Chelidonra punctata Eliot, 1903

Yonow, Nathalie, Anderson, R. Charles & Buttress, Susan G., 2002, Opisthobranch molluscs from the Chagos Archipelago, Central Indian Ocean, Journal of Natural History 36 (7), pp. 831-882 : 834-835

Chelidonra punctata Eliot, 1903

(®gure 2a)

Chelidonura hirundinina var. punctata Eliot, 1903a: 336 , pl. 13, ®gure 2.

Chelidonura punctata: Marcus and Marcus, 1970: 190 , ®gures 29±31; Yonow and Hayward, 1991: 4, ®gure 4f.

Material. Chag/96/1a, b: both 50 mm; inside Ile Boddam, Salomon Atoll; 8 February 1996; at 16 m depth. Chag/96/74a, b: 22 mm, 24 mm; Three Brothers, Great Chagos Bank; 29 February 1996; at 17 m depth.

Description. The body was dark brown, appearing almost black, with bright orange spots and dots; these orange markings extended on to the ventral surface (®gure 2a). Fine white edges were present on the parapodia, becoming less distinct and grey anteriorly. The body was slender, smooth and velvety. The left tail process was distinctly longer than the right, with orange spots in the larger specimens and without spots in the smaller. The head shield was trilobed anteriorly.

In formaldehyde specimens retain much of their original colour: the black is reduced to a ®ne dusting and the orange internal organs are visible through the shell and the skin. Orange pigment spots remain distinct and are present on both shields, both parapodia and on the sole. The head is distinctly trilobed. The shells of two specimens (96/74) are clearly visible and these specimens have been transferred to 70% alcohol.

Geographic distribution. Western Indian Ocean: East Africa ( Eliot, 1903a), Madagascar (Marcus and Marcus, 1970), and Mauritius (Yonow and Hayward, 1991). In addition to this ®rst record from the Chagos we have a new record from the Maldives (coll. R. C. Anderson and S. G. Buttress, 1996).

Remarks. This rarely recorded but distinctive species is similar only to C. castanea Yonow, 1994 from the Maldives (Yonow, 1994a) which is chocolate brown with apricot spots and a four-lobed head (see also photograph in Debelius, 1996: 132).