Halisarca australiensis

Halisarca australiensis
image_search Terms and anatomy

Size: Varies according to host ascidian

Distribution: All SA coastal and gulf waters

Habitat: Encrusts ascidians including Pyura spinifera

Depth: Subtidal to 10+ metres

This fast-growing sponge is found almost exclusively in conjunction with the ascidians Pyura spinifera and Cnemidocarpa pedata, where it forms a thin encrustation and is often mistaken for part of the animal itself. It is usually found in light pink or yellow, and has a smooth but slightly bumpy texture, with small osculae at the terminal ends of each bump or node. It is most easily identified by its host, and is the only sponge that commonly encrusts these ascidian species.