Phakellia folium Schmidt, 1870

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 52-53

Phakellia folium Schmidt, 1870

Figures 33 a–d

Phakellia folium Schmidt, 1870: 62 ; Van Soest & Stentoft 1988: 103, pl. XI fig. 3, text-fig. 51; Alvarez et al. 1998: 28, fig. 16 (with further synonyms and comments).

Material examined. RMNH Por. 6309, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 53, 7.7°N 56.9917°W, no depth data, 30 August 1970 ; RMNH Por. 9295, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station B23B, 7.297°N 55.3883°W, depth 99–101 m, rectangular dredge, 27 April 1966 ; RMNH Por. 9768, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 51, 7.6833°N 57.0333°W, depth 98 m, bottom calcareous sand, 30 August 1970 ; RMNH Por. 9780, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station E66, 7.1°N 56.1783°W, depth 65 m, Agassiz trawl, 13 May 1966 .

Description. Funnel- or cup-shaped individuals ( Figs 33 a,a1) with a short stalk and paper-thin (2 mm) blades. Sizes up to 8 cm high and wide, stalk about 1.5 cm, widest at the attachment to the substratum. Color (alcohol) light beige. Surface optically smooth, but feels hispid. Consistency incompressible, parchment-like, easily damaged.

Skeleton. The blades have a rectangular reticulation of a primary tracts consisting of sinuous strongyles and interconnecting tracts composed of sinuous strongyles and styles. Smaller styles ‘echinate’ tracts and cause the hispidation.

Spicules. ( Figs 33 b–d) Styles, sinuous strongyles.

Styles, smooth, curved, in a large size range, divisible in (1) larger (longer and thicker) gradually curved styles ( Figs 33 b,b1,b2), 267– 357 –451 x 6 – 7.7 –9 µm, and (2) smaller styles with a subapical abrupt curve ( Figs 33 c,c1), 119– 139 –207 x 3 – 4.7 –7 µm.

Strongyles ( Figs 33 d,d1,d2), lightly to strongly, sinuously, curved, quite variable in length and thickness, but not divisible in size categories, 263– 434 –579 x 5 – 11.6 –16 µm.

Distribution and ecology. Guyana Shelf, Florida, Barbados, Grenada, St. Vincent, on sandy and hard bottoms between 65 and 600 m depth ( Guyana Shelf 65–101 m).

Remarks. According to measurements given by Alvarez et al. (1998) (their table 13) the type material from Florida has the upper size limit of the styles up to 1900 x 45 µm, thus much higher than those of the Grenada, Barbados and present specimens. This casts some doubt about the conspecificity of all the cited specimens, excepting the types.

Figures

FIGURE 33. Phakellia folium Schmidt, 1870, a, habitus of RMNH Por. 9295 (scale bar = 1 cm), a 1 ditto of RMNH Por. 9768 (scale bar = 1 cm), b – d, SEM images of spicules, b, larger style, b 1, detail of b, b 2, shorter version of large style, c, short style with curved upper part, c 1, detail of c, d, long thick sinuous strongyles, d 1, detail of d, d 2, thinner sinuous strongyle.