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This species has been observed on Reunion Island

Order : Nudibranchia Suborder : Euctenidiacea Superfamily : Doridoidea Family : Dorididae Distribution : Indo West Pacific Maximal size : 25 mm Abundance : Seldom if ever on the fore reef zone Species characteristics : This species show quite a bit of variation in the mantle colour, including khaki, orange, dirty yellow, and blue-black mantles. There is an opaque white or brown inverted ‘Y' or hourglass pattern extending mid-dorsally from between the rhinophores to just in front of the gill. In some specimens this pattern can be interrupted or almost absent. The whole dorsum is covered with rounded, slightly conical tubercles, all of them similar in size. The largest tubercles are those situated in the central region of the body.
	Showing species characteristics...	Photo Christophe Cadet Reunion, Etang salé, on the rocky coast, less 1 m, 9 December 2011, size : 10 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Nathalie Yonow
    There are different opinion about the valid name : Siraius immonda for Rudman and Yonow, Doris immonda for Valdès and Gosliner, Siraius nucleola for Debelius and Nudipixel,
    Synonynymous : (According Worms).
          - Platydoris immonda Risbec, 1928
          - Siraius immonda, (Risbec, 1928)
          - Siraius nucleola, (Pease, 1860)

Bibliographic data :

Some of the dorsal tubercles, and those situated on the dorsal hourglass pattern, are dark purple-brown.     The rhinophores are elongate, having eight lamellae in a 21-mm preserved length specimen. They have a purple club and a white base     There are five tripinnate branchial leaves, forming a circle. The branchial leaves are yellow-orange with some of the apices dark brown or blue-black.     The rhinophoral sheaths have several slightly stalked tubercles, larger than those surrounding the sheath, but not larger than the largest tubercles on the dorsum.     The underside is orange-yellow.     It had an orange egg mass.

References :

Bill Rudman Seaslug site : Sea Slug Forum : Siraius immonda
   Nudipixel Siraius nucleola

Publications :

Baba, K (1993) A new record of Siraius nucleola (Pease, 1860) (Nudibranchia: Dorididae) from Japan. Venus, The Japanese Journal of Malacology 52(4) : 291-297.
    Brodie, G.D. & Willan, R.C (1993) Redescription and taxonomic reappraisal of the tropical Indo-Pacific nudibranch Siraius nucleola (Pease, 1860) (Anthobranchia: Doridoidea: Dorididae). The Veliger 36(2) : 124-133.
    Kay, E.A. & Young, D.K. (1969) The Doridacea (Opisthobranchia: Mollusca) of the Hawaiian Islands. Pacific Science 23(2) : 172-231.
    Pease, W.H. (1860) Descriptions of new species of Mollusca from the Sandwich Islands. Proceedings of the Zoological Society of London 28 : 18-36.
    Risbec, J. (1928) Contribution a l'etude des nudibranches Neo-Caledoniens. Faune des Colonies Francaises 2(1) : 1-328, Pls.1-12.
    Valdés, A. (2002) A phylogenetic analysis and systematic revision of the cryptobranch dorids (Mollusca, Nudibranchia, Anthobranchia). Zoological Journal of the Linnean Society 136: 535-636.

Other photos of Doris immonda :

Alexandre Laporte Reunion, Etang sale on the rocky coast, less 1 m, 8 Februay 2017

Alexandre Laporte Reunion, Etang sale on the rocky coast, less 1 m, 11 February 2017, size : 5-10 mm

Christophe Cadet        Reunion, Marine de Vincendo, less 1 m, 4 January 2011, size : 12 mm The underside (a) is orange-yellow. There is an opaque white or brown inverted ‘Y' or hourglass pattern extending mid-dorsally from between the rhinophores to just in front of the gill. In some specimens this pattern can be interrupted (b) or almost absent.

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