Polymastia croceus

Polymastia croceus is a species of demosponge belonging to the family Polymastiidae. It is found in subtidal habitats below 6 m depth in the far north of the North Island of New Zealand.

This is a globular sponge up to 4 cm across or an encrusting sponge up to 7 cm across. This soft-textured sponge is very bright yellow outside and in with the surface covered in small papillae, some with pores, some without. This sponge is frequently infested with the parasitic amphipod Polycheria antarctica. At least three species of symbiont foraminifera are found within this 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.