Haliclona simulans (Johnston, 1842)


Family : Chalinidae

Form: Polymorphic sheets, thin cushions to branching-repent, with the branches frequently anastomosing. Grows from a basal crust which may spread across rocks.

Colour: Orange, beige, light brown. Boundaries between colour zones are typically sharp, a useful diagnostic character.

Smell: None.

Consistency: Hard, brittle, incompressible. Feels like a stick of wood.

Surface: Smooth.

Apertures: Oscules are regularly scattered along the branches, usually on small 'mounds'.

Contraction: None.

Internal characters

Skeleton: Surface skeleton is very regularly reticulated, unispicular; the interior is a dense polyspicular network, with considerable amounts of spongin present, especially at the nodes of the net.

Spicules: Short, fat oxea 120-150 x 5-12Ám.

Habitat: In sheltered microhabitats although the site may generally be quite exposed, frequently with appreciable current. On boulder/bedrock, often bridging cavities/crevices in the rock.

Distribution: Known recently from north, south and east coasts of Ireland, including Strangford Lough; Anglesey; Devon, Jersey, Isle of Wight. Probably commoner in the south and west of the British Isles. Records from Scotland would be of interest.

Distribution Map from NBN: Grid map (fast) : Interactive map (slower, requires login to view records) : National Biodiversity Network mapping facility, data for UK.

Identity: The hardness, repent branching, neat arrangements of oscules which remain open when sponge is preserved, together with a typically Haplosclerid skeleton are, taken together, fairly distinctive.

Voucher: BELUM : Mc1419. Brittany, France.

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

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