Nembrotha aurea
Pola, Cervera & Gosliner, 2008

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: ANADORIDOIDEA
Family: Polyceridae
Subfamily: Nembrothinae

DISTRIBUTION

Tropical Indo-West Pacific

PHOTO

Upper: near Padar Island, Indonesia (part of Komodo National Park). Photo: Ken Knezick. Lower: Sodwana Bay, 30 metres, South Africa, Indian, 13 March 2006, Coral reef. Length: 30 mm. Photographer: Colin Ogden.

Externally the animals are characterised by the presence of longitudinal brown lines of irregular width and large diffuse patches of yellow and orange. Usually, the lines are arranged as follows: one broad mid-dorsal line between the rhinophores and the gills and two shorter ones of similar width on each side of the middle line; There is also a similar line outside these, at the edge of the mantle, which  runs outside the gills and then behind them to converge with the corresponding line on the otherside to form a single line which runs back to the posterior end of the foot. Anteriorly this line runs around the rhinophores to join its counterpart in the anterior midline. There are also similar lines running down each side of the body. In some animals the brown bands can be very wide and can even coalesce to form an almost solid brown dorsal patch., while in others the lines can be thin and more numerous making the animal look more like N. lineolata.

The ground colour of the body is white or cream white. There is a large dorsal orange to orange-brown background patch yellow patch between the gills and the rhinophores and another large dorsal orange patch behind the gills. Often the rest of the dorsal background can be bright yellow, or parts of it have yellow patches. There can also be distinctive blue or purple markings, but in some animals these are only very faint. They can be present on the oral tentacles, the margin of the foot, the base of the rhinophore sheaths, and the base of the gills. The rhinophores are red. The  rhinophore sheaths range from white to blue, and in some specimens are edges with dark brown. The gills are red and their stalks white or blue.

Apart from the orange patches it is quite difficult to differentiate this species from N. purpureolineata (which is now considered the senior synonym of N. rutilans). Both show a very similar range of colour variation, and both have a very similar internal anatomy.

• O'Donoghue, C. H. (1924) Report on Opisthobranchiata from the Abrolhos Islands, Western Australia, with description of a new parasitic copepod. Journal of the Linnean Society, London 35: 521-579, Pls.27-30.
• Pola, M., Cervera, J.L. and Gosliner, T.M. 2008. Revision of the Indo-Pacific genus Nembrotha (Nudibranchia: Dorididae: Polyceridae), with description of two new species. Scientia Marina 72(1): 145-183.

Authorship details
Rudman, W.B., 2008 (March 4) Nembrotha aurea Pola, Cervera & Gosliner, 2008. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/nembaure

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