Platydoris scabra (Cuvier, 1804)

Version française...

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


Order : Nudibranchia
Suborder : Euctenidiacea
Superfamily : Doridoidea
Family : Discodorididae
Distribution : Tropical Indo-West Pacific
Maximal size : 100 mm
Abundance : Seldom on the reef flat zone

Species characteristics :

The background colour of the living animals is white or pale cream.There are dark, large, irregular markings of brown, purple, or grey on the dorsum. These markings vary in distribution, often covering most of the dorsum. They are composed of a number of small dark spots, which are more densely arranged in several areas.

The mantle margin, the foot and the rhinophoral and branchial sheaths are edged by a thin orange or yellow line.

The rhinophores are yellowish, often with darker orange tips.

 

Platydoris scabra
Showing species characteristics...
Photo Philibert Bidgrain
Mayotte, Mtsanga Guini, less 1 m, 3 August 2010, size : 50 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Angel Valdès
    In some specimens from our area, the edge of the mantle, foot, rhinophore pockets and gill pockets are orange or yellow, but in many specimens they are not
    Synonymous : (according Worms)
          - Platydoris eurychlamys, Bergh, 1877
          - Platydoris noumeae, Risbec, 1928

Bibliographic data :

This species, with P. formosa, P. striata, P. cruenta and P. cinerobranchia form a group of very similar species.

Remark : Dorgan, K.M., A. Valdés & T.M. Gosliner. 2002 consider that P. cruenta ( Quoy & Gaimard, 1832 ) and P. striata (Kelaart, 1858) are regarded as synonyms.

 

P. formosa

P. scabra

P.cruenta

P. striata

P.cinerobranchiata

Localisation

Tropical Indo-West Pacific

Tropical Indo-West Pacific

Tropical West Pacific

Tropical Indo-West Pacific

Solomon Islands

Mantle coloration

Brown spotted
with red patches

Brown spotted
without red patches

Brown lined
with red patches

Brown lined
without red patches

Reddish, or orange patches and no brown specks or lines.

Rhinophore coloration

They are uniformly red, with the tips somewhat lighter

They are yellowish, often with darker orange tips.

They have a dark brown clavus with white flecks on the lamellae

They are dark red or brown

They are dark red or brown

Underside of the mantle and foot

The underside is white and has many large, bright orange red spots (not always easily visible). These spots are larger and densely concentrated near the foot, where some of them can be fused together

The underside of the mantle is dirty white and there are some brown speckles on the side of the foot.

The underside of the mantle is white with brown lines near the foot, and scattered red patches. The sole of the foot can also have brown lines

The underside of the mantle is white without red patches

The underside of the mantle is white with red patches

The brown patches on the mantle are arranged more or less symmetrically either side of the midline.
    The gill is composed of five to six tripinnate branchial leaves. The branchial leaves are white with irregular dark lines on the rachis of the lamellae.
    The opening of the branchial sheath has five to six lobes, with the anterior and posterior ones being larger than the others.
    The perfoliate rhinophores have 37 lamellae in one specimen examined. They are yellowish, often with darker orange tips.
    The underside of the mantle is dirty white and there are some brown speckles on the side of the foot.
    Species of Platydoris are easily recognized by their flattened, normally rigid (or coriaceous) body. This genus is also characterized by the dorsum covered with very small caryophyllidia and generally a lobate branchial sheath
    It probably feeds on siliceous sponges
    Found on shallow water under coral heads. Often crawling in the open during the night
    Breeds from May to september in Red Sea, laying an orange yellow ribbon in a spiral approximatively 100 mm across (Soliman, 1978)

References :

Bill Rudman Seaslug site : Sea Slug Forum : Platydoris scabra
   Nudipixel Platydoris scabra

Publications :

Dorgan, K.M., A. Valdés & T.M. Gosliner. 2002. Phylogenetic systematics of the genus Platydoris (Mollusca, Nudibranchia, Doridoidea) with descriptions of six new species. Zoologica Scripta. 31(3): 271-319.
    Soliman, G. N. 1978 The redescription, reproductive and development of the Dorid Nudibranch Platydoris csabra (Cuvier) from the northwestern Red Sea. Journal of Molluscan Studies 44 (2): 151-165.

Other photos of Platydoris scabra :


Philibert Bidgrain


Mayotte, Mtsanga Guini, less 1 m, 3 August 2010, size : 50 mm

The mantle margin, the foot (a) and the rhinophoral (b) and branchial (d) sheaths are edged by a thin orange or yellow line.

The rhinophores are yellowish, often with darker orange tips (c).

The gill is composed of five to six tripinnate branchial leaves. The branchial leaves are white with irregular dark lines (e) on the rachis of the lamellae.

The opening of the branchial sheath has five to six lobes, with the anterior and posterior ones being larger than the others.

 


Olivier Police                                              Mayotte, Petite-Terre, less 1 m, 25 December 2010, size : 100 mm

A specimen without orange margin ion the mantle, the foot and the rhinophoral and branchial sheaths


Olivier Police

Mayotte, Petite-Terre, less 1 m, 25 December 2010, size : 100 mm

A second specimen without orange margin ion the mantle, the foot and the rhinophoral and branchial sheaths

The brown patches on the mantle are arranged more or less symmetrically either side of the midline.


Christophe Cadet

Reunion, Etang salé, less 1 m, 9 January, size : 35-40 mm

A dead specimen... With the characteristic orange border on the rhinophores, gills and foot...


 More photos from Indian Ocean

Madagascar, Platydoris scabra with pale orange margin, at Andavadoaka, by Alain Barrère

Mayotte, Platydoris scabra with orange margin, at Tanaraki, by Fabrice Schubert

Mauritius, Platydoris scabra, at Pointe d'Esny, by Geoffrey Summers