Polymastia lorum is a species of demosponge

Demosponge

The Demospongiae are the largest class in the phylum Porifera. Their "skeletons" are made of spicules consisting of fibers of the protein spongin, the mineral silica, or both. Where spicules of silica are present, they have a different shape from those in the otherwise similar glass sponges...

 belonging to the family Polymastiidae

Polymastiidae

Polymastiidae is a family of demosponges found in oceans throughout the world. A useful diagnostic characteristic of members of this family is the presence of numerous surface papillae although this feature is shown by some other sponges.-References:*...

. It is only known from a single specimen found attached to a dead Glycimeris

Glycimeris shell

Glycimeris is a genus of marine bivalve mollusks. The genus includes many species and is found worldwide.Glycimeris shells have a special archaeological significance in the southwestern USA, because the shells were used in trade item production by the Hohokam tribe of Amerindians.These Glycimeris...

valve on a reef

Reef

In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....

 near Ohinau Island, one of the Mercury Islands

Mercury Islands

The Mercury Islands lie off the northeast coast of New Zealand's North Island. They are located off the coast of the Coromandel Peninsula, and northeast of the town of Whitianga....

 off North Island

North Island

The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...

, New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

.

This is a small encrusting sponge 4 cm across. The outer layer is yellow with an orange-red interior. The most remarkable feature of this sponge is the very long (up to 6 cm) strap-like papillae.