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

Order : Cephalaspidea Superfamily : Philinoidea Family : Aglajidae Distribution : Tropical Indo-West Pacific, Caribbean. Maximal size : 40 mm Abundance : From time to time on the rocky coast Species characteristics : It can be distinguished by brown to black coloration with a "T shape marking" on its head This is a black to brown species variably decorated with blue/green and sometimes orange lines There is usually a white marking in the shape of a crescent on the posterior shield
	Showing species characteristics...	Photo Philibert Bidgrain Reunion, "Kelonia center", at Saint Leu, 15 April 2009, size : 20 mm

See more about : Sightening and mating periods
See more about : Chelidonura hirundinina variability in Southwest Indian ocean

Remarks :

Identification confirmed by Nathalie Yonow et Hsini Lin
    Synonymous : (according Worms)
          - Bulla hirundinina Quoy & Gaimard, 1833                                           - Chelidonura philinopsis Eliot, 1903

Bibliographic data :

The most consistent characteristic is the ring of blue/green surrounding an orange bar on the top of the head with a central extension onto the notum forming the "T shape marking". The width of the lines is variable. Portions of the blue/green lines may be replaced by white in some animals
    The flap araising from the sides of the foot (parapodia) are large but they do not meet in the midline
    The "tails" are also highly variable ranging from short and symmetrical to long and asymmetrical. In asymmetrical animals, either the right or left hand "tail" may be longer in contrast to most Chelidonura spp (perhaps reflecting loss to predators and regeneration?). Usually in Chelidonura, the left one is slightly longer than the right one. Some "tails" may also have rounded rather than acute tips.
    Species of Chelidonura are also characterised by the mounds of sensory bristles on either side of the mouth. Sensory bristles are present in all aglajids, but they are most prominent in Chelidonura . They are used to detect prey.
    Round white globular egg masses are deposited on rock surface. According to Rose (1985), ova (82 µm in diameter) occur singly in capsules within the spawn mass
    Chelidornura hirundinina, is a sand-dwelling species feeding on small flatworms. Common on rocky or sandy substrates in shallow water It feeds on small acoel flatworms like Convoluta and swallows them whole with its muscular pharynx

References :

Bill Rudman Seaslug site : Sea Slug Forum : Chelidonura hirundinina

Publications :

Gosliner T.M. (1988) The Philinacea (Mollusca: Gastropoda: Opisthobranchia) of Aldabra Atoll, with descriptions of five new species and a new genus. Bulletin of the Biological Society of Washington 8: 79-100. [13 September 1988]
    Redfern. C., 2001Bahamian Seashells: a Thousand Species from Abaco, Bahamas .
    Rose, R.A. 1985. The spawn and development of twenty-nine New South Wales opistobranchs (Mollusca: Gastropa). Proceedings of the Linnean Society of New South Wales 108(1): 23-36
    Rudman,W.B., 1974. A comparison of Chelidonura, Navanax and Aglaja with other genera of the Aglajidae. Zoological Journal of the Linnean Society, 54 : 185-212.
    Rudman,W.B. 1973. On some species of Chelidonura (Opisthobranchia: Aglajidae) from Zanzibar and Fiji. Zoological Journal of the Linnean Society, 52 : 201-215.
    Thompson, T.E. (1977) Jamaican opisthobranch molluscs I. Journal of Molluscan Studies, 43(2) : 93-139, pls.1-3.
    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 Chelidonura hirundinina :

Maurice Jay Cap la Houssaye, on the rocky coast, November to December, size : animal 25 mm, shell 7mm Shell trapezoidal with a curved apex. Very delicate, never found dead

Shell : Internal view	Shell : External view

Philibert Bidgrain Reunion, "Kelonia center", at Saint Leu, 15 April 2009, size : 10-12 mm A large population was observed in April, the average size is about 15 mm This is a black to brown species variably decorated with blue lines. This is the most frequent pattern observed in this population (a) There white marking in the shape of a crescent on the posterior shield (b) Species of Chelidonura are also characterised by the mounds of sensory bristles on either side of the mouth.

Philibert Bidgrain Reunion, "Kelonia center", at Saint Leu, 1 April 2009, size : 13-15 mm This is a black to brown species variably decorated with green lines

Philibert Bidgrain Reunion, "Kelonia center", at Saint Leu, 8 April 2009, size : 16-18 mm without the tail This is a black to brown species variably decorated with blue and orange lines

Seb Vasquez Reunion, Piscine du Cap la Houssaye, 13 November 2014

Seb Vasquez Reunion, Piscine du Cap la Houssaye, 13 November 2014   Mating behavior

Seb Vasquez Reunion, "piscine du cap la Houssaye", less 1 m, 21 February 2015   During the night   There is usually a white marking in the shape of a crescent on the posterior shield

Alain-Benoît Rassat Madagascar, Kalakadjoro, 15 m, 2 November 2016, size : 15 mm

See more about : Chelidonura hirundinina variability in Southwest Indian ocean

Mayotte, Chelidonura hirundinina with partial white lines, by Sylvain Le Bris  

Reunion, Chelidonura hirundinina with large orange lines, at Etang salé, by Philibert Bidgrain  

Reunion, mating in Chelidonura hirundinina small population, at Sainte Rose, by Thierry Cailleux

Seychelles, Chelidonura hirundinina, at Mahé, by Christophe Mason-Parker

Mauritius, Chelidonura hirundinina, at Anse Jonchée, by Yann von Arnim