Desmacella annexa

Schmidt, 1870

Species Overview

Desmacella annexa Schmidt, 1870 is a massive or encrusting sponge with irregular, hispid surface. It has characteristic spiculation (microscopic examination). It has been dubiously recorded from Western Europe, mostly from deeper water.

Taxonomic Description

Colour: Live colour not recorded; light grey in alcohol.
Shape, size, surface and consistency: Massive or more encrusting, occasionally forming erect masses, with irregular hispid surface. Size may exceed 5 cm. Size of oscules not recorded. Consistency fragile.
Spicules: (Desmacella annexa spics) Megascleres : Tylostyles with prominent tyles, quite variable in size: 220-1050 x 2.5-14 µm.
Microscleres : Sigmas in two size classes: 25-42 and 11-15 µm; toxiform raphides, with a bend in the middle with a slight counter bend on both sides: 50-115 x 0.5-2 µm.
Skeleton: Plumose, with ill-defined bundles and scattered single spicules generally directed towards the surface; no special ectosomal skeleton.
Ecology: Encrusting on other sponges, mostly in deep water but recorded from 5 m (Könnecker, 1973).
Distribution: Roscoff, SW Ireland, Norway (Mediterranean, North Atlantic, Caribbean, Indian Ocean).
Etymology: Annexus (Latin) = linking, joining; Schmidt gives no indication why he chose that name.
Type specimen information: There is a slide of the type in the Natural History Museum, London, BMNH 1870: 5: 3; 29; this appears to be the only extant type material (Desqueyroux-Faúndez and Stone, 1992).

Remarks

This species was originally described from 350 m deep off the coast of Florida, with a tantalizingly short description. The assignment of European specimens to Schmidt's species is tentative and conspecificity with specimens from the Indian Ocean likewise needs further corroboration. It differs from the Western European D . ornata in the possession of the peculiar toxiform microscleres.
Source: Burton, 1930a.