Pseudosuberites sulphureus (Bean, 1866)


Family : Suberitidae

Form: Thin sheets, typically about 1mm in thickness. Forms extensive irregular patches, to at least 30cm across.

Colour: A bright, deep, sulphurous orange or bright yellow.

Smell: None?

Consistency: Compact, too thin to determine.

Surface: Even, smooth, with subsurface cavities visible through the pellucid ectosome, which is readily detachable.

Apertures: According to Topsent, 0.2 to 1mm in diameter and flush with the surface. ? not visible on collection ?

Contraction: Too thin to determine.

Internal characters

Skeleton: The ectosome consists of megascleres of varying size lying tangentially to the surface in bundles that intercross to form a network visible to the naked eye. The choanosomal skeleton is essentially halichondroid, with megascleres orientated in all directions, sometimes in bundles.

Spicules: The megascleres are tylostyles in the size range 150-400Ám (or more) by 3-7Ám. Considerable variation in spicule size occurs in a given specimen. There is no clear division into 2 size classes as found in other suberitid species. Most of the tylostyles are straight, but when curved, the curvature occurs about a third (or less) of the way along the shaft. The shafts tend not to be parallel sided, their widest point being about midway. The tyles vary from being smoothly rounded to sharply mucronate. There are no microscleres.

Habitat: Bedrock, boulders, shells. Possibly confined to areas of strong water movement. In tidal rapids on shore, beneath boulders.

Distribution: Shetlands, Scarborough, South coast of UK, Guernsey, Roscoff.

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

Identity: The tangentially arranged tylostyles in the ectosome are characteristic. A microscopic examination is essential to separate this yellow or orange encrusting sponge both from other species of suberitids, and from other taxa. It is possible that the brightness of the colour is a useful field characteristic, but more evidence is needed to confirm this.

Voucher: BELUM : Mc4354, Newquay, Co Clare, Ireland.

Editors: D. Moss, B.E. Picton.

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