Picton & Goodwin, 2007
Hymeraphia breeni Picton & Goodwin (2007) is a thin orange-red hispid crust on rocks, often covered with silt. Very similar to congeneric species H. stellifera and H. elongata. Microscopic examination and measurement of spicules is necessary to identify this species with certainty. So far, only known from Northern Ireland.
Colour: Bright red/orange
Shape, size, surface and consistency: Thin crust with a hispid appearance, caused by the projection of long styles. Silt is often present over sponge surface. 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.
Spicules: Tylostyles: these have tylote heads and are entirely smooth, 240-1850 by 5-12 µm. The longest spicules tend to break on sectioning and therefore the length given is of the longest intact spicules visible in the tissue sections. 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 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.
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
Distribution: Known only from Rathlin Island, Northern Ireland.
Ecology: On rocks in deeper water, 24-36 m.
Etymology: Named for Joe Breen, head of marine biodiversity in the Environment and Heritage Service Northern Ireland.
Type material: Holotype: [Mc2486]. Sample in IMS, section and spicule preparation, Damicornis Bay (55°17.453'N 006°15.180'W; water depth: 24-29 m); coll. by J.Jones and L.Scalle, 14 June 2005.
Differs from H. stellifera, the only other species with this form of spicule, 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.
Source: Picton & Goodwin, 2007.