Polymastia aurantium

Polymastia aurantium is a species of demosponges belonging to the family Polymastiidae. It is found in intertidal habitats including tide pools in the vicinity of Auckland, New Zealand.

This is a thickly encrusting sponge with a soft, fleshy texture, growing in patches up to 18 cm across. The outer layer is bright orange with a yellowish-brown interior. The surface is marked with widely spaced papillae: When the sponge is in a location affected by wave action, the papillae are located on distinct lamellae running in a single direction over the whole surface of the sponge.

References

• Michelle Kelly-Borges & Patricia R. Bergquist (1997). "Revision of Southwest Pacific Polymastiidae (Porifera: Demospongiae: Hadromerida) with descriptions of new species of Polymastia Bowerbank, Tylexocladus Topsent, and Acanthopolymastia gen. nov. from New Zealand and the Norfolk Ridge, New Caledonia" (PDF). New Zealand Journal of Marine and Freshwater Research. 31 (3): 367–402. doi:10.1080/00288330.1997.9516772.