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This species has been observed on Mauritius and Rodrigues Islands

Order : Nudibranchia Suborder : Euctenidiacea Superfamily : Polyceroidea Family : Gymnodorididae Distribution : Indo West Pacific Maximal size : 20 mm Abundance : Frequently on the fore reef zone Species characteristics : The body colour was uniformly deep yellow orange. The yellow orange gills are arranged in a horseshoeshape The bulbous rhinophores were a darker yellow-orange
	Showing species characteristics...	Photo Vanessa Bechard Mauritius, Trou d'eau douce, 1.5 m, 15 November 2014

See more about : Sightening and mating periods

Remarks :

Dr. Richard C. Willan writes:"What this means is that neither the animal from Madagascar called G. subflava in Indo-Pacific Nudibranchs (bottom of page 151) nor any of the specimens called G. subflava on NudiPixel are true G. subflava."
    Under the name Gymnodoris sp 44 in Nudibranch and Sea Slug identification from Indo Pacific, Gosliner, Valdés and Behrens, 2015

Bibliographic data :

The >20 gills are located in the last third of the dorsum. They are arranged in a horseshoeshape as simple upstanding lamellae
    The genital papilla is located just behind and below the right rhinophore
    The rhinophores are very bulbous in the preserved material, with eight thick diagonal widely-spaced lamellae and a rounded terminal knob
    The foot appears to have a darker yellow-orange margin.
    The black visceral casement is often visible through the skin in the living specimens

References :

Bill Rudman Seaslug site : Sea Slug Forum : Gymnodoris subflava
   Nudipixel Gymnodoris subflava

Publications :

Baba, K. (1949) Opisthobranchia of Sagami Bay . Iwanami Shoten, Tokyo. 211pp + pl
    Yonow, N. (2001) Results of the Rumphius Biohistorical Expedition to Ambon (1990). Part 11. Doridacea of the families Chromodorididae and Hexabranchidae (Mollusca, Gastropoda, Opisthobranchia, Nudibranchia), including additional Moluccan material. Zoologische Mededelingen uitgegeven Rijks Museum van Natuurlijke Historie te Leiden 75: 1-50.

Other photos of Gymnodoris sp 1 :

Olivier Aubrespine Mauritius, Ile aux Cerfs, 16 August 2004, less 1 m, size : 25 mm, With its spawn...

Yann von Arnim Mauritius, Ferme Marine de Mahébourg, 16 m, July 2013, size : 25 mm Large population observed, about 4/10 specimens/m2

..

Geoffrey Summers Mauritius, size : 15 mm "Lots of these here at Pt d'Esny all year, and also at Mont Choisy in the north of Mauritius. Common along the shore, perhaps as many as one ever metre"

Rachel Lebatard Rodrigues, 13 May 2011, size : 10 mm