(Stephens, 1916)
Species Overview
Clathria (Microciona) acanthotoxa (Stephens, 1916) is one of the many thin Microcionidae, which can only be identified by microscopic examination. Its distinctive characters are the combination of long, robust megascleres and spined toxas. It is a boreal deep-water species, recorded only a few times.
Taxonomic Description
Colour: Not recorded (presumably red or orange).
Shape, size, surface and consistency: A thin, small encrustation, about 5 mm2, on a piece of dead coral. The surface is hispid.
Spicules: Megascleres : Ectosomal subtylostyles, with microspined heads: 500-750 x 8 µm; choanosomal styles, curved, with a rather short point, head covered with short, stout, blunt spines, shaft smooth: 500-900 x up to 25 µm (smaller styles also occur); echinating acanthostyles, covered entirely in sharp recurved spines: 60-300 µm. Microscleres : Palmate isochelae, with relatively short alae: 19 µm; toxas, well-rounded, quite variable in length, with spined tips: from tiny up to 350 x 3 µm.
Skeleton: Leptoclathriid or hymedesmoid, i.e. the (acantho-)styles are erect on the substrate. Ectosomal subtylostyles lie in oblique bundles.
Ecology: Deep-water, 83-900 m, on dead corals.
Distribution: W-coast of Ireland, Isle of Man, Skagerak, Iceland.
Type specimen information: The type is in the National Museum of Ireland, Dublin; BMNH 1953.11.11.120 (slide).
Remarks
The distinctive characters of this deep-water species are the combination of robust spined toxas and long and robust megascleres.
Sources: Stephens, 1916, 1920 (1921); Lévi, 1960.