Monocrepidium minutum (Cabioch, 1968) is a thinly encrusting sponge with a hispid surface. It can only be recognized after microscopic examination. It is a deep water sponge known only from a single record from Roscoff, NW France.
Colour: Whitish grey in alcohol.
Shape, size, surface and consistency: Thinly encrusting. Surface hispid.
Spicules: Tylostyles, very variable in length, with well-defined head, often slightly below the base, 200-1160 x 3.5-10 µm; vermicular strongyles, flexuous, irregularly bent, covered with rounded tubercles and warts: 150-160 x 7-9 µm.
Skeleton: Single megascleres are arranged perpendicularly on the substrate, pointed ends outwards, the longer penetrating the surface and causing the hispidation.
Ecology: Deep water (65 m), on pebbles.
Distribution: Known only from the Roscoff area, NW France.
Type specimen information: The type is in the collection of the Station Biologique at Roscoff.
This thin encrustation can only be identified on its spicules. It is similar to Bubaris vermiculata in many aspects, but its flexuous strongyles are warty, rather than smooth.
The species is the type of the genus Skeizia Cabioch, 1968, but this differs from Monocrepidium Topsent (1898) only in the fact that it has tylostyles in stead of styles; this difference is not considered of generic value. It is possible, that this species is in fact a deviating form of Monocrepidium vermiculatum Topsent from North Atlantic deep sea habitats.
Source: Cabioch, 1968.