This species has been observed on Reunion Island

Order : Pleurobranchomorpha Superfamily : Pleurobranchoidea Family : Pleurobranchidae Distribution : Reunion and Western Pacific Maximal size : 50 mm Abundance : Seldom on the rocky coast Species characteristics : It is characterized by a dark red-brown hole spot in the centre of the mantle surrounded by a brighter region. This central spot varies in size and may be absent in some animals. The colour of the mantle varies from cream to pale red-violet with scattered white flecks Its notum is covered with very small tubercles ringed with darker brown pigment at their bases.
	Showing species characteristics...	Photo Christophe Cadet Reunion, Etang Salé on the rocky coast, less 1 m, 26 November 2010, size : 20 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Nathalie Yonow
    According Bill Rudman : " There are not that many characters which conclusively differentiate Pleurobranchus from Berthella, but one external feature is the way Pleurobranchus has a deep cleft in the anterior mantle to acommodate the rhinophores. This is absent in Berthella and certainly not present in P. caledonicus. The absence of denticles, as reported by Risbec, combined with the absence of an anterior mantle notch, would suggest that P. caledonicus is most likely to be a species of Berthella. However confirming the identification and its generic position must wait until the anatomy of this animal  can be investigated"
    Synonymes (d'après worms) :
               - Pleurobranchus caledonicus Risbec, 1928

Bibliographic data :

The brownish spot in the hole is the horny colour of the exposed internal shell
    In 50 mm specimen, the internal shell is approx 18 mm in length and covers the digestive gland and reproductive organs.
    Berthella caledonica was described by Risbec (1928) from three 50 mm long animals he collected from under a block of dead coral at Noumea, New Caledonia.
    It has many external similarities to the Atlantic species Berthella africana

References :

Bill Rudman Seaslug site : Sea Slug Forum : Pleurobranchus caledonicus
   Nudipixel Pleurobranchus caledonicus

Publications :

Risbec, J. (1928) Etude anatomique des gastéropodes Tectibranches de la presqu'île de Nouméa, avec description de cinq espèces nouvelles. Archives du Museum d'Histoire naturelle, Paris , 3, 37-68.
    Carlson C. & Hoff P.J. (2003). The opisthobranchs of the Mariana Islands. Micronesica. 35-36:271-293

Other photos of Berthella caledonica :

Philibert Bidgrain Reunion, Etang Salé on the rocky coast, less 1 m, 23 April 2011, size : 12-15 mm

Christophe Cadet Reunion, Etang Salé on the rocky coast, less 1 m, 27 December 2010, size : 6 mm The brownish spot in the hole is the horny colour of the exposed internal shell The colour of the mantle varies from cream to pale red-violet with scattered white flecks

Florence Trentin Réunion, Etang Salé lagoon, during the night, less 1 m, 30 January 2016, size : 10 mm

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