(Topsent, 1893)
Species Overview
Paratimea constellata (Topsent, 1893) forms thin irregular yellow patches with very bristly, hairy surface. Consistency is tough, not easily damaged. It is a rather rare southern deep-sublittoral species known from Ireland, W coast of France, Azores and Mediterranean.
Taxonomic Description
Colour: Pale yellow. Often there is adhering detritus due to the long projecting spicule brushes.
Shape, size, surface and consistency: Encrusting in thin irregular patches. Surface strongly villose, very bristly, with long projecting spicules (to 2 mm), which often trap quantities of silt. The oscules are small and inconspicuous, but there are excurrent channels which are just visible on close inspection of living specimens in situ. Consistency fairly tough, not inclined to crumble when scraped off.
Spicules: (Paratimea constellata spics) The largest megascleres are tylostyles: 1500-2700 µm. The surface brushes consist of slender oxeas or anisoxeas, often with a slight central swelling or tyle: 440-1140 µm.
Microscleres are euasters: 21-45 µm. Compared with Stelligera spp. these asters have fewer rays, and are more irregular in shape.
Skeleton: Irregular. Long tylostyles stand perpendicular to the substratum, with their heads embedded in a basal spongin layer, and their shafts protruding from the surface. Smaller tylostyles lie jumbled sparsely in the interior. Slender megascleres form divergent brushes around the projecting spicules at the surface. The microscleres form a conspicuous layer at the surface.
Ecology: Usually in deep water, > 25 m, both in sheltered locations and in exposed sites. Found in Lough Hyne (SW Ireland) on vertical rock faces with heavy siltation. Probably more common than records suggest.
Distribution: Recorded from the Channel coast of France, SW Ireland, the Mediterranean and the Azores, down to 800 m. Recent records from Ireland: Lough Hyne (Co. Cork), Dingle peninsula (Co. Kerry), and St. John's Point (Co. Donegal).
Etymology: The name refers to the abundant asters.
Type specimen information: The type is in the Muséum National d'Histoire Naturelle; MCS voucher BELUM Mc1707, Lough Hyne.
Remarks
The external appearance of irregular thin bristly yellow encrustations is not very distinctive, but the spiculation, including surface brushes and euasters, is very distinctive. Timea species also have euasters, but no surface brushes of oxeas.
Source: Ackers et al., 1992