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This species has been observed on Reunion, Mayotte and Mauritius Islands

Unassigned Heterobranchia Superfamily : Acteonoidea Family : Aplustridae Distribution : Tropical Indo-West Pacific Maximal size : Shell 25 mm Abundance : From time to time on the reef flat zone and the rocky coast Species characteristics : Shell with alternating pink and white spiral bands, separated by narrow black lines. The animal is a uniform translucent white. The front of the head shield is developed into a pair of tentacles on each side.
	Showing species characteristics...	Photo Philibert Bidgrain Reunion, Etang salé, on the rocky coast, less 1 m, 27 August 2006, size : 15 mm

See more about : Sightening and mating periods
   See more about : Aplustrum amplustre variability in Southwest Indian ocean

Remarks :

Identification confirmed by Bill Rudman
    Synonymous : (according Worms)
          - Amplustrum amplustre, (Linnaeus, 1758))
          - Amplustrum fasciatum, (Schumacher, 1817)
          - Aplustrum thalassiarchi, (A. Adams, 1855)
          - Bulla amplustre, Linnaeus, 1758
          - Bulla pulchella, Swainson, 1840
          - Bulla thalassiarchi, A. Adams, 1855
          - Hydatina amplustre, (Linnaeus, 1758)
          - Hydatina aplustre, (misspelling)

Bibliographic data :

The Hydatinidae are the most modified of a group of cephalaspids which show the gradual diminution in the importance of the shell as a protective organ. In Hydatina and Micromelo the shell has become thin and the animal large and brightly coloured.
   The animal, can retract back into their shell but they seldom do. Most other mollusks have a solid shell and a central heavily calcified columella around which the shell, and animal, spirals. There is a huge columella muscle which attaches the animal to the shell and can quickly pull the animal back inside when necessary. In Hydatina, in which the shell is becoming reduced in importance, the columella has become very reduced, as has the associated columellar muscle, so their poor ability to retract back into their shell
   They rely on distasteful acid glands in their skin and burrowing in the sand to protect them.
   Smaller and with a more heavily calcified shell than the other species of Hydatina. The protective operculum has disappeared.
    Like H. Physis it is a specialized predator on cirratulid polychaete worms.
The cirratulids have no head appendages but have long thread-like tentacles along most of the body but especially around the head. They live in crevices, empty burrows or under rocks partially embedded in the sand or mud. They live surrounded by a "coccoon'" of debris, and they extend their tentacles out like the head tentacles of terebellid worms, to collect food particles.
    A shallow water species found on reefs with a mix of sand, rock and turf algae.

Material examined by Nathalie Yonow ( see reference/publications). Numerous shells found on different beachs (Mauritius), no specimen alive.. Maximun shell size : 20x13 mm References : Bill Rudman Seaslug site : Sea Slug Forum : Hydatina amplustre Publications :

Rudman, W.B. (1972) The anatomy of the opisthobranch genus Hydatina and the functioning of the mantle cavity and the alimentary canal. Zoological Journal of the Linnean Society 51(2) : 121-139. <
    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 Aplustrum amplustre :

Christophe Cadet Reunion, Etang salé, on the rocky coast, less 1 m, 5 December 2010   a Mating behavior... The genital aperture is situated on the right side, like other species....

Hugues Flodrops Reunion, Etang Sale lagoon 13 November 2006 size : about 20 mm. The front of the head shield is developed into a pair of tentacles on each side.

Nathalie Rodrigues Reunion, Saint Paul, piscine du cap, less 1 m, 30 May 2014 With its spawn...

Philibert Bidgrain Reunion, Etang salé, on the rocky coast, less 1 m, 6 September 2010 During the night A specimen with a very pale pink coloration on the shell

Nathalie Rodrigues Reunion, Saint Paul, piscine du cap, less 1 m, 30 May 2014 A spécimen with strange narrow black line disposition. The two black spots onthe head-shield are the eyes

See more about : Aplustrum amplustre variability in Southwest Indian ocean

Reunion, Aplustrum amplustre, at Etang Salé, by Hugues Flodrops

Reunion, Aplustrum amplustre from the rocky coast, at Etang salé, by Hugues Flodrops  

Mayotte, shell of Aplustrum amplustre, at Petite-Terre, by Norbert Verneau  

Reunion, small population of Aplustrum amplustre, at Etang salé, by Christophe Cadet  

Reunion, albinos form of Aplustrum amplustre, at Etang salé, by Nathalie Rodrigues