Stiliger aureomarginatus      Jensen, 1993

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This species has been observed on Reunion Island


Order : Sacoglossa
Superfamily : Limapontioidea
Family : Limapontiidae
Distribution : Indo-West Pacific
Maximal size : 5 mm
Abundance : From time to time on the reef flat zone and rocky coast on Codium sp


Species characteristics :

These sacoglosans are black or dark bluish-green with orange tips to the cerata and pedal lobes

The cerata cover almost all of the dorsal surface of the body

The black or dark bluish-green rhinophores are folded through their entire lenght

stiliger aureomarginatus
Showing species characteristics...

Photo Christophe Cadet
Réunion, Etang salé, on the rocky coast, less 1 m, 19 February 2010, size : 3 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Kathe Jensen
    Synonymous : (according Worms)
               - No other name

Bibliographic data :

There is a black or dark bluish-green band mediodorsally on the head. The black band on the head continues behind the eyes down to the lateral surface of the head, and also on the pericardium. Also there is black pigment on the dorsal surface of the body behind pericardium
    Below the orange tips of the large black cerata is a subterminal band of dense white dots with a light yellowish tinge. Towards the base the cerata are blue-green
    The rhinophores are long, thin, and tapering towards the tips, and their bases almost meet mediodorsally
    There is a long anal spout, black with a white tip, on the anterior surface of the pericardium
    There is a single unbranched digestive gland duct in each cerata, which is a character of the genus Stiliger
    The eye are located in transparent areas just behind the bases of the rhinophores

The egg mass is a cylindrical band rolled into an irregular spiral. The eggs are white
    When the cerata are spread out (when the animal is quiescent or feeding), the orange tips of the cerata form an almost complete circular band around the animal. The specific name refers to the orange coloration of the tips of the cerata in that position
    It feeds on Codium sp. At Rottnest Island, Western Australia, the Sacoglosssans Stiliger aureamarginatus feeds exclusively on the rugose Codium spongiosum; But also found in Codium cf. perriniae, Codium intricatum, ...
    Aggregative behavior
              - At Rottnest Island, Western Australia, the Sacoglosssans Stiliger aureamarginatus feeds exclusively on the rugose Codium spongiosum, and often occurs in group of 4 or more animals on one algal thallus. The maximun number of animals in a group was 7.
              - Codium spongiosum is a large, rugose species in which the utricules are arranged in large clusters. Thalli are only attached at small area on the lower surface, and the major part of the thallus does not touched the substrat.
              - S. aureomarginatus always occured on the upper surface of Codium spongiosum. Single animals occured in depressions as well as on the protuberances, whereas groups of animals only occured in depressions
              - Sometimes animals formed a chain (trailing) when crawling with the pedal lobes of one animal touching the tip of the tail of the animal in front. The smallest animal was at the back of the chain

References :

Bill Rudman Seaslug site : Sea Slug Forum : Stiliger aureomarginatus
    Nudipixel Stiliger aureomarginatus

Publications :

Jensen, K.R. (1993) Sacoglossa (Mollusca, Opisthobranchia) from Rottnest Island and central Western Australia. In: Proceedings of the 5th International marine Biological Workshop: The marine Flora and Fauna of Rottnest Island, Western Australia . (Eds: Wells,FE; Walker,DI; Kirkman,H; Lethbridge,R) Western Australian Museum, Perth, 207-253
    Jensen, K.R. (1999) Aggregative behavior in the sacoglossan opistobranch Stiliger aureamarginatus Jensen, 1993, in Rottnest Island, Western Australia
    Jensen, K.R. (2007). Biogeography of the Sacoglossa (Mollusca, Opisthobranchia). Bonner Zoologische Beiträge. 55: 255–281

Other photos of Stiliger aureomarginatus :

 

The cerata are black (f) with orange tips (e), a subterminal band of dense white dots with a light yellowish tinge (non observed in our specimens). Towards the base the cerata are blue-green (g)

The pedal lobes (a) are orange
    The eye (b) are located in transparent areas just behind the bases of the rhinophores
    There is a black to dark bluish-green band mediodorsally on the head (d). This band on the head continues behind the eyes down to the lateral surface of the head (c)

 

Christophe Cadet

Réunion, Etang salé, on the rocky coast, less 1 m, 19 February 2010, size : 3 mm

Stiliger aureamarginatus feeds exclusively on Codium sp, and often occurs in group of 4 or more animals (from 2 to 7 specimens) on one algal thallus

The probably egg mass (a) is a cylindrical band rolled into an irregular spiral. The eggs are white. We need other photo to confirm that it's really its spawn....

 

 

Christophe Cadet

Reunion, La Saline lagoon, less 1 m, 30 December 2009, size 3 mm

Sometimes animals formed a chain (trailing) when crawling with the pedal lobes of one animal touching the tip of the tail of the animal in front. The smallest animal was at the back of the chain

   More photos from Indian Ocean
Reunion, Stiliger aureomarginatus on its favorite algae, at Saint Gilles, by Christophe Cadet