Form: Thinly encrusting, forming sheets 5-10 cm or more in extent.
Colour: Yellow, reported in the literature also as dark orange.
Consistency: Thin fragile crust.
Surface: Bumpy, slightly hispid, with a granular appearance in undisturbed specimens.
Apertures: Oscules small, with transparent rims. Branching excurrent channels visible through the surface, converging on oscules.
Contraction: Some contraction of the surface and oscules on disturbance.
Skeleton: The large tylostyles are erect on the substrate, with their heads embedded in a layer of rhabdostyles and curved oxeotes.
Spicules: Tylostyles, smooth, straight, with well-developed heads: 500-800 x 3-13 Ám. Rhabdostyles and centrotylote oxeas, smooth, strongly recurved and spirally twisted: 120-300 x 4-5 Ám.
Habitat: On boulders and bedrock in strong to moderate tidal streams, open coast.
Distribution: Mediterranean, Azores, Roscoff. Occasional at Rathlin Island, Co Antrim, Northern 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: This species differs from its congener H . intermedia in the smaller rhabdostyles and the possession of centrotylote oxeas instead of strongyles. The latter are less strongly curved.
Editors: Christine Morrow, Bernard Picton & Rob van Soest.
|Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. [In] Sponges of Britain and Ireland |
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