Form: Cushions to massive-lobose, with a tendency to throw out occasional, or many, fistulae and tassel-like extensions. These vary in length from short (usually fistulae), which give a warty appearance, to long (tassels), up to 4cm. The latter can anastomose with other tassels. The growth of the fistulae can be either vertical or lateral, and they are easily broken on collection. Narrow fistulae end 'blind', whereas wider ones possess terminal oscules. These may be borne on fistulae of any length (up to about 2cm), or can be flush with the surface of the main body, or possess rims. Oscules tend to be sparse. Specimens tend to remain compact, with a typical diameter of about 7cm, and height 2.5cm.
Colour: The ectosome is translucent white; the interior tissue is brownish- orange or greyish-orange. The two in combination can cause specimens to appear to be off-white, greyish, or pinkish. The fistulae normally consist solely of ectosomal tissue, and so are t
Smell: None, or very slight: difficult to describe ('fresh ozone', 'faint herbal', 'faint marine').
Consistency: The ectosomal surface is brittle, crisp and quite hard, requiring high pressure before it 'gives'. The subdermal tissue is friable. As a whole the sponge is moderately to very firm.
Surface: The surface layer is distinct, and peels off fairly easily. There are cavities below the ectosomal layer, in which air tends to become trapped on removal from the water, thus enhancing the translucent appearance. Minutely hispid, with moderate to high friction.
Apertures: See under 'Form' for a description of the oscules. They are of varying diameter, up to about 0.75cm, and remain open on collection and preservation. They may be sparse, or even apparently absent in some specimens.
Skeleton: An anisotropic reticulation, regular and open in the surface layer, jumbled and dense in the interior. The tangential surface reticulation has triangular and square meshes, with sides unispicular in length and width. In the interior the primary tracts are 1-2 spicules in diameter, the secondaries are unispicular. Spongin is very scarce, confined to the nodes of the spicules.
Spicules: The oxea are typically slightly curved, but may be straight, 140-200 x 6.5-9.5Ám with a long, sharp point. There are also accessory oxea, 105-160 x 1-3Ám, occasional in the surface layer, numerous in the interior.
Habitat: This sponge is found from the shore to the lower circalittoral. The orientation is variable, but it is more frequently found on vertical rather than horizontal surfaces. It is typically found in moderately sheltered, silty, areas with moderate tidal currents. According to GA, silt does not settle on the sponge, but BEP reports that the sponge may be covered by silt. Rather common.
Distribution: Known recently from Strangford Lough, Down; Arranmore Island, Mulroy Bay, Donegal; Newquay, Galway; W. coast of Scotland; Ravens Pt., Anglesey; Lundy; Scilly Isles; E. Channel (Pullar Bank, Outer Mulberry, Shelly Rocks, Sussex).
Distribution Map from NBN: Grid map (fast) : Interactive map (slower, requires login to view records) : National Biodiversity Network mapping facility, data for UK.
Identity: The fistulae or tassels, translucent crisp dermal surface, and whitish or pinkish colour are characteristic. This description is compiled largely from 14 specimens in the collection of G. Ackers. Other specimens may differ slightly in detail.
Voucher: BELUM : Mc480. Rutland Harbour, Donegal.
Editors: D. Moss, B.E. Picton.
|Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. [In] Sponges of Britain and Ireland |
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