Hypselodoris regina     Ev. Marcus & Er. Marcus, 1970

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This species has been observed on Mayotte and Madagascar Islands


Order : Nudibranchia
Suborder : Euctenidiacea
Superfamily : Doridoidea
Family : Chromodorididae
Distribution : Western Indian Ocean
Maximal size : 60 mm
Abundance :


Species characteristics :

The median black line forms a ring anteriorly between the rhinophores

Halfway between the gills and rhinophores, in between the outer two dark lines, is a large orange patche. There is also diffuse orange longitudinal markings on either side of the median black line.

The bluish white gills are triangular in cross section, edged with orange and the gill sheath elevated. The rhinophores are orange.

The ground colour is pale milky blue and there is a broad orange band bordering the mantle.

hypselodoris regina
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Photo Philibert Bidgrain
Mayotte, Mtsanga Guini, less 1 m, 12 October 2008, size : 30-35 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Nathalie Yonow
    Synonynymous : No other name

Bibliographic data :

There are three deep reddish-purple, almost black, lines running the length of the mantle. The central one runs forward from the gills pocket to just behind the rhinophores, where it splits and form a loop between and in front of the rhinophores. On each side another line runs from just outside of the rhinophore pocket, backwards, ending behind the gills.
   The seven gills are triangular in cross section, the outer side smooth and the two inner sides bearing pinnules. They form a complete circlet
   The foot has a broad orange border. The ground colour is pale milky blue with on each side a dark purple line. On the dorsal part of the posterior foot there is a pair of cross connections joining the two dark lines.

This species present somes pattern variations such as :
            - Three large orange patches on each side of the mantle. These are equally spaced in the region between the gills and the rhinophores and lie along the edge of the mantle, covering the orange border and extending into the light blue region inside the border.
            - A few dark purple spots scattered on the mantle.
            - The dark purple stripe along the side of the foot has a number of elongate patches extending down from it.
            - The dark purple stripe along the foot can be broken twice
            - The orange is replaced by a yellow-brown colour
            - The central dark line on the dorsum forms a loop sometimes broken.
   Found on swaller reefs where it feeds on the sponge Dysidea sp
   This species is very similar in colour to species of the Chromodoris quadricolor colour group, such as C. hamiltoni and C. elisabethina, with three black or dark purple longitudinal lines but Hypselodoris regina is caracterized by :
            - The bluish white gills triangular in cross section, edged with orange and the gill sheath elevated.
            - The ring that the median black line forms anteriorly between the rhinophores.
            - The relatively narrow and high body shape like other Hypselodoris
   It was first described from Madagascar by Marcus & Marcus

References :

Bill Rudman Seaslug site : Sea Slug Forum : Hypselodoris regina
   Nudipixel Hypselodoris regina

Publications :

Johnson R.F. & Gosliner T.M. (2012) Traditional taxonomic groupings mask evolutionary history: A molecular phylogeny and new classification of the chromodorid nudibranchs. PLoS ONE 7(4): e33479
   Marcus, Er. & Marcus, Ev. 1970. Opistobranch mollusks from the souther tropical Pacific. Pacific Science 14(2) : 155_179
   Rudman, W.B. (1977) Chromodorid opisthobranch Mollusca from East Africa and the tropical West Pacific. Zoological Journal of the Linnean Society 61 : 351-397
   Rudman, W.B. (1982) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris quadricolor, C. lineolata and Hypselodoris nigrolineata colour groups. Zoological Journal of the Linnean Society, 76 : 183-241
   Gosliner, T.M. & Johnson, R.F. (1999) Phylogeny of Hypselodoris (Nudibranchia: Chromodorididae) with a review of the monophyletic clade of Indo-Pacific species, including descriptions of twelve new species. Zoological Journal of the Linnean Society, 125 : 1-114.

Other photos of Hypselodoris regina :


Philibert Bidgrain

Mayotte, Mtsanga Guini, less 1 m, 12 October 2008, size : 30-35 mm

The seven gills are triangular in cross section, the outer side (a) smooth and the two inner sides (b) bearing pinnules. They form a complete circlet

The gill sheath (c) is elevated and have a deep reddish-purple rim.

 

Halfway between the gills and rhinophores, in between the outer two dark lines, is a large orange patche (a).

Three large orange patches (b) on each side of the mantle. These are equally spaced in the region between the gills and the rhinophores and lie along the edge of the mantle, covering the orange border and extending into the light blue region inside the border.

Trace of the very pale and diffuse orange longitudinal (c) markings on either side of the median black line.


Nathalie Bazard

Madagascar, Nosy bé, secret de la licorne, 22m, 4 November 2013, size : 50 mm

 

 


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