Nembrotha rosannulata is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of colorful sea slug

Sea slug

Sea slug is a common name used for several different groups of saltwater snails that either lack a shell or have only an internal shell, in other words this name is used for various lineages of marine gastropod mollusks that are either not conchiferous or appear not to be.The phrase "sea slug" is...

, a dorid nudibranch

Nudibranch

A nudibranch is a member of what is now a taxonomic clade, and what was previously a suborder, of soft-bodied, marine gastropod mollusks which shed their shell after their larval stage. They are noted for their often extraordinary colors and striking forms...

, a marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusk in the family Polyceridae

Polyceridae

Polyceridae is a taxonomic family of sea slugs, dorid nudibranchs, marine gastropod mollusks within the Superfamily Polyceroidea.- Taxonomy :...

. It was first described in 2008.

Distribution

This species is known only from Eastern Australia (Northern New South Wales

New South Wales

New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

 & Southern Great Barrier Reef

Great Barrier Reef

The Great Barrier Reef is the world'slargest reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres over an area of approximately...

). It is most commonly seen at Cabbage Tree Island

Cabbage Tree Island

Cabbage Tree Island, also known as the John Gould Nature Reserve, is an uninhabited island with an area of 300,000 m2 lying 1.4 km off the mouth of Port Stephens on the coast of New South Wales, Australia. It is named for the Cabbage-tree Palms which are a feature of the island’s rainforest...

, Port Stephens, NSW.

Description

Nembrotha rosannulata is a large dull green nembrothid that grows to at least 12 cm in length. The body is textured with rounded longitudinal ridges and scattered raised pustules of various sizes. The pustules are black and each is surrounded by a pink ring which give this species its characteristic colour pattern - and name. The rhinophores are black, and the pink rhinophores sheaths are edged in black. The front of the mantle has a pink band which is edged in black, and the oral tentacles are pink with black tips. The gill stalks and branches are pink while the gill pinnae are black.

Ecology

Present information suggest that this nudibranch feeds exclusively on the stalked ascidian Sigillina cyanea.