Bowerbank, 1862
Species Overview
Halicnemia patera Bowerbank, 1862 is an orange encrusting sponge with irregular, conulose surface. The consistency of the crust is rather tough and slime is produced when it is taken out of the water. Formerly regarded as rather rare, but SCUBA investigations have established that in certain areas (SW Ireland and Wales) it is not at all uncommon on vertical rock faces.
Taxonomic Description
Colour: Pale orange-pink.
Shape, size, surface and consistency: A thin crust (to 2 mm thickness) forming discrete rounded patches on rock surfaces. Surface conulose with tissue supported on bundles of long spicules which lie at an angle to the surface, facing the same direction and giving a swept appearance. Oscules are small and inconspicuous, not raised above the surface. Consistency tough. Considerable quantities of slime are released from the sponge on removal from water. No contraction noticeable, but collected specimens have a tendency to curl. The photo shows a typical specimen approximately 6 cm in extent occurring in Lough Hyne, Co. Cork. (B. E. Picton, Mc1598)
Spicules: (Halicnemia patera spics) Large tylostyles measure up to 2000 x 22 µm but are normally broken during preparation. Centrotylote oxeas: up to 2000 x 10 µm. Acanthoxeas have a characteristic sharp bend in the middle of their length: 150 x 6 µm.
Skeleton: A basal mass of large tylostyles radiating at an angle to the substratum with their swollen heads lying in contact with the substratum. Long thin centrotylote oxeas form dense sheaths around the tylostyles and ascend at an angle through the sponge to the surface. The entire sponge is filled with a dense mass of small acanthoxeas and these form a definite surface crust.
Ecology: Originally described from deep water as totally enclosing pebbles or stones. Recent observations of this species in shallow water have been from steep rock faces with considerable amounts of silt.
Distribution: Old records are from Shetland and Bretagne. Recent finds have been from Roaringwater Bay and Lough Hyne in West Cork, Ireland, and from Skomer Island, South Wales.
Etymology: Patera (Latin) = saucer, referring to the shape of the sponge.
Type specimen information: The type is in the Natural History Museum, London. MCS voucher: Mc1598, Lough Hyne, Co. Cork.
Remarks
The external appearance of the surface combined with the colour of this species makes tentative field identification possible. The spicule compliment is unusual and characteristic.
Source: Ackers et al., 1992 (editor B. E. Picton).