Actinocyclus cf. papillatus   (Berg, 1878)

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This species has been observed on Madagascar Island

Order : Nudibranchia
Suborder : Euctenidiacea
Superfamily : Doridoidea
Family : Actinocyclidae
Distribution : Western Pacific and Madagascar ?
Maximal size : 50mm
Abundance :

Species characteristics :

'The dorsum is covered with numerous simple conical to rounded tubercles scattered irregularly. The tubercles situated on the center of the dorsum and near the gill opening are larger than the others.

The background color is reddish cream. The entire dorsum is covered with a number of short, irregular, very densely arranged dark grey lines.There are also irregular white areas, composed of the aggregation of numerous opaque white spots

The tubercles are pale brown or ochre, with the apex darker.

The gill and rhinophores are pale brown to cream.

Actinocyclus cf. papillatus
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Photo Alain-Benoît Rassat
Madagascar, Nosy Bé, 21 October 2017

Remarks :

Identification confirmed by Hsini Lin

Bibliographic data :

The central part of the body is clearly elevated over the mantle margin.
    A pale brown or ochre irregular line surrounds the mantle margin.
    Some animals are brown with little craemy speckling, while others are mainly cream white with only patches of the brown background colour showing through. In Valdes's review he describes 'a number of short, irregular, very densely arranged dark grey lines ...' and ' numerous white spots'. This is very dependent on how much white pigmentation is present in the specimen being observed. While the white spots are very obvious, the lines are only present in specimens with quite dense white pigmentation
    In general, the species of Actinocyclus have a tough leathery mantle, with a circlet of many short gills held in a cup-shaped arrangement similar to Hallaxa .

References :

Bill Rudman Seaslug site : Sea Slug Forum : Actinocyclus papillatus
    Medslug Actinocyclus papillatus

Publications :

Bergh, L. S. R. (1878) Malacologische Untersuchungen. In: C.G. Semper, Reisen im Archipel der Philippinen, Wissenschaftliche Resultate . Band 2, Heft 13: 547-601,Pls.62-65
    Valdés, A. (2002) Review of the genus Actinocyclus Ehrenberg, 1831 (Opisthobranchia: Doridoidea). The Veliger 45: 193-202

Other photos of Actinocyclus cf. papillatus :

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