This species has been observed on Reunion, Mauritius and Madagascar Islands

Order : Pleurobranchomorpha Superfamily : Pleurobranchoidea Family : Pleurobranchidae Distribution : Tropical Indo-West Pacific Maximal size : 75 (120 ?) mm Abundance : Frequently on the fore reef zone, seldom on te reef flat zone. Species characteristics : Variable in colour and easely recognized by the shear zones on the mantle. The body is divided dorsally into four (fused) parts, three of which readily autotomize. The main central section is surrounded by three crescent-shaped lobes, two lateral ones which meet anteriorly at the midline, and a posterior one. The extremity of the two cylindrical rhinophores and the two oral tentacles attached to either side of an oral veil visible on the head are black
	Showing species characteristics...	Photo Sully Bachel Reunion, Cap la Houssaye, 30 August 2008

See more about : Sightening and mating periods
   See more about : Berthella martensi, spawning behavior
   See more about : Berthella martensi variability in Southwest Indian ocean

Remarks :

Identification confirmed by Bill Rudman , Nathalie Yonow and Hsini Lin
     We can observed three color form in our area : A yellow-brown reticulated form, a yellow-brown dotted form and a white form.
    Synonymous : (according Worms)
               - Berthella kaniae Sphon, 1972                    
               - Gymnotoplax martensi pilsbry, 1896   
               - Pleurobranchus scutatus Martens, 1880  

Bibliographic data :

This species is extremely variable in color and ranges from white, yellow, brown or black, with or without mottlings of a different color.
    The trapezoidal oral veil and rhinophores are visible from above but the tail is usually covered by the mantle. The rhinophores are fused at their bases
    There is a brown line edging the foot and one extending from the oral veil edges posteriorly between the mantle and the foot.
    The gill is located on the right side, orange with dark brown to black rachides on the pinnae.
    It is characterised by its ability to autotomise (break off) large sections of its mantle when disturbed. The brown central ring and the lines visible in paler animals marks the breakage point when the animals breaks off its mantle skirt.
    The metapodium bears a brown patch on the end in the larger specimen and a median line on the smaller animal.
    The mantle can produce a white fluid when the animal is disturbed.
    The animals found in shallow water were associated, for the most part, with a mixed live/dead stony coral reef environment; those animals collected from deeper waters usually on vertical, invertebrate-covered walls at the reef drop off.
    According to bill Rudman, this species feeds on sponges (as other species of Berthella). And according to Gosliner this species feeds upon tunicates.
    According to Willan (1984) it lays a flaccid white spawn coil. Ova measuring 75-95 µm occur singly in capsules (up to 190 µm diameter) that are loosely coiled in cylinders within the spawn. Approximately 315 ova make up a single spawn.
    Thin, convex, "papyracée" and yellowish shell. The internal face is cover by a thin calcareous layer.
    In Reunion Island , we have actually found three color forms :
      - A yellow-brown form (upper photo), the preponderant form in our island. Marina Poddubetskaia observed the same color form in Mauritius.
      - A white form (see below, Emmanuel Eby's specimen), sometimes spcekled with black to dark brown spots.
      - A small yellow-brown dotted form, ( see below Hugues Flodrops' specimen and "spawning behavior")
    Recorded from Mauritius by Martens (1880) and Bergh (1898) as Pleurobranchus scutatus and by Yonow and Hayward (1991) as B. martensi
If you found an other color form in Reunion Island, please Contact us...

References :

Bill Rudman Seaslug site : Sea Slug Forum : Berthella martensi
   Nudipixel Berthella martensi

Publications :

Ortea J., Moro L. & Caballer M. (2014). Contribución al estudio de la familia Pleurobranchidae Gray, 1827 (Mollusca: Opisthobranchia) en la Macaronesia y las islas Galápagos. Vieraea. 42: 117-148.
    Tsubokawa, R. & Bolland, R.F. (1991). Berthella martensi (Pilsbry, 1896), new to the Japanese Notaspidea Fauna. Venus, Japanese Journal of Malacology, 50(3) : 184-195
    Willan, R.C. (1984) The Pleurobranchidae (Opisthobranchia: Notaspidea) of the Marshall Islands, Central-West Pacific Ocean. The Veliger, 27(1) : 37-53.
    Yonow, N. (1994) Opisthobranchs from the Maldive Islands, including descriptions of seven new species (Mollusca: Gastropoda). Revue fr. Aquariol., 20(4) : 97-130.

Other photos of Berthella martensi :

It is characterised by its ability to autotomise (break off) large sections of its mantle when disturbed.this specimen has lost the right section of the mantle... The gill (a) is located on the right side, orange with dark brown to black rachides on the pinnae. The reproductive aperture (b)	Kévin Bourdon Reunion, Cap La Houssaye, 14m, 22 June 2013

Maurice Jay Reunion, 10-12 m          size of animal : : 25 mm          size of internal shell : 10 mm Thin, convex, "papyracée" and yellowish shell. The internal face is cover by a thin calcareous layer.

Emmanuel Eby Reunion, "Les antennes" at Saint leu, 12m, size : 20-25 mm, 04 May 2005. A white form. We clearly see in this photo the internal face of the cylindrical rhinophore.

Hugues Flodrops Reunion, Etang salé on a rocky coast, 30 cm, 6 January 2007, size 25 mm A small yellow-brown dotted form

Emmanuel Eby Reunion, Saint Leu, 15 October 2005 A yellow-brown reticulated form. In this specimen you can observe the large plume-like gill located between the well developed foot and overlapping mantle, on the right side of the body The gill is orange with dark brown to black rachides on the pinnae.

Emmanuel Eby Reunion, Saint Leu, 02 September 2005 The metapodium bears a brown patch on the end in the larger specimen and a median line on the smaller animal. The body is divided dorsally into four (fused) parts, three of which readily autotomize. The main central section is surrounded by three crescent-shaped lobes, two lateral ones which meet anteriorly at the midline, and a posterior one.

Nathalie Bazard Madagascar, Nosy Bé, Plateau des arches, 15 m, size : 30- 40 mm

See more about : Berthella martensi spawing behavior
    See more about : Berthella martensi variability in Southwest Indian ocean
   Mauritius, Berthella martensi, at Pereybere, by Marina Poddubetskaia
   Reunion, a decolorated white form of Berthella martensi, at Saint Leu, by Sebastien Pomarede
   Mauritius, Berthella martensi, at Grand Baie, by Mathieu Bayon
   Reunion, hide and seek with Berthella martensi, at Saint Leu, by Emmanuel Eby
   Reunion, Berthella martensi, in Saint Leu lagoon, by Guillaume Boeye
   Reunion, a white and dark brown form of Berthella martensi, at Saint Leu, by Philippe Cao Van
   Reunion, a dark brown speckled Berthella martensi, by Philippe Cao Van 
   Reunion, two form of Berthella martensi, at Etang salé, by Hugues Flodrops 
   Reunion, gills of white form of Berthella martensi, at Saint Leu, by Sully Bachel 
   Rodrigues, a yellow-brown dotted form of Berthella martensi, at Mourouck, by Raphaël Roland Gosselin
   Reunion, white form with numerous grey spots B. martensi, at Saint Gilles, by Raphaël Roland Gosselin
   Reunion, partially eaten Berthella martensi, at Trou d'eau, by Philibert Bidgrain
   Reunion, when a large seaslug crawl on a small one, at Etang salé, by Jean-Marie Gradot