Thorunna cf. horologia   Rudman, 1984

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This species has been observed on Reunion and Madagascar Islands

Order : Nudibranchia
Suborder : Euctenidiacea
Superfamily : Doridoidea
Family : Chromodorididae
Distribution : South Africa, Sri Lanka, Madagascar and Reunion
Maximal size :
Abundance :

Species characteristics :

Colour opaque white with violet pigment concentrated around edges and on head around and between rhinophores

Fine sub-marginal white line, followed by an orange marginal band more prominent in the central constriction

Rhinophores very large with translucent stalk and white core covered in orange-red lamellae

Eight gills simply pinnate, arranged in circle around anal papilla; white ‘core’ and orange lamellae; orange line along both inner and outer edges of each gill.

thorunna cf horologia
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Photo Kevin Bourdon
Reunion, La Possession, 6 m, 7 august 2013

Remarks :

Identification proposed by Nathalie Yonow. (Yonow, 2012) Rudman considered that it's a variant of Thorunna horologia
    Looks like Thorunna horologia but T. horologia is white with orange then red marginal band and the rhinophore are white with only a red mark along the upper half of the anterior and posterior midlines

Bibliographic data :

Margin permanently convoluted with three indentations: one behind rhinophores, largest in centre of body, one just beyond gills.
    Foot pale violet, darker concentration of violet in band around metapodium

References :

Bill Rudman Seaslug site : Sea Slug Forum : Thorunna horologia

Publications :

Yonow N (2012) Opisthobranchs from the western Indian Ocean, with descriptions of two new species and ten new records (Mollusca, Gastropoda). ZooKeys 197: 1-129. doi: 10.3897/zookeys.197.1728

Other photos of Thorunna cf. horologia :

Alain-Benoît Rassat

Madagascar, Nosy bé, Plateau des arches, 18 m, size : 4 mm

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