Form: Described from a single preserved specimen. Type specimen thinly incrusting on barnacles. Size typically covering several square centimetres, uniformly about 1 mm thick. Recent material from Rathlin Island formed patches up to 10cm in extent on rock surfaces and wrecks.
Colour: Type specimen reported ro be orange (cream in alcohol). Rathlin Island material always yellow.
Consistency: Fragile, crumbly.
Surface: Type specimen reported to be microhispid, oscules not apparent.
Apertures: Rathlin Island material had conspicuous excurrent channels and a few large oscules with transparent rims.
Skeleton: Ectosomal : hispid due to large choanosomal styles piercing the organic skin, which is strengthened by tangential bundles of subtylostyles. Choanosomal : a basal anisotropic reticulation of acanthostrongyles forming a rectangular mesh; sides of mesh of unequal length, i.e. ascending primary tracts composed of 2 or 3 smaller acanthostrongyles, reinforced by long overlapping styles, connected by 1 or 2 larger acanthostrongyles, forming the connectives, a spicule length in width; brushes of 2 or 3 larger slightly diverging smooth styles project at the surface; they are the terminal continuations of the choanosomal primary tracts, and span an askeletal zone (though filled with cells and mesohyl) covering ca. 1/3 body depth, before they pierce the surface; the primary tract configuration gives a scalariform pattern to the skeleton: spongin is present at the nodes.
Spicules: Megascleres : Ectosomal subtylostyles with microspined heads: 220-410 by 3-5 μm; choanosomal smooth styles, almost straight: 442-765 by 8 μm; choanosomal smaller styles with acanthose heads, almost straight-shafted: 160-195 by 10 μm; choanosomal acanthostrongyles of primary tracts, entirely but sparsely spined: 90-115 by 2-8 μm; choanosomal acanthostrongyles of connectives, entirely but sparsely spined, often more pronounced at the ends, very slightly curved shaft: 125-130 by 2-8 μm. Microscleres : Palmate isochelae: 17-24 μm; toxas in two size categories: 140-160 μm and 30-40 μm; J-shaped spicules (crocae): 10-14 by 0.5 μm (croca).
Habitat: On bedrock, boulders and stones at sites exposed to strong tidal streams (35-45m depth).
Distribution: The type specimen was described from the Bergen area, Norway. It has recently been recorded from Rathlin Island, the Maidens and the entrance to Belfast Lough (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: It has a unique feature in the possession of numerous crocae (tiny walking stick-like spicules); otherwise it is most closely related to Antho coriacea.
Editors: Claire Goodwin, Bernard Picton & Rob van Soest
|Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. [In] Sponges of Britain and Ireland |
|Copyright © National Museums of Northern Ireland, 2007-2015|