Marine Species Identification Portal : Aplysina aerophoba

Nardo, 1833

Species Overview

Aplysina aerophoba Nardo, 1833 forms characteristic bright yellow masses of tubes, which when taken out of the water turn dark blue-black. The sponges are compressible, feeling rubbery. It is a Mediterranean species which penetrates the Atlantic along the coasts of Portugal and NW Spain.

Taxonomic Description

Colour: Bright yellow in life, turning characteristically dark greenish blue-black when taken out of the water, discolouring one's fingers. In alcohol, the black colour extends into the alcohol and also blackens labels to the point of becoming illegible.
Shape, size, surface and consistency: Massive base from which issue irregular tubular digitations. These digitations are 3-4 cm high, 1-2.5 cm in diameter, and end in a flattened top in the center of which is an oscule with an iris-type of diaphragm. The surface of the basal mass as well as the tubes frequently bare thin long solid "fistules" of variable length. The surface is slippery to the touch and irregularly covered with small conules. Consistency relatively firm, somewhat rubbery.
Spicules: Absent.
Skeleton: Fibroreticulate, without distinction in main and secondary fibres, forming irregularly rounded three-dimensional meshes of up to 3 mm in diameter. The conules at the surface are formed by short blind-ending fibres. The fibres of 80-150 µm in diameter are cylindrical, with a well-developed striated bark and a wide central pith of 30-70 µm in diameter (Aplysina aerophoba fibre). The pith is visible in transmitted light as a dark brown to black central mass in an amber coloured spongin envelope.
Ecology: Shallow water, 0-20 m, habitats exposed to direct sunlight (cf. below).
Distribution: Mediterranean, penetrating Portuguese and NW Spanish waters.
Etymology: aerophobus (Greek) = "afraid of air", referring to the colour change effected by exposure to air.
Type specimen information: Type probably lost.

Remarks

A second Mediterranean species of Aplysina, i.e. A. cavernicola (Vacelet, 1959) has been described which specializes in living in caves, differing in a number of aspects from A. aerophoba, but its specific distinctness has been challenged by Voultsiadou-Koukoura (1987). A. cavernicola was recorded from the coast south of Lisbon by Lopes and Boury-Esnault, 1981. Both species have distinct chemistry but are difficult to tell apart from habit or microscopic details.
Source: Vacelet, 1959.

Images

Aplysina aerophoba fibre (drawing R. van Soest)

Aplysina aerophoba