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This species has been observed on Reunion, Mauritius, Mayotte and Magagascar Islands

Order : Nudibranchia Suborder : Doridina Family : Dorididae Distribution : Indo-West Pacific. Maximal size : max 200 mm Abundance : Frequently on the reef flat zone Species characteristics : The large and high branchial pocket make the gills stand erect. The mantle is covered with small yellow/orange spots and brownish lines forming a large irregular reticulate. Near the edge of the mantle there are several broken, longitudinal white lines.
	Showing species characteristics...	Photo Philibert Bidgrain Réunion, Etang salé les bains lagoon, 220 mm 01 January 2005

See more about : Sightening and mating periods
   See more about : Mating behavior and spawn event, Jorunna rubescens
   See more about : A sponge predator, Jorunna rubescens
   See more about : Excretion, Jorunna rubescens
   See more about : Jorunna rubescens abnormality
   See more about : Annual change in population of Jorunna rubescens in l'Hermitage lagoon

Remarks :

Identification confirmed by Bill Rudman

Bibliographic data :

The body is elongate, narrow and very elevated. The texture is soft and velvety. The dorsum is entirely covered with long spiculate papillae (caryophyllidia), about 130 µm in length which are characteristic of that genus.
    The general colour of the living animals varies from cream to pale orange. Normally, the anterior and posterior edges of the notum, as well as the edges of the rhinophoral and branchial sheaths, are darker, sometimes almost black.
      The entire dorsum is covered with numerous longitudinal dark brown streaks. Among them, there are several yellow/orange low protuberances, which are also present in the rhinophoral and branchial sheaths.
    The mantle margin is wide, but stays close to the laterals of the foot. The foot has the same colour as the dorsum, with an irregular pattern of broken brown streaks and some white lines.
    The rhinophoral and branchial sheaths are very elevated and regular.
         - There are seven, branchial leaves, forming a circle, posteriorly closed by the anal papilla. The branchial leaves have the same colour as the dorsum, except for the rachis, which is white proximally and dark brown distally. The rachis of the secondary and tertiary branches is also dark brown.
         - The rhinophores are elongate, with 25 lamellae in a 38 mm preserved length specimen. The rhinophores are dark brown with the apex white. They may have dark brown spots near the apex.
    The egg mass is a pink convoluted ribbon.
    Bill Rudman would have suggested, that Jorunna rubescens was a spasmodic visitor rather than a permanent resident. He has only seen it alive a few times, the first time was in Tanzania, where he came across a very large population in a relatively shallow reefal lagoon with mixed sand, sea grass and coral heads. Most were large animals and there were many egg ribbons. Within a month they had all gone. That is the only time he has seen more than two at a time.
    In Reunion Island I observed sometimes J. rubescens crawling or laying in "Etang salé les bains lagoon" and "La Saline lagoon" during all the year with a maximum in summer (November to February).
   Emmanuel Eby observed a pair of Jorunna rubescens ( see photo below) mating on Saint Leu reef (15 m) in late December.

References :

Bill Rudman Seaslug site : Sea Slug Forum : Jorunna rubescens
   Nudipixel Jorunna rubescens

Publications :

Bergh, L.S.R. (1876). Malacologische Untersuchengen. In: C.G. Semper, Reisen im Archipel der Philippinen, Wissenschaftliche Resultate, 10: 377-427
    Valdes, A. and Gosliner, T. M. (2001). Systematics and phylogeny of the caryophyllidia bearing dorids (Mollusca, Nudibranchia), with descriptions of a new genus and four new species from Indo-Pacific deep waters Zoological Journal of the Linnean Society, 133: 103–198.

Other photos of Jorunna rubescens :

Philibert Bidgrain Réunion, Etang salé les bains lagoon, 220 mm 01 January 2005 This specimen (the same as the upper photo) presents on posterial position an abnormal excroissance of its body.

Florence Trentin Réunion, Etang salé les bains lagoon 02 February 2006 Spawn diameter, about 6 to 8 cm.

Christine Bottin Réunion, Etang salé les bains lagoon, 17 December 2006 at 9 a.m The egg mass is a pink convoluted ribbon.

		Philibert Bidgrain Réunion, "Saint Pierre lagoon", 1 December 2006, size 100-120 mm
	1 : The dorsum is entirely covered with long spiculate papillae (caryophyllidia), about 130 µm in length which are characteristic of that genus. 2 : The branchial leaves have the same colour as the dorsum, except for the rachis, which is white proximally and dark brown distally. The rachis of the secondary and tertiary branches is also dark brown. 3 : The rhinophores are dark brown with the apex white. They may have dark brown spots near the apex.    You can see the mouth between the two mantle flap...

Emmanuel Eby Réunion, A pair of Jorunna rubescens mating on Saint Leu reef (15 m) "Maison verte" at Saint Leu, 26 December 04

Hugues Flodrops   Réunion, Etang salé les bains lagoon, 60 cm, temperature 26°C, 28 October 2005 (17h45). size 110 mm A Specimen eating a sponge during the day...

Philibert Bidgrain Réunion, Etang salé les bains lagoon The foot has the same colour as the dorsum, with an irregular pattern of broken brown streaks and some white lines.

See more about : Mating behavior and spawn event, Jorunna rubescens
   See more about : A sponge predator, Jorunna rubescens
   See more about : Excretion, Jorunna rubescens
   See more about : Jorunna rubescens abnormality
   Reunion, Jorunna rubescens, in Saint Pierre lagoon, by Alain Barrère.
   Mauritius, Jorunna rubescens, at Recif corsaire, by Mathieu Bayon
   Reunion, Jorunna rubescens beside his spawn, in Etang salé lagoon, by Hugues Flodrops
   Reunion, Jorunna rubescens smile, at Etang salé, by Hugues Flodrops
   Reunion, 6 Jorunna rubescens on a sponge, at Saint Gilles, by Eva Fontaine 
   Reunion, Jorunna rubescens, at Saint Benoît, by Sully Bachel
   Mauritius, Jorunna rubescens, at Trou aux Biches, by Richard Lai cheong 
   Mayotte, J. rubescens crawling on a sandy substrate, at Passe en S, by Freddy Fuentes and Nathalie Geffriaud
   Réunion, Jorunna rubescens mating, at Etang salé, by Florence Trentin  
   Réunion, Jorunna rubescens spawning, at Etang salé, Jean-Jacques Giordan 
   Réunion, Jorunna rubescens, at Etang salé, by Carole Nussbaumer 
   Reunion, importante population of Jorunna rubescens, at Saint Gilles, by Eva Fontaine
   Reunion , video on "you tube" of Jorunna rubescens and its spawn, by Thierry Peres
   Madagascar, Jorunna rubescens, at Antongil, by Olivier Fournajoux
   Mauritius, Jorunna rubescens with its spawn, at Point d'esny, by Geoffrey Summers