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This species has been observed on Réunion and Mauritius Islands

Order : Cephalaspidea Superfamily : Philinoidea Family : Aglajidae Distribution : Tropical Indo-West Pacific Maximal size : 30 mm Abundance : Seldom if ever on the rocky coast and the lagoon Species characteristics : This species can be recognized by its brown to dark brown coloration with small opaque white spots and transverse bars of opaque white with smaller areas of yellow-orange pigment.
	Showing species characteristics...	Photo Philibert Bidgrain Reunion, Etang salé, on the rocky coast, less 1 m , 11 November 2004

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Bill Rudman
    Synonymous : (according Worms)
               - Aglaja orientalis Baba, 1949
               - Philinopsis orientalis (Baba, 1949)

Bibliographic data :

The external body form is elongated with moderate caudal lobes
    Living animal with bilobed outer margin of the head shield, truncated posteriorly
    Internal shell longer than broad, completely calcified
    They have huge mucus glands around the head which produce mucus secreted when they crawling on the substrate or burrowing through sand or mud.

References :

Bill Rudman Seaslug site : Sea Slug Forum : Aglaja orientalis
   Nudipixel Aglaja orientalis

Publications :

Baba, K. (1949) Opisthobranchia of Sagami Bay . Iwanami Shoten, Tokyo. 211pp + pls.
    Camacho-García Y.E., Ornelas-Gatdula E., Gosliner T.M. & Valdés A. (2013) Phylogeny of the family Aglajidae (Pilsbry, 1895) (Heterobranchia: Cephalaspidea) inferred from mtDNA and nDNA. Molecular Phylogenetics and Evolution 71: 113–126.
    Gosliner, T. M. (1980) Systematics and phylogeny of the Aglajidae (Opisthobranchia: Mollusca). Zoological Journal of the Linnean Society, 68: 325-360.
    Zamora-Silva A. & Malaquias M.A.E. (2017). Molecular phylogeny of the Aglajidae head-shield sea slugs (Heterobranchia: Cephalaspidea): new evolutionary lineages revealed and proposal of a new classification. Zoological Journal of the Linnean Society.

Other photos of Spinoaglala orientalis :

Philibert Bidgrain Reunion, La Saline lagoon, less 1 m, 2 April 2010, size : 20-22 mm This species can be recognized by its brown to dark brown coloration with small opaque white spots (a) and transverse bars of opaque white (b) with smaller areas of yellow-orange pigment. (c)

Chritophe Cadet Reunion, L'abri côtier (Bassin pirogue), Etang-Salé, less 1m, 29 September 2009, size : 10 mm   They have huge mucus glands around the head which produce mucus (a) secreted when they crawling on the substrate or burrowing through sand or mud.

Hugues Flodrops   Reunion, Etang salé, on the rocky coast, less 1 m , 25 December 2008, size : 22 mm

Mauritius, Spinoaglala orientalis, at Mahebourg, by Yann von Arnim