Crella (Pytheas) fusifera Sarà, 1969 is a grey to light violet, encrusting sponge with smooth surface. It differs from other Crella species of the area in colour and in the fusiform shape of its ectosomal acanthoxeas. It is a rare Mediterranean species, recorded also from NW Spain.
Colour: Rosy or grey to light violet.
Shape, size, surface and consistency: Encrusting. Surface smooth, with crateriform oscules. Consistency firm.
Spicules: Megascleres: Tornotes straight, oxeote, slightly fusiform, with short points: 220-273 x 3-5 µm; ectosomal acanthoxeas, fusiform, with sharp points at both ends, heavily spined: 75-110 x 3.5-7.5 µm; acanthostyles with heavily spined heads, and more lightly spined shafts: 90-135 x 10-13 µm.
Microscleres: Arcuate chelae: 17-21.5 µm.
Skeleton: An ectosomal crust of tangential acanthoxeas. Choanosomal columns of smooth tornotes, echinated by acanthostyles, which are also echinating the substrate.
Ecology: On rocks in the sublittoral.
Distribution: Mediterranean, NW Spain.
Etymology: fusus (Latin) = spindle, referring to the surface skeleton carrying numerous spindle shaped spicules.
Type specimen information: The type is presumably in the Istituto e Museo di Zoologia dell'Università di Napoli.
This is a rare species and more information on its characters is needed. Durán and Solórzano (1982) have some apparent misprints in the spicule sizes (they state their acanthoxeas are over 230-270 µm) and also the colour of their specimens differed somewhat from that cited for the type.
Source: Sarà, 1969; Durán and Solórzano, 1982.