This species has been observed on Mayotte and Madagascar Islands

Order : Nudibranchia Suborder : Euctenidiacea Superfamily : Polyceroidea Family : Gymnodorididae Distribution : Ryukyu Archipelago, Solomon Islands, Malaisie, Maldives, and Mayotte Maximal size : 10 mm Abundance : Species characteristics : Body smooth, uniformly bluish black Gills small, consisting of 9 plumes arranged in a complete circle around the anus. Rhinophores and gills also bluish black.
	Showing species characteristics...	Photo Eva Fontaine Mayotte, Mtsanga Mboueanatsa, on the reef flat zone, less 1 m, 4 August 2008, size : 10-15 mm.

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Nathalie Yonow
    Synonymous : (according Worms)
               - No other name

Bibliographic data :

It has a remarkable association with a number of species of gobies ( Amblyeleotris steinitzi, Amblyeleotris wheeleri, Ctenogobiops pomastictus), apparently living permanently on their fins, and feeding on the skin between the fin rays. Osumi & Yamasu (1994) suggest that the association is nearer to parasitism than symbiosis.
    The nudibranchs have been seen on all eight fins of the gobies: pectoral, pelvic, first dorsal, second dorsal, caudal, and anal. In some cases multiple nudibranchs have been seen on the same goby...

References :

Bill Rudman Seaslug site : Sea Slug Forum : Gymnodoris nigricolor

Publications :

Baba,K (1960): The genera Gymnodoris and Nembrotha from Japan (Nudibranchia - Polyceridae). Publications of the Seto Marine Biological Laboratory 8(1) : 71-74.
    Williams, E.H. & Williams, L.B. (1986) The first association of an adult mollusk (Nudibranchia: Doridae) and a fish (Perciformes: Gobiidae). Venus, The Japanese Journal of Malacology, 45(3) : 210-211
    Mulliner, D.K. (1991) Contact Association between the nudibranch Gymnodoris nigricolor Baba, 1960 (Gymnodorididae) and the Datehaze Goby (Perciformes: Gobiidae). Western Society of Malacologists Annual Report 23 : 17.
    Osumi, D. & Yamasu, T. (1994) The nudibranch Gymnodoris nigricolor Baba, parasitic with marine Gobies. Zoological Science, 11 (Supplement: Proceedings of the 65th Annual Meeting of the Zoological Society of Japan) : 54.

Other photos of Gymnodoris nigricolor :

Alain-Benoît Rassat Madagascar, Nosy bé, Sakatia bay, 6 m, 29 March 2014, size : 30 mm

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