Dictyonella madeirensis

(Topsent, 1928)

Species Overview

Dictyonella madeirensis (Topsent, 1928) is an erect-lobate firm orange yellow sponge with numerous lobe-like branches. The surface is typically provided with longitudinal grooves. The species was recorded only once from Western Europe (Roscoff) and this record needs to be confirmed. It lives in deeper water below 30 m.

Taxonomic Description

Colour: Yellow-orange.
Shape, size, surface and consistency: Erect-massive-lobate with a pedicel made up of several coalesced columns which widen out and branch-off numerous lobes/branches. These are typically provided with longitudinal grooves. Size up to 12 cm high, 11 cm in diameter. Surface uneven, but not conulose or hispid; may be shiny. Oscules not apparent. There is an organic "skin" which may be peeled off easily. Consistency firm, compressible.
Spicules: (Dictyonella madeirensis spics) Styles in a wide size variation, with occasionally subtylote or tylote swellings some distance from the blunt end; pointed end often telescoped: 400-700 x 3-35 µm.
Skeleton: Spongin-encased bundles of styles follow a meandering, anastomosing, dendritic course towards the surface, thinning out while subdividing. Many loose interstitial styles.
Ecology: Deeper water, from 30 m downwards.
Distribution: Roscoff; Madeira, Gibraltar.
Type specimen information: The type is in the Monaco Museum.

Remarks

The occurrence of this species in Western Europe needs to be confirmed, because there are several closely related species (Dictyonella alonsoi Carballo et al., 1996, D . incisa (Schmidt, 1868), D . plicata (Schmidt, 1862) and D . pelligera (Schmidt, 1862, cf. next description) in the Mediterranean and some of these may occur also along the coasts of Spain and France. Carballo et al. (1996) transferred D . madeirensis to Scopalina , but this is clearly unwarranted: Scopalina is encrusting and strongly conulose; its skeletal fibres do not anastomose.
Source: Topsent, 1928