), smooth, with conical, sharply pointed rays, 46– 56.5 –66 µm, with 9– 10.3 –13 rays.

Acanthoxyasters/acanthostrongylasters ( Fig. 110 e), with smooth center and irregularly spined apices (with peculiar proliferated clusters of larger and smaller spines), 15– 22.3 –27 µm, with 8– 10.6 –12 rays.

Micrasters ( Fig. 110 f), tiny, tylaster-like, with smooth center and rather strongly spines apices, 3– 3.8 –5 µm, with 6– 7.4 –8 rays.

Distribution and ecology. Guyana Shelf, Gulf of Mexico, soft bottom, at 30–37 m depth. Remarks. The present specimen conforms closely to (re-)descriptions of Sarà & Bavestrello (1996) and Sarà (2002). A few size discrepancies are noticeable: the upper size of the styles, which is cited as up to 2000 µm by Sarà, were short of 1500 µm in the specimen from Suriname. Likewise, the size of the megasters (up to 80 µm according to Sarà) did not reach over 66 µm in the Suriname specimen.

Figures

FIGURE 110. Columnitis squamata Schmidt, 1870, a, habitus of RMNH Por. 9818 (scale bar = 1 cm), b – f, SEM images of the spicules, b, large style, b 1, details of b, c, small style, c 1, details of c, d, megaster, e, acanthostrongylaster, f, micraster / tylaster.