Elysia obtusa    Baba, 1938

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This species has been observed on Reunion and Mayotte Islands


Order : Sacoglossa
Superfamily : Plakobranchoidea
Family : Plakobranchidae
Distribution : Widespread western Pacific distribution from Japan & Hong Kong to eastern Australia and now Reunion
Maximal size : 10 mm
Abundance : Seldom on the reef flat zone


Species characteristics :

The general body color is a translucent pale green or greenish yellow with a darker green internal pigmentation

The animal is basically smooth with some small sparse conical projections occurring over the parapodia, head and rhinophores. The conical projections are white as is the edge of the parapodia

Elysia obtusa
Showing species characteristics...

Photo Christophe Cadet
Reunion, Etang salé lagoon, less 1 m , 28 October 2009, size : 7 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Kathe Jensen
    According Kathe Jensen " It certainly seems to be Elysia obtusa. This is quite an extension of its known range (Japan to Australia) - and it makes me wonder again if this species may be a synonym of Elysia flava (Verrill, 1901), originally described from Bermuda, but also found in the Mediterranean
    For some author, it is probable that E. obtusa is a synonym of E. flava from the tropical Atlantic Ocean and Mediterranean Sea, but the anatomical investigation required for verification remains to be undertaken.
    Synonymous : (according Worms)
               - No other name

Bibliographic data :

In some animals the green of the digestive gland causes the parapodia to be dark green in colour. It appears that the green colouration is probably a temporary colouration dependent on how recently an animal has been feeding. Dark green parapodia probably corresponds to a recently fed animal while predominantly yellow animals have probably not fed for some time.
    The short rhinophores are held almost parallel with the substrate and tend to point more laterally than anteriorly.
    The conspicuous eyes are situated at the surface at the base of the rhinophores
    The margins are thick and bear a band of low papillae. The papillae on the margins of the parapodia correspond with a broad opaque white line

References :

Bill Rudman Seaslug site : Sea Slug Forum : Elysia obtusa
   Nudipixel Elysia obtusa

Publications :

Baba, K (1938) Opisthobranchia of Kii, Middle Japan. J. Dept. Agric. Kyusyu Imp. Univ., 6(1) : 1-19.
    Baba, K. (1949) Opisthobranchia of Sagami Bay collected by His Majesty The Emperor of Japan . Iwanami Shoyen, Tokyo. 194pp., 50 Pls.
    Carlson, C.H. & Hoff, P.J. (1978) The identifiable Elysia from Guam (Elysiidae, Sacoglossa, Opisthobranchia). Micronesica, 14 : 89-113.
    Jensen, K.R. (2007). Biogeography of the Sacoglossa (Mollusca, Opisthobranchia). Bonner Zoologische Beiträge. 55: 255281.

Other photos of Elysia obtusa :


Philibert Bidgrain

Mayotte, Mtsanga Sakouli, less 1 m, 5 September 2012, size : 10 mm

The conspicuous eyes (a) are situated at the surface at the base of the rhinophores


 

Christophe Cadet

Reunion, Etang salé lagoon, less 1 m , 9 October 2009, size : 7 mm

In some animals the green of the digestive gland causes the parapodia to be dark green in colour.

It appears that the green colouration is probably a temporary colouration dependent on how recently an animal has been feeding. Dark green parapodia probably corresponds to a recently fed animal while predominantly yellow animals have probably not fed for some time.


 

Christophe Cadet

Reunion, Etang salé lagoon, less 1 m , 9 October 2009, size : 6 mm

In some animals the green of the digestive gland causes the parapodia to be dark green in colour.

It appears that the green colouration is probably a temporary colouration dependent on how recently an animal has been feeding. Dark green parapodia probably corresponds to a recently fed animal while predominantly yellow animals have probably not fed for some time.


Christophe Cadet

Reunion, La Saline lagoon, less 1 m, 30 December 2009, size : 5 mm

The margins are thick and bear a band of low papillae. The papillae on the margins of the parapodia correspond with a broad opaque white line

 

 

 


Philibert Bidgrain

Reunion, La Saline, less 1 m , 21 May 2010, size : 8 mm

The conspicuous eyes are situated at the surface at the base of the rhinophores


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