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This species has been observed on Mayotte, Madagascar and Seychelles

Order : Nudibranchia Suborder : Euctenidiacea Superfamily : Doridoidea Family : Chromodorididae Distribution : Throughout the tropical Indo-West Pacific Maximal size : 40 mm Abundance : (May) Seldom on the fore reef zone Body shape cream, with a purple to violet pink margin on the mantle and foot    Three purple to violet pink longitudinal lines down the dorsum, between which there are pale diffuse brown to ochre yellow stripe     Both the stalks and the lamellae of the rhinophores are bright red orange with sometimes a white tip    The 9-11 gills are simply pinnate but fluffy, and the same colour as the rhinophores    The foot has a purple to violet pink edge
	Showing species characteristics...	Photo Marina Poddubetskaia Mayotte, Passe en S, buoy n°3, 8 m, 5 November 2003, size : 20 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Bill Rudman

Bibliographic data :

There is a series of longitudinal purple to violet pink lines on the cream dorsum :
               - The median extends from the rhinophores to the gills and forms a ring around the latter
               - A line joins the rhinophores anteriorly in an arch and continues down each side , joining together behind the gills and extending a short way as a single line
               - Finally there is a line running around the margin of the mantle, but the very edge is whitish
    Sometimes the orange-brown bands between the purple lines are very indistinct.
    The mantle is spatula-shaped, the anterior end rounded and much wider than the rest of the notum
    The 9 to 11simple gills form a complete circle around the anus
    The rhinphores pockets are bordered with purple to violet pink
    The foot and the head are creamy white
    The underside of the mantle is creamy white to pale yellow, as are the oral tentacles, with the purple border showing throught the notum
    It discharges a white fluid with a most repugnant odour from the mantle when it is irritated
    It feeds on siliceous sponge
    The spawn consist of a red (orange in Mayotte specimen) coil and the free edge is elaborately wavy
    Hypselodoris emma have similarity with Hypselodoris maridadilus, Hypselodoris whitei and Hypselodoris centenculus (whitei?) . But they are distinguished by the number of purple longitudinal lines on the notum. H. emma has 3 purple lines, while H. maridadilus, H. whitei and H. centenculus have 5.

References :

Bill Rudman Seaslug site : Sea Slug Forum : Hypselodoris emma
   Nudipixel Hypselodoris emma

Publications :

Johnson R.F. & Gosliner T.M. (2012) Traditional taxonomic groupings mask evolutionary history: A molecular phylogeny and new classification of the chromodorid nudibranchs. PLoS ONE 7(4): e33479
    Rudman, W.B. (1977) Chromodorid opisthobranch Mollusca from East Africa and the tropical West Pacific. Zoological Journal of the Linnean Society 61 : 351-397.
    .Yonow, N. (1994) Opisthobranchs from the Maldive Islands , including descriptions of seven new species (Mollusca: Gastropoda). Revue fr. Aquariol., 20(4) : 97-130.

Other photos of Hypselodoris emma :

Fabrice Schubert Mayotte, Bandrele, 3 January 2010, The mantle is spatula-shaped, the anterior end rounded and much wider than the rest of the notum The rhinphores pockets are bordered with purple to violet pink

Mathiass Deuss Mayotte, ilôt des Badamiers, less 1 m, 17 January 2010. In this specimen, the orange-brown bands between the purple lines are very indistinct. The purple to violet pink line joins the rhinophores anteriorly in an arch and continues down each side, joining together behind the gills and extending a short way as a single line (a)

Fabrice Schubert Mayotte, 8 m, 7 February 2010, A mating Behavior.... The 9 to 11simple gills form a complete circle around the anus

Fabrice Schubert Mayotte, 6 m, 12 February 2010 Hypselodoris emma with its spawn. The spawn consist of a orange (a) not red coil and the free edge is elaborately wavy The foot has a purple to violet pink edge (b)

 Madagascar, Hypselodoris emma, by Philippe Cao Van

Mayotte, head detail of Hypselodoris emma, at N'gouja, by Philibert Bidgrain

Seychelles, Hypselodoris emma, at Mahé, by Christophe Mason-Parker