| Polymastia umbraculum | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Porifera |
| Class: | Demospongiae |
| Order: | Polymastiida |
| Family: | Polymastiidae |
| Genus: | Polymastia |
| Species: | P. umbraculum |
| Binomial name | |
| Polymastia umbraculum Kelly-Borges & Bergquist, 1997 | |
Polymastia umbraculum is a species of sea sponge belonging to the family Polymastiidae. It is only known from rocky subtidal habitats around Kawau Island off the North Island of New Zealand.
Polymastiidae is a family of demosponges found in oceans throughout the world. I 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 although this feature is shown by some other sponges.
Kawau Island is in the Hauraki Gulf, close to the north-eastern coast of the North Island of New Zealand. At its closest point it lies 1.4 km (0.87 mi) off the coast of the North Auckland Peninsula, just south of Tawharanui Peninsula, and about 8 km (5.0 mi) by sea journey from Sandspit Wharf, and shelters Kawau Bay to the north-east of Warkworth. It is 40 km (25 mi) north of Auckland. Mansion House in the Kawau Island Historic Reserve is an important historic tourist attraction. Almost every property on the Island relies on direct access to the sea. There are only two short roads serving settlements at Schoolhouse Bay and South Cove, and most people have private wharves for access to their front door steps.
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 Cook Strait. The island's area is 113,729 square kilometres (43,911 sq mi), making it the world's 14th-largest island. It has a population of 3,749,200.
This is a thickly encrusting sponge with a very firm texture, growing in loosely attached patches up to 7 cm across. The granular outer layer is brilliant yellow-orange with a rather darker interior carrying many symbiont foraminifera. It is often infested with the parasitic amphipod Polycheria antarctica .
Foraminifera are members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell of diverse forms and materials. Tests of chitin are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment, while a smaller variety float in the water column at various depths. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA.
