Form: Massive, lamellate or with very flattened branches; irregular lamellae with conulate projections. Sizes to 20cm high and across the base.
Colour: Pale beige, yellow or green. When dried, becomes orange-brown or purple.
Consistency: Fairly compressible.
Surface: Rugose, with very porous appearance; "open" in appearance.
Apertures: Oscules are at the edges and on the faces of the lamellae, on conulate projections at regular intervals. Excurrent channels converging on the oscules are obvious. Pores are conspicuous and distributed fairly uniformly over the surface.
Skeleton: A reticulate skeleton of curved smooth styles, sparsely echinated with entirely spined acanthostyles. The ectosomal skeleton consists of tangential, relatively slender, subtylostyles. Very fine toxa are present in internal membranes.
Spicules: Megascleres are smooth styles (a), which are usually abruptly curved near the head, and taper to a fine point, size range at least 350-580Ám, and slender subtylostyles (b) with microspined heads in the ectosome. Entirely spined acanthostyles (c), ca. 90Ám, occasionally echinate nodes in the interior. Microscleres are palmate isochelae (d), ca. 18-21Ám and toxa (e) with an abrupt central flexion, ca. 260-500Ám. Some of these categories may be absent in a given specimen.
Habitat: Circalittoral, on Lophelia, rock, stones, etc. to depths in excess of 100m, usually below 40m.
Distribution: Arctic, southwards to west coasts of Ireland and France. Scarce within diving range, but recently rcorded from Rockall; Insh Is., Firth of Lorne; Loch Sunart, Sound of Mull; and Rathlin Is., and the Maidens, N. Ireland.
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 spiculation of this species is very variable, and any of the categories toxa, acanthostyles, isochelae or acanthostyles and isochelae, may be absent or rare in a given specimen. This has in the past caused specimens to be assigned to a variety of species, genera and families.
Voucher: BELUM : Mc490. Lunga, Firth of Lorne, Scotland.
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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