Cuthona sibogae (Bergh, 1905)

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This species has been observed on Reunion and Mayotte Islands

Order : Nudibranchia
Suborder : Dexiarchia
Superfamily : Fionoidea
Family : Fionidae
Distribution : Indo-West Pacific
Maximal size : 35mm
Abundance : (Run) Seldom if ever... (May) Seldom on the fore reef zone

Species characteristics :

The general body colouration is pale lilac purple to pink

The cerata are similar in colour to the body except for a bright golden yellow tip and a band just below the yellow tip which ranges from deep reddish purple to deep purple

The oral tentacles and the upper half of the slender smooth rhinophores are a purple to reddish purple.

Cuthona sobogae
Showing species characteristics...
Photo C Tasset et Y Laurelut
Passe en S, Mayotte, 10 m, 10 December 2007, size : 35 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Bill Rudman
    Synonymous (according worms) :
          - Hervia sibogae Bergh, 1905                         - Trinchesia sibogae (Bergh, 1905)

Bibliographic data :

In Cuthona sibogae like other Cuthona, cnidosac are present at the apex of the cerata.
    A moderately large aeolid nudibranch in which the cerata are arranged in about eight fan-like clusters on each side of the body. The cerata are cylindrical, tapering at the tip to a rounded point
    Usualy, many of the smaller outer cerata in each row are golden yellow with no purplish basal region
    The anterior foot corners are enlarged into short blunt tentacles
    Juvenile appears more pink than purple
    It is usually found associated with its food, an orange thecate hydroid, Sertularella quadridens
    It could be mistaken for Flabellina rubrolineata, but that has papillose rhinophores and three magenta strpes along the body

References :

Bill Rudman Seaslug site : Sea Slug Forum : Cuthona sibogae
   Nudipixel Trinchesia sibogae

Publications :

Bergh, L.S.R. (1905). Die Opisthobranchiata. Siboga Expeditie Report, 50 : 248pp., Pls 1-20.
    Marshall, J.G. & Willan, R.C. (1999). Nudibranchs of Heron Island, Great Barrier Reef. A survey of the Opisthobranchia (Sea Slugs) of Heron and Wistari Reefs . Backhuys Publishers, Leiden, pp. 1-257, figs 1-280

Other photos of Cuthona sibogae :

Hugues and Sandrine Flodrops

"Boulevard des platax", Passe en S, Mayotte, 19 m, 2 March 2009, size : 25 mm


Strange detail on the cerata surface of this specimen...


Sully Bachel

Reunion, Ravine à Jacques, 6 m, 15 December 2009, size : 25-35 mm

Several specimens was observed on the same rock...

It is usually found associated with its food, an orange thecate hydroid, Sertularella quadridens



Emmanuel Eby

Mayotte, 20 January 2008.

Crawling on its food ?



Cédric Péneau

Reunion, Cap La houssaye, 16 m, 22 May 2010 , size : 15 mm


The cerata tips have a strange pale yellow coloration in this specimen

 More photos from Indian Ocean

Mayotte, Cuthona sibogae on it food, at Passe en S, by Freddy Fuentes and Nathalie Geffriaud