This species has been observed on Reunion and Mayotte Islands

Order : Nudibranchia Suborder : Dexiarchia unassigned Cladobranchia... Family : Embletoniidae Distribution : Indo West Pacific Maximal size : 30 mm Abundance : Species characteristics : This translucent white nudibranch is characterised by the single row of cerata down each side of the body, the tip of each cerata usually being divided into four, and containing nematocysts. Opaque white granules speckled rather heavily on dorsum from just anterior of rhinophores to last pair of cerata. Head broad, produced anteriorly into two large flattened lobes (oral veil).
	Showing species characteristics...	Photo Philibert Bidgrain Mayotte, M'Bouanatsa on the fringing reef, less 1 m, 26 July 2012, size : 20 mm.

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Nathalie Yonow
    Synonymous : (according Miller, M.C. & Willan, R.C., 1992)
          - Embletonia gracile, Risbec, 1928
          - Embletonia gracilis (sic) paucipapillata, Baba & Hamatani, 1963
          - Embletonia gracilis (sic) (Risbec), Burn, 1966
          - Embletoniella paucipapillata, (Baba & Hamatani), Baba, 1967
          - Embletoniella gracilis (Risbec), Gordon & Ballantine, 1977

Bibliographic data :

Cerata numerous, arising in a single row on each side, 8 (specimen of 6 mm length) to 16 pairs (specimen of 18 mm length), first two pairs (pre-pericardial) precisely opposite, remainder subalternate, those on left side being slightly anterior to those on right.
    Cerata large, elongate, progressively more bulbous posteriorly, largest broader than dorsum.
    Ceratal apex divided into two (anterior pairs) or four (middle pairs) of regularly set knobs separated by deep grooves; apex of posterior cerata generally bifid, knobs indistinct, sometimes completely absent.
    In some specimen, a conspicuous white ring at base where cerata attached to body.
    The cerata range from cream to peach to brown depending on the food source.
    Cerata directed posteriorly and slightly outwards, held erect when animal provoked, autotomised very readily
    Rhinophores smooth, short and stout, widely separated at a little distance posterior to oral veil
    Reproductive apertures on right side, below and just posterior to first ceras, anus just below and anterior to third ceras, renal pore just above and anterior to anus.
    They feed on cnidarians and hydroids, but possibly also bryozoans and detritus

References :

Bill Rudman Seaslug site : Sea Slug Forum : Embletonia gracilis
   Nudipixel Embletonia gracilis

Publications :

Baba, K. & Hamatani, I., 1963. Anatomy of Embletonia gracilis paucipapillata n. ssp. from Osaka Bay, Japan (Nudibranchia - Eolidoidea). Publications of the Seto Marine Biological Laboratory, 11(2) : 399-402, Pl. 17.
    Miller, M.C. & Willan, R.C., 1992. Redescription of Embletonia gracile Risbec, 1928 (Nudibranchia: Embletoniidae): Relocation to Suborder Dendronotacea with taxonomic and phylogenetic implications. Journal of Molluscan Studies, 58 : 1-12, Figs 1-8.
    Risbec, J., 1928. Contribution à l'étude des nudibranches Néo-Calédoniens. Faune des Colonies Françaises, 2 : 1-328.

Other photos of Embletonia gracile :

Philibert Bidgrain Mayotte, M'Bouanatsa on the fringing reef, less 1 m, 26 July 2012, size : 20 mm. Cerata numerous (8 to 16 pairs), arising in a single row on each side, first two pairs (a) (pre-pericardial) precisely opposite, remainder subalternate, those on left side being slightly anterior to those on right (b).

Philibert Bidgrain Mayotte, Mtsanga Tanaraki, less 1 m, 22 September 2012, size : 25 mm

Christophe Cadet Reunion, 23 december 2015

Alexandre Laporte Réunion, on the rocky coast, less 1 m, 17 June 2015, size : 8 mm