Hallaxa iju   Gosliner & Johnson, 1994

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This species has been observed on Madagascar Island

Order : Nudibranchia
Suborder : Euctenidiacea
Superfamily : Doridoidea
Family : Actinocyclidae
Distribution : Western and Central Pacific and Madagascar
Maximal size : 10 mm
Abundance :

Species characteristics :

The body is reddish-brown to black. There are small, scattered opaque white spots situated on small tubercles scattered on the notum and on the basal third of the gills

Opaque white pigment covers the distal two-thirds of the rhinophoral rachis and lamellae in most specimens.

:The expanded margins of the rhinophoral lamellae are caracteristic of this species

hallawa iju
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Photo Alain-Benoît Rassat
Madagascar, Nosy Bé, 28 m, 21 November 2016,size : 15 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Terry Gosliner and Hsini Lin

Bibliographic data :

There are five to nine expanded rhinophoral lamellae.
    The branchial plume consists of 8-10 unipinnate gills. The cup-shaped or goblet-shaped gill circle is quite characteristic of the genus
    Hallaxa iju can be immediately distinguished from all other members of the genus by the expanded margins of the rhinophoral lamellae
    In Hawai Island, there are two color forms: violet-brown with few to no white flecks and cream with numerous white flecks.
    Most members of the genus are cryptic on their sponge prey, and H. iju is probably a sponge predator
    Etymology: The specific name is the Marshallese word for star, which refers to the stellate appearance of the rhinophores when viewed from above.

References :

Bill Rudman Seaslug site : Sea Slug Forum : Hallaxa iju
    Nudipixel Hallaxa iju
    Seaslug of Hawaii Hallaxa iju

Publications :

Gosliner T.M. & Johnson S. (1994) Review of the genus Hallaxa (Nudibranchia: Actinocyclidae) with descriptions of nine new species. The Veliger 37(2): 155-191

Other photos of Hallaxa iju :


Alain-Benoît Rassat

Madagascar, Nosy Bé,


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