Form: Encrusting sheets to cushions with lobes and ridges.
Colour: White, pale grey.
Consistency: Firm, crisp, friable.
Apertures: Small, distributed along the tops of lobes or ridges, "naked" (i.e. without collar of spicules).
Skeleton: The ectosomal skeleton consists of several tangential layers of triradiates; the skeleton of chamber layer is of triradiates and microxea, irregularly arranged. The endosomal skeleton, and linings of exhalant canals, are tangential layers of quadriradiates.
Spicules: The ectosomal triradiates (a) have rays ca. 120Ám long, those of the chamber layer (b) 50-1200Ám; microxea (c) are 40-60Ám long. The endosomal quadriradiates (d) are sagittal and have paired rays ca. 20Ám long and basal ray ca. 60Ám.
Habitat: In strong water movement beneath boulders in shallow water and in surge gullies on vertical rock surfaces.
Distribution: A common species in the British Isles. "Spitzbergen; Norway; Heligoland; France; Mediterranean. "Littoral to 128m, on rock."
Distribution Map: NBN map : National Biodiversity Network mapping facility, data for UK.
Identity: Superficially this species can be confused with Leuconia johnstoni (see Burton, 1963:266) and Leuconia gossei (see Burton, 1963:505). It would be useful to see if the three species occupy different ecological niches.
Voucher: BELUM : Mc1778. St. Kilda, W. 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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