Spongosorites calcicola Picton & Goodwin, 2007


Family : Halichondriidae

Form: Bright, lemon yellow, massive sponge with large oscules. Forms a thick crust with a shiny, rubbery appearance. Patches can be fairly large, some larger than 20 cm maximum diameter. Unlike many other species in this genus it does not undergo a colour change when removed from water.

Internal characters

Skeleton: Thick ectosomal layer thicker than 1 mm in some places, a dense mesh mainly composed of smaller oxea (<200 μm). Choanosome is a disordered mass of oxea of both large and small sizes, this mesh is less dense than that of the ectosome.

Spicules: There is a single type of spicule, slightly bent oxea (50–410 by 4–10 μm) most of which have bluntly pointed, mucronate ends. In a few of these one or both ends are rounded, giving these spicules a style or strongyle like form. The width of the spicules is generally proportional to the length with the shorter ones being substantially thinner than the longest, however, occasionally long thin spicules are present. The spicules are straight or slightly, smoothly, curved.

Habitat: This species appears to be closely associated with limestone, the only records are from areas of limestone bedrock and amongst Lophelia pertusa, cold water coral reefs.

Distribution: There are other, previously unidentified, records from Ballintoy, County Antrim, Northern Ireland and St. John’s Point, County Donegal, Republic of Ireland, also Altachuile Bay, north-east of Farganlack Point, north-west of Derginan Point on Rathlin. Specimens from Mingulay deep-water coral reefs (western Scotland) in the collections of the Zoological Museum of Amsterdam have been found to be this species.

Distribution Map: NBN map : National Biodiversity Network mapping facility, data for UK.

Identity: Spongosorites coralliophaga (Stephens, 1914), originally described as Cliona coralliophaga, was originally described from deep water coral reefs off the west coast of Ireland. It was recorded from coral reefs at Rockall Bank and Mingulay, near the Hebrides, relatively close to Rathlin (van Soest, 2006) but one of the Mingulay specimens was recently found to be Spongosorites calcicola. It has oxea of a similar size-range (80–550 by 2.5–11 μm). However, these are described as tapering to long points and are bent twice in the same direction, Stephens says ‘bi-angulated’, whereas the majority of those in S. calcicola are only slightly and smoothly curved and have rounded ends. It is also described as undergoing a colour change in spirit whereas none is observed in S. calcicola. Furthermore, S. coralliophaga is formed of small lobes (7 mm by 5 mm), rather than being massive, and has much smaller oscules (4–5 mm diameter).

Editors: Claire Goodwin & Bernard Picton

 Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. [In] Sponges of Britain and Ireland