Atagema ornata (Ehrenberg, 1831)

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This species has been observed on Reunion, Mayotte and Madagascar Islands

Order : Nudibranchia
Suborder : Euctenidiacea
Superfamily : Doridoidea
Family : Discodorididae
Distribution : Tropical Indo-West Pacific
Maximal size : 80 mm
Abundance : Seldom if ever...

Species characteristics :

The humped mantle is generally reddish or reddish brown to dark chocolate brown with a central ridge of tubercles in contrasting white or “coral sand” colour.

Other compound tubercles are scattered over the rest of the mantle. The tip of the tubercles have pointed spicules giving the skin a rough texture.

White spots are usually present on the mantle, gills and rhinophores



atagema ornata
Showing species characteristics...
Photo Maurice Jay
Reunion, Le Port, 3 m, 25 May 1986, size : 50 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Nathalie Yonow
     According Willan "Atagema ornata and Atagema intecta both relate to the same species and we must use Atagema ornata (instead of Atagema intecta - which is more common in the literature) because it is the older name."  So I changed  Atagema intecta (Kelaart, 1859) [ Doris ] into Atagema ornata (Ehrenberg, 1831) [ Doris ]
    Synonymous : (according Worms)
          - Doriopsis ornata, Berg, 1877
          - Doris ornata, Ehrenberg, 1831
          - Petelodoris triphylla, Bergh, 1881

Bibliographic data :

Each tubercle is covered with a number of small caryophyllidia, about 50 µm. The tubercles in the centre of the dorsum are lined up and fused together forming a longitudinal ridge.
    The lamellate rhinophores are tall and stout. The rim of the rhinophoral pocket is raised and covered with papillae. The rhinophore have a translucent brown stalk, reddish or reddish brown to dark chocolate brown clavus with whites flecks on the lamellae, and a white tip
    The six, large, compound gills form a complete circle around the anus. The gills are the same color of the rhinophore with white speckles. The branchial sheath is composed of three large lobes
    The ventral colour is the same as the dorsum.
    It feeds on siliceous sponges belonging to the genus Iotrochota
    Juveniles are often much paler.
    The egg ribbon is creamy yellow, slightly undulated on the free edge. At hatching the ribbon is light pinkish violet

References :

Bill Rudman Seaslug site : Sea Slug Forum : Atagema intecta
   Nudipixel Atagema ornata

Publications :

Ehrenberg CG. (1831). Symbolae physicae animalia evertebrata exclusis insectis. Series prima cum tabularum decade prima continent animalia Africana et Asiatica. Decas Prima. In : Hemprich FG, Ehrenberg CG, eds. Symbolae physicae, seu Icones adhue ineditae corporum naturalium novorum aut minus cognitorum, quae ex itineribus per Libyam, Aegyptum, Nubiam, Dengalam, Syriam, Arabiam, et Habessiniam. Pars Zoologica, 4. Berlin: Officina Academica.
    Kelaart, E.F. (1858). Description of new and little known species of Ceylon nudibranchiate molluscs and zoophytes. Journal of the Ceylon Branch of the Royal Asiatic Society, Columbo, 3(1) : 84-139.
    Valdés, A. & Gosliner, T. M. (2001) Systematics and phylogeny of the caryophyllidia-bearing dorids (Mollusca, Nudibranchia), with the description of a new genus and four new species from Indo-Pacific deep waters. Zoological Journal of the Linnean Society, 133 : 103-198. --

Other photos of Atagema ornata :

Norbert Verneau

Mayotte, Dzaoudzi le Rocher, les 1 m, 28 May 2014, size : 30 mm



Maurice Jay

Reunion, Le Port, 3 m, 25 May 1986, size : 50 mm

Alain-Benoît Rassat


Madagascar, Nosy Bé, 3 August 2017


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