Axinella verrucosa

(Esper, 1791-1794)

Species Overview

Axinella verrucosa (Esper, 1791-1794) is an erect-branching sponge with anastomosed cylindrical branches, very variable in form. It was originally described from the Mediterranean, but subsequently reported from Roscoff.

Taxonomic Description

Colour: Ochre yellow.
Shape, size, surface and consistency: Arborescent (Spongia verrucosa), quite variable in shape (Axinella verrucosa Pansini), occasionally club-shaped, with cylindrical branches. Surface grooved and hispid (Axinella verrucosa Vos). Size up to 10 cm high, branches up to 1 cm in diameter. Consistency stiffly spongy.
Spicules: (Axinella verrucosa spics) Oxeas and styles. Styles, often modified to tylostyles: 520-900 µm. Oxeas are generally curved, but bent and even flexuous ones do occur. Stepped ends are very frequent and transformation to strongyles occur; occasionally there are centrotylotes: 450-730 x 7-17 µm.
Skeleton: Axially condensed with oxeas concentrated in the axial skeleton.
Ecology: On cliffs and on pebble bottom, 10-74 m
Distribution: Roscoff; Mediterranean.
Etymology: The name refers to the irregular surface.
Type specimen information: Type probably lost.

Remarks

This species may be confused with Axinella damicornis . The following table (from Ackers et al., 1992) may help to focus on differentiating characters: A. verrucosa & A. damicornis.
Source: Pansini, 1983.