Thuridilla livida (Baba, 1955)

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This species has been observed on Reunion and Mayotte Islands


Order : Sacoglossa
Superfamily : Plakobranchoidea
Family : Plakobranchidae
Distribution : Indo West Pacific
Maximal size : 20 mm
Abundance :


Species characteristics :

The parapodia are lined with a series of longitudinal lines. The outermost line is black followed by lines of orange, black and iridescent bright blue

Black, orange and blue lines are also present along the anterior margin of the foot

The body, head and rhinophores are dark brown to black.

The apical half of the rhinophores has varying amounts of opaque white pigment

thuridilla livida
Showing species characteristics...

Photo Philibert Bidgrain
Mayotte, Mtsanga Tanaraki, less 1 m, 24 July 2010, size : 12 mm

See more about : Sightening and mating periods
   See more about : Thuridilla phylogeny by Gosliner 1995

Remarks :

Synonymous : (according Worms)
               - Elysia livida Baba, 1955

Bibliographic data :

 In external morphology, T livida most closely resembles to T. hoffae, but
            - T. livida has a distinct narrow iridescent blue submarginal line while T. hoffae has a series of iridescent blue to blue green patches or a diffuse broad light blue to blue green band.
            - T. livida has orange and blue lines on the anterior margin of the foot that are absent in T. hoffae
            - The general body color is darker in T. hoffae than in T. livida
    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 livida
   Nudipixel Thuridilla livida

Publications :

  Baba, K. (1955) Opisthobranchia of Sagami Bay, Supplement . Iwanami Shoten, Tokyo. 59pp
     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 livida :


Philibert Bidgrain

Mayotte, Mtsanga Tanaraki, less 1 m, 24 July 2010, size : 12 mm

The parapodia are lined with a series of longitudinal lines. The outermost line is black (a) followed by lines of orange (b), black (c) and iridescent bright blue (d)


Christophe Cadet

Reunion, Trou d'eau lagoon, less 1 m, 27 September 2010, size : 12 mm

The apical half of the rhinophores has varying amounts of opaque white pigment


 More photos from Indian Ocean

See more about : Thuridilla phylogeny by Gosliner 1995

Reunion, a small Thuridilla livida, at Trou d'eau, by Philibert Bidgrain