Craniella cranium (O F Mller, 1776)


Family : Tetillidae

Form: Ball-shaped, globular or egg-shaped sponges. Size may be up to 9 cm in diameter.

Colour: Yellowish orange to whitish.

Consistency: Tough, hard.

Surface: Conulous, warty, hispid surface. In living specimens the oscules are grouped at the apex of the sponge.

Internal characters

Skeleton: Strictly radiate; cortical oxeas are arranged singly, whereas choanosomal oxeas and triaenes are arranged in tracts or bundles.

Spicules: Megascleres : Oxeas of the cortical region, short, fusiform: 400-1400 x 32-55; oxeas of the radiate skeleton: 2100-9200 x 27-70 m; protriaenes with shaft 3200-8500 x 8-30 m, cladi 150-236 m; anatriaenes with shaft 2100-20, 000 x 11-35 m and cladi 50-150 m. Microscleres : Sigmaspires: 9-20 m.

Habitat: On bedrock, stones and dead corals, 27-1000 m.

Distribution: Norway, Faroes, Shetland, SW Ireland, Sweden; also recorded from many other localities outside European waters, but these need to be confirmed.

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

Identity: Tetilla zetlandica (Carter, 1872) is similar in appearance and can be told apart only by microscopic examination. It apparently lacks the sigmaspire microscleres and also the sizes of the spicules are considerably smaller than those of the present species.

Editors: Christine Morrow, Bernard Picton & Rob van Soest.

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