Thuridilla indopacifica    Gosliner, 1995

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This species has been observed on Reunion, Mayotte, Madagascar and Seychelles Islands


Order : Sacoglossa
Superfamily : Plakobranchoidea
Family : Plakobranchidae
Distribution : Known from South Africa, Kenya, Seychelles, Indonesia to Western Australia.
Maximal size : 18 mm
Abundance :


Species characteristics :

The parapodia are lined with a thin band of black, followed by a broad band of orange, an irregular band of black with a serie of ventral extensions of pigment. Between the black extensions are patches of reflective bright blue

The body is green, covered with minute opaque white spots

The head is blue with a centrally placed Y-shaped opaque white patch, the arms of the Y extending up onto the rhinophores

The rhinophores have a dark (blue or black) tip with a thin orange transversal line

thuridilla indopacifica
Showing species characteristics...

Photo Philibert Bidgrain
Reunion, "Trou d'eau", Saint Gilles, less 1 m, 2 July 2010, size : 10-12 mm

See more about : Sightening and mating periods
   See more about : Thuridilla phylogeny by Gosliner 1995
   See more about : Thuridilla indopacifica variability in Southwest Indian ocean

Remarks :

Identification confirmed by Terry Gosliner and Kathe Jensen
    Gosliner description (1995) of the rhinophores : " The head is covered with opaque white, which extends on to the basal half of the rhinophores. Above this, is a diffuse band of blue followed by black, orange and blue bands "
    Our specimens like others ( see Bill Rudman Seaslug Site and Nudipixel) haven't this kind of pattern on the rhinophores... They have a dark tip with a thin orange transversal line
    Synonymous : (according Worms)
               - No other name

Bibliographic data :

The anterior margin of the foot has black, orange, black and blue bands
    This species is name for the indo-pacific tropics, the region where Thuridilla reaches its highest diversity
    In external morphology, T indopacifica most closely resembles to T. picta, which is known from the tropical Atlantic
            - T. indopacifica has a black parapodial line sometimes absent in T. picta
            - The parapodial lines of T. picta are far more undulating than in T. indopacifica
            - T. indopacifica has more white pigment on the head than does T. picta
    Comparative data of the five Thuridilla with black, orange and blue margin found in our area...

 

T. multimarginata

T. indopacifica

T. livida

T. hoffae

T. undula

Parapodial margin

Narrow white edge enlarged at regular intervals, then a narrow stripes of orange, black, pale blue, and black.

Thin brownish black edge, then a broad band of yellow-orange, and an irregular band of black. In the spaces between the blackish extensions are bright blue

Black edge followed by lines of orange, black and narrow iridescent blue

Bright yellow-orange edge, followed by a thin black line and a diffuse broad light blue to blue green band.

Broad burnt orange edge, followed by lines of black and vivid blue

Head

Opaque white pigment with sometimes orange marks

Blue with a centrally placed Y-shaped opaque white patch

Dark brown to black

Black to dark blue

Black and reflective blue pigment.

Rhinophores

They have opaque white pigment with sometimes orange marks
    The tips of the rhinophores are black

The base are whitish to pale blue. At the tips are bands of blue, black, orange-yellow and black.
   Not observed in our specimens

They are dark brown to black
    The apical half has opaque white pigment

They are light blue except for the tip which is dark-blue

The base are turquoise bluish green. At the middle are narrow bands of blue and black. The apex is orange

Body

Orange or light to dark green

Translucent green with scattered opaque white spots

Dark brown to black

Black to dark blue

Turquoise bluish green

Anterior margin of the foot

It has orange, black, blue and black lines

It has black, orange-yellow , black and blue bands

It has black, orange and blue lines .

It hasn't blue and orange lines

It has orange, black and blues bands.

References :

Bill Rudman Seaslug site : Sea Slug Forum : Thuridilla indopacifica
   Nudipixel Thuridilla indopacifica

Publications :

  Gosliner, T.M. (1995) The genus Thuridilla (Opisthobranchia: Elysiidae) from the tropical Indo-Pacific, with a revision of the phylogeny and systematics of the Elysiidae. Proceedings of the California Academy of Sciences, 49(1) : 1-54.
    Jensen, K.R. (2007). Biogeography of the Sacoglossa (Mollusca, Opisthobranchia). Bonner Zoologische Beiträge. 55: 255281.

Other photos of Thuridilla indopacifica :


Alain Benoît Rassat

Madagascar Nosy bé


Philibert Bidgrain

Mayotte, Mtsanga Tanaraki, less 1 m, 24 July 2010, size : 15 mm

The parapodia are lined with a thin band of black (a), followed by a broad band of orange (b), an irregular band of black (c) with a serie of ventral extensions. Between these extensions are patches of reflective bright blue (d)


Philibert Bidgrain

Mayotte, Mtsanga Tanaraki, less 1 m, 25 July 2010, size : 3-4 mm and 12 mm for the larger

Two specimens of a small population found crawling during the day on Tanaraki reef flat area

The anterior margin of the foot has black, orange, black and blue bands


Philibert Bidgrain

Mayotte, Mtsanga Tanaraki, less 1 m, 24 July 2010, size : 3 mm

A juvenile, 3 mm long...

 

 

 


Philibert Bidgrain

Reunion, "Trou d'eau", Saint Gilles, less 1 m, 10 October 2010, size : 20 mm

 

In this specimen the orange band on the rhinophore is larger than usual...


Philibert Bidgrain

Mayotte, Mtsanga Tanaraki, less 1 m , 8 August 2012, size : 3 mm

A partially eaten specimen...


 More photos from Indian Ocean

See more about : Thuridilla phylogeny by Gosliner 1995

See more about : Thuridilla indopacifica variability in Southwest Indian ocean

Mayotte, Thuridilla indopacifica, at Sakouli, by Matthias Deuss

Reunion, Thuridilla indopacifica on a strange substrate, by Alain Barrère  

Seychelles, Thuridilla indopacifica with pale rhinophore tip, at Mahé, by Christophe Mason-Parker