Form: Thin crust with a hispid appearance, caused by the projection of long styles. Silt is often present over sponge surface.
Colour: Bright red/orange.
Apertures: Oscules are present at the end of raised papillae, these are fairly evenly spaced over the surface but are less prominent and may not be easily visible when closed.
Skeleton: Hymedesmoid with heads of tylostyles and acanthostyles embedded in a thin basal layer of spongin. The longer tylostyles penetrate the surface of the sponge and the ectosomal spicules form bouquets around their points. The ectosomal spicules are asymmetrical with the thicker end being embedded in the sponge surface.
Spicules: Tylostyles: these have tylote heads and are entirely smooth, 240–1850 by 5–12 μm. Ectosomal styles: 215–400 by 0.5–1 μm. Very thin styles, head rounded but not tylote. Acanthostyles: distinctive acanthostyles with stellate spined points, 60–125 by 8–12 μm. The shafts are straight and their points are irregularly spined with a few large spines. Unlike those in Hymeraphia stellifera these stellate ends are not neat and aster-like in form, the spines are large, comparatively few in number and may straggle down the length of the shaft.
Identity: Differs from H. stellifera, in the form of the acanthostyle. These are straight, whereas in H. stellifera the head is curved back from the shaft, giving the spicule a hockey-stick like form. The spines on the tips are much larger, sparser, and less regular in position.
Editors: Claire Goodwin & Bernard Picton.
|Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. [In] Sponges of Britain and Ireland |
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