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

Order : Anaspidea Superfamily : Aplysioidea Family : Aplysiidae Distribution : Circum-tropical ; Indo-West Pacific & Atlantic. Maximal size : 65 mm Abundance : Frequently on the reef flat zone Species characteristics : Translucent and elongate body with patches of greens, browns and white, and often with many branched papillae. Sea Hare with usually dark longitudinal lines and scattered eye spots with blue center..
	Showing species characteristics...	Photo Philibert Bidgrain Reunion, Etang salé, 9 August  2007, size : 30 mm

See more about : Sightening and mating periods
   See more about : swarming behavior in Stylocheilus striatus species
   See more about : Stylocheilus striatus variability in Southwest Indian ocean
   See more about : observation of Stylocheilus striatus spawning event
   See more about : thousands of Stylocheilus striatus drifting in open water

Remarks :

Identification confirmed by Bill Rudman and Nathalie Yonow
    Synonymous : (according Worms)
               - Aclesia polyomma (Mörch, 1863)                        - Notarchus polyomma Mörch, 1863
               - Aplysia striata Quoay & Gaimard, 1832               - Stylocheilus lineolatus Gould, 1852

Bibliographic data :

This moderately large sea hare has a slender and very soft body ending in a long and narrow, tapering tail.
 

Like many Sea Hares they produce a purple ink when disturbed. According Bill Rudman, In Sea Hares, such as Stylocheilus, in which the shell is lost, the "roof'" of the mantle cavity, which used to enclose the shell, is also absent, except for a small ridge on the inside of the left parapodia. The Purple Gland in Stylocheilus opens on the underside of the anterior end of this ridge (purple patches in my diagram). I have marked the position of the Opaline Gland in brown.   Diagram : Bill Rudman

    This species feeds on Lyngbya majuscula a cyano-bacteria ( "blue-green algae" ) which form a mat or film over rocks or the surface of muddy shores.
    According to Johnson and Boucher (1983), tha spawn consists of an irregular tangle or brown, spaghetti-like strands laid directly onto the substrata.
    Found from the intertidal to about 30 m, Stylocheilus striatus can sometimes be found in large numbers : swarming behaviour.
    The body pattern with dark longitudinal lines distinguishes this species from S. longicauda
    This species looks like Bursatella leachii but there is some differences.
            - The parapodial flaps are almost completely fused in Bursatella, but not in Stylocheilus
            - Stylocheilus striatus have usually dark longitudinal lines, not observed in Bursatella leachii
            - The foot sole of Bursatella leachii have numerous small dark dots. The sole of Stylocheilus striatus have dark longitudinal lines

Material examined by Nathalie Yonow ( see reference/publications). Tree specimens collected from Grand Baie, 9 October 1985, size : 10, 15 and 25 mm References Bill Rudman Seaslug site : Sea Slug Forum : Stylocheilus striatus    Nudipixel Stylocheilus striatus

Publications :

Bebbington, A. (1974) Aplysiid species from East Africa with notes on the Indian Ocean Aplysiomorpha (Gastropoda: Opisthobranchia). Zoological Journal of the Linnean Society, 54 : 63-99.
    Quoy, J.R. & Gaimard, J.P. (1832). Voyage de decouvertes de L'Astrolabe pendant les annees 1826-1827-1828-1829, sous le commandement de M.J. Dumont D'Urville, Zoologie, 2 : 1-686.
    Yonow, N. and Hayward , P. J. (1991). Opistobranches de l'île Maurice, avec la description de deux espèces nouvelles (Mollusca : Opistobranchia) Revue française d'aquariologie herpétologie, 18 (1), 1-30

Other photos of Stylocheilus striatus :

Philibert Bidgrain Reunion, Etang salé lagoon, 16 November 2006 According Nathalie Yonow " It is the gill (a), huge in this species, usually white, a bit like an accordion. It is also pigmented in this picture, and the two parapodia are clearly visible, one larger than the other"

Philibert Bidgrain Reunion, Etang salé, on the rocky coast, less 1 m, 25 October  2005, size : 45 mm   Sea Hare with usually dark longitudinal lines and scattered eye spots with blue center

Daniel Nardin Reunion, "Trou d'eau lagoon" at La Saline 27 October  2005. More informations about this swarming behavior ( October 2005)

Alain Diringer Reunion, Pointe du Cap La Houssaye, Saint Paul, 18 m, 14 November 2008 Dark longitudinal lines and scattered eye spots with blue center. Rare eye spots with blue center in this specimen

Philibert Bidgrain Mtsanga Mboueanatsa, Mayotte, on the reef flat zone, less 1 m, 24 July 2008, size : 30-40 mm A colorless specimen but always with scattered eye spots with blue center and dark longitudinal lines (a)

Philibert Bidgrain Reunion, at "Kélonia center" a Marine Turtle Center in Saint Leu, 28 November 2006, size : 30 mm "Excretory time" for these highly papillate Stylocheilus.

Philibert Bidgrain Reunion, Etang salé lagoon, 9 July 2007, size 30 mm (a) The mouth... The foot sole with dark longitudinal lines. The sole of Bursatella leachii have numerous small dark dots

See more about : swarming behavior in Stylocheilus striatus species

See more about : Stylocheilus striatus variability in Southwest Indian ocean

See more about : observation of Stylocheilus striatus spawning event

See more about : thousands of Stylocheilus striatus drifting in open water

See more about : Looking for a stowaway on Stylocheilus striatus...

See more about : Looking for a stowaway on Stylocheilus striatus...

Mauritius, Stylocheilus striatus swarming, at Mahebourg, by Yann Von arnim

Madagascar, Stylocheilus striatus swarning, at Sainte Marie Island, by Sully Bachel  

Mayotte, Stylocheilus striatus important spawning event, at Mboueanatsa, by Eva Fontaine 

Reunion, a hightly branched Stylocheilus striatus, at Etang salé, by Philibert Bidgrain 

Reunion, Stylocheilus striatus spawning event, at Etang salé, by Philibert Bidgrain 

Reunion, head detail of Stylocheilus striatus, at Etang salé, by Philibert Bidgrain 

Reunion, a small Stylocheilus striatus swarning, at Saint Gilles, by Philibert Bidgrain  

Mayotte, Stylocheilus striatus swarming behavior, at Petite Terre, by Norbert Verneau