Hypselodoris apolegma (Yonow, 2001) [Risbecia]

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Hypselodoris apolegma is characterized by its purple background colour, and by the white edging of the mantle: At the edge of the mantle the border is solid white, but inside this is a region of varying width in which the white forms a reticulate pattern gradually merging into the purple. The rhinophore stalks and the base of the gills are purple, the rhinophore clubs and the gills are orange yellow.
Pretty similar are:
Hypselodoris bullockii which differs by the pale pinkish background colour, and by thin white marginal band,
Thorunna halourga which differs by solid broad white mantle margin, and by the low gill pocket,
Hypselodoris sp. 07 which differs by the light purple background colour, by the solid white marginal band, and by the colour of the gills and the rhinophores
Hypselodoris sp. 08 which differs by the solid broad white marginal band, and by the dark blueish-purple colour of the gills
Hypselodoris sp. 10 which differs by the dark blueish-purple colour of the rhinophore clubs, by the solid broad white marginal band marginal band, and by the colour of the gills.
The specimen #1 was originally posted at these websites as Hypselodoris bullockii (Collingwood, 1881) [Chromodoris],
on 19 June 2003 changed into Hypselodoris apolegma (Yonow, 2001) [Risbecia],
on 12 Feb. 2010 changed into Risbecia apolegma  Yonow, 2001, because of the comment of Nathalie Yonow at NUDIPIXEL,
I follow the recent article (published: 10 April 2012)
Rebecca Fay Johnson & Terrence M. Gosliner. 2012.
Traditional Taxonomic Groupings Mask Evolutionary History:
A Molecular Phylogeny and New Classification of the Chromodorid Nudibranchs. online at
and move Risbecia apolegma again to the genus Hypselodoris  Stimpson, 1855.
More information on Hypselodoris apolegma are on Bill Rudman's Sea-Slug Forum!