''Polymastia echinus'' is a species of

sea sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

belonging to the family

Polymastiidae Polymastiidae is a family of demosponges found in oceans throughout the world. It is the only family in the monotypic order Polymastiida. A useful diagnostic characteristic of members of this family is the presence of numerous surface papillae ...

. It is only known from shallow subtidal habitats off

Te Hāwere-a-Maki / Goat Island Goat Island or Te Hāwere-a-Maki is a tiny island (approximately ) in New Zealand located close to the North Island coast, north of Auckland, northeast of Warkworth, and directly west of Little Barrier Island. It is within Cape Rodney-Okakari Po ...

in the north of the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

of New Zealand. This is an encrusting sponge with an extraordinary appearance. The sponge is always largely covered in sand, grit and fragments of shells apart from smooth, cylindrical, peach-coloured

papilla Papilla (Latin, 'nipple') or papillae may refer to: In animals * Papilla (fish anatomy), in the mouth of fish * Basilar papilla, a sensory organ of lizards, amphibians and fish * Dental papilla, in a developing tooth * Dermal papillae, part of ...

e up to 15 mm in height which are always free of such material. The specific name refers to this rather

hedgehog A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introducti ...

-like appearance.

References

* echinus Sponges of New Zealand Animals described in 1997 Taxa named by Patricia Bergquist Taxa named by Michelle Kelly (marine scientist) {{demosponge-stub