Form: Irregular cushion with tendency to form outgrowths, which may be mushroom shaped, fistulose or irregular in shape.
Colour: Pale pink/grey.
Consistency: Firm, crisp and somewhat brittle.
Surface: Even, translucent, porous; slightly hispid, sometimes shaggy.
Apertures: Oscules are not conspicuous.
Skeleton: "The ectosome is a regular and characteristic, open, isotropic reticulation of intercrossing oxea. The choanosome is a rather confused, sub-halichondroid reticulation, in places consisting of paucispicular primary and unispicular secondary lines, in places multispicular tracts. There is very little spongin, confined to the nodes of the spicules, or absent."
Spicules: Long thin oxea (a) with long, rather sharp points, 250-350 x 3-14Ám. Toxa, (b) very slender, sharply bent, with recurved apices, 43-75 x 0.2-2.5Ám. Sigmata, (c) strongly curved, somewhat accolada-shaped, small, 7-15 x 0.2-1.2Ám.
Habitat: On rocks in exposed places. (?)
Distribution: A southern species in the British Isles, not uncommon on the south coast, in the Scilly Isles and Channel Isles. Known from Gurley Rock, near Padstow, N. Cornwall.
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 presence of the characteristic microscleres in a renieroid skeleton is very distinctive. More observations are needed to see if the external appearance is always characteristic. Haliclona rava (Stephens, 1912) (q.v) is very similar but differs largely in the size of the oxea and shape of the toxa. Haliclona fibulata (q.v) is similar in spiculation but lacks toxa. Several genera have been established in the past for different microsclere combinations, e.g. Gellius for sigmata and toxa; Sigmadocia for sigmata only; and Toxadocia for toxa alone. All are recognized as being artificial and are abandoned here in line with de Weerdt 1986.
Voucher: BELUM : Mc1358. Longue Pierre, Guernsey, Channel Is.
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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